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Sample records for neutron-irradiated titanium-modified stainless

  1. Tensile properties of a titanium modified austenitic stainless steel and the weld joints after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, K.; Ioka, I.; Jitsukawa, S.; Hamada, A.; Hishinuma, A. [and others

    1996-10-01

    Tensile specimens of a titanium modified austenitic stainless steel and its weldments fabricated with Tungsten Inert Gas (TIG) and Electron Beam (EB) welding techniques were irradiated to a peak dose of 19 dpa and a peak helium level of 250 appm in the temperature range between 200 and 400{degrees}C in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) and the High Flux Isotope Reactor (HFIR). The He/dpa ratio of about 13 appm/dpa is similar to the typical helium/dpa ratio of a fusion reactor environment. The tensile tests were carried out at the irradiation temperature in vacuum. The irradiation caused an increase in yield stress to levels between 670 and 800 MPa depending on the irradiation temperature. Total elongation was reduced to less than 10%, however the specimens failed in a ductile manner. The results were compared with those of the specimens irradiated using irradiation capsules producing larger amount of He. Although the He/dpa ratio affected the microstructural change, the impact on the post irradiation tensile behavior was rather small for not only base metal specimens but also for the weld joint and the weld metal specimens.

  2. Irradiation creep and creep rupture of titanium-modified austenitic stainless steels and their dependence on cold work level

    International Nuclear Information System (INIS)

    Garner, F.A.; Hamilton, M.L.; Eiholzer, C.R.; Toloczko, M.B.; Kumar, A.S.

    1991-11-01

    A titanium-modified austenitic type stainless steel was tested at three cold work levels to determine its creep and creep rupture properties under both thermal aging and neutron irradiation conditions. Both the thermal and irradiation creep behavior exhibit a complex non-monotonic relationship with cold work level that reflects the competition between a number of stress-sensitive and temperature-dependent microstructural processes. Increasing the degree of cold work to 30% from the conventional 20% level was detrimental to its performance, especially for applications above 550 degrees c. The 20% cold work level is preferable to the 10% level, in terms of both in-reactor creep rupture response and initial strength

  3. First results of laser welding of neutron irradiated stainless steel

    International Nuclear Information System (INIS)

    Osch, E.V. van; Hulst, D.S. d'; Laan, J.G. van der.

    1994-10-01

    First results of experimental investigations on the laser reweldability of neutron irradiated material are reported. These experiments include the manufacture of 'heterogeneous' joints, which means joining of irradiated stainless steel of type AISI 316L-SPH to 'fresh' unirradiated material. The newly developed laser welding facility in the ECN Hot Cell Laboratory and experimental procedures are described. Visual inspections of welded joints are reported as well as results of electron microscopy and preliminary metallographic examinations. (orig.)

  4. High Ni austenite stainless steel resistant to neutron irradiation degradation

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Iwamura, Toshihiko; Kanasaki, Hiroshi; Fujimoto, Koji; Nakata, Shizuo; Ajiki, Kazuhide; Nakamura, Mitsuhiro.

    1997-01-01

    The composition of the stainless steel of the present invention comprises from 0.005 to 0.08% of C, up to 3% of Mn, up to 0.2% of Si+P+S, from 25 to 40% of Ni, from 25 to 40% of Cr, up to 3% of Mo, up to 0.3% of Nb+Ta, up to 0.3% of Ti, up to 0.001% of B and the balance of Fe. A solid solubilization treatment at a temperature of from 1,000 to 1,150degC is applied to the stainless steel having the composition. The stainless steel is excellent in stress corrosion cracking-resistance at a working circumstance of a LWR type reactor (high temperature and high pressure water at from 270 to 350degC/from 70 to 160 atm even after undergoing neutron irradiation of about 1 x 10 22 n/cm 2 (E>1 MeV) which is a maximum neutron irradiation amount undergone till the final stage of the working life of the LWR-type reactor. In addition, the average thermal expansion coefficient at from room temperature to 400degC ranges from 15x10 -6 - 19x10 -6 /K. (I.N.)

  5. Neutron irradiation effect of thermally-sensitized stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hide, Kouitiro [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1998-03-01

    Intergranular stress corrosion cracking (IGSCC) susceptibility of irradiated thermally-sensitized Type 304 Stainless Steels (SSs) was studied as a function of neutron fluence and correlated with mechanical responses of the materials. Neutron irradiation was carried out to neutron fluences up to 1.1 x 10{sup 24} n/m{sup 2} (E > 1MeV) at the light water reactor temperature in the Japan Material Test Reactor. The irradiated specimens were examined by slow strain rate stress corrosion cracking tests in 290degC pure water of 0.2 ppm dissolved oxygen concentration and microhardness measurements. The IGSCC susceptibility of the irradiated specimens increased with neutron fluence up to 1.1 x 10{sup 24} n/m{sup 2}. From an attempt to correlate the IGSCC susceptibility with the mechanical properties, an excellent correlation was identified between the susceptibility and microhardness increments at the grain boundary relative to the grain center. While intergranular corrosion rate of thermally sensitized SS increased with neutron fluence up to 1.1 x 10{sup 24} n/m{sup 2}, that of solution annealed SS did not change. The incremental grain boundary hardening and degradation of intergranular corrosion resistance may presumably be the major factors affecting IGSCC performance. (author)

  6. Microstructural evolution in fast-neutron-irradiated austenitic stainless steels

    International Nuclear Information System (INIS)

    Stoller, R.E.

    1987-12-01

    The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs

  7. DT fusion neutron irradiation of BPNL niobium nickel and 316 stainless steel at 1750C

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1977-01-01

    The DT fusion neutron irradiation at 175 0 C of 17 niobium wires, one niobium foil, 14 316 stainless steel wires, one 316 stainless steel foil, nine nickel wires, and two nickel foils from BPNL is described. The sample position, beam-on time, neutron dose record, and neutron fluence are given

  8. Effect of prior cold work on creep properties of a titanium modified austenitic stainless steel

    International Nuclear Information System (INIS)

    Vijayanand, V.D.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Laha, K.; Mathew, M.D.

    2013-01-01

    Prior cold worked (PCW) titanium-modified 14Cr–15Ni austenitic stainless steel (SS) is used as a core-structural material in fast breeder reactor because of its superior creep strength and resistance to void swelling. In this study, the influence of PCW in the range of 16–24% on creep properties of IFAC-1 SS, a titanium modified 14Cr–15Ni austenitic SS, at 923 K and 973 K has been investigated. It was found that PCW has no appreciable effect on the creep deformation rate of the steel at both the test temperatures; creep rupture life increased with PCW at 923 K and remained rather unaffected at 973 K. The dislocation structure along with precipitation in the PCW steel was found to change appreciably depending on creep testing conditions. A well-defined dislocation substructure was observed on creep testing at 923 K; a well-annealed microstructure with evidences of recrystallization was observed on creep testing at 973 K

  9. Influence of sodium evnironment on the uniaxial tensile behavior of titanium modified type 316 stainless steel

    International Nuclear Information System (INIS)

    Natesan, K.; Chopra, O.K.; Kassner, T.F.

    1978-01-01

    True stress-true strain tensile data have been obtained for titanium modified type 316 stainless steel in the solution annealed condition and after exposure to a flowing sodium environment at temperature of 700, 650, 600 and 550 0 C. The specimens were exposed to sodium for times between 120 and 5012 h to produce carbon penetration depths in the range 0.05-0.30 mm. The Voce equation was used to describe tensile flow curves for plastic strains above 0.005. The results showed that, when compared with solution annealed specimens, the tensile flow behavior of the sodium exposed specimens is characterized by a higher strain hardening rate, which decreases rapidly as the flow stress increases. The loss in tensile ductility of the material due to carburization in sodium environment was found to be minimal. (Auth.)

  10. The corrosion performance of microcrystalline titanium-modified 316 stainless steel

    International Nuclear Information System (INIS)

    Saito, N.; Searson, P.C.; Latanision, R.M.

    1986-01-01

    The corrosion performance of rapidly solidified (RS), consolidated RS and conventionally processed titanium-modified nuclear grade 316 stainless steel was studied. As-solidified RS foils exhibited general corrosion behavior identical to that of the conventionally processed alloy, but inferior pitting resistance, due to the presence of dendritic microsegregation. The consolidated RS alloy exhibited inferior general and pitting corrosion performance due to the detrimental effect of the prior foil boundary formed during the consolidation process. The results of immersion tests in 6% FeC1 3 .6H 2 O solution showed that pit initiation occured primarily at the prior foil boundaries in the consolidated RS alloy. Studies of sensitization were inconclusive due to preferential attack on prior foil boundaries in the consolidated RS specimens which made the determination of the degree of sensitization difficult. (author)

  11. Effect of phase instabilities on the correlation of nickel ion and neutron irradiation swelling in solution annealed 316 stainless steel

    International Nuclear Information System (INIS)

    Rowcliffe, A.F.; Lee, E.H.; Sklad, P.S.

    1979-01-01

    Annealed 316 stainless steel specimens were neutron irradiated to establish steady-state microstructures and then subjected to further high temperature irradiations with 4 MeV Ni ions. It is shown that void growth under neutron irradiation is simulated in ion irradiations carried out at approx. 180 0 C above reactor temperature. However, the precipitate microstructure developed during neutron irradiation is unstable during subsequent ion irradiation. As a result, the relative swelling rates at various reactor temperatures are not simulated correctly

  12. Neutron irradiation test of copper alloy/stainless steel joint materials

    International Nuclear Information System (INIS)

    Yamada, Hirokazu; Kawamura, Hiroshi

    2006-01-01

    As a study about the joint technology of copper alloy and stainless steel for utilization as cooling piping in International Thermonuclear Experimental Reactor (ITER), Al 2 O 3 -dispersed strengthened copper or CuCrZr was jointed to stainless steel by three kinds of joint methods (casting joint, brazing joint and friction welding method) for the evaluation of the neutron irradiation effect on joints. A neutron irradiation test was performed to three types of joints and each copper alloy. The average value of fast neutron fluence in this irradiation test was about 2 x 10 24 n/m 2 (E>1 MeV), and the irradiation temperature was about 130degC. As post-irradiation examinations, tensile tests, hardness tests and observation of fracture surface after the tensile tests were performed. All type joints changed to be brittle by the neutron irradiation effect like each copper alloy material, and no particular neutron irradiation effect due to the effect of joint process was observed. On the casting and friction welding, hardness of copper alloy near the joint boundary changed to be lower than that of each copper alloy by the effect of joint procedure. However, tensile strength of joints was almost the same as that of each copper alloy before/after neutron irradiation. On the other hand, tensile strength of joints by brazing changed to be much lower than CuAl-25 base material by the effect of joint process before/after neutron irradiation. Results in this study showed that the friction welding method and the casting would be able to apply to the joint method of piping in ITER. This report is based on the final report of the ITER Engineering Design Activities (EDA). (author)

  13. Radiation damage in stainless steel under varying temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1998-03-01

    Microstructural evolution of model alloys of 316SS was examined by neutron irradiation at JMTR under cyclic temperature varying condition. In the case of Fe-16Cr-17Ni, formation of interstitial loops and voids are strongly suppressed by varying the temperature from 473K to 673K. By adding Ti as miner element (0.25wt%), however, abnormal accumulation of vacancies (void swelling of 11%dpa at 0.1dpa) was observed. Theoretical analysis standing on the rate theory of defect clustering and simulation irradiation experiments with heavy ions indicates that the vacancy-rich condition which appears temporally during and after changing the temperature from low to high brings these results. It was also shown that only 1 dpa pre-irradiation at low temperature changes swelling behavior at high temperature above several 10 dpa. The understanding of non-steady-state defect processes under temperature varying irradiation is very important to estimate the radiation damage under fusion environment where short-term and long-term temperature variation is expected. (author)

  14. Microhardness measurement in AISI 321 stainless steel with niobium additions before and after fast neutron irradiation

    International Nuclear Information System (INIS)

    Galli, V.L.; Lucki, G.

    1980-01-01

    Data about influence of neutron irradiation on the microhardness of stainless steel of type AISI 321 with 0.05 and 0.1wt.% Nb additions are presented. The microhardness measurements were made in the range of 300 to 650 0 C, before and after fast neutron irradiation with fluences about 10 17 n/cm 2 . Our results indicate that radiation damage peaks occur around 480 0 C for the stainless steel of type AISI 321 without Nb addition, around 500 0 C for the composition with 0.05 wt.% Nb addition and around 570 0 C for the composition with 0.1 wt.% Nb addition. Microhardness data are in agreement with those obtained by means of electrical resistivity measurements, performed at the same conditions. (Author) [pt

  15. The effects of fast-neutron irradiation on the mechanical properties of austenitic stainless steel

    International Nuclear Information System (INIS)

    Dalton, J.H.

    1978-01-01

    The paper reviews the effects of fast-neutron irradiation on the tensile properties of austenitic stainless steels at irradiation temperatures of less than 400 degrees Celcius, using as an example, work carried out at Pelindaba on an AISI 316 type steel produced in South Africa. Damage produced in these steels at higher irradiation temperatures and fluences is also briefly discussed. The paper concludes with a discussion of some methods of overcoming or decreasing the effects of irradiation damage [af

  16. Study of 316 stainless steel swelling due to neutron irradiation

    International Nuclear Information System (INIS)

    Furutani, Gen; Konishi, Takao

    2000-01-01

    Large stresses will be generated in the austenitic stainless steel core internals of pressurized water reactors (PWRs) if excessive swelling occurs after long periods of operation. As a result, deformation or stress corrosion cracking (SCC) could occur in the core internals. However, data on the swelling of irradiated austenitic stainless steel in actual PWRs is limited. In this study, mechanical tests, measurement of produced helium amount and analysis using transmission electron microscopes were carried out on a cold-worked (CW) 316 stainless steel flux thimble tube irradiated up to approximately 35 dpa in a Japanese PWR. The swelling was evaluated to be approximately 0.02%. This level of swelling was much lower than the swelling of the more than several percent that has been observed in fast breeder reactors. (author)

  17. Self-ion emulation of high dose neutron irradiated microstructure in stainless steels

    Science.gov (United States)

    Jiao, Z.; Michalicka, J.; Was, G. S.

    2018-04-01

    Solution-annealed 304L stainless steel (SS) was irradiated to 130 dpa at 380 °C, and to 15 dpa at 500 °C and 600 °C, and cold-worked 316 SS (CW 316 SS) was irradiated to 130 dpa at 380 °C using 5 MeV Fe++/Ni++ to produce microstructures and radiation-induced segregation (RIS) for comparison with that from neutron irradiation at 320 °C to 46 dpa in the BOR60 reactor. For the 304L SS alloy, self-ion irradiation at 380 °C produced a dislocation loop microstructure that was comparable to that by neutron irradiation. No voids were observed in either the 380 °C self-ion irradiation or the neutron irradiation conditions. Irradiation at 600 °C produced the best match to radiation-induced segregation of Cr and Ni with the neutron irradiation, consistent with the prediction of a large temperature shift by Mansur's invariant relations for RIS. For the CW 316 SS alloy irradiated to 130 dpa at 380 °C, both the irradiated microstructure (dislocation loops, precipitates and voids) and RIS reasonably matched the neutron-irradiated sample. The smaller temperature shift for RIS in CW 316 SS was likely due to the high sink (dislocation) density induced by the cold work. A single self-ion irradiation condition at a dose rate ∼1000× that in reactor does not match both dislocation loops and RIS in solution-annealed 304L SS. However, a single irradiation temperature produced a reasonable match with both the dislocation/precipitate microstructure and RIS in CW 316 SS, indicating that sink density is a critical factor in determining the temperature shift for self-ion irradiations.

  18. Microchemical evolution of neutron-irradiated stainless steel

    International Nuclear Information System (INIS)

    Brager, H.R.; Garner, F.A.

    1980-04-01

    The precipitates that develop in AISI 316 stainless steel during irradiation play a dominant role in determining the dimensional and mechanical property changes of this alloy. This role is expressed primarily in a large change in matrix composition that alters the diffusional properties of the alloy matrix and also appears to alter the rate of acceptance of point defects at dislocations and voids. The major elemental participants in the evolution have been identified as nickel, silicon, and carbon. The exceptional sensitivity of this evolution to many variables accounts for much of the variability of response exhibited by this alloy in nominally similar irradiations

  19. Grain boundary segregation in neutron-irradiated 304 stainless steel studied by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, T., E-mail: ttoyama@imr.tohoku.ac.jp [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nozawa, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Van Renterghem, W. [SCK Bullet CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium); Matsukawa, Y.; Hatakeyama, M.; Nagai, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Al Mazouzi, A. [EDF R and D, Avenue des Renardieres Ecuelles, 77818 Moret sur Loing Cedex (France); Van Dyck, S. [SCK Bullet CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium)

    2012-06-15

    Radiation-induced segregation (RIS) of solute atoms at a grain boundary (GB) in 304 stainless steel (SS), neutron-irradiated to a dose of 24 dpa at 300 Degree-Sign C in the fuel wrapper plates of a commercial pressurized water reactor, was investigated using laser-assisted atom probe tomography (APT). Ni, Si, and P enrichment and Cr and Fe depletion at the GB were evident. The full-width at half-maximum of the RIS region was {approx}3 nm for the concentration profile peaks of Ni and Si. The atomic percentages of Ni, Si, and Cr at the GB were {approx}19%, {approx}7%, and {approx}14%, respectively, in agreement with previously-reported values for neutron-irradiated SS. A high number density of intra-granular Ni-Si rich precipitates formed in the matrix. A precipitate-denuded zone with a width of {approx}10 nm appeared on both sides of the GB.

  20. Preliminary microstructural characterization by transmission electron microscopy of 14 MeV neutron irradiated type 316 stainless steel

    International Nuclear Information System (INIS)

    Echer, C.J.

    1977-01-01

    Substantial changes in the mechanical properties of 316 stainless steel were observed after neutron irradiation (phi/sub t/ = 2.3 x 10 21 n/m 2 and E = 14 MeV) at 25 0 C. Comparison of microstructures of the unirradiated and neutron irradiated materials were evaluated using transmission electron microscopy. Evidence of small defect clusters in the irradiated material was found. These findings are consistent with other investigators also evaluating low dose irradiations

  1. Evaluation of neutron irradiation effect on SCC crack growth behaviour of austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-08-15

    Austenitic stainless steels are widely used as structural materials alloy in reactor pressure vessel internal components because of their high strength, ductility and fracture toughness. However, exposure due to neutron irradiation results in changes in microstructure, mechanical properties and microchemistry of the material. Irradiation assisted stress corrosion cracking (IASCC) caused by the effect of neutron irradiation during long term operation in high temperature water environments in nuclear power plants is considered to take the form of intergranular stress corrosion cracking (IGSCC) and the critical fluence level has been reported to be about 5x10{sup 24}n/m{sup 2} (E>1MeV) for Type 304 SS in BWR environment. JNES had been conducting IASCC project during from JFY 2000 to JFY 2008, and prepared an engineering database on IASCC. However, the data of crack growth rate (CGR) below the critical fluence level are not sufficient. Therefore, evaluation of neutron irradiation effect project (ENI) was initiated to obtain the CGR data below the critical fluence level, and prepare the SCC growth rate diagram for life time evaluation of core shroud. Test specimens have been irradiated in the OECD/Halden reactor, and the post irradiation experiments (PIE) have been conducting during from JFY 2011 to JFY 2013, finally the modified IASCC guide will be prepared in JFY 2013. (author)

  2. Degradation of austenitic stainless steel (SS) light water ractor (LWR) core internals due to neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Appajosula S., E-mail: Appajosula.Rao@nrc.gov

    2014-04-01

    Austenitic stainless steels (SSs) are extensively being used in the fabrication of light water reactor (LWR) core internal components. It is because these steels have relatively high ductility, fracture toughness and moderate strength. However, the LWR internal components exposure to neutron irradiation over an extended period of plant operation degrades the materials mechanical properties such as the fracture toughness. This paper summarizes some of the results of the existing open literature data on irradiation assisted stress corrosion cracking (IASCC) of 316 CW steels that have been published by the United States Nuclear Regulatory Commission (USNRC), industry, academia, and other research agencies.

  3. Evaluation of neutron irradiation effect on SCC crack growth behaviour for austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    Austenitic stainless steels are widely used as structural components in reactor pressure vessel internals because of their high strength, ductility, and fracture toughness. However, exposure to neutron irradiation results in changes in microstructure, mechanical properties and microchemistry of the steels. Irradiation assisted stress corrosion cracking (IASCC) caused by the effect of neutron irradiation during long term plant operation in high temperature water environments is considered to take the form of intergranular stress corrosion cracking (IGSCC) and the critical fluence level has been reported to be about 5x10{sup 24}n/m{sup 2} (E>1MeV) in Type 304 stainless steel in BWR environment. JNES had been conducting IASCC project during the JFY (2000) - JFY (2008) period, and prepared an engineering database on IASCC. However, the data of Crack Growth Rate (CGR) below the critical fluence level are not sufficient. So, this project was initiated to obtain the CGR data below the critical fluence level. Test specimens have been irradiated in the Halden reactor, operating by the OECD Halden Reactor Project, and the post irradiation examination (PIE) will be conducted from JFY (2011) to JFY (2013), finally the modified IASCC guide will be prepared in JFY (2013). (author)

  4. Overview of microstructural evolution in neutron-irradiated austenitic stainless steels

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1993-01-01

    Austenitic stainless steels are important structural materials common to several different reactor systems, including light water and fast breeder fission, and magnetic fusion reactors (LWR, FBR, and MFR, respectively). The microstructures that develop in 300 series austenitic stainless steels during neutron irradiation at 60-700 C include combinations of dislocation loops and networks, bubbles and voids, and various kinds of precipitate phases (radiation-induced, or -enhanced or -modified thermal phases). Many property changes in these steels during neutron irradiation are directly or indirectly related to radiation-induced microstructural evolution. Even more important is the fact that radiation-resistance of such steels during either FBR or MFR irradiation is directly related to control of the evolving microstructure during such irradiation. The purpose of this paper is to provide an overview of the large and complex body of data accumulated from various fission reactor irradiation experiments conducted over the many years of research on microstructural evolution in this family of steels. The data can be organized into several different temperature regimes which then define the nature of the dominant microstructural components and their sensitivities to irradiation parameters (dose, helium/dpa ratio, dose rate) or metallurgical variables (alloy composition, pretreatment). The emphasis in this paper will be on the underlying mechanisms driving the microstructure to evolve during irradiation or those enabling microstructural stability related to radiation resistance. (orig.)

  5. Weldability of neutron-irradiated stainless steel and nickel-base alloy

    International Nuclear Information System (INIS)

    Koyabu, Ken; Asano, Kyoichi; Takahashi, Hidenori; Sakamoto, Hiroshi; Kawano, Shohei; Nakamura, Tomomi; Hashimoto, Tsuneyuki; Koshiishi, Masato; Kato, Takahiko; Katsura, Ryoei; Nishimura, Seiji

    2000-01-01

    Degradation of of weldability caused by helium, which is generated by nuclear transmutation irradiated material, is an important issue to be addressed in planning of proactive maintenance of light water reactor core internal components. In this work, the weldability of neutron.irradiated stainless steel and nickel-base alloy, which are major constituting materials for components, was practically evaluated. The weldability was first examined by TIG welding in relation to the weld heat input and helium content using various specimens (made of SUS304 and SUS316L) sampled from reactor internal components. The specimens were neutron irradiated in a boiling water reactor to fluences from 4 x 10 24 to 1.4 x 10 26 n/ m 2 (E> l MeV ), and resulting helium generation ranged from 0.1 to 103 appm. The weld defects were characterized by dye penetrant test and cross-sectional metallography. The weldability of neutron-irradiated stainless steel was shown to be better at lower weld heat input and lower helium content. To evaluate mechanical properties of welded joints, thick plates (20 mm) specimens of SUS304 and Alloy 600 were prepared and irradiated in Japan Material Test Reactor (JMTR). The helium content of the specimens was controlled to range from 0.11 to 1.34 appm selected to determine threshold helium content to weld successfully. The welded joints had multiple passes by TIG welding process at 10 and 20 kJ/cm heat input. The welded joints of thick plate were characterized by dye penetrant test, cross-sectional metallography, tensile test, side bend test and root bend test. It was shown that irradiated stainless steel containing below 0.14 appm of helium could be welded with conventional TIG welding process (heat input below 20 kJ/cm). Nickel-base alloy, which contained as much helium as stainless steel could be welded successfully, could also be welded with conventional TIG welding process, These results served as basis to evaluate the applicability of repair welding to

  6. In-reactor precipitation and ferritic transformation in neutron-irradiated stainless steels

    International Nuclear Information System (INIS)

    Porter, D.L.; Wood, E.L.

    1979-01-01

    Ferritic transformation (γ→α) was observed in type 304L, 20% cold-worked AISI 316, and solution-annealed AISI 316 stainless steels when subjected to fast neutron irradiation. Each material demonstrated an increasing propensity for transformation with increasing irradiation temperature between 40 and 550 0 C. Irradiation-induced segregation of Ni solute to precipitates was found not to be a controlling factor in the transformation kinetics in 304L. Similar composition data from 316 materials demonstrates a much greater dependence of matrix Ni depletion by precipitation reactions during neutron irradiation. The 316 data establishes a strong link between such depletion and the observed γ→α transformation. Moreover, the lack of correlation between precipitate-related Ni depletion and the γ→α transformation in 304L can be related to the fact that irradiation-induced voids nucleate very quickly in 304L steel during irradiation. These voids present competing sites for Ni segregation through a defect drag mechanism, and hence Ni segregates to voids rather than to precipitates, as evidenced by observed stable γ shells around voids in areas of complete transformation. (Auth.)

  7. In-reactor precipitation and ferritic transformation in neutron--irradiated stainless steels

    International Nuclear Information System (INIS)

    Porter, D.L.; Wood, E.L.

    1978-01-01

    Ferritic transformation (γ → α) was observed in Type 304L, 20% cold-worked AISI 316, and solution-annealed AISI 316 stainless steels subjected to fast neutron irradiation. Each material demonstrated an increasing propensity for transformation with increasing irradiation temperature between 400 and 550 0 C. Irradiation-induced segregation of Ni solute to precipitates was found not to influence the transformation kinetics in 304L. Similar composition data from 316 materials demonstrates a much greater temperature dependence of precipitation reactions in the process of matrix Ni depletion during neutron irradiation. The 316 data establishes a strong link between such depletion and the observed γ → α transformation. Moreover, the lack of correlation between precipitate-related Ni depletion and the γ → α transformation in 304L can be related to the fact that irradiation-induced voids nucleate very quickly in 304L steel during irradiation. These voids present preferential sites for Ni segregation through a defect trapping mechanism, and hence Ni segregates to voids rather than to precipitates, as evidenced by observed stable γ shells around voids in areas of complete transformation

  8. Dose dependence of the microstructural evolution in neutron-irradiated austenitic stainless steel

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Maziasz, P.J.; Stoller, R.E.

    1993-01-01

    Microstructural data on the evolution of the dislocation loop, cavity, and precipitate populations in neutron-irradiated austenitic stainless steels are reviewed in order to estimate the displacement damage levels needed to achieve the 'steady state' condition. The microstructural data can be conveniently divided into two temperature regimes. In the low temperature regime (below about 200 degrees C) the microstructure of austenitic stainless steel is dominated by 'black spot' defect clusters and faulted interstitial dislocation loops. The dose needed to approach saturation of the loop and defect cluster densities is generally on the order of 1 displacement per atom (dpa) in this regime. In the high temperature regime (∼300 to 700 degrees C), cavities, precipitates, loops and network dislocations are all produced during irradiation; doses in excess of 10 dpa are generally required to approach a 'steady state' microstructural condition. Due to complex interactions between the various microstructural components that form during irradiation, a secondary transient regime is typically observed in commercial stainless steels during irradiation at elevated temperatures. This slowly evolving secondary transient may extend to damage levels in excess of 50 dpa in typical 300-series stainless steels, and to >100 dpa in radiation-resistant developmental steels. The detailed evolution of any given microstructural component in the high-temperature regime is sensitive to slight variations in numerous experimental variables, including heat-to-heat composition changes and neutron spectrum

  9. Changes in grain boundary composition induced by neutron irradiation of austenitic stainless steels

    International Nuclear Information System (INIS)

    Asano, K.; Nakata, K.; Fukuya, K.; Kodama, M.

    1992-01-01

    The radiation induced segregation of solutes to the grain boundary in austenitic stainless steels were studied. Type 304 and type 316 steel samples neutron irradiated at 561K up to 9.2x10 25 n/m 2 were obtained and minute compositional profiles across grain boundaries were examined using an analytical scanning transmission electron microscope equipped with a field emission electron gun. Chromium was slightly enriched at grain boundaries at the lowest irradiation dose but decreased with increasing fluence. Higher fluence irradiation resulted in depletion in chromium and molybdenum, and enrichment in nickel, silicon and phosphorus. These changes in grain boundary chemistry were limited within about 5nm of the boundary. Significant depletion of chromium and enrichment of impurities on the grain boundary occurred at fluences roughly coincidental with that of SCC susceptibility change obtained from another project

  10. Temperature dependence of the deformation behavior of 316 stainless steel after low temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pawel-Robertson, J.E.; Rowcliffe, A.F.; Grossbeck, M.L. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-01

    The effects of low temperature neutron irradiation on the tensile behavior of 316 stainless steel have been investigated. A single heat of solution annealed 316 was irradiated to 7 and 18 dpa at 60, 200, 330, and 400{degrees}C. The tensile properties as a function of dose and as a function of temperature were examined. Large changes in yield strength, deformation mode, strain to necking, and strain hardening capacity were seen in this irradiation experiment. The magnitudes of the changes are dependent on both irradiation temperature and neutron dose. Irradiation can more than triple the yield strength over the unirradiated value and decrease the strain to necking (STN) to less than 0.5% under certain conditions. A maximum increase in yield strength and a minimum in the STN occur after irradiation at 330{degrees}C but the failure mode remains ductile.

  11. Crack initiation behavior of neutron irradiated model and commercial stainless steels in high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, Kale J., E-mail: kalejs@umich.edu; Was, Gary S.

    2014-01-15

    Highlights: • Environmental constant extension rate tensile tests were performed on neutron irradiated steel. • Percentage of intergranular cracking quantified the cracking susceptibility. • Cracking susceptibility varied with test environment, solute addition, and cold work. • No singular microstructural change could explain increases in cracking susceptibility with irradiation dose. • The increment of yield strength due to irradiation correlated well with cracking susceptibility. -- Abstract: The objective of this study was to isolate key factors affecting the irradiation-assisted stress corrosion cracking (IASCC) susceptibility of eleven neutron-irradiated austenitic stainless steel alloys. Four commercial purity and seven high purity stainless steels were fabricated with specific changes in composition and microstructure, and irradiated in a fast reactor spectrum at 320 °C to doses between 4.4 and 47.5 dpa. Constant extension rate tensile (CERT) tests were performed in normal water chemistry (NWC), hydrogen water chemistry (HWC), or primary water (PW) environments to isolate the effects of environment, elemental solute addition, alloy purity, alloy heat, alloy type, cold work, and irradiation dose. The irradiated alloys showed a wide variation in IASCC susceptibility, as measured by the relative changes in mechanical properties and crack morphology. Cracking susceptibility measured by %IG was enhanced in oxidizing environments, although testing in the lowest potential environment caused an increase in surface crack density. Alloys containing solute addition of Ni or Ni + Cr exhibited no IASCC. Susceptibility was reduced in materials cold worked prior to irradiation, and increased with increasing irradiation dose. Irradiation-induced hardening was accounted for by the dislocation loop microstructure, however no relation between crack initiation and radiation hardening was found.

  12. Strain hardening and plastic instability properties of austenitic stainless steels after proton and neutron irradiation

    International Nuclear Information System (INIS)

    Byun, T.S.; Farrell, K.; Lee, E.H.; Hunn, J.D.; Mansur, L.K.

    2001-01-01

    Strain hardening and plastic instability properties were analyzed for EC316LN, HTUPS316, and AL6XN austenitic stainless steels after combined 800 MeV proton and spallation neutron irradiation to doses up to 10.7 dpa. The steels retained good strain-hardening rates after irradiation, which resulted in significant uniform strains. It was found that the instability stress, the stress at the onset of necking, had little dependence on the irradiation dose. Tensile fracture stress and strain were calculated from the stress-strain curve data and were used to estimate fracture toughness using an existing model. The doses to plastic instability and fracture, the accumulated doses at which the yield stress reaches instability stress or fracture stress, were predicted by extrapolation of the yield stress, instability stress, and fracture stress to higher dose. The EC316LN alloy required the highest doses for plastic instability and fracture. Plastic deformation mechanisms are discussed in relation to the strain-hardening properties of the austenitic stainless steels

  13. Microstructural response of titanium-modified austenitic stainless steels to neutron exposure of 70 dpa in FFTF/MOTA

    International Nuclear Information System (INIS)

    Katoh, Yutai; Kohno, Yutaka; Kohyama, Akira

    1994-01-01

    JPCA, a titanium-modified austenitic stainless steel, in solution-annealed or cold-worked condition and a compositionally modified JPCA in solution-annealed condition were examined by transmission electron microscopy following irradiation in FFTF/MOTA to an exposure level of up to about 70 dpa at 390 to 600 C. At lower temperatures, all the materials developed qualitatively similar cavity-, dislocation- and precipitate-microstructures. The lower-temperature swelling peak, which appeared at near 410 C, was more efficiently suppressed by phosphorus addition than cold-working. Irradiation at or above 520 C produced substantially large swelling in solution-annealed JPCA. The cavities contributed to this higher-temperature swelling developed in association with M 6 C-type precipitates. Neither cavities other than very small helium bubbles nor massive particles of M 6 C-type precipitates were observed in cold-worked and phosphorus-modified materials, in which MC-type precipitates developed at very high concentration. The effect of pre-irradiation microstructure and compositional modification on the behavior of these precipitates is discussed. ((orig.))

  14. A comparative wear study of sputtered ZrN coatings on Si and titanium modified stainless steel substrates

    International Nuclear Information System (INIS)

    Singh, Akash; Kuppusami, P.; Thirumurugesan, R.; Mohandas, E.; Geetha, M.; Kamaraj, V.; Kumar, Niranjan

    2010-01-01

    In the present work wear behaviour of ZrN films grown by a pulsed direct current magnetron sputtering method is reported. The films were grown on silicon (100) and titanium modified stainless steel (alloy-D9) substrates by reactive sputtering in a mixture of argon and nitrogen gases. The structural parameters, preferred orientation and crystallite size as a function of substrate temperatures in the range 300-873 K were studied using X-Ray Diffraction. Deposition parameters have been found to influence the growth rate, crystalline structure and surface roughness, which affect the tribological behaviour of the films. A comparative wear study was performed on these substrates with steel and ceramic balls to evaluate the frictional properties of films. The best tribological performance was found for the sample grown with low flow rates of nitrogen (≤ 2 SCCM) at 873K. The coefficient of friction was found to be lower for the films deposited at higher temperature using steel and ceramic balls. This behaviour was correlated with microstructure and deformation behaviour of coatings. (author)

  15. Effects of thermal aging and neutron irradiation on the mechanical properties of three-wire stainless steel weld overlay cladding

    International Nuclear Information System (INIS)

    Haggag, F.M.; Nanstad, R.K.

    1997-05-01

    Thermal aging of three-wire series-arc stainless steel weld overlay cladding at 288 degrees C for 1605 h resulted in an appreciable decrease (16%) in the Charpy V-notch (CVN) upper-shelf energy (USE), but the effect on the 41-J transition temperature shift was very small (3 degrees C). The combined effect of aging and neutron irradiation at 288 degrees C to a fluence of 5 x 10 19 neutrons/cm 2 (> 1 MeV) was a 22% reduction in the USE and a 29 degrees C shift in the 41-J transition temperature. The effect of thermal aging on tensile properties was very small. However, the combined effect of irradiation and aging was an increase in the yield strength (6 to 34% at test temperatures from 288 to -125 degrees C) but no apparent change in ultimate tensile strength or total elongation. Neutron irradiation reduced the initiation fracture toughness (J Ic ) much more than did thermal aging alone. Irradiation slightly decreased the tearing modulus, but no reduction was caused by thermal aging alone. Other results from tensile, CVN, and fracture toughness specimens showed that the effects of thermal aging at 288 or 343 degrees C for 20,000 h each were very small and similar to those at 288 degrees C for 1605 h. The effects of long-term thermal exposure time (50,000 h and greater) at 288 degrees C will be investigated as the specimens become available in 1996 and beyond

  16. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, P.J.

    1985-11-01

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs.

  17. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1985-11-01

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs

  18. Irradiation-induced precipitates in a neutron irradiated 304 stainless steel studied by three-dimensional atom probe

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, T., E-mail: ttoyama@imr.tohoku.ac.jp [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Nozawa, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Van Renterghem, W. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium); Matsukawa, Y.; Hatakeyama, M.; Nagai, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Al Mazouzi, A. [EDF R and D, Avenue des Renardieres Ecuelles, 77818 Moret sur Loing Cedex (France); Van Dyck, S. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium)

    2011-11-15

    Highlights: > Irradiation-induced precipitates in a 304 stainless steel were investigated by three-dimensional atom probe. > The precipitates were found to be {gamma}' precipitates (Ni{sub 3}Si). > Post-irradiation annealing was performed to discuss the contribution of the precipitates to irradiation-hardening. - Abstract: Irradiation-induced precipitates in a 304 stainless steel, neutron-irradiated to a dose of 24 dpa at 300 deg. C in the fuel wrapper plates of a commercial pressurized water reactor, were investigated by laser-assisted three-dimensional atom probe. A high number density of 4 x 10{sup 23} m{sup -3} of Ni-Si rich precipitates was observed, which is one order of magnitude higher than that of Frank loops. The average diameter was {approx}10 nm and the average chemical composition was 40% Ni, 14% Si, 11% Cr and 32% Fe in atomic percent. Over a range of Si concentrations, the ratio of Ni to Si was {approx}3, close to that of {gamma}' precipitate (Ni{sub 3}Si). In some precipitates, Mn enrichment inside the precipitate and P segregation at the interface were observed. Post-irradiation annealing was performed to discuss the contribution of the precipitates to irradiation-hardening.

  19. Application of thermoelectricity to NDE of thermally aged cast duplex stainless steels and neutron irradiated ferritic steels

    International Nuclear Information System (INIS)

    Coste, J.F.; Leborgne, J.M.; Massoud, J.P.; Grisot, O.; Miloudi, S.

    1997-10-01

    The thermoelectric power (TEP) of an alloy depends mainly on its temperature, its chemical composition and its atomic arrangement. The TEP measurement technique is used in order to study and follow two degradation phenomena affecting some components of the primary loop of Pressurized Water Reactors (PWR). The first degradation phenomenon is the thermal aging of cast duplex stainless steel components. The de-mixing of the ferritic Fe-Cr-Ni slid solution is responsible for the decreasing of the mechanical characteristics. Laboratory studies have shown the sensitivity of TEP to the de-mixing phenomenon. TEP increases linearly with the ferrite content and with and Arrhenius-type aging parameter depending on time, temperature and activation energy. TEP is also correlated to mechanic characteristics. The second degradation phenomenon is the aging of ferritic steels due to neutron irradiation at about 290 deg C. In this case, the degradation mechanism is the formation of clusters of solute atoms and/or copper rich precipitates that causes the hardening of the material. As a first approach, a study of binary Fe-Cu alloys irradiated by electrons at 288 deg C has revealed the possibility of following the copper depletion of the ferritic matrix. Moreover, the recovery of the mechanical properties of the alloy by annealing can be monitored. Finally, a correlation between Vickers hardness and TEP has been established. (author)

  20. Modeling the effects of fast-neutron irradiation on the subsequent mechanical behaviour of type 316 stainless steel

    International Nuclear Information System (INIS)

    Dimelfi, R.J.; Kramer, J.M.

    1980-01-01

    A model describing the subsequent mechanical behaviour of type 316 stainless steel exposed to a fast reactor environment is presented. A constitutive law for the flow stress, based on the Voce equation, is introduced. The strain-rate and temperature-dependence of the flow stress is formulated in this equation; and it is assumed that all contributions to changes in the flow stress, at a given temperature and strain-rate, are manifested in a single hardness parameter. Physically-based models for work hardening, irradition hardening, and irradiation softening are presented. By combining the constitutive law with the relations describing the hardness, a system of equations is presented which describes the mechanical response of the material after specified neutron irradiation and thermal exposure. When the model is used to analyze flow stress data on unirradiated material as well as material irradiated over a wide range of fluence and temperature, agreement between predicted and observed behaviour is shown, supporting the assumption of a single flow law incorporating a single hardness parameter. (orig.)

  1. The occurrence of an ordered fcc phase in neutron irradiated M316 stainless steel

    International Nuclear Information System (INIS)

    Cawthorne, C.; Brown, C.

    1977-01-01

    A small precipitate giving a superlattice type diffraction pattern has been observed in M316 type stainless steel irradiated in the Dounreay Fast Reactor. The precipitate was observed in cold worked and solution treated samples which were unstressed and irradiated below 540 0 C, but not in those irradiated above this temperature or in the stressed samples. (B.D.)

  2. Effect of ageing on the microstructural stability of cold-worked titanium-modified 15Cr-15Ni-2.5Mo austenitic stainless steel

    International Nuclear Information System (INIS)

    Venkadesan, S.; Bhaduri, A.K.; Rodriguez, P.; Padmanabhan, K.A.

    1992-01-01

    A titanium-modified 15Cr-15Ni-2.5Mo austenitic stainless steel conforming to ASTM A 771 (UNS S 38660), commercially called Alloy D9, is being indigenously developed for application as material for the fuel clad and the hexagonal wrapper for fuel subassemblies of the Prototype Fast Breeder Reactor. As this material would be used in the cold-worked condition and would be subjected to prolonged exposure to elevated service temperatures, the effect of ageing on the microstructural stability was studied as a function of the amount of cold work. The material was given 2.5-30% prior cold work and then aged at temperatures in the range 923 to 1173 K for times ranging from 0.25 to 1000 h. Hardness measurements made before and after ageing were correlated with the Larson-Miller parameter to determine the highest stable prior cold-work level. Optical microscopy was used to study the microstructural changes. The influence of prolonged exposure for two and three years at the operating temperatures of clad and wrapper, on the elevated temperature tensile properties of a 20% prior cold-worked Alloy D9 was also studied through accelerated ageing treatments based on the present parametric approach. (orig.)

  3. Relationship between swelling and elastic properties in neutron-irradiated 316 stainless steel

    International Nuclear Information System (INIS)

    Bates, J.F.

    1976-04-01

    The results encompass elastic property measurements on several alloys, which differ in silicon, molybdenum and phosphorus contents but have a nominal 316 stainless steel composition. It is shown that there is a good correlation between the initial shear modulus of the material and the resultant swelling rate of that material. It is also shown that the bias factor concept does not satisfactorily account for the observed compositional sensitivity of swelling in the alloys investigated. 6 fig

  4. Fatigue behavior of Type 316 stainless steel following neutron irradiation inducing helium

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1980-01-01

    Since a tokamak reactor operates in a cyclic mode, thermal stresses will result in fatigue in structural components, especially in the first wall and blanket. There has been limited work on fatigue in irradiated alloys but none on irradiated materials containing significant amounts of irradiation-induced helium. To provide scoping data and to study the effects of irradiation on fatigue behavior, 20%-cold-worked type 316 stainless steel from the MFE reference heat was studied

  5. Influence of neutron irradiation at 550C on the properties of austenitic stainless steels

    International Nuclear Information System (INIS)

    Wiffen, F.W.; Maziasz, P.J.

    1981-01-01

    Types 316 and 316 + 0.23 wt % Ti stainless steels and 16-8-2 weldment were irradiated in HFIR at 55 0 C to fluences up to 1.35 x 10 26 neutrons/m 2 ( 0 C strength properties, with the weldments the weakest of the materials. The ductility of all materials was reduced by the irradiation, the uniform elongation to only 0.4% in the cold-worked material. Tests at temperatures above the irradiation temperature showed an approach to unirradiated properties as the temperature was increased from 200 to 600 0 C. Helium embrittlement at 700 0 C severely reduced elongation

  6. Fatigue behavior of type 316 stainless steel following neutron irradiation inducing helium

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1980-01-01

    Since a tokamak fusion reactor operates in a cyclic mode, thermal stresses will result in fatigue in structural components, especially the first wall and blanket. Type 316 stainless steel in the 20% cold-worked condition has been irradiated in the HFIR in order to introduce helium as well as displacement damage. A miniature hourglass specimen was developed for the reactor irradiations and subsequent fully reversed low cycle fatigue testing. For material irradiated and tested at 430 0 C in vacuum to a damage level of 7 to 15 dpa and containing 200 to 1000 appm He, a reduction in life by a factor of 3 to 10 was observed. An attempt was made to predict irradiated fatigue life by fitting data from irradiated material to a power law equation similar to the universal slopes equation and using ductility ratios from tensile tests to modify the equation for irradiated material

  7. Mechanical properties of 1950's vintage 304 stainless steel weldment components after low temperature neutron irradiation

    International Nuclear Information System (INIS)

    Sindelar, R.L.; Caskey, G.R. Jr.; Thomas, J.K.; Hawthorne, J.R.; Hiser, A.L.; Lott, R.A.; Begley, J.A.; Shogan, R.P.

    1991-01-01

    The reactor vessels of the nuclear production reactors at the Savannah River Site (SRS) were constructed in the 1950's from Type 304 stainless steel plates welded with Type 308 stainless steel filler using the multipass metal inert gas process. An irradiated mechanical properties database has been developed for the vessel with materials from archival primary coolant system piping irradiated at low temperatures (75 to 150 degrees C) in the State University of New York at Buffalo reactor (UBR) and the High Flux Isotope Reactor (HFIR) to doses of 0.065 to 2.1 dpa. Fracture toughness, tensile, and Charpy-V impact properties of the weldment components (base, weld, and weld heat-affected-zone (HAZ)) have been measured at temperatures of 25 degrees C and 125 degrees C in the L-C and C-L orientations for materials in both the irradiated and unirradiated conditions for companion specimens. Fracture toughness and tensile properties of specimens cut from an SRS reactor vessel sidewall with doses of 0.1 and 0.5 dpa were also measured at temperatures of 25 and 125 degrees C. The irradiated materials exhibit hardening with loss of work hardenability and a reduction in toughness relative to the unirradiated materials. The HFIR-irradiated materials show an increase in yield strength between about 20% and 190% with a concomitant tensile strength increase between about 15% to 30%. The elastic-plastic fracture toughness parameters and Charpy-V energy absorption both decrease and show only a slight sensitivity to dose. The irradiation-induced decrease in the elastic-plastic fracture toughness (J def at 1 mm crack extension) is between 20% to 65%; the range of J 1C values are 72.8 to 366 kJ/m 2 for the irradiated materials. Similarly, Charpy V-notch results show a 40% to 60% decrease in impact energies

  8. Effect of phosphorus and boron additions on helium bubble microstructure in titanium-modified austenitic stainless steels

    International Nuclear Information System (INIS)

    Jitsukawa, Shiro; Hojou, Kiichi; Hishinuma, Akimichi

    1992-01-01

    Ti-modified austenitic stainless steels (0.06C-0.5Si-15Cr-15Ni-2Mo-0.2Ti) plus P and/or B additions up to 0.06 wt% and 60 wtppm respectively, were irradiated with 10keV He + ions at a dose rate of 1.8 x 10 18 He + /m 2 s at 923K. Irradiation was performed on foil specimens in a transmission electron microscope equipped with an ion-accelerator up to a fluence of 1 x 10 21 He + /m 2 . Small (5 nm >) bubbles were formed in the depth region ranging between 5 and 15 nm from the foil surface of the specimen irradiated up to a fluence of 9 x 10 18 He + /m 2 . These bubbles grew continuously during the following irradiation. They were often observed to grow by coalescence. Bubble growth by coalescence was suppressed by Ti-modification. Both P and B additions enhanced the suppression effect of Ti-modification. (author)

  9. The role of dislocation channeling in IASCC initiation of neutron irradiated stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, Kale J., E-mail: kalejs@umich.edu; Was, Gary S.

    2016-12-01

    This study intended to understand how dislocation channeling affects IASCC initiation using a novel four-point bend test. Stainless steels used in this study (irradiated in the BOR-60 reactor) included a commercial purity 304L alloy irradiated to 5.5, 10.2, and 47.5 dpa, and two high purity alloys, Fe−18Cr−12Ni and Fe−18Cr−25Ni, irradiated to ∼10 dpa. IASCC was enhanced by MnS inclusions, which dissolve in the NWC environment and form oxide caps, creating a crevice condition with a high propensity for crack initiation. Stress concentration at the grain boundary intersecting these sites induced crack initiation, resulting from discontinuous dislocation channels (DC). Stress to initiate IASCC decreased with dose due to earlier DC initiation. The HP Fe−18Cr−12Ni alloy had low IASCC susceptibility and the high Ni alloy did not crack. The difference was attributed to the propensity for DCs to transmit across grain boundaries, which controls stress accumulation at DC – grain boundary intersections. - Highlights: • MnS inclusions enhance susceptibility to IASCC initiation. • Local stress (typically caused by an intersecting dislocation channel) was required to cause cracking at a MnS inclusion. • The remotely applied stress at which IASCC initiation occurred decreased with increasing irradiation dose. • IASCC resistant alloys were more likely to transmit dislocation channels across grain boundaries.

  10. Effects of neutron irradiation and fatigue on ductility of stainless steel DIN 1.4948

    International Nuclear Information System (INIS)

    Vries, M.I. de; Schaaf, B. van der; Staal, H.U.; Elen, J.D.

    1978-10-01

    Test specimens of stainless steel DIN 1.4948, which is similar to AISI type 304, have been irradiated at 723 K and 823 K up to fluences of 1.10 23 neutrons (n).m -2 and 5.10 24 n.m -2 (E > 0.1 MeV). These are representative conditions for the SNR-300 reactor vessel and inner components after 16 years of operation. High temperature (723 K to 1023 K) tensile tests at strain rates (depsilon/dt) from 10 -7 s -1 to 10 s -1 show a considerable decrease of tensile ductility. The extent depends on helium content, test temperature and strain rate. The atomic helium fractions of 3.10 -7 and 7.10 -6 result from the reactions of thermal neutrons with the 14 ppm boron, present in the steel. Helium embrittlement sets in at strain rates below 1 s -1 to 10 s -1 (the range of interest for Bethe-Tait accident analyses). A minimum total elongation value of 6% is shown at 923 K. The post-irradiation fatigue life is reduced by up to about 50% due to intergranular cracking. The combination of irradiation and fatigue causes a decrease of ductility after a smaller number of prior fatigue cycles than in the case of unirradiated material. (Auth.)

  11. Effects of neutron irradiation and fatigue on ductility of stainless steel DIN-1-4948

    International Nuclear Information System (INIS)

    de Vries, M.I.; van der Schaaf, B.; Staal, H.U.; Elen, J.D.

    1978-01-01

    Test specimens of stainless steel DIN 1.4948, which is similar to AISI Type 304, have been irradiated at 723 and 823 K up to fluences of 1*10$sup 23$ neutrons (n)*m$sup -2$ and 5*10$sup 24$ n*m$sup -2$ (E>0.1 MeV). These are representative conditions for the reactor vessel and inner components of the liquid metal fast breeder reactor SNR-300 after 16 years of operation. High-temperature (723 to 1023 K) tension tests at strain rates ($epsilon$) from 10$sup -7$ to 10 s$sup -1$ show a considerable decrease of tensile ductility. The extent depends on helium content, test temperature, and strain rate. The atomic helium fractions of 3*10$sup -7$ and 7*10$sup -6$ result from the reactions of thermal neutrons with the 14 ppm boron present in the steel. Helium embrittlement sets in at strain rates below 1 to 10 s$sup -1$ (the range of interest for Bethe-Tait accident analyses). A minimum total elongation value of 6 percent is shown at 923 K. The postirradiation fatigue life is reduced by up to about 50 percent due to intergranular cracking. The combination of irradiation and fatigue causes a decrease of ductility after a smaller number of prior fatigue cycles than in the case of unirradiated material. 8 refs

  12. Effect of fast-neutron irradiation on plastic deformation of Type 304 stainless steel

    International Nuclear Information System (INIS)

    Yamada, H.

    1978-01-01

    Plastic deformation of EBR-II-irradiated Type 304 stainless steel was investigated by a stress-relaxation method. The stress-strain-rate relationships for the irradiated specimens at room temperature are concave upward, which are similar to those for the unirradiated specimens. However, concave downward behavior in the stress-strain-rate relationships were observed at much lower temperatures for the irradiated specimens in contrast to the unirradiated specimens. These results were analyzed succccessfully using Hart's mechanical equation-of-state concept. It was found that the hardness sigma*, which is the minimum stress necessary for the dislocation to overcome obstacles without thermal activation, increases linearly with fast-neutron fluence. This increase in sigma* is consistent with so-called ''irradiation hardening.'' In addition, resistance to dislocation glide, which is quantitatively measured in terms of sigma 0 , was observed to decrease linearly with fast-neutron fluence. The decrease in sigma 0 can be attributed to a decrease of solute drag due to irradiation-induced solute segregation

  13. Effect of stress during neutron irradiation on the microstructure of type 316 stainless steel

    International Nuclear Information System (INIS)

    Brager, H.R.; Garner, F.A.; Guthrie, G.L.

    1976-04-01

    A transmission electron microscopy (TEM) examination was performed on solution annealed and 20 percent cold-worked Type 316 stainless steel specimens stressed during irradiation at 500 0 C in EBR-II. Hoop stress levels ranged from 0 to 327 MN/m 2 (47,300 psi) and fluences between 2.0 and 3.0 x 10 22 n/cm 2 (E greater than 0.1 MeV). Data confirm that applied tensile stresses enhance swelling in the solution annealed steel. The number densities of both voids and Frank loops were sensitive to the stress environment. Total swelling in the annealed material increased with stress, but not in direct proportion to the increased void nucleation. While the effect of cold working was to suppress swelling, the nucleation and growth of Frank loops was unaffected by the cold worked microstructure. The individual planar loop densities within any one specimen were quite sensitive to the magnitude of the stress component normal to the loop plane, while the total loop number density was sensitive to a smaller degree of the magnitude of the hydrostatic stress level. The number and size distribution of the loop populations were unaffected by the planar shear stress components, but the mean loop sizes were found to be limited by the probability of loop intersection with dislocations and loops. The stress dependence of void and loop densities allowed determination of the critical nuclei sizes, approximately sixteen vacancies for voids and six atoms for loops. Many observations were made on the probable creep mechanisms. Both dislocation and void microstructures evolved in a consistent stress-dependent manner, giving support to models which predict a coupling of the swelling and irradiation creep phenomena through the stress environment. 13 figures, 3 tables

  14. Effect of post-weld heat treatment and neutron irradiation on a dissimilar-metal joint between F82H steel and 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Haiying, E-mail: haigirl1983@gmail.com [SOKENDAI - The Graduated University for Advanced Studies, Toki (Japan); Nagasaka, Takuya [SOKENDAI - The Graduated University for Advanced Studies, Toki (Japan); National Institute for Fusion Science, Toki (Japan); Kometani, Nobuyuki [Nagoya University, Nagoya (Japan); Muroga, Takeo [SOKENDAI - The Graduated University for Advanced Studies, Toki (Japan); National Institute for Fusion Science, Toki (Japan); Guan, Wenhai; Nogami, Shuhei; Yabuuchi, Kiyohiro; Iwata, Takuya; Hasegawa, Akira [Tohoku University, Sendai (Japan); Yamazaki, Masanori [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University (Japan); Kano, Sho; Satoh, Yuhki; Abe, Hiroaki [Institute for Materials Research, Tohoku University, Sendai (Japan); Tanigawa, Hiroyasu [Japan Atomic Energy Agency, Rokkasho (Japan)

    2015-10-15

    Highlights: • Significant hardening after neutron irradiation at 300 °C for 0.1 dpa was found in the fine-grain HAZ of F82H for the dissimilar-metal joint between F82H and 316L. • The possible hardening mechanism was explained from the viewpoint of carbon behavior. • However, the significant hardening did not degrade the impact property significantly. - Abstract: A dissimilar-metal joint between F82H steel and 316L stainless steel was fabricated by using electron beam welding (EBW). By microstructural analysis and hardness test, the heat-affected zone (HAZ) of F82H was classified into interlayer area, fine-grain area, and coarse-carbide area. Post-weld heat treatment (PWHT) was applied to control the hardness of HAZ. After PWHT at 680 °C for 1 h, neutron irradiation at 300 °C with a dose of 0.1 dpa was carried out for the joint in Belgian Reactor II (BR-II). Compared to the base metals (BMs) and weld metal (WM), significant irradiation hardening up to 450HV was found in the fine-grain HAZ of F82H. However, the impact property of F82H-HAZ specimens, which was machined with the root of the V-notch at HAZ of F82H, was not deteriorated obviously in spite of the significant irradiation hardening.

  15. Structural integrity of stainless steel components exposed to neutron irradiation. Change in failure strength of cracked components due to cold working

    International Nuclear Information System (INIS)

    Kamaya, Masayuki; Hojo, Tomohiro; Mochizuki, Masahito

    2015-01-01

    Load carrying capacity of austenitic stainless steel component is increased due to hardening caused by neutron irradiation if no crack is included in the component. On the other hand, if a crack is initiated in the reactor components, the hardening may decrease the load carrying capacity due to reduction in fracture toughness. In this paper, in order to develop a failure assessment procedure of irradiated cracked components, characteristics of change in failure strength of stainless steels due to cold working were investigated. It was experimentally shown that the proof and tensile strengths were increased by the cold working, whereas the fracture toughness was decreased. The fracture strengths of a cylinder with a circumferential surface crack were analyzed using the obtained material properties. Although the cold working altered the failure mode from plastic collapse to the unsteady ductile crack growth, it did not reduce failure strengths even if 50% cold working was applied. The increase in failure strength was caused not only by increase in flow stress but also by reduction in J-integral value, which was brought by the change in stress-strain curve. It was shown that the failure strength of the hardened stainless steel components could be derived by the two-parameter method, in which the change in material properties could be reasonably considered. (author)

  16. Precipitate evolution in low-nickel austenitic stainless steels during neutron irradiation at very low dose rates

    International Nuclear Information System (INIS)

    Isobe, Y.; Sagisaka, M.; Garner, F.; Okita, T.

    2007-01-01

    Full text of publication follows: Not all components of a fusion reactor will be subjected to high atomic displacement rates. Some components outside the plasma containment may experience relatively low displacement rates but data generated under long-term irradiation at low dpa rates is hard to obtain. In another study the neutron-induced microstructural evolution in response to long term irradiation at very low dose rates was studied for a Russian low-nickel austenitic stainless steel that is analogous to AISI 304. The irradiated samples were obtained from an out-of-core anti-crush support column for the BN-600 fast reactor with doses ranging from 1.5 to 22 dpa generated at 3x10 -9 to 4x10 -8 dpa/s. The irradiation temperatures were in a very narrow range of 370-375 deg. C. Microstructural observation showed that in addition to voids and dislocations, an unexpectedly high density of small carbide precipitates was formed that are not usually observed at higher dpa rates in this temperature range. These results required us to ask if such unexpected precipitation was anomalous or was a general feature of low-flux, long-term irradiation. It is shown in this paper that a similar behavior was observed in a western stainless steel, namely AISI 304 stainless steel, irradiated at similar temperatures and dpa rates in the EBR-II fast reactor, indicating that irradiation at low dpa rates for many years leads to a different precipitate microstructure and therefore different associated changes in matrix composition than are generated at higher dpa rates. One consequence of this precipitation is a reduced lattice parameter of the alloy matrix, leading to densification that increases in strength with increasing temperature and dose. A. non-destructive method to evaluate these precipitates is under development and is also discussed in this paper. (authors)

  17. Observation of oscillatory radiation induced segregation profiles at grain boundaries in neutron irradiated 316 stainless steel using atom probe tomography

    Science.gov (United States)

    Barr, Christopher M.; Felfer, Peter J.; Cole, James I.; Taheri, Mitra L.

    2018-06-01

    Radiation induced segregation in austenitic Fe-Ni-Cr stainless steels is a key detrimental microstructural modification experienced in the current generation of light water reactors. In particular, Cr depletion at grain boundaries can be a significant factor in irradiation-assisted stress corrosion cracking. Therefore, having a complete knowledge and mechanistic understanding of radiation induced segregation at high dose and after a long thermal history is desired for continued sustainability of existing reactors. Here, we examine a 12% cold worked AISI 316 stainless steel hexagonal duct exposed in the lower dose, outer blanket region of the EBR-II reactor, by using advanced characterization and analysis techniques including atom probe tomography and analytical scanning transmission electron microscopy. Contrary to existing literature, we observe an oscillatory w-shape Cr and M-shape Ni concentration profile at 31 dpa. The presence and characterization through advanced atom probe tomography analysis of the w-shape Cr RIS profile is discussed in the context of the localized GB plane interfacial excess of the other major and minor alloying elements. The key finding of a co-segregation phenomena coupling Cr, Mo, and C is discussed in the context of the existing solute segregation literature under irradiation with emphasis on improved spatial and chemical resolution of atom probe tomography.

  18. Experimental assessments of notch ductility and tensile strength of stainless steel weldments after 1200C neutron irradiation

    International Nuclear Information System (INIS)

    Hawthorne, J.R.; Menke, B.H.; Awadalla, N.G.; O'Kula, K.R.

    1986-01-01

    The Charpy-V (C/sub v/) properties of AISI 300 series stainless steel plate, weld, and weld heat-affected zone (HAZ) materials from commercial production weldments in 406-mm-diameter pipe (12.7-mm wall) were investigated in unirradiated and irradiated conditions. Weld and HAZ tensile properties were also assessed in the two conditions. The plates and weld filler wires represent different steel melts; the welds were produced using the multipass MIG process. Weldment properties in two test orientations were evaluated. Specimens were irradiated in the UBR reactor to 1 x 10 20 n/cm 2 , E >0.1 MeV in a controlled temperature assembly. Specimen tests were performed at 25 0 C and 125 0 C. The radiation-induced reductions in C/sub v/ energy absorption at 25 0 C were about 42 percent for the weld and HAZ materials evaluated. A trend of energy increase with temperature was observed. The concomitant elevation in yield strength was about 53%. In contrast, the increase in tensile strength was only 16%. The postirradiation yield strength of the axial test orientation in the pipe was less than that of the circumferential test orientation. Results for the HAZ indicate that this component may be the weakest link in the weldment from a fracture resistant viewpoint

  19. Experimental assessments of notch ductility and tensile strength of stainless steel weldments after 1200C neutron irradiation

    International Nuclear Information System (INIS)

    Hawthorne, J.R.; Menke, B.H.; Awadalla, N.G.; O'Kula, K.R.

    1987-01-01

    The Charpy-V (C/sub V/) properties of American Iron and Steel Institute (AISI) 300 series stainless steel plate, weld, and weld heat-affected zone (HAZ) materials from commercial production weldments in 406-mm-diameter pipe (12.7-mm wall) were investigated in unirradiated and irradiated conditions. Weld and HAZ tensile properties were also assessed in the two conditions. The plates and weld filler wires represent different steel melts; the welds were produced using the multipass metal inert gas (MIG) process. Weldment properties in two test orientations were evaluated. Specimens were irradiated in a light water cooled and moderated reactor to 1 x 10/sup 20/ n/cm/sup 2/, E > 0.1 MeV, using a controlled temperature assembly. Specimen tests were performed at 25 and 125 0 C. The radiation-induced reductions in C/sub V/ energy absorption at 25 0 C were about 42% for the weld and the HAZ materials evaluated. A trend of energy increase with temperature was observed. The concomitant elevation in yield strength was about 53%. The increase in tensile strength in contrast was only 16%. The postirradiation yield strength of the axial test orientation in the pipe was less than that of the circumferential test orientation. Results for the HAZ indicate that this component may be the weakest link in the weldment from a fracture resistance viewpoint

  20. Gas phase hydrogen permeation through ferritic iron, austenitic stainless steel and neutron irradiated austenitic stainless steel from near 3000K to 8730K

    International Nuclear Information System (INIS)

    Quick, N.R.

    1976-01-01

    Hydrogen permeation through iron was studied over the temperature range 300 to 873 0 K by an ultra high vacuum, monopole gas analyzer technique. Hydrogen gas input pressures were varied from 0.0043 to 0.62 atm and membrane thicknesses from 0.0165 to 0.243 cm. Volume diffusion control of the permeation process was demonstrated by the pressure and membrane thickness dependence of the steady state flux. The permeation coefficient, with an activation enthalpy found to be 8.1 +-.4 kcal/mole, was independent of both gas pressure and membrane thickness. At temperatures below approximately 600 0 K, the effective diffusivity increased with both increasing hydrogen gas pressure and increasing membrane thickness. The transition temperature from classical to anomalous behavior decreases with increasing thickness. Apparent activation enthalpies for diffusion were found to range from 1.6 to 8.2 kcal/mole with the lower values associated with thicker membranes. The permeation coefficient activation enthalpy was found to be 13.1 +- .4 kcal/mole while that for diffusivity was found to be 11.2 +- .45 kcal/mole. However, samples neutron irradiated at a fluence of 10 17 n/cm 2 showed anomalous effects in that both effective diffusivity and permeation were reduced in value

  1. Swelling behavior of titanium-modified AISI 316 alloys

    International Nuclear Information System (INIS)

    Garner, F.A.; Brager, H.R.; Puigh, R.J.

    1984-01-01

    It appears that titanium additions to stainless steels covering a wide compositional range around the specifications of AISI 316 result only in an increased delay period before neutron-induced void swelling proceeds. Once swelling is initiated the post transient behavior of both annealed and cold-worked titanium-modified steels is quite consistent with that of AISI 316, approaching a relatively temperature-independent swelling rate of approx. 1% per dpa

  2. Applications of neutron irradiation

    International Nuclear Information System (INIS)

    Ito, Yasuo

    1999-01-01

    The present state of art of applications of neutron irradiation is overviewed taking neutron activation analysis, prompt gamma-ray analysis, fission/alpha track methods, boron neutron capture therapy as examples. What is common among them is that the technologies are nearly matured for wide use by non- nuclear scientists. But the environment around research reactors is not prospective. These applications should be encouraged by incorporating in the neutron science society. (author)

  3. Tensile and fracture toughness properties of copper alloys and their HIP joints with austenitic stainless steel in unirradiated and neutron irradiated condition

    International Nuclear Information System (INIS)

    Taehtinen, S.; Pyykkoenen, M.; Singh, B.N.; Toft, P.

    1998-03-01

    The tensile strength and ductility of unirradiated CuAl25 IG0 and CuCrZr alloys decreased continuously with increasing temperature up to 350 deg C. Fracture toughness of unirradiated CuAl25 IG0 alloy decreased continuously with increasing temperature from 20 deg C to 350 deg C whereas the fracture toughness of unirradiated CuCrZr alloy remained almost constant at temperatures up to 100 deg C, was decreased significantly at 200 deg C and slightly increased at 350 deg C. Fracture toughness of HIP joints were lower than that of corresponding copper alloy and fracture path in HIP joint specimen was always within copper alloy side of the joint. Neutron irradiation to a dose level of 0.3 dpa resulted in hardening and reduction in uniform elongation to about 2-4% at 200 deg C in both copper alloys. At higher temperatures softening was observed and uniform elongation increased to about 5% and 16% for CuAl25 IG0 and CuCrZr alloys, respectively. Fracture toughness of CuAl25 IG0 alloy reduced markedly due to neutron irradiation in the temperature range from 20 deg C to 350 deg C. The fracture toughness of the irradiated CuCrZr alloy also decreased in the range from 20 deg C to 350 deg C, although it remained almost unaffected at temperatures below 200 deg C and decreased significantly at 350 deg C when compared with that of unirradiated CuCrZr alloy. (orig.)

  4. Neutron irradiation therapy machine

    International Nuclear Information System (INIS)

    1980-01-01

    Conventional neutron irradiation therapy machines, based on the use of cyclotrons for producing neutron beams, use a superconducting magnet for the cyclotron's magnetic field. This necessitates complex liquid He equipment and presents problems in general hospital use. If conventional magnets are used, the weight of the magnet poles considerably complicates the design of the rotating gantry. Such a therapy machine, gantry and target facilities are described in detail. The use of protons and deuterons to produce the neutron beams is compared and contrasted. (U.K.)

  5. PDS 1-5. Divertor heat sink materials pre- and post-neutron irradiation. Tensile and fatigue tests of brazed joints of molybdenum alloys and 316L stainless steel

    International Nuclear Information System (INIS)

    Lind, Anders.

    1994-01-01

    Tensile specimens from brazed joints of molybdenum alloys (TZM or Mo-5%Re) and Type 316L austenitic stainless steel tubes have been tested at ambient temperature and 127 degrees C before and after neutron irradiation at about 40 degrees C to approximately 0.2 dpa. The unirradiated specimens showed generally ductile behaviour, but the irradiated specimens were notch sensitive and failed in a brittle manner with zero elongation; in all cases the fracture occurred in the molybdenum alloy. The brittle behaviour is consistent with previously published data and results from the increase in strength (radiation hardening) and the associated increase in the ductile-brittle transition temperature (radiation embrittlement) induced in the body-centered-cubic (BCC) molybdenum alloys by irradiation to relatively low displacement doses. The same type of irradiated specimens were also used in fatigue tests. However, the results from the fatigue tests are too limited and complementary studies are needed. During exposure to water locally up to 25% of the wall thickness of the Mo-alloys has corroded away. These observations cast serious doubts on the viability of the molybdenum alloys for divertor applications in fusion systems. 8 refs, 29 figs

  6. Response to annealing and reirradiation of AISI 304L stainless steel following initial high-dose neutron irradiation in EBR-II

    International Nuclear Information System (INIS)

    Porter, D.L.; McVay, G.L.; Walters, L.C.

    1980-01-01

    The object of this study was to measure the stability of irradiation-induced microstructure upon annealing and, by selectively annealing out some of these features and reirradiating the material, it was expected that information could be gained concerning the role of microstructural changes in the void swelling process. Transmission electron microscopic examinations of isochronally annealed (200 to 1050 0 C) AISI 304L stainless steel, which had been irradiated at approximately 415 0 C to a fast (E > 0.1 MeV) neutron fluence of approximately 5.1 x 10 26 n/m 2 , verified that the two-stage hardness recovery with temperatures was related to a low temperature annealing of dislocation structures and a higher temperature annealing of voids and solute redistribution

  7. Neutron irradiation effects on plasma facing materials

    Science.gov (United States)

    Barabash, V.; Federici, G.; Rödig, M.; Snead, L. L.; Wu, C. H.

    2000-12-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.

  8. Neutron irradiation effects on plasma facing materials

    International Nuclear Information System (INIS)

    Barabash, V.; Federici, G.; Roedig, M.; Snead, L.L.; Wu, C.H.

    2000-01-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed

  9. Emulation of neutron irradiation effects with protons: validation of principle

    International Nuclear Information System (INIS)

    Was, G.S.; Busby, J.T.; Allen, T.; Kenik, E.A.; Jensson, A.; Bruemmer, S.M.; Gan, J.; Edwards, A.D.; Scott, P.M.; Andreson, P.L.

    2002-01-01

    This paper presents the results of the irradiation, characterization and irradiation assisted stress corrosion cracking (IASCC) behavior of proton- and neutron-irradiated samples of 304SS and 316SS from the same heats. The objective of the study was to determine whether proton irradiation does indeed emulate the full range of effects of in-reactor neutron irradiation: radiation-induced segregation (RIS), irradiated microstructure, radiation hardening and IASCC susceptibility. The work focused on commercial heats of 304 stainless steel (heat B) and 316 stainless steel (heat P). Irradiation with protons was conducted at 360 deg. C to doses between 0.3 and 5.0 dpa to approximate those by neutron irradiation at 275 deg. C over the same dose range. Characterization consisted of grain boundary microchemistry, dislocation loop microstructure, hardness as well as stress corrosion cracking (SCC) susceptibility of both un-irradiated and irradiated samples in oxygenated and de-oxygenated water environments at 288 deg. C. Overall, microchemistry, microstructure, hardening and SCC behavior of proton- and neutron-irradiated samples were in excellent agreement. RIS analysis showed that in both heats and for both irradiating particles, the pre-existing grain boundary Cr enrichment transformed into a 'W' shaped profile at 1.0 dpa and then into a 'V' shaped profile between 3.0 and 5.0 dpa. Grain boundary segregation of Cr, Ni, Si, and Mo all followed the same trends and agreed well in magnitude. The microstructure of both proton- and neutron-irradiated samples was dominated by small, faulted dislocation loops. Loop size distributions were nearly identical in both heats over a range of doses. Saturated loop size following neutron irradiation was about 30% larger than that following proton irradiation. Loop density increased with dose through 5.0 dpa for both particle irradiations and was a factor of 3 greater in neutron-irradiated samples vs. proton-irradiated samples. Grain boundary

  10. Neutron irradiation creep in stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schuele, Wolfgang (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy)); Hausen, Hermann (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy))

    1994-09-01

    Irradiation creep elongations were measured in the HFR at Petten on AMCR steels, on 316 CE-reference steels, and on US-316 and US-PCA steels varying the irradiation temperature between 300 C and 500 C and the stress between 25 and 300 MPa. At the beginning of an irradiation a type of primary'' creep stage is observed for doses up to 3-5 dpa after which dose the secondary'' creep stage begins. The primary'' creep strain decreases in cold-worked steel materials with decreasing stress and decreasing irradiation temperature achieving also negative creep strains depending also on the pre-treatment of the materials. These primary'' creep strains are mainly attributed to volume changes due to the formation of radiation-induced phases, e.g. to the formation of [alpha]-ferrite below about 400 C and of carbides below about 700 C, and not to irradiation creep. The secondary'' creep stage is found for doses larger than 3 to 5 dpa and is attributed mainly to irradiation creep. The irradiation creep rate is almost independent of the irradiation temperature (Q[sub irr]=0.132 eV) and linearly dependent on the stress. The total creep elongations normalized to about 8 dpa are equal for almost every type of steel irradiated in the HFR at Petten or in ORR or in EBR II. The negative creep elongations are more pronounced in PCA- and in AMCR-steels and for this reason the total creep elongation is slightly smaller at 8 dpa for these two steels than for the other steels. ((orig.))

  11. Neutron irradiation facility and its characteristics

    International Nuclear Information System (INIS)

    Oyama, Yukio; Noda, Kenji

    1995-01-01

    A neutron irradiation facility utilizing spallation reactions with high energy protons is conceived as one of the facilities in 'Proton Engineering center (PEC)' proposed at JAERI. Characteristics of neutron irradiation field of the facility for material irradiation studies are described in terms of material damage parameters, influence of the pulse irradiation, irradiation environments other than neutronics features, etc., comparing with the other sorts of neutron irradiation facilities. Some perspectives for materials irradiation studies using PEC are presented. (author)

  12. Neutron irradiation of seeds 2

    Energy Technology Data Exchange (ETDEWEB)

    1968-10-01

    The irradiation of seeds with the fast neutron of research reactors has been hampered by difficulties in accurately measuring dose and in obtaining repeatable and comparable results. Co-ordinated research under an international program organized by the FAO and IAEA has already resulted in significant improvements in methods of exposing seeds in research reactors and in obtaining accurate dosimetry. This has been accomplished by the development of a standard reactor facility for the neutron irradiation of seeds and standard methods for determining fast-neutron dose and the biological response after irradiation. In this program various divisions of the IAEA and the Joint FAO/IAEA Division co-operate with a number of research institutes and reactor centres throughout the world. Results of the preliminary experiments were reported in Technical Reports Series No. 76, ''Neutron Irradiation of Seeds''. This volume contains the proceedings of a meeting of co-operators in the FAO/IAEA Neutron Seed Irradiation Program and other active scientists in this field. The meeting was held in Vienna from 11 to 15 December 1967. Refs, figs and tabs.

  13. Neutron irradiation of seeds 2

    International Nuclear Information System (INIS)

    1968-01-01

    The irradiation of seeds with the fast neutron of research reactors has been hampered by difficulties in accurately measuring dose and in obtaining repeatable and comparable results. Co-ordinated research under an international program organized by the FAO and IAEA has already resulted in significant improvements in methods of exposing seeds in research reactors and in obtaining accurate dosimetry. This has been accomplished by the development of a standard reactor facility for the neutron irradiation of seeds and standard methods for determining fast-neutron dose and the biological response after irradiation. In this program various divisions of the IAEA and the Joint FAO/IAEA Division co-operate with a number of research institutes and reactor centres throughout the world. Results of the preliminary experiments were reported in Technical Reports Series No. 76, ''Neutron Irradiation of Seeds''. This volume contains the proceedings of a meeting of co-operators in the FAO/IAEA Neutron Seed Irradiation Program and other active scientists in this field. The meeting was held in Vienna from 11 to 15 December 1967. Refs, figs and tabs

  14. Formation of austenite in high Cr ferritic/martensitic steels by high fluence neutron irradiation

    Science.gov (United States)

    Lu, Z.; Faulkner, R. G.; Morgan, T. S.

    2008-12-01

    High Cr ferritic/martensitic steels are leading candidates for structural components of future fusion reactors and new generation fission reactors due to their excellent swelling resistance and thermal properties. A commercial grade 12%CrMoVNb ferritic/martensitic stainless steel in the form of parent plate and off-normal weld materials was fast neutron irradiated up to 33 dpa (1.1 × 10 -6 dpa/s) at 400 °C and 28 dpa (1.7 × 10 -6 dpa/s) at 465 °C, respectively. TEM investigation shows that the fully martensitic weld metal transformed to a duplex austenite/ferrite structure due to high fluence neutron irradiation, the austenite was heavily voided (˜15 vol.%) and the ferrite was relatively void-free; whilst no austenite phases were detected in plate steel. Thermodynamic and phase equilibria software MTDATA has been employed for the first time to investigate neutron irradiation-induced phase transformations. The neutron irradiation effect is introduced by adding additional Gibbs free energy into the system. This additional energy is produced by high energy neutron irradiation and can be estimated from the increased dislocation loop density caused by irradiation. Modelling results show that neutron irradiation reduces the ferrite/austenite transformation temperature, especially for high Ni weld metal. The calculated results exhibit good agreement with experimental observation.

  15. Effect of neutron irradiation on vanadium alloys

    International Nuclear Information System (INIS)

    Braski, D.N.

    1986-01-01

    Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600 0 C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520 0 C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys

  16. Effect of neutron irradiation on vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braski, D.N.

    1986-01-01

    Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600/sup 0/C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520/sup 0/C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys.

  17. Hydriding and neutron irradiation in zircaloy-4

    International Nuclear Information System (INIS)

    Ramos, Ruben Fortunato; Martin, Juan Ezequiel; Orellano, Pablo; Dorao, Carlos; Analia Soldati; Ghilarducci, Ada Albertina; Corso, Hugo Luis; Peretti, Hernan Americo; Bolcich, Juan Carlos

    2003-01-01

    The composition of Zircaloy-4 for nuclear applications is specified by the ASTM B350 Standard, that fixes the amount of alloying elements (Sn, Fe, Cr) and impurities (Ni, Hf, O, N, C, among others) to optimize good corrosion and mechanical behavior.The recycling of zircaloy-4 scrap and chips resulting from cladding tube fabrication is an interesting issue.However, changes in the final composition of the recycled material may occur due to contamination with tool pieces, stainless steel chips, turnings, etc. while scrap is stored and handled. Since the main components of the possible contaminants are Fe, Cr and Ni, it arises the interest in studying up to what limit the Fe, Ni and Cr contents could be exceeded beyond the standard specification without affecting significantly the alloy properties.Zircaloy-4 alloys elaborated with Fe, Cr and Ni additions and others of standard composition in use in nuclear plants are studied by tensile tests, SEM observations and EDS microanalysis.Some samples are tested in the initial condition and others after hydriding treatments and neutron irradiation in the RA6

  18. Neutron irradiation of bacteriophage λ

    International Nuclear Information System (INIS)

    Bozin, D.; Milosevic, M. . E-mail address of corresponding author: bozinde@vin.bg.ac.yu

    2005-01-01

    Double strand breaks (DSB) are the most dangerous lesions in DNA caused by irradiation, but many other lesions, usually called mutations, have not been clearly identified. These lesions, like DSB, can be the source of serious chromosomal damages and finally - cell death. Growing interest in heavy particles for radiotherapy and radioprotection encourages the search of the molecular basis of their action. In this respect, we chose bacteriophage λ1390 as the model system for the study of consequences of neutron irradiation. This derivative of λ phage possesses an unique ability to reversibly reorganize their genome in response to various selective pressures. The phages were irradiated with 13 Gy of mixed neutrons (7.5 Gy from fast and 5.6 Gy from thermal neutrons) and phages genomes were tested to DSB and mutations. Additionally, the stability of λ capsid proteins were tested. After all tests, we can conclude that, under our conditions, low flux of neutrons does not induce neither DNA strand break or DNA mutation nor the stability of λ capsid proteins. (author)

  19. Hair dosimetry following neutron irradiation.

    Science.gov (United States)

    Lebaron-Jacobs, L; Gaillard-Lecanu, E; Briot, F; Distinguin, S; Boisson, P; Exmelin, L; Racine, Y; Berard, P; Flüry-Herard, A; Miele, A; Fottorino, R

    2007-05-01

    Use of hair as a biological dosimeter of neutron exposure was proposed a few years ago. To date, the (32)S(n,p)(32)P reaction in hair with a threshold of 2.5 MeV is the best choice to determine the fast neutron dose using body activation. This information is essential with regards to the heterogeneity of the neutron transfer to the organism. This is a very important parameter for individual dose reconstruction from the surface to the deeper tissues. This evaluation is essential to the adapted management of irradiated victims by specialized medical staff. Comparison exercises between clinical biochemistry laboratories from French sites (the CEA and COGEMA) and from the IRSN were carried out to validate the measurement of (32)P activity in hair and to improve the techniques used to perform this examination. Hair was placed on a phantom and was irradiated at different doses in the SILENE reactor (Valduc, France). Different parameters were tested: variation of hair type, minimum weight of hair sample, hair wash before measurement, delivery period of results, and different irradiation configurations. The results obtained in these comparison exercises by the different laboratories showed an excellent correlation. This allowed the assessment of a dose-activity relationship and confirmed the feasibility and the interest of (32)P measurement in hair following fast neutron irradiation.

  20. Effect of neutron irradiation on vitreous carbon

    International Nuclear Information System (INIS)

    Kurolenkin, E.I.; Virgil'ev, Yu.S.; Chugunova, T.K.

    1989-01-01

    The change in mass (m), volume (V), specific electric resistance (ρ), coefficient of linear thermal expansion (α), dynamic elasticity modulus (E), and limit of bending strength (σ) of vitreous carbon are studied upon neutron irradiation. Samples for study were two forms of vitreous carbon obtained by hardening thermally reactive polymers at 900-1,000 degree K. Phenol-formaldehyde (bakelite lacquer A, Bakelite A) and furfural-phenol-formaldehyde (FM-2) resin were used. They were irradiated in the experimental water - water VVR-M reactor between 360-1,030 degree K. The maximal neutron flux was 1.65·10 21 neut/cm 2 . Neutron irradiation of vitreous carbon led to its shrinkage and accompanied weakening. Shrinkage and weakening of vitreous carbon was decreased with an increase of treatment and irradiation temperatures

  1. Chemical reactions induced by fast neutron irradiation

    International Nuclear Information System (INIS)

    Katsumura, Y.

    1989-01-01

    Here, several studies on fast neutron irradiation effects carried out at the reactor 'YAYOI' are presented. Some indicate a significant difference in the effect from those by γ-ray irradiation but others do not, and the difference changes from subject to subject which we observed. In general, chemical reactions induced by fast neutron irradiation expand in space and time, and there are many aspects. In the time region just after the deposition of neutron energy in the system, intermediates are formed densely and locally reflecting high LET of fast neutrons and, with time, successive reactions proceed parallel to dissipation of localized energy and to diffusion of the intermediates. Finally the reactions are completed in longer time region. If we pick up the effects which reserve the locality of the initial processes, a significant different effect between in fast neutron radiolysis and in γ-ray radiolysis would be derived. If we observe the products generated after dissipation and diffusion in longer time region, a clear difference would not be observed. Therefore, in order to understand the fast neutron irradiation effects, it is necessary to know the fundamental processes of the reactions induced by radiations. (author)

  2. Effect of periodic temperature variations on the microstructure of neutron-irradiated metals

    DEFF Research Database (Denmark)

    Zinkle, S.J.; Hashimoto, N.; Hoelzer, D.T.

    2002-01-01

    Specimens of pure copper, a high purity austenitic stainless steel, and V–4Cr–4Ti were exposed to eight cycles of either constant temperature or periodic temperature variations during neutron irradiation in the High Flux Isotopes Reactor to a cumulative damage level of 4–5 displacements per atom.......-induced microstructural features consisted of dislocation loops, stacking fault tetrahedra and voids in the stainless steel, Ti-rich precipitates in the V alloy, and voids (along with a low density of stacking fault tetrahedra) in copper.......Specimens of pure copper, a high purity austenitic stainless steel, and V–4Cr–4Ti were exposed to eight cycles of either constant temperature or periodic temperature variations during neutron irradiation in the High Flux Isotopes Reactor to a cumulative damage level of 4–5 displacements per atom....... Specimens exposed to periodic temperature variations experienced a low temperature (360 °C) during the initial 10% of accrued dose in each of the eight cycles, and a higher temperature (520 °C) during the remaining 90% of accrued dose in each cycle. The microstructures of the irradiated stainless steel...

  3. Evaluation of radiation-induced sensitization using electrochemical potentiokinetic reactivation technique for austenitic stainless steels

    International Nuclear Information System (INIS)

    Inazumi, T.; Bell, G.E.C.; Hishinuma, A.

    1990-01-01

    The electrochemical potentiokinetic reactivation (EPR) test technique was applied to the determination of sensitization in a neutron-irradiated (420 degree C, 10 dpa) titanium-modified austenitic stainless steel. Miniaturized specimens (3 mm diam by 0.25 mm thick) in solution-annealed and 25% cold-worked conditions were tested. The degree of sensitization (DOS) was calculated in terms of the reactivation charge (Pa). Results indicated the occurrence of radiation-induced sensitization when compared to control specimens thermally aged at the irradiation temperature. Post-EPR examination of the specimen surfaces showed etching across the face of each grain as well as at grain boundaries. This indicates that the Pa value normalized by the total grain boundary area, which is an accepted EPR-DOS criterion, cannot be directly used as an indicator of the DOS to determine the susceptibility of this irradiated material to intergranular stress corrosion cracking (IGSCC). Further investigations are necessary to correlate the results in this study to the IGSCC susceptibility of the irradiated stainless steel. 26 refs., 7 figs., 3 tabs

  4. Impact of neutron irradiation on thermal helium desorption from iron

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xunxiang, E-mail: hux1@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Field, Kevin G. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Taller, Stephen [University of Michigan, Ann Arbor, MI 48109 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wirth, Brian D. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); University of Tennessee, Knoxville, TN 37996 (United States)

    2017-06-15

    The synergistic effect of neutron irradiation and transmutant helium production is an important concern for the application of iron-based alloys as structural materials in fission and fusion reactors. In this study, we investigated the impact of neutron irradiation on thermal helium desorption behavior in high purity iron. Single crystalline and polycrystalline iron samples were neutron irradiated in HFIR to 5 dpa at 300 °C and in BOR-60 to 16.6 dpa at 386 °C, respectively. Following neutron irradiation, 10 keV He ion implantation was performed at room temperature on both samples to a fluence of 7 × 10{sup 18} He/m{sup 2}. Thermal desorption spectrometry (TDS) was conducted to assess the helium diffusion and clustering kinetics by analyzing the desorption spectra. The comparison of He desorption spectra between unirradiated and neutron irradiated samples showed that the major He desorption peaks shift to higher temperatures for the neutron-irradiated iron samples, implying that strong trapping sites for He were produced during neutron irradiation, which appeared to be nm-sized cavities through TEM examination. The underlying mechanisms controlling the helium trapping and desorption behavior were deduced by assessing changes in the microstructure, as characterized by TEM, of the neutron irradiated samples before and after TDS measurements.

  5. Swelling and tensile properties of neutron-irradiated vanadium alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Smith, D.L.

    1990-07-01

    Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600 degree C to neutron fluences ranging from 0.3 to 1.9 x 10 27 neutrons/m 2 (17 to 114 atom displacements per atom [dpa])

  6. Neutron irradiation damage in transition metal carbides

    International Nuclear Information System (INIS)

    Matsui, Hisayuki; Nesaki, Kouji; Kiritani, Michio

    1991-01-01

    Effects of neutron irradiation on the physical properties of light transition metal carbides, TiC x , VC x and NbC x , were examined, emphasizing the characterization of irradiation induced defects in the nonstoichiometric composition. TiC x irradiated with 14 MeV (fusion) neutrons showed higher damage rates with increasing C/Ti (x) ratio. A brief discussion is made on 'cascade damage' in TiC x irradiated with fusion neutrons. Two other carbides (VC x and NbC x ) were irradiated with fission reactor neutrons. The irradiation effects on VC x were not so simple, because of the complex irradiation behavior of 'ordered' phases. For instance, complete disordering was revealed in an ordered phase, 'V 8 C 7 ', after an irradiation dose of 10 25 n/m 2 . (orig.)

  7. EDX microanalysis of neutron-irradiated alloys

    International Nuclear Information System (INIS)

    Thomas, L.E.

    1981-09-01

    Energy-dispersive X-ray (EDX) spectrometry of 50 nm thick specimens in the scanning transmission electron microscope provides quantitative elemental analyses of selected regions as small as 20 nm in diameter. To analyze highly radioactive neutron-irradiated alloys it is necessary to reduce the high counting deadtimes caused by energetic γ-Compton scattering in the Si(Li) detector, and to account for spurious background contributions from γ-rays and characteristic x-ray emissions. Several simple methods for overcoming effects of specimen radioactivity are described, including use of a tungsten collimator to attenuate γ and x-rays coming from the thick edges of self-supporting disk specimens. These methods allow analyses of Fe-Cr-Ni based alloys with γ-activities up to 1000 μC/sub i/. Techniques used to maintain high spatial resolution and accuracy in quantitatve analysis are also described, and their use is illustrated

  8. Neutron irradiation induced amorphization of silicon carbide

    International Nuclear Information System (INIS)

    Snead, L.L.; Hay, J.C.

    1998-01-01

    This paper provides the first known observation of silicon carbide fully amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60 C to a total fast neutron fluence of 2.6 x 10 25 n/m 2 . Amorphization was seen in both materials, as evidenced by TEM, electron diffraction, and x-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density (-10.8%), elastic modulus as measured using a nanoindentation technique (-45%), hardness as measured by nanoindentation (-45%), and standard Vickers hardness (-24%). Similar property changes are observed for the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than 130 C

  9. ATF Neutron Irradiation Program Technical Plan

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-03-01

    The Japan Atomic Energy Agency (JAEA) under the Civil Nuclear Energy Working Group (CNWG) is engaged in a cooperative research effort with the U.S. Department of Energy (DOE) to explore issues related to nuclear energy, including research on accident-tolerant fuels and materials for use in light water reactors. This work develops a draft technical plan for a neutron irradiation program on the candidate accident-tolerant fuel cladding materials and elements using the High Flux Isotope Reactor (HFIR). The research program requires the design of a detailed experiment, development of test vehicles, irradiation of test specimens, possible post-irradiation examination and characterization of irradiated materials and the shipment of irradiated materials to JAEA in Japan. This report discusses the technical plan of the experimental study.

  10. Neutron irradiation effects in advanced superconductors

    International Nuclear Information System (INIS)

    Yoshida, H.; Kodaka, H.; Miyata, K.; Hayashi, Y.; Atobe, K.

    1988-01-01

    This paper reports the effects of neutron irradiation on superconducting transitions studied by susceptibility and resistivity measurements for A15 type compounds, Laves-phase compounds and oxide superconductors. For A15 superconductors, the transition temperature (T c ) decreased with increasing neutron fluence and showed large drop started at about 5 x 10 18 n/cm 2 (E > 0.1 MeV). Post-irradiation annealing gave recovery of T c , but the behaviors were different for the materials with different composition and microstructure. The Laves-phase compounds showed less degradation than the A15 superconductors. For oxide superconductors very sensitive transition change was observed, including the radiation-induced superconductivity

  11. A standard fission neutron irradiation facility

    International Nuclear Information System (INIS)

    Sahasrabudhe, S.G.; Chakraborty, P.P.; Iyer, M.R.; Kirthi, K.N.; Soman, S.D.

    1979-01-01

    A fission neutron irradiation facility (FISNIF) has been set up at the thermal column of the CIRUS reactor at BARC. The spectrum and the flux have been measured using threshold detectors. The paper describes the setting up of the facility, measurement and application. A concentric cylinder containing UO 2 powder sealed inside surrounds the irradiation point of a pneumatic sample transfer system located in the thermal column of the reactor. Samples are loaded in a standard aluminium capsule with cadmium lining and transported pneumatically. A sample transfer time of 1 s can be achieved in the facility. Typical applications of the facility for studying activation of iron and sodium in fission neutrons are also discussed. (Auth.)

  12. A neutron irradiator applied to cancer treatment

    International Nuclear Information System (INIS)

    Campos, Tarcisio P.R.; Andrade, Ana P. de

    2000-01-01

    Cancer and the way of treating it with neutron capture therapy are addressed. This paper discusses also the type of neutron facilities used to treat cancer around the world, as follow: discrete neutron sources, accelerators, and nuclear reactors. The major features of an epithermal neutron irradiation facility applied to BNCT treatment are addressed. The main goal is to give another choice of neutron irradiators to be set in a hospital. The irradiation facility embeds a set of 252 Cf neutron source coupled with a homogeneous mixture of uranium-zirconium hydride alloy containing 8.4 wt % uranium enriched to 20% U 235 . The facility delivers an epithermal neutron beam with low background of fast neutron and gamma rays. The N particle transport code (MCNP-4A) has been used during the simulation in order to achieve the desired configurations and to estimate the multiplication factor, k eff . The present facility loaded with 30 mg of 252 Cf neutron source generates an external beam with an intensity of 10 7 n/cm 2 .s on the spectrum of 4 eV to 40 KeV. The 252 Cf - facility coupled with fissile material was able to amplify the epithermal flux to 10 8 n/cm 2 .s, maintaining the figure-of-merits represented by the ratios of the fast dose and gamma dose in air per epithermal neutron flux closed to those values presented by BMRR, MITR-II and Petten Reactor. The medical irradiation facility loaded with 252 Cf- 235 U can be a choice for BNCT. (author)

  13. Radiation damage of pixelated photon detector by neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Isamu [KEK, 1-1 Oho Tsukuba 305-0801 (Japan)], E-mail: isamu.nakamura@kek.jp

    2009-10-21

    Radiation Damage of Pixelated Photon Detector by neutron irradiation is reported. MPPC, one of PPD or Geiger-mode APD, developed by Hamamatsu Photonics, is planned to be used in many high energy physics experiments. In such experiments radiation damage is a serious issue. A series of neutron irradiation tests is performed at the Reactor YAYOI of the University of Tokyo. MPPCs were irradiated at the reactor up to 10{sup 12}neutron/cm{sup 2}. In this paper, the effect of neutron irradiation on the basic characteristics of PPD including gain, noise rate, photon detection efficiency is presented.

  14. Influence of neutron irradiation on ferromagnetic metallic glasses

    International Nuclear Information System (INIS)

    Miglierini, M.; Nasu, Saburo; Sitek, J.

    1992-01-01

    Transmission 57 Fe Moessbauer spectroscopy is used to study effects of neutron irradiation on magnetic properties of Fe-based ferromagnetic metallic glasses. Elastic stress centers are produced during the process of neutron irradiation as a result of atom mixing. Rearrangement of the atoms causes changes in the average value of the hyperfine field distribution and orientation of the net magnetic moment. They are shown to depend on the composition of the investigated samples. Cr-doped metallic glasses depict transformation from ferromagnetic to paramagnetic state at room temperature after neutron irradiation implying changes in the Curie temperature. Presence of Ni in the samples reduces the effects of radiation damage. (orig.)

  15. Intense neutron irradiation facility for fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Kenji; Oyama, Yukio; Kato, Yoshio; Sugimoto, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Technical R and D of d-Li stripping type neutron irradiation facilities for development of fusion reactor materials was carried out in Fusion Materials Irradiation Test Facility (FMIT) project and Energy Selective Neutron Irradiation Test Facility (ESNIT) program. Conceptual design activity (CDA) of International Fusion Materials Irradiation Facility (IFMIF), of which concept is an advanced version of FMIT and ESNIT concepts, are being performed. Progress of users` requirements and characteristics of irradiation fields in such neutron irradiation facilities, and outline of baseline conceptual design of IFMIF were described. (author)

  16. The mechanism of solute-enriched clusters formation in neutron-irradiated pressure vessel steels: The case of Fe-Cu model alloys

    Energy Technology Data Exchange (ETDEWEB)

    Subbotin, A.V., E-mail: Alexey.V.Subbotin@gmail.com [Scientific and Production Complex Atomtechnoprom, Moscow 119180 (Russian Federation); Panyukov, S.V., E-mail: panyukov@lpi.ru [PN Lebedev Physics Institute, Russian Academy of Sciences, Moscow 117924 (Russian Federation)

    2016-08-15

    Mechanism of solute-enriched clusters formation in neutron-irradiated pressure vessel steels is proposed and developed in case of Fe-Cu model alloys. The suggested solute-drag mechanism is analogous to the well-known zone-refining process. We show that the obtained results are in good agreement with available experimental data on the parameters of clusters enriched with the alloying elements. Our model explains why the formation of solute-enriched clusters does not happen in austenitic stainless steels with fcc lattice structure. It also allows to quantify the method of evaluation of neutron irradiation dose for the process of RPV steels hardening.

  17. Induced defects in neutron irradiated GaN single crystals

    International Nuclear Information System (INIS)

    Park, I. W.; Koh, E. K.; Kim, Y. M.; Choh, S. H.; Park, S. S.; Kim, B. G.; Sohn, J. M.

    2005-01-01

    The local structure of defects in undoped, Si-doped, and neutron irradiated free standing GaN bulk crystals, grown by hydride vapor phase epitaxy, has been investigated by employing Raman scattering and cathodoluminescence. The GaN samples were irradiated to a dose of 2 x 10 17 neutrons in an atomic reactor at Korea Atomic Energy Research Institute. There was no appreciable change in the Raman spectra for undoped GaN samples before and after neutron irradiation. However, a forbidden transition, A 1 (TO) mode, appeared for a neutron irradiated Si-doped GaN crystal. Cathodoluminescence spectrum for the neutron irradiated Si-doped GaN crystal became much more broadened than that for the unirradiated one. The experimental results reveal the generation of defects with locally deformed structure in the wurtzite Si-doped GaN single crystal

  18. The intrinsic gettering in neutron irradiation Czochralski-silicon

    CERN Document Server

    Li Yang Xian; Niu Ping Juan; Liu Cai Chi; Xu Yue Sheng; Yang Deren; Que Duan Lin

    2002-01-01

    The intrinsic gettering in neutron irradiated Czochralski-silicon is studied. The result shows that a denuded zone at the surface of the neutron irradiated Czochralski-silicon wafer may be formed through one-step short-time annealing. The width of the denuded zone is dependent on the annealing temperature and the dose of neutron irradiation, while it is irrelated to the annealing time in case the denuded zone is formed. The authors conclude that the interaction between the defects induced by neutron irradiation and the oxygen in the silicon accelerates the oxygen precipitation in the bulk, and becomes the dominating factor of the quick formation of intrinsic gettering. It makes the effect of thermal history as the secondary factor

  19. F-type centers in neutron-irradiated AIN

    International Nuclear Information System (INIS)

    Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru; Okada, Moritami; Nakagawa, Masuo.

    1990-01-01

    The production of point defects by neutron irradiation and thermal decay in sintered AIN polycrystal are investigated. The absorption band at 370 nm is observed after reactor neutron irradiation to a dose of 10 16 n/cm 2 (E > 0.1 MeV). The defect corresponding to the band is tentatively assigned as an F-type center from the optical absorption and electron spin resonance. (author)

  20. Simulation analysis of radiation fields inside phantoms for neutron irradiation

    International Nuclear Information System (INIS)

    Satoh, Daiki; Takahashi, Fumiaki; Endo, Akira; Ohmachi, Y.; Miyahara, N.

    2007-01-01

    Radiation fields inside phantoms have been calculated for neutron irradiation. Particle and heavy-ion transport code system PHITS was employed for the calculation. Energy and size dependences of neutron dose were analyzed using tissue equivalent spheres of different size. A voxel phantom of mouse was developed based on CT images of an 8-week-old male C3H/HeNs mouse. Deposition energy inside the mouse was calculated for 2- and 10-MeV neutron irradiation. (author)

  1. Phase transformations in neutron-irradiated Zircaloys

    International Nuclear Information System (INIS)

    Chung, H.M.

    1986-04-01

    Microstructural evolution in Zircaloy-2 and -4 spent-fuel cladding specimens after ∼3 years of irradiation in commercial power reactors has been investigated by TEM and HVEM. Two kinds of precipitates induced by the fast-neutron irradiation in the reactors have been identified, i.e., Zr 3 O and cubic-ZrO 2 particles approximately 2 to 10 nm in size. By means of a weak-beam dark-field ''2-1/2D-microscopy'' technique, the bulk nature of the precipitates and the surficial nature of artifact oxide and hydride phases could be discerned. The Zr(Fe/sub x/,Cr/sub 1-x/) 2 and Zr 2 (Fe/sub x/,Ni/sub 1-x/) intermetallic precipitates normally present in the as-fabricated material virtually dissolved in the spent-fuel cladding specimens after a fast-neutron fluence of ∼4 x 10 21 ncm -2 in the power reactors. The observed radiation-induced phase transformations are compared with predictions based on the currently available understanding of the alloy characteristics. 29 refs

  2. A neutron irradiator to perform nuclear activation

    International Nuclear Information System (INIS)

    Zamboni, C. B.; Zahn, G.S.; Figueredo, A. M. G.; Madi, T. F.; Yoriyaz, H.; Lima, R. B.; Shtejer, K.; Dalaqua Jr, L.

    2001-01-01

    The development of appropriate nuclear instrumentation to perform neutron activation analyze (NAA), using thermal and fast neutrons, can be useful to investigate materials outside the reactor premises. Considering this fact, a small size neutron irradiator prototype was developed at IPEN facilities (Instituto de Pesquisas Energeticas e Nucleares - Brazil). Basically, this prototype consists of a cylinder of 1200 mm long and 985 mm diameter (filled with paraffin) with two Am-Be sources (600GBq each) arranged in the longitudinal direction of its geometric center. The material to be irradiated is positioned at a radial direction of the cylinder between the two Am-Be sources. The main advantage of this irradiator is a very stable neutron flux eliminating the use of standard material (measure of the induced activity in the sample by comparative method). This way the process became agile, practical and economic, but quantities at mg levels of samples are necessary to achieve good sensitivity, when the material has a low microscopy neutron cross section. As fast and thermal neutron can be used, the flux distribution, for both, were calculated and the prototype performance is discussed

  3. Tritium release from neutron irradiated beryllium pebbles

    Energy Technology Data Exchange (ETDEWEB)

    Scaffidi-Argentina, F.; Werle, H. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Neutronenphysik und Reactortechnik

    1998-01-01

    One of the most important open issues related to beryllium for fusion applications refers to the kinetics of the tritium release as a function of neutron fluence and temperature. The EXOTIC-7 as well as the `Beryllium` experiments carried out in the HFR reactor in Petten are considered as the most detailed and significant tests for investigating the beryllium response under neutron irradiation. This paper reviews the present status of beryllium post-irradiation examinations performed at the Forschungszentrum Karlsruhe with samples from the above mentioned irradiation experiments, trying to elucidate the tritium release controlling processes. In agreement with previous studies it has been found that release starts at about 500-550degC and achieves a maximum at about 700-750degC. The observed release at about 500-550degC is probably due to tritium escaping from chemical traps, while the maximum release at about 700-750degC is due to tritium escaping from physical traps. The consequences of a direct contact between beryllium and ceramics during irradiation, causing tritium implanting in a surface layer of beryllium up to a depth of about 40 mm and leading to an additional inventory which is usually several times larger than the neutron-produced one, are also presented and the effects on the tritium release are discussed. (author)

  4. Neutron irradiation of rat embryos in utero

    International Nuclear Information System (INIS)

    Vogel, H.H. Jr.

    1978-01-01

    In the rat radiation is most effective in producing congenital anomalies during the organ-forming period (days 9 to 13), which is approximately equivalent to the 14th to 50th days of human pregnancy. We have exposed female Sprague--Dawley rats on the 18th day of pregnancy to single whole-body doses of fission neutrons (20 to 150 rads). After 20 rads there was a small decrease in body weight which lasted from birth to weaning. During this period 9% of the irradiated rats died compared with 4% of the controls. After 50 rads, 65/275 (23.6%) of the rats died between birth and weaning, and the body-weight loss of the survivors was increased. After 100 rads, 62/133 (47%) died at birth or day 1 and 103/133 (77.4%) died before weaning. A large and significant decrease in body weight persisted in the survivors. After 150 rads of fission neutrons, all 95 rats died within 48 hr of birth. From cross-fostering experiments, we believe this is a direct effect of radiation on the embryos and not an indirect action through the mother or her milk. The LD 50 for the period from birth to weaning is approximately 75 rads of fission neutrons. Studies of organ weight were conducted daily for the first week after birth in an attempt to find the cause of radiation mortality. Body weight of the irradiated animals averaged only about one-half that of the controls. The liver, kidney, brain, and testes of the neutron-irradiated rats weighed significantly less than those of the controls. The weights of the spleen, lungs, duodenum, and stomach were decreased but not significantly. The bone marrow appeared depleted in the irradiated long bones, but the spleen maintained active hematopoiesis 1 to 2 months after neutron exposure

  5. New facility for post irradiation examination of neutron irradiated beryllium

    International Nuclear Information System (INIS)

    Ishitsuka, Etsuo; Kawamura, Hiroshi

    1995-01-01

    Beryllium is expected as a neutron multiplier and plasma facing materials in the fusion reactor, and the neutron irradiation data on properties of beryllium up to 800 degrees C need for the engineering design. The acquisition of data on the tritium behavior, swelling, thermal and mechanical properties are first priority in ITER design. Facility for the post irradiation examination of neutron irradiated beryllium was constructed in the hot laboratory of Japan Materials Testing Reactor to get the engineering design data mentioned above. This facility consist of the four glove boxes, dry air supplier, tritium monitoring and removal system, storage box of neutron irradiated samples. Beryllium handling are restricted by the amount of tritium;7.4 GBq/day and 60 Co;7.4 MBq/day

  6. Neutron irradiation effects in pressure vessel steels and weldments

    Energy Technology Data Exchange (ETDEWEB)

    Ianko, L [International Atomic Energy Agency, Vienna (Austria). Div. of Nuclear Power; Davies, L M

    1994-12-31

    This paper deals with the effects of neutron irradiation on the steel and welds used for the pressure vessels which house the reactor cores in light water reactors: irradiation effects on mechanical properties and the shift in ductile-brittle transition temperature, importance of the knowledge of the neutron fluence and of the monitoring and surveillance programmes; empirical and mechanistic modelling of irradiation effects and the necessity of data extension to new operational limits; consequences on the manufacturing and structural design of materials and structures; mitigation of irradiation effects by annealing; international activities and programmes in the field of neutron irradiation effects on PV steels and welds. 37 refs., 22 figs.

  7. Neutron irradiation effects of iron alloys and ceramics

    International Nuclear Information System (INIS)

    Kuramoto, Eiichi; Takenaka, Minoru; Hasegawa, Masayuki.

    1991-01-01

    Positron annihilation angular correlation measurements have been performed for the neutron irradiated various metals and ceramics in order to obtain the information of the microvoids and positronium formation in them. Positronium (Ps) formation was observed in Nb containing a small amount of oxygen and Fe-15%Cr-16%Ni-0.006%B 10 . In practical steels such as JPCA and JFMS no Ps formation was observed. High temperature deformation might induce microvoids into metals, but the positron annihilation angular correlation measurements could not confirm this. In non-metallic materials neutron irradiated no Ps formation has so far been observed. (author)

  8. Behavior of fluorine 18 in neutron irradiated zeolites

    International Nuclear Information System (INIS)

    Estevez Lopez, D.R.

    1992-01-01

    The transformation of Li-exchanged H-Y zeolite has been investigated at 300, 550, 850 and 1050 Centigrade degree, formation of quartz structure in addition to an amorphous phase, was nited. The Li-aluminosilicate obtained was neutron irradiated and the chemical behavior of 18 F produced by the reaction sequence 6 Li (n, α) 3 H, 16 O ( 3 H, n) 18 F, was studied. The neutron irradiated material was purged with argon-hydron gas streams. It was found that the amount of released 18 F depends on the temperature used (Author)

  9. Microstructural evolution in neutron irradiated reactor pressure vessel steels

    International Nuclear Information System (INIS)

    English, C.A.; Phythian, W.J.

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. The microstructural evolution in neutron irradiated reactor pressure vessel steels is described. The damage mechanisms are elaborated and techniques for examining the microstructure are suggested. The importance of the initial damage event is analysed, and the microstructural evolution in RPV steels is examined

  10. Response of neutron-irradiated RPV steels to thermal annealing

    International Nuclear Information System (INIS)

    Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K.

    1997-01-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the fracture toughness properties that have been degraded by neutron irradiation. This paper summarizes experimental results of work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response of several irradiated RPV steels

  11. Thermogravimetric analysis of reactor-neutrons-irradiated LEXAN polycarbonate film

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2000-01-01

    The effects of reactor-neutrons irradiation on the thermogravimetric (TG) analysis of LEXAN polycarbonate film in air were studied. Irradiation enhances the degradation rate and the effect increases further with increasing neutron fluence. The kinetics of the different steps of degradation were also evaluated from the TG curves. The activation energy values calculated for all the degradation stages decrease on irradiation. (author)

  12. Specific Heat Capacity of Alloy 690 for Simulating Neutron Irradiation

    International Nuclear Information System (INIS)

    Park, Dae Gyu; Kim, Hee Moon; Song, Woong Sub; Baik, Seung Je; Joo, Young Sun; Ahn, Sang Bok; Park, Jin Seok; Lee, Won Jae; Ryu, Woo Seok

    2011-01-01

    The KAERI(Korea Atomic Energy Research Institute) is developing new type of nuclear reactor, so called 'SMART'(System Integrated Modular Advanced Reactor) which has many features of small power and system integrated modular type. Alloy 690 was selected as the candidate material for the heat exchanger tube of the steam generator of SMART. The SMART R and D is now facing the stage of engineering verification and approval of standard design to apply to DEMO reactors. Therefore, the material performance under the relevant environment is required to be evaluated. The important material performance issues are mechanical properties i.e. (fracture toughness, tensile and hardness) and thermal properties i.e. (thermal diffusivity, specific heat capacity and thermal conductivity) for which the engineering database is necessary to design a steam generator. However, the neutron post irradiation characteristics of the alloy 690 are barely known. As a result, PIE(Post Irradiation Examination) of thermal properties are planed and performed successfully. But specific heat capacity measurement is not performed because of not having proper test system for irradiated materials. Therefore in order to verify the effect of neutron irradiation for alloy 690, simulation method is adopted. In general, high energy neutron bombardment in material bring about lattice defects i.e. void, pore and dislocation. Dominant factor to impact to heat capacity is mainly dislocation in material. Therefore, simulation of neutron irradiation is devised by material rolling method in order to make artificial dislocation in alloy 690 as same effect of neutron irradiation. After preparing test specimens, heat capacity measurements are performed and results are compared with rolled materials and un-rolled materials to verify the effect of neutron irradiation simulation. Main interest of simulation is that heat capacity value is changed by neutron irradiation

  13. Irradiation response in titanium modified austenitic stainless steels prepared by rapid solidification processing. Pt. 3

    International Nuclear Information System (INIS)

    Imeson, D.; Tong, C.H.; Parker, C.A.; Vander Sande, J.B.; Grant, N.J.; Harling, O.K.; Massachusetts Inst. of Tech., Cambridge

    1984-01-01

    Titanium carbide precipitation on dislocations during irradiation and recoil-induced particle dissolution are considered. The outline analysis given indicates that complete swelling suppression may occur in favorable conditions due to a counterbalancing of the effective dislocation interstitial bias. The behavior is, however, not stable against a return to normal swelling levels for type 316 steels. A model is presented which may serve as a basis for the interpretation of some aspects of the irradiation response in this system. (orig.)

  14. Temperature effects on the mechanical properties of candidate SNS target container materials after proton and neutron irradiation

    International Nuclear Information System (INIS)

    Byun, T.S.; Farrell, K.; Lee, E.H.; Mansur, L.K.; Maloy, S.A.; James, M.R.; Johnson, W.R.

    2002-01-01

    This report presents the tensile properties of EC316LN austenitic stainless steel and 9Cr-2WVTa ferritic/martensitic steel after 800 MeV proton and spallation neutron irradiation to doses in the range 0.54-2.53 dpa at 30-100 deg. C. Tensile testing was performed at room temperature (20 deg. C) and 164 deg. C. The EC316LN stainless steel maintained notable strain-hardening capability after irradiation, while the 9Cr-2WVTa ferritic/martensitic steel posted negative hardening in the engineering stress-strain curves. In the EC316LN stainless steel, increasing the test temperature from 20 to 164 deg. C decreased the strength by 13-18% and the ductility by 8-36%. The effect of test temperature for the 9Cr-2WVTa ferritic/martensitic steel was less significant than for the EC316LN stainless steel. In addition, strain-hardening behaviors were analyzed for EC316LN and 316L stainless steels. The strain-hardening rate of the 316 stainless steels was largely dependent on test temperature. A calculation using reduction of area measurements and stress-strain data predicted positive strain hardening during plastic instability

  15. In vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta Etel Treiger; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Lab. de Biologia Molecular]. E-mail: samanta@usp.br; Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Centro de Radiofarmacia]. E-mail: jaosso@ipen.br; Andrade Junior, Heitor Franco de [Instituto de Medicina Tropical de Sao Paulo (IMT-SP), SP (Brazil). Lab. de Protozoologia]. E-mail:hfandrad@usp.br

    2005-10-15

    Pentavalent antimony, as meglumine antimoniate (Glucantime) or sodium stibogluconate (Pentostam), is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer studies have a potential in pharmaceutical development. The aim of this study was to obtain a radiotracer for antimony, with suitable physical and biological properties. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes {sup 122} Sb and {sup 124} Sb, with high radionuclidic purity and good specific activity. This compound showed the same antileishmanial activity as the native compound. The use of the radiotracers, easily created by neutron irradiation, could be an interesting tool to solve important questions in antimonial pharmacology. (author)

  16. Study on neutron irradiation behavior of beryllium as neutron multiplier

    Energy Technology Data Exchange (ETDEWEB)

    Ishitsuka, Etsuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    1998-03-01

    More than 300 tons beryllium is expected to be used as a neutron multiplier in ITER, and study on the neutron irradiation behavior of beryllium as the neutron multiplier with Japan Materials Testing Reactor (JMTR) were performed to get the engineering data for fusion blanket design. This study started as the study on the tritium behavior in beryllium neutron reflector in order to make clear the generation mechanism on tritium of JMTR primary coolant since 1985. These experiences were handed over to beryllium studies for fusion study, and overall studies such as production technology of beryllium pebbles, irradiation behavior evaluation and reprocessing technology have been started since 1990. In this presentation, study on the neutron irradiation behavior of beryllium as the neutron multiplier with JMTR was reviewed from the point of tritium release, thermal properties, mechanical properties and reprocessing technology. (author)

  17. Mechanical behavior of AISI 304SS determined by miniature test methods after neutron irradiation to 28 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Rabenberg, Ellen M.; Jaques, Brian J. [Department of Materials Science and Engineering, Boise State University, 1910 University Dr., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Sencer, Bulent H. [Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Garner, Frank A. [Radiation Effects Consulting, 2003 Howell Ave., Richland, WA 99354 (United States); Freyer, Paula D. [Westinghouse Electric Company LLC, Pittsburgh, PA 15235 (United States); Okita, Taira [Research Into Artifacts Dept., Center for Engineering, University of Tokyo, Tokyo (Japan); Butt, Darryl P., E-mail: DarrylButt@BoiseState.edu [Department of Materials Science and Engineering, Boise State University, 1910 University Dr., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States)

    2014-05-01

    The mechanical properties of AISI 304 stainless steel irradiated for over a decade in the Experimental Breeder Reactor (EBR-II) were measured using miniature mechanical testing methods. The shear punch method was used to evaluate the shear strengths of the neutron-irradiated steel and a correlation factor was empirically determined to predict its tensile strength. The strength of the stainless steel slightly decreased with increasing irradiation temperature, and significantly increased with increasing dose until it saturated above approximately 5 dpa. An effective tensile strain hardening exponent was also obtained from the data which shows a relative decrease in ductility of steel with increased irradiation damage. Ferromagnetic measurements were used to observe and deduce the effects of the stress-induced austenite to martensite transformation as a result of shear punch testing.

  18. The proposed cold neutron irradiation facility at the Breazeale reactor

    International Nuclear Information System (INIS)

    Dimeo, R. M.; Sokol, P. E.; Carpenter, J. M.

    1997-01-01

    We discuss the design considerations of a Cold Neutron Irradiation Facility (CNIF) originally to have been installed at the Penn State Breazeale Reactor (PSBR). The goal of this project was to study the effects of radiation-induced damage to cryogenic moderators and, in particular, solid methane. This work evolved through the design stage undergoing a full safety analysis and received tentative approval from the PSBR Safeguards Committee but was discontinued due to budgetary constraints. (auth)

  19. Study of boron carbide evolution under neutron irradiation

    International Nuclear Information System (INIS)

    Simeone, D.

    1999-01-01

    Owing to its high neutron efficiency, boron carbide (B 4 C) is used as a neutron absorber in control rods of nuclear plants. Its behaviour under irradiation has been extensively studied for many years. It now seems clear that brittleness of the material induced by the 10 B(n,α) 7 Li capture reaction is due to penny shaped helium bubbles associated to a high strain field around them. However, no model explains the behaviour of the material under neutron irradiation. In order to build such a model, this work uses different techniques: nuclear microprobe X-ray diffraction profile analysis and Raman and Nuclear Magnetic Resonance Spectroscopy to present an evolution model of B 4 C under neutron irradiation. The use of nuclear reactions produced by a nuclear microprobe such as the 7 Li(p,p'γ) 7 Li reaction, allows to measure lithium profile in B 4 C pellets irradiated either in Pressurised Water Reactors or in Fast Breeder Reactors. Examining such profiles enables us to describe the migration of lithium atoms out of B 4 C materials under neutron irradiation. The analysis of X-ray diffraction profiles of irradiated B 4 C samples allows us to quantify the concentrations of helium bubbles as well as the strain fields around such bubbles.Furthermore Raman spectroscopy studies of different B 4 C samples lead us to propose that under neutron irradiation. the CBC linear chain disappears. Such a vanishing of this CBC chain. validated by NMR analysis, may explain the penny shaped of helium bubbles inside irradiated B 4 C. (author)

  20. Separation of Protactinium from Neutron Irradiated Thorium Oxide

    International Nuclear Information System (INIS)

    Dominguez, G.; Gutierrez, L.; Ropero, M.

    1983-01-01

    The chemical separation of thorium and protactinium can be carried out by leaching most of the last one, about 95%, with aqueous HF from neutron irradiated thorium oxide. This leaching reaction la highly favored by the transformation reaction of the ThO 2 material into ThF 4 . For both reactions, leaching and transformation, the reagents concentration, agitation speed and temperature influences were studied and the activation energies were found. (Author) 18 refs

  1. Neutron irradiation effects on high Nicalon silicon carbide fibers

    International Nuclear Information System (INIS)

    Osborne, M.C.; Steiner, D.; Snead, L.L.

    1996-01-01

    The effects of neutron irradiation on the mechanical properties and microstructure of SiC and SiC-based fibers is a current focal point for the development of radiation damage resistant SiC/SiC composites. This report discusses the radiation effects on the Nippon Carbon Hi-Nicalon trademark fiber system and also discusses an erratum on earlier results published by the authors on this material. The radiation matrix currently under study is also summarized

  2. Studies of neutron irradiation effects at IPNS-REF

    International Nuclear Information System (INIS)

    Kirk, M.A.

    1983-09-01

    Neutron irradiation effects studies at the Radiation Effects Facility (REF) at the Intense Pulsed Neutron Source (IPNS) located at Argonne National Laboratory (ANL) are reviewed. A brief history of the development of this user facility is followed by an overview of the scientific program. Experiments unique to a spallation neutron source are covered in more detail. Future direction of research at this facility is suggested

  3. National Low-Temperature Neutron-Irradiation Facility

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Klabunde, C.E.; Young, F.W. Jr.

    1983-08-01

    The Materials Sciences Division of the United States Department of Energy will establish a National Low Temperature Neutron Irradiation Facility (NLTNIF) which will utilize the Bulk Shielding Reactor (BSR) located at Oak Ridge National Laboratory. The facility will provide high radiation intensities and special environmental and testing conditions for qualified experiments at no cost to users. This report describes the planned experimental capabilities of the new facility

  4. Neutron irradiation effects on high Nicalon silicon carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, M.C.; Steiner, D.; Snead, L.L. [Oak Ridge National Laboratory, TN (United States)

    1996-10-01

    The effects of neutron irradiation on the mechanical properties and microstructure of SiC and SiC-based fibers is a current focal point for the development of radiation damage resistant SiC/SiC composites. This report discusses the radiation effects on the Nippon Carbon Hi-Nicalon{trademark} fiber system and also discusses an erratum on earlier results published by the authors on this material. The radiation matrix currently under study is also summarized.

  5. Needs of in-situ materials testing under neutron irradiation

    International Nuclear Information System (INIS)

    Noda, K.; Hishinuma, A.; Kiuchi, K.

    1989-01-01

    Under neutron irradiation, the component atoms of materials are displaced as primary knock-on atoms, and the energy of the primary knock-on atoms is consumed by electron excitation and nuclear collision. Elementary irradiation defects accumulate to form damage structure including voids and bubbles. In situ test under neutron irradiation is necessary for investigating into the effect of irradiation on creep behavior, the electric properties of ceramics, transport phenomena and so on. The in situ test is also important to investigate into the phenomena related to the chemical reaction with environment during irradiation. Accelerator type high energy neutron sources are preferable to fission reactors. In this paper, the needs and the research items of in situ test under neutron irradiation using a D-Li stripping type high energy neutron source on metallic and ceramic materials are described. Creep behavior is one of the most important mechanical properties, and depends strongly on irradiation environment, also it is closely related to microstructure. Irradiation affects the electric conductibity of ceramics and also their creep behavior. In this way, in situ test is necessary. (K.I.)

  6. Detection and measurement of neutron-irradiated gemstones

    International Nuclear Information System (INIS)

    Bunnak, S.; Jerachanchai, S.; Chinudomsub, K.; Saiyut, K.

    1990-01-01

    Color enhance gemstone, neutron-irradiated topaz, was analyzed by gamma spectrometry for examining characteristic and activity. Topaz was irradiated in the wet-tube facility of the Research Reactor TRR/1 which neutron fluence is 2.52x10 17 neutron per square centimeter. After 100 days of decay, topaz was sampling to the qualitative and quantitative analysis using multichannel analyzer of Nuclear Data Model ND65 and hyper pure germanium detector. Calculation and evaluation were done by microcomputer IBM/PC 640 KB RAM. The qualitative analysis showed that the neutron-irradiated topaz has 2 major isotopes, i.e., Ta-182 and Sc-46. Quantitative activity was compared with reference standard source Eu-152 (NBS) and the results were shown in the table 1. The Health Physics Division, OAEP, inspected on 6240.9 gm of the neutron-irradiated topaz using standard release limit 2 nCi/gm (74 Bq/gm). It was found that only 423.9 gm out of the total amount were over the standard release limit

  7. Structural properties and neutron irradiation effects of ceramics

    International Nuclear Information System (INIS)

    Yano, Toyohiko

    1994-01-01

    In high temperature gas-cooled reactors and nuclear fusion reactors being developed at present, various ceramics are to be used in the environment of neutron irradiation for undertaking important functions. The change of the characteristics of those materials by neutron irradiation must be exactly forecast, but it has been known that the response of the materials is different respectively. The production method of ceramics and the resulted structures of ceramics which control their characteristics are explained. The features of covalent bond and ionic bond, the synthesis of powder and the phase change by heating, sintering and sintering agent, and grain boundary phase are described. The smelling of ceramics by neutron irradiation is caused by the formation of the clusters of Frenkel defects and minute spot defects. Its restoration by annealing is explained. The defects remaining in materials after irradiation are the physical defects by flipping atoms cut due to the collision with high energy particles and the chemical defects by nuclear transformation. Some physical defects can be restored, but chemical defects are never restored. The mechanical properties of ceramics and the effect of irradiation on them, and the thermal properties of ceramics and the effect of irradiation on them are reported. (K.I.)

  8. Spectral effects in low-dose fission and fusion neutron irradiated metals and alloys

    International Nuclear Information System (INIS)

    Heinisch, H.L.; Atkin, S.D.; Martinez, C.

    1986-04-01

    Flat miniature tensile specimens were irradiated to neutron fluences up to 9 x 10 22 n/m 2 in the RTNS-II and in the Omega West Reactor. Specimen temperatures were the same in both environments, with runs being made at both 90 0 C and 290 0 C. The results of tensile tests on AISI 316 stainless steel, A302B pressure vessel steel and pure copper are reported here. The radiation-induced changes in yield strength as a function of neutron dose in each spectrum are compared. The data for 316 stainless steel correlate well on the basis of displacements per atom (dpa), while those for copper and A302B do not. In copper the ratio of fission dpa to 14 MeV neutron dpa for a given yield stress change is about three to one. In A302B pressure vessel steel this ratio is more than three at lower fluences, but the yield stress data for fission and 14 MeV neutron-irradiated A302B steel appears to coalesce or intersect at the higher fluences

  9. Temperature Effects on the Mechanical Properties of Candidate SNS Target Container Materials after Proton and Neutron Irradiation; TOPICAL

    International Nuclear Information System (INIS)

    Byun, T.S.

    2001-01-01

    This report presents the tensile properties of EC316LN austenitic stainless steel and 9Cr-2WVTa ferritic/martensitic steel after 800 MeV proton and spallation neutron irradiation to doses in the range 0.54 to 2.53 dpa. Irradiation temperatures were in the range 30 to 100 C. Tensile testing was performed at room temperature (20 C) and 164 C to study the effects of test temperature on the tensile properties. Test materials displayed significant radiation-induced hardening and loss of ductility due to irradiation. The EC316LN stainless steel maintained notable strain-hardening capability after irradiation, while the 9Cr-2WVTa ferritic/martensitic steel posted negative strain hardening. In the EC316LN stainless steel, increasing the test temperature from 20 C to 164 C decreased the strength by 13 to 18% and the ductility by 8 to 36%. The tensile data for the EC316LN stainless steel irradiated in spallation conditions were in line with the values in a database for 316 stainless steels for doses up to 1 dpa irradiated in fission reactors at temperatures below 200 C. However, extra strengthening induced by helium and hydrogen contents is evident in some specimens irradiated to above about 1 dpa. The effect of test temperature for the 9Cr-2WVTa ferritic/martensitic steel was less significant than for the EC316LN stainless steel. In addition, strain-hardening behaviors were analyzed for EC316LN and 316L stainless steels. The strain-hardening rate of the 316 stainless steels was largely dependent on test temperature. It was estimated that the 316 stainless steels would retain more than 1% true stains to necking at 164 C after irradiation to 5 dpa. A calculation using reduction of area (RA) measurements and stress-strain data predicted positive strain hardening during plastic instability

  10. Swelling in neutron irradiated nickel-base alloys

    International Nuclear Information System (INIS)

    Brager, H.R.; Bell, W.L.

    1972-01-01

    Inconel 625, Incoloy 800 and Hastelloy X were neutron irradiated at 500 to 700 0 C. It was found that of the three alloys investigated, Inconel 625 offers the greatest swelling resistance. The superior swelling resistance of Inconel 625 relative to that of Hastelloy-X is probably related to differences in the concentrations of the minor rather than major alloy constituents, and can involve (a) enhanced recombination of defects in the Inconel 625 and (b) preferential attraction of vacancies to incoherent precipitates. (U.S.)

  11. Defects investigation in neutron irradiated reactor steels by positron annihilation

    International Nuclear Information System (INIS)

    Slugen, V.

    2003-01-01

    Positron annihilation spectroscopy (PAS) based on positron lifetime measurements using the Pulsed Low Energy Positron System (PLEPS) was applied to the investigation of defects of irradiated and thermally treated reactor pressure vessel (RPV) steels. PLEPS results showed that the changes in microstructure of the RPV-steel properties caused by neutron irradiation and post-irradiation heat treatment can be well detected. From the lifetime measurements in the near-surface region (20-550 nm) the defect density in Russian types of RPV-steels was calculated using the diffusion trapping model. The post-irradiation heat treatment studies performed on non-irradiated specimens are also presented. (author)

  12. Microstructure and mechanical properties of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Ishitsuka, E.; Kawamura, H. [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Terai, T.; Tanaka, S.

    1998-01-01

    Microstructure and mechanical properties of the neutron irradiated beryllium with total fast neutron fluences of 1.3 - 4.3 x 10{sup 21} n/cm{sup 2} (E>1 MeV) at 327 - 616degC were studied. Swelling increased by high irradiation temperature, high fluence, and by the small grain size and high impurity. Obvious decreasing of the fracture stress was observed in the bending test and in small grain specimens which had many helium bubbles on the grain boundary. Decreasing of the fracture stress for small grain specimens was presumably caused by crack propagation on the grain boundaries which weekend by helium bubbles. (author)

  13. Isotropic nuclear graphites; the effect of neutron irradiation

    International Nuclear Information System (INIS)

    Lore, J.; Buscaillon, A.; Mottet, P.; Micaud, G.

    1977-01-01

    Several isotropic graphites have been manufactured using different forming processes and fillers such as needle coke, regular coke, or pitch coke. Their properties are described in this paper. Specimens of these products have been irradiated in the fast reactor Rapsodie between 400 to 1400 0 C, at fluences up to 1,7.10 21 n.cm -2 PHI.FG. The results show an isotropic behavior under neutron irradiation, but the induced dimensional changes are higher than those of isotropic coke graphites although they are lower than those of conventional extruded graphites made with the same coke

  14. High temperature superconductors for fusion magnets -influence of neutron irradiation

    International Nuclear Information System (INIS)

    Chudy, M.; Eisterer, M.; Weber, H. W.

    2010-01-01

    In this work authors present the results of study of influence of neutron irradiation of high temperature superconductors for fusion magnets. High temperature superconductors (type of YBCO (Yttrium-Barium-Copper-Oxygen)) are strong candidates to be applied in the next step of fusion devices. Defects induced by fast neutrons are effective pinning centres, which can significantly improve critical current densities and reduce J c anisotropy. Due to induced lattice disorder, T c is reduced. Requirements for ITER (DEMO) are partially achieved at 64 K.

  15. Ultrasonic attenuation measurements and 'glassy' behaviour of neutron irradiated quartz

    International Nuclear Information System (INIS)

    Laermans, C.; Esteves, V.; Vanelstraete, A.

    1986-01-01

    The ultrasonic attenuation of longitudinal acoustic waves in slightly disordered crystalline quartz has been measured over a temperature range from 1.3 to 300 K, using the pulse-echo technique. Neutron irradiation is demonstrated to increase the ultrasonic attenuation at low temperatures indicating the presence of two-level tunneling systems similar to those of glasses. The present low-temperature acoustic results agree with a frequency independence and a T 3 behaviour for the relaxation process predicted by the two-level tunneling TLS-model where the regime ωT 1 >> 1 holds. (author)

  16. Positron lifetime study of neutron-irradiated molybdenum

    International Nuclear Information System (INIS)

    Hinode, Kenji; Tanigawa, Shoichiro; Kumakura, Hiroaki; Doyama, Masao; Shiraishi, Kensuke.

    1978-01-01

    Annealing behavior of fast-neutron-irradiated molybdenum was studied by means of positron lifetime technique. It was found that Stage III annealing can be mainly identified as the vacancy migration process from the detailed analyses of data. The void growth after successive high temperature annealings was clearly detected through the changes of positron lifetime parameters. An attempt to analyse the size distribution of voids from positron lifetime spectra was presented, and discussions on the evaluation of void concentration from positron data are also given. (author)

  17. Gamma and neutron irradiation tests on commercial IC op amps

    International Nuclear Information System (INIS)

    Kennedy, E.J.; Morris, A.C. Jr.; Su, D.K.

    1985-01-01

    Experimental results of gamma and neutron irradiation tests on 30 types of integrated-circuit operational amplifiers from 11 manufacturers are presented. All units were low-cost, commercial-grade devices. Op amps were evaluated for changes in offset voltage, input bias current, power supply current, open-loop gain, gain-bandwidth product, slew rate, power-supply and common-mode rejection ratios. Bipolar transistor op amps with resistive collector load resistors for the input stage indicated the best radiation hardness

  18. Radiation defects produced by neutron irradiation in germanium single crystals

    International Nuclear Information System (INIS)

    Fukuoka, Noboru; Honda, Makoto; Atobe, Kozo; Yamaji, Hiromichi; Ide, Mutsutoshi; Okada, Moritami.

    1992-01-01

    The nature of defects produced in germanium single crystals by neutron irradiation at 25 K was studied by measuring the electrical resistivity. It was found that two levels located at E c -0.06 eV and E c -0.13 eV were introduced in an arsenic-doped sample. Electron traps at E c -0.10eV were observed in an indium-doped sample. The change in electrical resistivity during irradiation was also studied. (author)

  19. Swelling and fracturing of borides under neutron irradiation

    International Nuclear Information System (INIS)

    Krainy, A.G.; Ogorodnikov, V.V.; Grinik, E.U.; Chirko, L.I.; Shinakov, A.A.

    1994-01-01

    The neutron irradiation of high temperature borides, which are included in boron-containing reactor materials, results in high internal stresses, leading to considerable swelling and micro- and macro-fracturing. Experimental results over a large range of temperature and fluences, show a change of damage mechanism for borides within 400-530 C: the macro-cracking with formation of annular and radial cracks is observed below this temperature zone. The accumulation of micro-fractures and the process of gas swelling take place at irradiation temperatures above 530 C. The effect of the high internal stresses is compared to external pressure. 12 refs., 4 figs

  20. Effects of neutron irradiation on a superconducting metallic glass

    International Nuclear Information System (INIS)

    Kramer, E.A.; Johnson, W.L.; Cline, C.

    1979-06-01

    The effects of fast neutron irradiation on a superconducting metallic glass (Mo 6 Ru 4 ) 82 B 18 have been studied. Following irradiation to a total fluence of 10 19 n/cm 2 , T/sub c/ increases from 6.05 K to 6.19 K, and the width of the transition decreases sharply. The density of the material decreases by 1.5%, and the x-ray scattering intensity maxima are broadened. An improvement in the ductility of the samples is observed which together with the other observations suggests the production of defects having atomic scale dimensions and characterized by excess volume

  1. Characterization of neutron-irradiated HT-UPS steel by high-energy X-ray diffraction microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuan, E-mail: xuanzhang@anl.gov [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States); Park, Jun-Sang; Almer, Jonathan [Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439 (United States); Li, Meimei [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States)

    2016-04-01

    This paper presents the first measurement of neutron-irradiated microstructure using far-field high-energy X-ray diffraction microscopy (FF-HEDM) in a high-temperature ultrafine-precipitate-strengthened (HT-UPS) austenitic stainless steel. Grain center of mass, grain size distribution, crystallographic orientation (texture), diffraction spot broadening and lattice constant distributions of individual grains were obtained for samples in three different conditions: non-irradiated, neutron-irradiated (3dpa/500 °C), and irradiated + annealed (3dpa/500 °C + 600 °C/1 h). It was found that irradiation caused significant increase in grain-level diffraction spot broadening, modified the texture, reduced the grain-averaged lattice constant, but had nearly no effect on the average grain size and grain size distribution, as well as the grain size-dependent lattice constant variations. Post-irradiation annealing largely reversed the irradiation effects on texture and average lattice constant, but inadequately restored the microstrain.

  2. Impurities effect on the swelling of neutron irradiated beryllium

    International Nuclear Information System (INIS)

    Donne, M.D.; Scaffidi-Argentina, F.

    1995-01-01

    An important factor controlling the swelling behaviour of fast neutron irradiated beryllium is the impurity content which can strongly affect both the surface tension and the creep strength of this material. Being the volume swelling of the old beryllium (early sixties) systematically higher than that of the more modem one (end of the seventies), a sensitivity analysis with the aid of the computer code ANFIBE (ANalysis of Fusion Irradiated BEryllium) to investigate the effect of these material properties on the swelling behaviour of neutron irradiated beryllium has been performed. Two sets of experimental data have been selected: the first one named Western refers to quite recently produced Western beryllium, whilst the second one, named Russian refers to relatively old (early sixties) Russian beryllium containing a higher impurity rate than the Western one. The results obtained with the ANFIBE Code were assessed by comparison with experimental data and the used material properties were compared with the data available in the literature. Good agreement between calculated and measured values has been found

  3. Property change of advanced tungsten alloys due to neutron irradiation

    International Nuclear Information System (INIS)

    Fukuda, Makoto; Hasegawa, Akira; Tanno, Takashi; Nogami, Shuhei; Kurishita, Hiroaki

    2013-01-01

    This study investigates the effect of neutron irradiation on the functional properties of pure tungsten (W) and advanced tungsten alloys (e.g., lanthanum (La)-doped W, potassium (K)-doped W, and ultra-fine-grained (UFG) W–TiC alloys) tested in the Japan Materials Testing Reactor (JMTR) or experimental fast reactor Joyo. The irradiation temperature and damage were in the range 804–1073 K and 0.15–0.47 dpa, respectively. TEM images of all samples after 0.42 dpa irradiation at 1023 K showed voids, black dots, and dislocation loops, indicating that similar damage structures were formed in pure W, La-doped W, K-doped W, and UFG W–0.5 wt% TiC. The electrical resistivity of all specimens increased following neutron irradiation. Nearly identical electrical resistivity and irradiation hardening were observed in pure W, La-doped W, and K-doped W. The electrical resistivity of UFG W–TiC was higher than that of other specimens before and after irradiation, which may be attributed to its ultra-fine-grain structure, as well as the presence of impurities introduced during the alloying process. Compared to the other specimens, the UFG W–TiC was more resistant to irradiation hardening

  4. Neutron irradiation test of depleted CMOS pixel detector prototypes

    International Nuclear Information System (INIS)

    Mandić, I.; Cindro, V.; Gorišek, A.; Hiti, B.; Kramberger, G.; Mikuž, M.; Zavrtanik, M.; Hemperek, T.; Daas, M.; Hügging, F.; Krüger, H.; Pohl, D.-L.; Wermes, N.; Gonella, L.

    2017-01-01

    Charge collection properties of depleted CMOS pixel detector prototypes produced on p-type substrate of 2 kΩ cm initial resistivity (by LFoundry 150 nm process) were studied using Edge-TCT method before and after neutron irradiation. The test structures were produced for investigation of CMOS technology in tracking detectors for experiments at HL-LHC upgrade. Measurements were made with passive detector structures in which current pulses induced on charge collecting electrodes could be directly observed. Thickness of depleted layer was estimated and studied as function of neutron irradiation fluence. An increase of depletion thickness was observed after first two irradiation steps to 1 · 10 13 n/cm 2 and 5 · 10 13 n/cm 2 and attributed to initial acceptor removal. At higher fluences the depletion thickness at given voltage decreases with increasing fluence because of radiation induced defects contributing to the effective space charge concentration. The behaviour is consistent with that of high resistivity silicon used for standard particle detectors. The measured thickness of the depleted layer after irradiation with 1 · 10 15 n/cm 2 is more than 50 μm at 100 V bias. This is sufficient to guarantee satisfactory signal/noise performance on outer layers of pixel trackers in HL-LHC experiments.

  5. Results of neutron irradiation of liquid lithium saturated with deuterium

    International Nuclear Information System (INIS)

    Tazhibayeva, Irina; Ponkratov, Yuriy; Kulsartov, Timur; Gordienko, Yuriy; Skakov, Mazhyn; Zaurbekova, Zhanna; Lyublinski, Igor; Vertkov, Alexey; Mazzitelli, Giuseppe

    2017-01-01

    Highlights: • The results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1M research reactor are described. • At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10 9 exp(−144/RT). • The T 2 molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise. - Abstract: This paper describes the results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1 M research reactor. The neutron flux at the reactor core center at 2 MW was 5 10 −13 cm −2 s −1 . The efficiency coefficients of helium and tritium release from lithium saturated with deuterium were calculated. The tritium interaction with lithium atoms (formation and dissociation of lithium tritide) has an effect on tritium release. An increment of sample’s temperature results in tritium release acceleration due to rising of the dissociation rate of lithium tritide. At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10 9 exp(-144/RT). The T 2 molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise.

  6. Positron annihilation and Moessbauer studies of neutron irradiated reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Brauer, G.; Matz, W.; Liszkay, L.; Molnar, B.

    1990-11-01

    Positron annihilation (lifetime, Doppler broadening) and Moessbauer studies on unirradiated, neutron irradiated and neutron irradiated plus annealed reactor pressure vessel steels (Soviet type 15Kh2NMFA) are presented. The role of microstructural properties and the formation of irradiation-induced precipitates is discussed. (orig.) [de

  7. Cavity nucleation and growth during helium implantation and neutron irradiation of Fe and steel

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, Bachu Narain

    In order to investigate the role of He in cavity nucleation in neutron irradiated iron and steel, pure iron and Eurofer-97 steel have been He implanted and neutron irradiated in a systematic way at different temperatures, to different He and neutron doses and with different He implantation rates....

  8. Bootstrap calculation of ultimate strength temperature maxima for neutron irradiated ferritic/martensitic steels

    Science.gov (United States)

    Obraztsov, S. M.; Konobeev, Yu. V.; Birzhevoy, G. A.; Rachkov, V. I.

    2006-12-01

    The dependence of mechanical properties of ferritic/martensitic (F/M) steels on irradiation temperature is of interest because these steels are used as structural materials for fast, fusion reactors and accelerator driven systems. Experimental data demonstrating temperature peaks in physical and mechanical properties of neutron irradiated pure iron, nickel, vanadium, and austenitic stainless steels are available in the literature. A lack of such an information for F/M steels forces one to apply a computational mathematical-statistical modeling methods. The bootstrap procedure is one of such methods that allows us to obtain the necessary statistical characteristics using only a sample of limited size. In the present work this procedure is used for modeling the frequency distribution histograms of ultimate strength temperature peaks in pure iron and Russian F/M steels EP-450 and EP-823. Results of fitting the sums of Lorentz or Gauss functions to the calculated distributions are presented. It is concluded that there are two temperature (at 360 and 390 °C) peaks of the ultimate strength in EP-450 steel and single peak at 390 °C in EP-823.

  9. Study of neutron irradiation on F82H alloys by Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Huang, S.S., E-mail: h.shaosong@ht8.ecs.kyoto-u.ac.jp; Kitao, S.; Kobayashi, Y.; Yoshiie, T.; Xu, Q.; Sato, K.; Seto, M.

    2015-01-15

    The effects of neutron irradiation on F82H ferritic/martensitic stainless steel and its model alloys were studied by Mössbauer spectroscopy. The microstructural damage mechanisms of these alloys, during the void incubation period were interpreted using the short range order (SRO) parameters. Results show that within Fe–8Cr alloy, the atoms in the nearest neighbor (NN) of the Fe nuclei were inhomogeneous, prior to irradiation. A configuration trapping model of Cr supported the negative average SRO observed for the NN shells in our Fe–Cr alloys. We found that irradiation also accelerated the SRO in Fe–8Cr through a diffusion mechanism, where Cr atom repulsion was concentration dependent. Finally, comparative studies were conducted on F82H model alloys using the present Mössbauer measurements and our previously reported work on positron annihilation spectroscopy, which further established that irradiation of the alloys promoted the growth of a M{sub 23}C{sub 6} complex.

  10. On the recovery of neutron irradiation defects of some metals and alloys

    International Nuclear Information System (INIS)

    Mohamed, H.G.; Matta, M.K.

    2001-01-01

    This work deals with the recovery of mechanical properties of neutron irradiated material to the pre-irradiating values. Rate of migration of defects responsible for radiation hardening and those inducing radiation embrittlement is analyzed. Role of crystalline structure is also studied. Materials of FCC crystal structure used in these investigations are pure Cu, Cu-5 at. % , Al, Cu-5 at. % Si, some Ni base binary alloys and some austenitic stainless steels mainly of AISI types 304 and 316. Among materials of BCC crystalline structure Fe-6 wt % Cr alloy is used. Alloys with CPH structure used in the present investigations are Zr-l wt. % Nb and Mg - 4.8 wt % Li alloys. History of material is studied such as cold worked state and annealed condition. Character of alloying elements and their amounts were of interest in this study. The result showed that the higher the percentage radiation hardening, the slower is the migration of radiation defects. Irradiated pure metals recovered at a higher temperature than alloys. Cold work accelerated the migration of radiation defects. The amount of alloying elements had little effect on the recovery temperatures. Character of solute alloying elements (substitutional or interstitial) revealed sensitive effect on the migration of radiation defects. Rate of migration of defects causing hardening can be different from those causing embrittlement. (author)

  11. Microstructural evolution of NF709 (20Cr–25Ni–1.5MoNbTiN) under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.K. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Tan, L., E-mail: tanl@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Xu, C. [University of Florida, Gainesville, FL 32611 (United States); Yang, Y., E-mail: yongyang@ufl.edu [University of Florida, Gainesville, FL 32611 (United States); Zhang, X. [Argonne National Laboratory, Lemont, IL 60439 (United States); Li, M., E-mail: mli@anl.gov [Argonne National Laboratory, Lemont, IL 60439 (United States)

    2016-03-15

    Because of its superior creep and corrosion resistance as compared with general austenitic stainless steels, NF709 has emerged as a candidate structural material for advanced nuclear reactors. To obtain fundamental information about the radiation resistance of this material, this study examined the microstructural evolution of NF709 subjected to neutron irradiation to 3 displacements per atom at 500 °C. Transmission electron microscopy, scanning electron microscopy, and high-energy x-ray diffraction were employed to characterize radiation-induced segregation, Frank loops, voids, as well as the formation and reduction of precipitates. Radiation hardening of ∼76% was estimated by nanoindentation, approximately consistent with the calculation according to the dispersed barrier-hardening model, suggesting Frank loops as the primary hardening source.

  12. Preparation of 227Ac by neutron irradiation of 226Ra

    International Nuclear Information System (INIS)

    Kukleva, E.; Kozempel, J.; Vlk, M.; Micolova, P.; Vopalka, D.

    2015-01-01

    Radium-223 is prospective alpha-emitting therapeutic radionuclide for targeted radionuclide therapy. Although 223 Ra is formed naturally by the decay of 235 U, for practical reasons its preparation involves neutron irradiation of 226 Ra. The α-decay of the 227 Ra (T 12 = 43 min.) produced via 226 Ra(n,γ) 227 Ra reaction leads to 227 Ac, a mother nuclide of 227 Th and 223 Ra subsequently. Irradiation target radium material is generally available in multi-gram quantities from historical stock. Main aim of this study was to experimentally and theoretically evaluate and verify available literature data on production of 223 Ra. According to data obtained from γ-spectra, the approximate yield values were determined and effective cross-section for the 223 Ra production was calculated. (authors)

  13. Calculations on neutron irradiation damage in reactor materials

    International Nuclear Information System (INIS)

    Sone, Kazuho; Shiraishi, Kensuke

    1976-01-01

    Neutron irradiation damage calculations were made for Mo, Nb, V, Fe, Ni and Cr. Firstly, damage functions were calculated as a function of neutron energy with neutron cross sections of elastic and inelastic scatterings, and (n,2n) and (n,γ) reactions filed in ENDF/B-III. Secondly, displacement damage expressed in displacements per atom (DPA) was estimated for neutron environments such as fission spectrum, thermal neutron reactor (JMTR), fast breeder reactor (MONJU) and two fusion reactors (The Conceptual Design of Fusion Reactor in JAERI and ORNL-Benchmark). then, damage cross section in units of dpa. barn was defined as a factor to convert a given neutron fluence to the DPA value, and was calculated for the materials in the above neutron environments. Finally, production rates of helium and hydrogen atoms were calculated with (n,α) and (n,p) cross sections in ENDF/B-III for the materials irradiated in the above reactors. (auth.)

  14. Tensile and fracture toughness test results of neutron irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, R.; Moons, F.; Puzzolante, J.L. [Centre d`Etude de l`Energie Nucleaire, Mol (Belgium)

    1998-01-01

    Tensile and fracture toughness test results of four Beryllium grades are reported here. The flow and fracture properties are investigated by using small size tensile and round compact tension specimens. Irradiation was performed at the BR2 material testing reactor which allows various temperature and irradiation conditions. The fast neutron fluence (>1 MeV) ranges between 0.65 and 2.45 10{sup 21} n/cm{sup 2}. In the meantime, un-irradiated specimens were aged at the irradiation temperatures to separate if any the effect of temperature from irradiation damage. Test results are analyzed and discussed, in particular in terms of the effects of material grade, test temperature, thermal ageing and neutron irradiation. (author)

  15. Proceedings of neutron irradiation technical meeting on BNCT

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-01

    The 'Neutron Irradiation Technical Meeting for Boron Neutron Capture Therapy (BNCT)' was held on March 13, 2000 at Tokai Research Establishment. The Meeting is aimed to introduce the neutron beam facility for medical irradiation at JRR-4 to Japanese researchers widely, as well as providing an opportunity for young researchers, engineers, medical representatives such surgeons and doctors of pharmacology to present their research activities and to exchange valuable information. JAERI researcher presented the performance and the irradiation technology in the JRR-4 neutron beam facility, while external researchers made various and beneficial presentations containing such accelerator-based BNCT, spectrum-shifter, biological effect, pharmacological development and so on. In this meeting, a special lecture titled 'The Dawn of BNCT and Its Development.' was given by MD, Prof. Takashi Minobe, an executive director of Japan Foundation for Emergency Medicine. The 11 of the presented papers are indexed individually. (J.P.N.)

  16. Damages to gladiolu corm caused by fast neutron irradiation

    International Nuclear Information System (INIS)

    Zhang Zhiwei; Wang Dan; Zhang Dongxue; Zheng Chun

    2007-01-01

    Gladiolus corms were irradiated to 100-500kGy by fast neutrons in the CFBR-II pulsed reactor, Scanning electron microscope images of the irradiated samples revealed significant radiation damages to the gladiolus corms, and the mutagenic effects were studied by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Within the dose range, radiation damage to the corm increased with the dose, with corm epidermis of the samples irradiated in vertical incidence being more serious than those irradiated in side-incidence to the same dose. Biological characters were investigated via field experiments, and the bands of protein subunit were analyzed by SDS-PAGE. The results showed that the fast neutrons irradiation inhibited growth of M1 generation seedling significantly. Protein expression was obviously inhibited by the irradiation. The study indicates that fast neutron induction is an effective way for gladiolus breeding. And the results may lay a foundation for studies on fast neutron mutation breeding. (authors)

  17. Investigation of radiation damage effects in neutron irradiated CCD

    International Nuclear Information System (INIS)

    Brau, James E.; Igonkina, Olga; Potter, Chris T.; Sinev, Nikolai B.

    2005-01-01

    A Charge Coupled Devices (CCD)-based vertex detector is a leading option for vertex detection at the future linear collider. A major issue for this application is the radiation hardness of such devices. Tests of radiation hardness of CCDs used in the SLD vertex detector, VXD3, have been reported earlier. The first measurements of 1998 involved a spare VXD3 CCD that was irradiated with neutrons from a radioactive source (Pu-Be), and from a nuclear reactor. In 2003, we had the opportunity to disassemble the VXD3 detector and study the nature of the radiation damage it incurred during 3 years of operation at SLC. In the preparation for this study, additional experiments with the spare VXD3 CCD were performed. These included measurements of trapping times in neutron irradiated CCDs. Results, reported here, will help us better understand the mechanism of radiation damage effects and develop techniques to minimize performance degradation due to radiation damage

  18. Effect of neutron irradiation on single crystal V3Si

    International Nuclear Information System (INIS)

    Viswanathan, R.; Caton, R.; Cox, D.E.; Guha, A.; Sarachik, M.P.; Smith, F.W.; Testardi, L.R.

    1977-01-01

    We We have investigated the effect of successive neutron irradiation up to a fluence of approximately 2 x 10 19 n/cm 2 , by measurements of heat capacity, susceptibility, resistivity, acoustic velocity and neutron diffraction in a single crystal V 3 Si. We find that for low level doses (phi t greater than or equal to 3.5 x 10 18 n/cm 2 ) (a) the structural transformation is very sensitive, whereas the suerconducting transition temperature, T/sub c/, is hardly affected, and (b) except for low temperature heat capacity, most of the other measurements show very little change. For the highest fluence of 2 x 10 19 n/cm 2 used to date, the T/sub c/ dropped to 7.5 K with large changes in the linear heat capacity coefficient, magnetic susceptibility and sound velocity. These results are discussed briefly in this paper

  19. Design, Construction, and Modeling of a 252Cf Neutron Irradiator

    Directory of Open Access Journals (Sweden)

    Blake C. Anderson

    2016-01-01

    Full Text Available Neutron production methods are an integral part of research and analysis for an array of applications. This paper examines methods of neutron production, and the advantages of constructing a radioisotopic neutron irradiator assembly using 252Cf. Characteristic neutron behavior and cost-benefit comparative analysis between alternative modes of neutron production are also examined. The irradiator is described from initial conception to the finished design. MCNP modeling shows a total neutron flux of 3 × 105 n/(cm2·s in the irradiation chamber for a 25 μg source. Measurements of the gamma-ray and neutron dose rates near the external surface of the irradiator assembly are 120 μGy/h and 30 μSv/h, respectively, during irradiation. At completion of the project, total material, and labor costs remained below $50,000.

  20. Effect of neutron irradiation on p-type silicon

    International Nuclear Information System (INIS)

    Sopko, B.

    1973-01-01

    The possibilities are discussed of silicon isotope reactions with neutrons of all energies. In the reactions, 30 Si is converted to a stable phosphorus isotope forming n-type impurities in silicon. The above reactions proceed as a result of thermal neutron irradiation. An experiment is reported involving irradiation of two p-type silicon single crystals having a specific resistance of 2000 ohm.cm and 5000 to 20 000 ohm.cm, respectively, which changed as a result of irradiation into n-type silicon with a given specific resistance. The specific resistance may be pre-calculated from the concentration of impurities and the time of irradiation. The effects of irradiation on other silicon parameters and thus on the suitability of silicon for the manufacture of semiconductor elements are discussed. (J.K.)

  1. High-energy neutron irradiation of superconducting compounds

    International Nuclear Information System (INIS)

    Sweedler, A.R.; Snead, C.L.; Newkirk, L.; Valencia, F.; Geballe, T.H.; Schwall, R.H.; Matthias, B.T.; Corenswit, E.

    1975-01-01

    The effect of high-energy neutron irradiation (E greater than 1 MeV) at ambient reactor temperatures on the superconducting properties of a variety of superconducting compounds is reported. The materials studied include the A-15 compounds Nb 3 Sn, Nb 3 Al, Nb 3 Ga, Nb 3 Ge and V 3 Si, the C-15 Laves phase HfV 2 , the ternary molybdenum sulfide Mo 3 Pb 0 . 5 S 4 and the layered dichalcogenide NbSe 2 . The superconducting transition temperature has been measured for all of the above materials for neutron fluences up to 5 x 10 19 n/cm 2 . The critical current for multifilamentary Nb 3 Sn has also been determined for fields up to 16 T and fluences between 3 x 10 17 n/cm 2 and 1.1 x 10 19 n/cm 2

  2. Point defects in cubic boron nitride after neutron irradiation

    International Nuclear Information System (INIS)

    Atobe, Kozo; Honda, Makoto; Ide, Munetoshi; Yamaji, Hiromichi; Matsukawa, Tokuo; Fukuoka, Noboru; Okada, Moritami; Nakagawa, Masuo.

    1993-01-01

    The production of point defects induced by reactor neutrons and the thermal behavior of defects in sintered cubic boron nitride are investigated using the optical absorption and electron spin resonance (ESR) methods. A strong structureless absorption over the visible region was observed after fast neutron irradiation to a dose of 5.3 x 10 16 n/cm 2 (E > 0.1 MeV) at 25 K. This specimen also shows an ESR signal with g-value 2.006 ± 0.001, which can be tentatively identified as an electron trapped in a nitrogen vacancy. On examination of the thermal decay of the signal, the activation energy for recovery of the defects was determined to be about 1.79 eV. (author)

  3. Dielectric changes in neutron-irradiated rf window materials

    International Nuclear Information System (INIS)

    Frost, H.M.; Clinard, F.W. Jr.

    1987-01-01

    Ceramics used for windows in ECRH heating systems for magnetically-confined fusion reactors must retain adequate properties during and after intense neutron irradiation. Of particular concern is a decrease in transmissivity, a parameter inversely related to the product of dielectric constant K and loss tangent tanδ. Samples of polycrystalline Al 2 O 3 and BeO were irradiated to 1 x 10 26 n/m 2 at 660K in the EBR-II fission reactor, and the above properties subsequently measured at 95 GHz. It was found that ktanδ for both materials doubled, implying a doubling of thermal stresses and a consequent reduction of time-to-failure from an assumed one year to 20 min for beryllia and 2 s for alumina. In the case of BeO, a large increase in reflectance of the incident millimeter-wave power results from dielectrically uncompensated swelling. This phenomenon could significantly degrade source performance

  4. Microstructural defects in EUROFER 97 after different neutron irradiation conditions

    Directory of Open Access Journals (Sweden)

    Christian Dethloff

    2016-12-01

    Full Text Available Characterization of irradiation induced microstructural evolution is essential for assessing the applicability of structural steels like the Reduced Activation Ferritic/Martensitic steel EUROFER 97 in upcoming fusion reactors. In this work Transmission Electron Microscopy (TEM is used to determine the defect microstructure after different neutron irradiation conditions. In particular dislocation loops, voids and precipitates are analyzed concerning defect nature, density and size distribution after irradiation to 15 dpa at 300 °C in the mixed spectrum High Flux Reactor (HFR. New results are combined with previously obtained data from irradiation in the fast spectrum BOR-60 reactor (15 and 32 dpa, 330 °C, which allows for assessment of dose and dose rate effects on the aforementioned irradiation induced defects and microstructural characteristics.

  5. Proceedings of neutron irradiation technical meeting on BNCT

    International Nuclear Information System (INIS)

    2000-10-01

    The 'Neutron Irradiation Technical Meeting for Boron Neutron Capture Therapy (BNCT)' was held on March 13, 2000 at Tokai Research Establishment. The Meeting is aimed to introduce the neutron beam facility for medical irradiation at JRR-4 to Japanese researchers widely, as well as providing an opportunity for young researchers, engineers, medical representatives such surgeons and doctors of pharmacology to present their research activities and to exchange valuable information. JAERI researcher presented the performance and the irradiation technology in the JRR-4 neutron beam facility, while external researchers made various and beneficial presentations containing such accelerator-based BNCT, spectrum-shifter, biological effect, pharmacological development and so on. In this meeting, a special lecture titled 'The Dawn of BNCT and Its Development.' was given by MD, Prof. Takashi Minobe, an executive director of Japan Foundation for Emergency Medicine. The 11 of the presented papers are indexed individually. (J.P.N.)

  6. Germanium-doped gallium phosphide obtained by neutron irradiation

    Science.gov (United States)

    Goldys, E. M.; Barczynska, J.; Godlewski, M.; Sienkiewicz, A.; Heijmink Liesert, B. J.

    1993-08-01

    Results of electrical, optical, electron spin resonance and optically detected magnetic resonance studies of thermal neutron irradiated and annealed at 800 °C n-type GaP are presented. Evidence is found to support the view that the main dopant introduced via transmutation of GaP, germanium, occupies cation sites and forms neutral donors. This confirms the possibility of neutron transmutation doping of GaP. Simultaneously, it is shown that germanium is absent at cation sites. Presence of other forms of Ge-related defects is deduced from luminescence and absorption data. Some of them are tentatively identified as VGa-GeGa acceptors leading to the self-compensation process. This observation means that the neutron transmutation as a doping method in application to GaP is not as efficient as for Si.

  7. Results of neutron irradiation of liquid lithium saturated with deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Tazhibayeva, Irina, E-mail: tazhibayeva@ntsc.kz [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Ponkratov, Yuriy; Kulsartov, Timur; Gordienko, Yuriy; Skakov, Mazhyn; Zaurbekova, Zhanna [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Lyublinski, Igor [JSC «Red Star», Moscow (Russian Federation); NRNU «MEPhI», Moscow (Russian Federation); Vertkov, Alexey [JSC «Red Star», Moscow (Russian Federation); Mazzitelli, Giuseppe [ENEA, RC Frascati, Frascati (Italy)

    2017-04-15

    Highlights: • The results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1M research reactor are described. • At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10{sup 9} exp(−144/RT). • The T{sub 2} molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise. - Abstract: This paper describes the results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1 M research reactor. The neutron flux at the reactor core center at 2 MW was 5 10{sup −13} cm{sup −2} s{sup −1}. The efficiency coefficients of helium and tritium release from lithium saturated with deuterium were calculated. The tritium interaction with lithium atoms (formation and dissociation of lithium tritide) has an effect on tritium release. An increment of sample’s temperature results in tritium release acceleration due to rising of the dissociation rate of lithium tritide. At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10{sup 9} exp(-144/RT). The T{sub 2} molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise.

  8. Shielding of a neutron irradiator with {sup 241}Am-Be source

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, K.A.M. de; Crispim, V.R.; Silva, A.X., E-mail: koliveira@con.ufrj.b, E-mail: verginia@con.ufrj.b, E-mail: ademir@con.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear; Fonseca, E.S., E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    The equivalent dose rates at 1.0 cm from the outer surface of the shielding of a neutron irradiation system that uses {sup 241}Am-Be source with activity of 185 GBq (5 Ci) were determined. A theoretical-experimental approach including case studies, through computer simulations with MCNP code was employed to calculate the best shielding thickness. Following the construction of the neutron irradiator, dose measurements were conducted in order to validate data obtained from simulation. The neutron irradiator shielding was designed in such a way to allow transport of the neutron radiography system for in loco inspections ensuring workers' radiologic safety. (author)

  9. Uranium doping and neutron irradiation of Bi-2223 superconduction tapes for improved critical current density

    International Nuclear Information System (INIS)

    Moss, S.D.; Wang, W.G.; Dou, S.X.; Weinstein, R.

    1998-01-01

    It is demonstrated that a combination of neutron irradiation with uranium doping introduce fission tracks through a Bi-2223 tape which act as effective pinning centres, leading to a substantial increase in critical current. Preliminary data suggests that the combination of uranium doping and neutron irradiation produces improved flux pinning in Bi-2223 tapes over neutron irradiation alone. Before irradiation, SEM, DTA and XRD analyses were performed on the tapes. Both before and after irradiation the trapped maximum magnetic flux was measured at 77K. Before neutron irradiation, uranium doping has no effect on critical current. Preliminary SEM data suggested that the uranium is homogeneously distributed throughout the oxide core of the tape. The presence of 2212 and other secondary phases in the doped tapes suggest further refinement of the sintering procedure is necessary. (authors)

  10. Metal ion protection of DNA to fast neutron irradiation

    International Nuclear Information System (INIS)

    Constantinescu, B.; Bugoi, R.; Radulescu, I.; Radu, L.

    1998-01-01

    The most important effects of the ionising radiation are the single and double strand breaks (SSB and DBS), modifications of the DNA bases and deoxyribose, as well as the occurrence of alkali and heat labile sites (revealed as strand breaks after alkaline or thermic treatment of irradiated DNA). The ionising particles can have either direct effects on the DNA constituents or indirect effects, mediated by the OH - radicals, produced by water radiolysis. The occurrence of SSB and DSB in the chromatin DNA strands is supposed to hinder the DNA-dye complex formation. Usually, the dyes present different fluorescence parameters in the two possible states, so one can correlate the lifetime or the quantum yield with the extent of the damage. We took into account the protective effect offered both by histones, which behave as 'scavenger molecules' for OH - radicals and by the high compactness of DNA chromatin. Similar protective effects might be the results of the metallic ion addition which triggers some conformational transitions of the chromatin DNA towards a highly compacted structure. In this paper we present a study of the complexes of fast neutron irradiated chromatin with proflavine. Fluorimetric and time resolved spectroscopic determinations (single photon counting method) of chromatin-Pr complexes were realised. Information regarding the chromatin protein damage were obtained by monitoring the fluorescence of Trp. The chromatin was irradiated (20-100 Gy) with fast neutrons, obtained by the reaction of 13.5 MeV deuterons on a thick beryllium target at the IFIN-HH U-120 Cyclotron. The dose mean lineal energy in water at the point of interest was 50 keV/m and the mean dose rate was 1.5 Gy/min. By fluorescence determinations, changes of the Pr intercalation parameters in fast neutron irradiated chromatin DNA have been observed. Fluorescence techniques provide valuable information on the binding equilibrium by considering the radiation deexcitation of the complex. The

  11. In Vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    Directory of Open Access Journals (Sweden)

    Samanta Etel Treiger Borborema

    2005-10-01

    Full Text Available Pentavalent antimony, as meglumine antimoniate (Glucantime® or sodium stibogluconate (Pentostam® , is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer studies have a potential in pharmaceutical development. The aim of this study was to obtain a radiotracer for antimony, with suitable physical and biological properties. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes 122Sb and 124Sb, with high radionuclidic purity and good specific activity. This compound showed the same antileishmanial activity as the native compound. The use of the radiotracers, easily created by neutron irradiation, could be an interesting tool to solve important questions in antimonial pharmacology.Os antimoniais pentavalentes, como o antimoniato de meglumina (Glucantime® ou estibogluconato de sódio (Pentostam® , são o principal tratamento para a leishmaniose, um complexo de doenças causadas pelo protozoário parasita Leishmania, uma doença endêmica e negligenciada no Brasil. Apesar do seu uso clínico por mais de meio século, seu mecanismo de ação, toxicidade e dados de farmacocinética permanecem desconhecidos. Os métodos analíticos para determinação de antimônio em sistemas biológicos são complexos e apresentam baixa sensibilidade. Estudos utilizando radiotraçadores têm papel potencial no desenvolvimento farmacológico. O objetivo deste estudo foi desenvolver um radiotraçador de antimônio, com propriedades físicas e biológicas adequadas. O antimoniato de meglumina foi irradiado por nêutrons no reator nuclear IEA-R1, produzindo dois radioisótopos: 122

  12. Nuclear graphite based on coal tar pitch; behavior under neutron irradiation between 400 and 14000C

    International Nuclear Information System (INIS)

    Mottet, P.; Fillatre, A.; Schill, R.; Micaud, G.

    1977-01-01

    Two nuclear grades of coal tar pitch coke graphites have been developed and tested under neutron irradiation. The neutron irradiation induced dimensional changes between 400 and 1400 0 C, at fluences up to 1,2.10 22 n.cm -2 PHI.FG show a behavior comparable to anisotropic petroleum coke graphites. Less than 10% variation in thermal expansion, maximum decrease by a factor four in thermal conductivity, and large increase of the Young modulus have been observed

  13. Present status of ESNIT (energy selective neutron irradiation test facility) program

    International Nuclear Information System (INIS)

    Noda, K.; Ohno, H.; Sugimoto, M.; Kato, Y.; Matsuo, H.; Watanabe, K.; Kikuchi, T.; Sawai, T.; Usui, T.; Oyama, Y.; Kondo, T.

    1994-01-01

    The present status of technical studies of a high energy neutron irradiation facility, ESNIT (energy selective neutron irradiation test facility), is summarized. Technological survey and feasibility studies of ESNIT have continued since 1988. The results of technical studies of the accelerator, the target and the experimental systems in ESNIT program were reviewed by an International Advisory Committee in February 1993. Recommendations for future R and D on ESNIT program are also summarized in this paper. ((orig.))

  14. Inhomogeneous strain induced by fast neutron irradiation in NaKSO/sub 4/ crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, S.H.; Kassem, M.E.; El-Khatib, A.; El-Gamal, M.A.; El-Wahidy, E.F.

    1987-11-01

    The paper reports the effect of fast neutron irradiation on the thermal properties of NaKSO/sub 4/ crystals in the temperature range 400-475 K. Results are presented for the thermal expansion, tensile strain and specific heat of NaKSO/sub 4/, as a function of neutron irradiation dose. All these results revealed an inhomogeneous strain induced by the radiation. It is suggested that this induced inhomogeneous strain could be used to detect neutron exposure doses.

  15. Inhomogeneous strain induced by fast neutron irradiation in NaKSO4 crystals

    International Nuclear Information System (INIS)

    Kandil, S.H.; Kassem, M.E.; El-Khatib, A.; El-Gamal, M.A.; El-Wahidy, E.F.

    1987-01-01

    The paper reports the effect of fast neutron irradiation on the thermal properties of NaKSO 4 crystals in the temperature range 400-475 K. Results are presented for the thermal expansion, tensile strain and specific heat of NaKSO 4 , as a function of neutron irradiation dose. All these results revealed an inhomogeneous strain induced by the radiation. It is suggested that this induced inhomogeneous strain could be used to detect neutron exposure doses. (UK)

  16. Study of natural diamond detector spectrometric properties under neutron irradiation

    CERN Document Server

    Alekseyev, A B; Kaschuck, Y; Krasilnikov, A; Portnov, D; Tugarinov, S

    2002-01-01

    Natural diamond detector (NDD) performance was studied up to a neutron fluence of 10 sup 1 sup 5 neutron/cm sup 2. The variations of the NDD spectrometric response to incident alpha-particles from sup 2 sup 4 sup 1 Am source after exposure to fast neutron fluences up to 3x10 sup 1 sup 6 n/cm sup 2 were examined. No significant variations up to the level of 10 sup 1 sup 4 n/cm sup 2 were observed. Degradation of charge collection efficiency at higher fluences is reported. No remarkable increase of the NDD leakage current and count rate change had been observed up to a neutron fluence of 3x10 sup 1 sup 6 n/cm sup 2. The charge collection efficiency variations of neutron irradiated diamond spectrometer were studied ex situ under gamma-rays, beta-radiation and visible light excitation. Charge collection efficiency restoration up to 75% level and the NDD performance stabilization by extrinsic low-intensity visible light (550 nm

  17. Hyper-thermal neutron irradiation field for neutron capture therapy

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Tooru; Kanda, Keiji

    1994-01-01

    The utilization of hyper-thermal neutrons, which have an energy spectrum of a Maxwell distribution higher than the room temperature of 300 K, has been studied in order to improve the thermal neutron flux distribution in a living body for a deep-seated tumor in neutron capture therapy (NCT). Simulation calculations using MCNP-V3 were carried out in order to investigate the characteristics of the hyper-thermal neutron irradiation field. From the results of simulation calculations, the following were confirmed: (i) The irradiation field of the hyper-thermal neutrons is feasible by using some scattering materials with high temperature, such as Be, BeO, C, SiC and ZrH 1.7 . Especially, ZrH 1.7 is thought to be the best material because of good characteristics of up-scattering for thermal neutrons. (ii) The ZrH 1.7 of 1200 K yields the hyper-thermal neutrons of a Maxwell-like distribution at about 2000 K and the treatable depth is about 1.5 cm larger comparing with the irradiation of the thermal neutrons of 300 K. (iii) The contamination by the secondary gamma-rays from the scattering materials can be sufficiently eliminated to the tolerance level for NCT through the bismuth layer, without the larger change of the energy spectrum of hyper-thermal neutrons. ((orig.))

  18. Neutron irradiation of sputtered NbN films

    International Nuclear Information System (INIS)

    Weber, H.W.; Gregshammer, P.; Gray, K.E.; Kampwirth, R.T.

    1989-01-01

    In addition to the excellent high-field superconducting properties of NbN, it is the strain and radiation tolerance, measured in bulk NbN, which makes the material so attractive for large high-field magnets, especially for fusion applications. The authors report neutron irradiation experiments on sputtered NbN films, up to a fluence of 10/sup 23/ m/sup -2/ (E > 0.1 MeV), which prove that NbN films are also extremely radiation-hard high-field superconductors. Both the transition temperatures, T/sub c/, and the normal state resistivities show only small changes with neutron fluence. Concerning the critical current densities, j/sub c/, degradations by as much as 30% are observed at low fields, whereas in an intermediate field range (11-15 T) virtually no change of j/sub c/ and at high fields near 20 T even an increase of j/sub c/ are found. The latter observation is ascribed to a radiation-induced increase of the upper critical field, B/sub c2/, and to the occurence of peak effects near B/sub c2/

  19. Fracture mechanics behaviour of neutron irradiated Alloy A-286

    International Nuclear Information System (INIS)

    Mills, W.J.; James, L.A.

    The effect of fast-neutron irradiation on the fatigue-crack propagation and fracture toughness behaviour of Alloy A-286 was characterized using fracture mechanics techniques. The fracture toughness was found to decrease continuously with increasing irradiation damage at both 24 deg. C and 427 deg. C. In the unirradiated and low fluence conditions, specimens displayed appreciable plasticity prior to fracture, and equivalent Ksub(Ic) values were determined from Jsub(Ic) fracture toughness results. At high irradiation exposure levels, specimens exhibited a brittle Ksub(Ic) fracture mode. The 427 deg. C fracture toughness fell from 129 MPa√m in the unirradiated condition to 35 MPa√m at an exposure of 16.2 dpa (total fluence of 5.2x10 22 n/cm 2 ). Room temperature fracture toughness values were consistently 40 to 60 percent higher than the 427 deg. C values. Electron fractography revealed that the reduction in fracture resistance was attributed to a fracture mechanism transition from ductile microvoid coalescence to channel fracture. Fatigue-crack propagation tests were conducted at 427 deg. C on specimens irradiated at 2.4 dpa and 16.2 dpa. Crack growth rates at the lower exposure level were comparable to those in unirradiated material, while those at the higher exposure were slightly higher than in unirradiated material. (author)

  20. Tritium extraction from neutron-irradiated lithium aluminate

    International Nuclear Information System (INIS)

    Garcia H, F.

    1995-01-01

    Lithium aluminate is being strongly considered as a breeder material because of its thermophysical, chemical and mechanical stability at high temperatures and its favorable irradiation behavior. Furthermore, it is compatible with other blanket and structural materials. In this work, the effects of calcination temperature during preparation, extraction temperature and sweep gas composition were observed. Lithium aluminate prepared by four different methods, was neutron irradiated for 30 minutes at a flux of 10 12 -10 13 n/cm 2 s in the TRIGA Mark III reactor at Salazar, Mexico; and the tritium extraction rate was measured. Calcination temperature do not affect the tritium extraction rate. However, using high calcination temperature, gamma lithium aluminate was formed. The tritium extraction at 600 Centigrade degrees was lower than at 800 Centigrade degrees and the tritium amount extracted by distillation of the solid sample was higher. The sweep gas composition showed that tritium extraction was less with Ar plus 0.5 % H 2 that with Ar plus 0.1 % H 2 . This result was contrary to expected, where the tritium extraction rate could be higher when hydrogen is added to the sweep gas. Probably this effect could be attributed to the gas purity. (Author)

  1. The effect of neutron irradiation on silicon carbide fibers

    International Nuclear Information System (INIS)

    Newsome, G.A.

    1997-01-01

    Nine types of SiC fiber have been exposed to neutron radiation in the Advanced Test Reactor at 250 C for various lengths of time ranging from 83 to 128 days. The effects of these exposures have been initially determined using scanning electron microscopy. The fibers tested were Nicalon trademark CG, Tyranno, Hi-Nicalon trademark, Dow Corning SiC, Carborundum SiC, Textron SCS-6, polymethysilane (PMS) derived SiC from the University of Michigan, and two types of MER SiC fiber. This covers a range of fibers from widely used commercial fibers to developmental fibers. Consistent with previous radiation experiments, Nicalon fiber was severely degraded by the neutron irradiation. Similarly, Tyranno suffered severe degradation. The more advanced fibers which approach the composition and properties of SiC performed well under irradiation. Of these, the Carborundum SiC fiber appeared to perform the best. The Hi-Nicalon and Dow Corning Fibers exhibited good general stability, but also appear to have some surface roughening. The MER fibers and the Textron SCS-6 fibers both had carbon cores which adversely influenced the overall stability of the fibers

  2. ANITA-2000, Isotope Inventories from Neutron Irradiation, for Fusion Applications

    International Nuclear Information System (INIS)

    Cepraga, Dan-Gabriel

    2000-01-01

    1 - Description of program or function: ANITA-2000 is a code package for the activation characterisation of materials exposed to neutrons in fusion machines. The main component of the package is the activation code ANITA-4M that computes the radioactive inventory of a material exposed to neutron irradiation, continuous or stepwise. It provides activity, atomic density, decay heat, biological hazard, clearance index and gamma-ray source spectra at shut down and for different cooling times. An interactive utility module, MODBIN, to produce the neutron activation cross sections libraries in the required binary ANITA-4M Format, is also included. The GRANITA interactive module may plot activation parameters as a function of the cooling time. The main improvements include: -the number of irradiation time intervals has been increased to 2000; -different neutron wall loading can be used for each burn time interval; -the photon source calculation in the 18 energy group Scale structure has been added; -the clearance index can be calculated. In addition the code language has been standardized to Fortran '95 - by maintaining the backward compatibility (except for the time/date routines) - so as the same code package can be compiled and run on Unix environment and on PC, both under DOS-Windows and under Linux. 2 - Methods: The mathematical solution of the problem is given in analytical form using recurrence relations. Double precision arithmetic is used

  3. Effect of neutron irradiation on select MAX phases

    International Nuclear Information System (INIS)

    Tallman, Darin J.; Hoffman, Elizabeth N.; Caspi, El’ad N.; Garcia-Diaz, Brenda L.; Kohse, Gordon; Sindelar, Robert L.; Barsoum, Michel W.

    2015-01-01

    Herein we report on the effect of neutron irradiation – of up to 0.1 displacements per atom at 360(20) °C or 695(25) °C – on polycrystalline samples of Ti 3 AlC 2 , Ti 2 AlC, Ti 3 SiC 2 and Ti 2 AlN. Rietveld refinement of X-ray diffraction patterns of the irradiated samples showed irradiation-enhanced dissociation into TiC of the Ti 3 AlC 2 and Ti 3 SiC 2 phases, most prominently in the former. Ti 2 AlN also showed an increase in TiN content, as well as Ti 4 AlN 3 after irradiation. In contrast, Ti 2 AlC was quite stable under these irradiation conditions. Dislocation loops are seen to form in Ti 2 AlC and Ti 3 AlC 2 after irradiation at 360(20) °C. The room temperature electrical resistivity of all samples increased by an order of magnitude after irradiation at 360(20) °C, but only by 25% after 695(25) °C, providing evidence for the MAX phases’ dynamic recovery at temperatures as low at 695(25) °C. Based on these preliminary results, it appears that Ti 2 AlC and Ti 3 SiC 2 are the more promising materials for high-temperature nuclear applications

  4. Effect of neutron irradiation on the microstructure of tungsten

    Directory of Open Access Journals (Sweden)

    M. Klimenkov

    2016-12-01

    Full Text Available Two grades of pure tungsten, single and polycrystalline, were irradiated for 282 days in the HFR reactor, Petten, at 900 °C to an average damage level of 1.6dpa. Each grade of tungsten was investigated using the transmission electron microscope (TEM to assess the effect of neutron irradiation on tungsten microstructure. Investigations revealed the formation of faceted cavities, whose diameter varies from 4 to 14nm in both materials. The cavities are homogeneously distributed only inside single crystalline tungsten. The local distribution of cavities in polycrystalline tungsten is strongly influenced by grain boundaries. The number densities of cavities were measured to be 4×1021 m−3 for polycrystalline and 2.5×1021 m−3 for single crystalline tungsten. This corresponds to volumetric densities of 0.45% and 0.33% respectively. High-resolution transmission electron microscopy (HRTEM revealed that faces of cavities are oriented in (110 plane. Analytical investigations showed precipitation of rhenium and osmium produced by a transmutation reaction around cavities and at grain boundaries.

  5. Recovery characteristics of neutron-irradiated V-Ti alloys

    International Nuclear Information System (INIS)

    Leguey, T.; Pareja, R.

    2000-01-01

    The recovery characteristics of neutron-irradiated pure V and V-Ti alloys with 1.0 and 4.5 at.% Ti have been investigated by positron annihilation spectroscopy. Microvoid formation during irradiation at 320 K is produced in pure V and V-1Ti but not in V-4.5Ti. The results are consistent with a model of swelling inhibition induced by vacancy trapping by solute Ti during irradiation. The temperature dependencies of the parameter S in the range 8-300 K indicate a large dislocation bias for vacancies and solute Ti. This dislocation bias prevents the microvoid nucleation in V-4.5Ti, and the microvoid growth in V-1Ti, when vacancies become mobile during post-irradiation annealing treatments. A characteristic increase of the positron lifetime is found during recovery induced by isochronal annealing. It is attributed to a vacancy accumulation into the lattice of Ti oxides precipitated during cooling down, or at their matrix/precipitate interfaces. These precipitates could be produced by the decomposition of metastable phases of Ti oxides formed during post-irradiation annealing above 1000 K

  6. Neutron-Irradiated Samples as Test Materials for MPEX

    International Nuclear Information System (INIS)

    Ellis, Ronald James; Rapp, Juergen

    2015-01-01

    Plasma Material Interaction (PMI) is a major concern in fusion reactor design and analysis. The Material-Plasma Exposure eXperiment (MPEX) will explore PMI under fusion reactor plasma conditions. Samples with accumulated displacements per atom (DPA) damage produced by fast neutron irradiations in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) will be studied in the MPEX facility. This paper presents assessments of the calculated induced radioactivity and resulting radiation dose rates of a variety of potential fusion reactor plasma-facing materials (such as tungsten). The scientific code packages MCNP and SCALE were used to simulate irradiation of the samples in HFIR including the generation and depletion of nuclides in the material and the subsequent composition, activity levels, gamma radiation fields, and resultant dose rates as a function of cooling time. A challenge of the MPEX project is to minimize the radioactive inventory in the preparation of the samples and the sample dose rates for inclusion in the MPEX facility

  7. Resistivity measurements on the neutron irradiated detector grade silicon materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng

    1993-11-01

    Resistivity measurements under the condition of no or low electrical field (electrical neutral bulk or ENB condition) have been made on various device configurations on detector grade silicon materials after neutron irradiation. Results of the measurements have shown that the ENB resistivity increases with neutron fluence ({Phi}{sub n}) at low {phi}{sub n} (<10{sup 13} n/cm{sup 2}) and saturates at a value between 300 and 400 k{Omega}-cm at {phi}{sub n} {approximately}10{sup 13} n/cm{sup 2}. Meanwhile, the effective doping concentration N{sub eff} in the space charge region (SCR) obtained from the C-V measurements of fully depleted p{sup +}/n silicon junction detectors has been found to increase nearly linearly with {phi}{sub n} at high fluences ({phi}{sub n} > 10{sup 13} n/cm{sup 2}). The experimental results are explained by the deep levels crossing the Fermi level in the SCR and near perfect compensation in the ENB by all deep levels, resulting in N{sub eff} (SCR) {ne} n or p (free carrier concentrations in the ENB).

  8. Neutron irradiation behavior of ITER candidate beryllium grades

    Energy Technology Data Exchange (ETDEWEB)

    Kupriyanov, I.B.; Gorokhov, V.A.; Nikolaev, G.N. [A.A.Bochvar All-Russia Scientific Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Melder, R.R.; Ostrovsky, Z.E.

    1998-01-01

    Beryllium is one of the main candidate materials both for the neutron multiplier in a solid breeding blanket and for the plasma facing components. That is why its behaviour under the typical for fusion reactor loading, in particular, under the neutron irradiation is of a great importance. This paper presents mechanical properties, swelling and microstructure of six beryllium grades (DshG-200, TR-30, TshG-56, TRR, TE-30, TIP-30) fabricated by VNIINM, Russia and also one - (S-65) fabricated by Brush Wellman, USA. The average grain size of the beryllium grades varied from 8 to 25 {mu}m, beryllium oxide content was 0.8-3.2 wt. %, initial tensile strength was 250-680 MPa. All the samples were irradiated in active zone of SM-3 reactor up to the fast neutron fluence (5.5-6.2) {center_dot} 10{sup 21} cm{sup -2} (2.7-3.0 dpa, helium content up to 1150 appm), E > 0.1 MeV at two temperature ranges: T{sub 1} = 130-180degC and T{sub 2} = 650-700degC. After irradiation at 130-180degC no changes in samples dimensions were revealed. After irradiation at 650-700degC swelling of the materials was found to be in the range 0.1-2.1 %. Beryllium grades TR-30 and TRR, having the smallest grain size and highest beryllium oxide content, demonstrated minimal swelling, which was no more than 0.1 % at 650-700degC and fluence 5.5 {center_dot} 10{sup 21} cm{sup -2}. Tensile and compression test results and microstructure parameters measured before and after irradiation are also presented. (author)

  9. Effect of neutron irradiation on mechanical properties of ferritic steels

    International Nuclear Information System (INIS)

    Kass, S.B.; Murty, K.L.

    1995-01-01

    Effect of neutron radiation exposure was investigated in various ferritic steels with the main emphasis being the effects of thermal neutrons on radiation hardening. Pure iron of varied grain sizes was also used for characterizing the grain size effects on the source hardening before and after neutron irradiation. While many steels are considered in the overall study, the results on 1020, A516 and A588 steels are emphasized. Radiation hardening due to fast neutrons was seen to be sensitive to the composition of the steels with A354 being the least resistant and A490 the least sensitive. Majority of the radiation hardening stems from friction hardening, and source hardening term decreased with exposure to neutron radiation apparently due to the interaction of interstitial impurities with radiation produced defects. Inclusion of thermal neutrons along with fast resulted in further decrease in the source hardening with a slight increase in the friction hardening which revealed a critical grain size below which exposure to total (fast and thermal) neutron spectrum resulted in a slight reduction in the yield stress compared to the exposure to only fast neutrons. This is the first time such a grain size effect is reported and this is shown to be consistent with known radiation effects on friction and source hardening terms along with the observation that low energy neutrons have a nonnegligible effect on the mechanical properties of steels. In ferritic steels, however, despite their small grain size, exposure to total neutron spectrum yielded higher strengths than exposure to only fast neutrons. This behavior is consistent with the fact that the source hardening is small in these alloys and radiation effect is due only to friction stress

  10. Neutron irradiation effects on magnetic properties of some Heusler alloys

    International Nuclear Information System (INIS)

    Onodera, Hideya; Shinohara, Takeshi; Yamamoto, Hisao; Watanabe, Hiroshi

    1975-01-01

    The neutron irradiation effects were studied with measurements of temperature dependence of magnetization in ordered and disordered Heusler alloys. The irradiation was carried out in JMTR with a total flux of fast neutrons of 10 20 nvt. Fully ordered Cu 2 MnIn, partially ordered Cu 2 MnAl and completely disordered Cu 2 MnSn were prepared with various temperature treatments. The magnetization-temperature curves of each specimen were measured before and after irradiation. In the irradiated Cu 2 MnIn, the disordering by the irradiation gave rise to a decrease of magnetization, and the temperature dependence of magnetization showed that the disordered region contained various regions with different degrees of disorder. For the distribution of the disordered region, the calculation based on the theory of temperature spike by Seitz and Koekler gave a feasible result that a disordered region comprised a central core with a radius of 5.4 A which was completely disordered and a periphery of 3.3 A thickness which was partially disordered. From the magnetization-temperature curves of Cu 2 MnAl, it was considered that the disordered regions induced by the irradiation had different properties from those induced by the heat treatment. The former were the localized and comprised regions corresponding to various degrees of disorder, while the latter spread spatially in a wide range with a certain degree of disorder. The ordering by enhanced diffusion occurred simultaneously to an extent comparable to the disordering, and so it played an important role in the magnetization in the partially disordered Cu 2 MnAl. In the disordered Cu 2 MnSn, however, the ordering effect was very small. It is supposed to be difficult for the A2 structure to transform into the L2 1 structure by the enhanced diffusion. (auth.)

  11. Study of damages by neutron irradiation in lithium aluminates

    International Nuclear Information System (INIS)

    Palacios G, O.

    1999-01-01

    Lithium aluminates proposed to the production of tritium in fusion nuclear reactors, due to the thermal stability that they present as well as the behavior of the aluminium to the irradiation. As a neutron flux with profile (≅ 14 Mev) of a fusion reactor is not available. A irradiation experiment was designed in order to know the micro and nano structure damages produced by fast and thermal neutrons in two irradiation positions of the fusion nuclear reactor Triga Mark III: CT (Thermal Column) and SIFCA (System of Irradiation Fixed of Capsules). In this work samples of lithium aluminate were characterized by XRD (X-Ray Diffraction), TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy). Two samples were prepared by two methods: a) coalition method and b) peroxide method. This characterization comprised original and irradiated samples. The irradiated sample amounted to 4 in total: one for each preparation method and one for each irradiation position. The object of this analysis was to correlate with the received neutron dose the damages suffered by the samples with the neutron irradiation during long periods (440 H), in their micro and nano structure aspects; in order to understand the changes as a function of the irradiation zone (with thermal and fast neutron flux) and the preparation methods of the samples and having as an antecedent the irradiation in SIFCA position by short times (2h). The obtained results are referred to the stability of γ -aluminate phase, under given conditions of irradiation and defined nano structure arrangement. They also refer to the proposals of growth mechanism and nucleation of new phases. The error associated with the measurement of neutron dose is also discussed. (Author)

  12. Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhangbo; Lo, Wei-Yang [Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States); Chen, Yiren [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States); Pakarinen, Janne [Belgian Nuclear Research Center (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); Wu, Yaqiao [Department of Materials Science and Engineering, Boise State University, Boise, ID 83715 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Allen, Todd [Engineering Physics Department, University of Wisconsin, Madison, WI 53706 (United States); Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Yang, Yong, E-mail: yongyang@ufl.edu [Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States)

    2015-11-15

    To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10{sup 19} n/cm{sup 2}, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10{sup −9} dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.

  13. Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

    International Nuclear Information System (INIS)

    Li, Zhangbo; Lo, Wei-Yang; Chen, Yiren; Pakarinen, Janne; Wu, Yaqiao; Allen, Todd; Yang, Yong

    2015-01-01

    To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10"1"9 n/cm"2, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10"−"9 dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.

  14. Colony form variation of Bacillus pumilus E601 after cultured and neutron irradiation

    International Nuclear Information System (INIS)

    Chen Xiaoming; Wei Baoli; Zhang Jianguo

    2008-01-01

    The distribution of two colony forms of Bacillus pumilus E601 and the effect of neutron irradiation on the colony form were reported. The translucent and opaque colonies were cultured several generations to observe the proportion of two form colonies. The spores of opaque colony were irradiated at 80, 800 and 2000 Gy of fast neutron from CFBR-II pulse pile, and the survivors of opaque colony were irradiated again at the same doses. The results showed that: (1) Bacillus pumilus E601 observed two types of colony form: translucent and opaque colony; (2) the translucent colony could produce both translucent and opaque colonies in equal, while the opaque colony couldn't produce translucent colony generally; (3) neutron irradiation could affect the colony form distribution. The ratio of survival translucent colony was increased with the increase of the first neutron irradiation doses, and the second neutron irradiation also increased the ratio of translucent colony. It was concluded that the instability of translucent colony was the main reason to produce two colony forms of Bacillus pumilus E601. The strain of translucent colony had a stronger ability to resist neutron irradiation than the opaque colony. (authors)

  15. Comparison of deuterium retention for ion-irradiated and neutron-irradiated tungsten

    International Nuclear Information System (INIS)

    Oya, Yasuhisa; Kobayashi, Makoto; Okuno, Kenji; Shimada, Masashi; Calderoni, Pattrick; Oda, Takuji; Hara, Masanori; Hatano, Yuji; Watanabe, Hideo

    2014-01-01

    The behavior of D retentions for Fe 2+ irradiated tungsten with the damage of 0.025-3 dpa was compared with that for neutron irradiated tungsten with 0.025 dpa. The D 2 TDS spectra for Fe 2+ irradiated tungsten consisted of two desorption stages at 450 K and 550 K although that for neutron irradiated tungsten was composed of three stages and addition desorption stage was found around 750 K. The desorption rate of major desorption stage at 550 K increased as the number of dpa by Fe 2+ irradiation increased. In addition, the first desorption stage at 450 K was only found for the damaged samples, indicating that the second stage would be based on intrinsic defects or vacancy produced by Fe 2+ irradiation and the first stage should be the accumulation of D in mono vacancy leading to the lower activation energy, where the dislocation loop and vacancy was produced. The third one was only found for the neutron irradiation, showing the D trapping by void or vacancy cluster and the diffusion effect is also contributed due to high FWHM of TDS spectrum. It can be said that the D 2 TDS spectra for Fe 2+ -irradiated tungsten could not represent that for neutron-irradiated one, showing that the deuterium trapping and desorption mechanism for neutron-irradiated tungsten has a difference from that for ion-irradiated one. (author)

  16. Tensile properties of neutron irradiated solid HIP 316L(N). ITER Task T214, NET deliverable GB6 ECN-5

    International Nuclear Information System (INIS)

    Van Osch, E.V.; Tjoa, G.L.; Boskeljon, J.; Van Hoepen, J.

    1998-05-01

    The tensile properties of neutron irradiated Hot Isostatically Pressed (HIP) joints of type 316L(N) stainless steel (heat PM-130) have been measured. Cylindrical tensile test specimens of 4 mm diameter were irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands, simulating the first wall conditions by a combination of high displacement damage with proportional amounts of helium. The solid HIP specimens were irradiated up to a target dose level of 5 dpa at a temperature of 550K. The damage levels realized range from 3.0 to 4.1 dpa, with helium contents up to 38 appm. Post irradiation testing temperatures ranged from 300 to 700K. The report contains the experimental conditions and summarises the results, which are given in terms of engineering stresses and strains and reduction of area. The main conclusions are that the unirradiated solid-HIP material is very soft, assumingly due to the relatively large grain size. Neutron irradiation induces both hardening and reduction of ductility, similar to the behaviour of 316L(N) plate. No failures related to debonding were observed for the tests of the unirradiated samples, however one of eight tested irradiated specimens fractured in the HIP joint, showing a flat fracture surface and a low reduction of area. 6 refs

  17. Commercial Applications at FRM II Based on Neutron Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Gerstenberg, H.; Draack, A.; Kastenmuller, A. [Technische Universitaet Muenchen, Munchen (Germany)

    2013-07-01

    Due to its design as a heavy water moderated reactor with a very compact core FRM II, Germany's most modern and most powerful research reactor, offers excellent conditions for basic research using beam tubes. On the other hand it is equipped with various irradiation facilities to be used mainly for industrial purposes. From the very beginning of reactor operation a dedicated department had been implemented in order to provide a neutron irradiation service to interested parties on a commercial basis. As of today the most widely used application is Si doping. The semiautomatic doping facility accepts ingots with diameters between 125 mm and 200 mm and a maximum height of 500 mm. The irradiation channel is located deep in the heavy water tank and exhibits a ratio of thermal/fast neutron flux density of > 1000. This value allows the doping of Si to a target resistivity as high as 1100 Ωcm within the tight limits regarding accuracy and homogeneity specified by the customer. Typically the throughput of Si doped in FRM II sums up to about 15 t/year. Another topic of growing importance is the use of FRM II aiming the production of radioisotopes mainly for the radiopharmaceutical industry. The maybe most challenging example is the production of Lu-177 n. c. a. based on the irradiation of Yb{sub 2}O{sub 3} to a high fluence of thermal neutrons of typically 1.5E20 cm{sup -2}. The Lu-177 activity delivered to the customer is in the range of 750 GBq. With respect to further processing it turned out to be a highly advantageous to have the laboratories of ITG, the company extracting the Lu-177 from the freshly irradiated Yb{sub 2}O{sub 3} on site FRM II. Further irradiation facilities are available at FRM II in order to allow the activation of samples for analytical purposes or to irradiate samples for geochronological investigations using the fission track technique. Finally a project on the future installation of a facility dedicated to the irradiation of U-targets for

  18. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Directory of Open Access Journals (Sweden)

    Hu J.-P.

    2016-01-01

    Full Text Available Radiation dosimetry for Neutron Capture Therapy (NCT has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR. In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1 in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2 out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3 beam shutter upgrade to reduce strayed neutrons and gamma dose, (4 beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5 beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates to reduce prompt gamma and fast neutron doses, (6 sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7 holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4–7

  19. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N.

    2014-05-23

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4 - 7

  20. Conceptual design, neutronic and radioprotection study of a fast neutron irradiation station at SINQ

    International Nuclear Information System (INIS)

    Zanini, L.; Baluc, N.; Simone, A. De; Eichler, R.; Joray, S.; Manfrin, E.; Pouchon, M.; Rabaioli, S.; Schumann, D.; Welte, J.; Zhernosekov, K.

    2011-12-01

    This comprehensive, illustrated report by the Paul Scherrer Institute PSI in Switzerland documents the proposals concerning the conceptual design, neutronic and radioprotection study of a fast neutron irradiation station at the PSI's Swiss Spallation Neutron Source SINQ facility. The need for fast neutron irradiation is discussed and the possibility of using SINQ as a fast neutron irradiation facility is considered. The production of isotopes, tracers and medical isotopes is discussed, as are fission and fusion reactor technologies. The characteristics of the neutron spectrum in SINQ are discussed. The neutronic and radioprotection calculations for an irradiation station at SINQ are looked at in detail and extensive examples of work done and results obtained are presented and discussed. Radioprotection issues are also looked at. Further contributions in the report cover the hot/cold irradiation station in the SINQ target. An appendix provides detailed drawings of the facility's pneumatic delivery system

  1. Characterization of defect accumulation in neutron-irradiated Mo by positron annihilation spectroscopy

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Li, Meimei; Snead, L.L.

    2008-01-01

    Positron annihilation lifetime spectroscopy measurements were performed on neutron-irradiated low carbon arc cast Mo. Irradiation took place in the high flux isotope reactor, Oak Ridge National Laboratory, at a temperature of 80 +/- 10 degrees C. Neutron fluences ranged from 2 x 10(21) to 8 x 10(......, as predicted by molecular dynamics simulations. (C) 2008 Elsevier B.V. All rights reserved....... at a very low-dose of similar to 10(-4) dpa. The average size of the cavities did not change significantly with dose, in contrast to neutron-irradiated bcc Fe where cavity sizes increased with increasing dose. It is suggested that the in-cascade vacancy clustering may be significant in neutron-irradiated Mo...

  2. Effects of neutron irradiation on red blood cell labeling with technetium-99m

    International Nuclear Information System (INIS)

    Eng, R.R.; Conklin, J.J.; Grissom, M.P.

    1982-01-01

    The effects of in vivo and in vitro neutron irradiation on red blood cell radiolabeling with technetium-99m (Tc-99m) were studied. Blood from three dogs was irradiated with neutrons (725 rads, free in air dose) followed by radiolabeling with Tc-99m. The three dogs were subsequently whole body, neutron irradiated (250 rads, midline dose); and blood samples were drawn for radiolabeling at 24, 48, 72 and 96 hours post-irradiation. Blood from three control dogs was also drawn and radiolabeled on each day for comparison. The results show that there were no significant differences between the radiolabeling capacities of in vivo or in vitro neutron irradiated and control RBCs

  3. Neutron irradiation effects on magnetic properties of Fe-based ferromagnetic metallic glasses

    International Nuclear Information System (INIS)

    Miglierini, M.; Nasu, Saburo; Skorvanek, I.; Sitek, J.

    1992-01-01

    Transmission 57 Fe Moessbauer spectroscopy, J-H quasistatic hysteresis loop and AC susceptibility measurements are used to study effects of neutron irradiation on magnetic properties of Fe-based-ferromagnetic metallic glasses. Elastic stress centers are produced during the process of neutron irradiation as a result of atom mixing. Rearrangement of the atoms causes changes in the average value of the hyperfine field distribution and orientation of the net magnetic moment. They are shown to depend on the composition of the investigated samples. Cr-doped metallic glasses depict transition from the ferromagnetic to paramagnetic state at room temperature after neutron irradiation implying changes in the Curie temperature. The presence of Ni in the samples reduces the effects of radiation damage as revealed also from position lifetime data. Possible sources of a radiation damage are discussed using the results of γ-ray spectroscopy. (author)

  4. Neutron irradiation effects on magnetic properties of Fe-based ferromagnetic metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Miglierini, M.; Nasu, Saburo (Osaka Univ., Toyonaka (Japan). Faculty of Science); Skorvanek, I.; Sitek, J.

    1992-04-01

    Transmission {sup 57}Fe Moessbauer spectroscopy, J-H quasistatic hysteresis loop and AC susceptibility measurements are used to study effects of neutron irradiation on magnetic properties of Fe-based-ferromagnetic metallic glasses. Elastic stress centers are produced during the process of neutron irradiation as a result of atom mixing. Rearrangement of the atoms causes changes in the average value of the hyperfine field distribution and orientation of the net magnetic moment. They are shown to depend on the composition of the investigated samples. Cr-doped metallic glasses depict transition from the ferromagnetic to paramagnetic state at room temperature after neutron irradiation implying changes in the Curie temperature. The presence of Ni in the samples reduces the effects of radiation damage as revealed also from position lifetime data. Possible sources of a radiation damage are discussed using the results of {gamma}-ray spectroscopy. (author).

  5. Protons in neutron-irradiated and thermochemically reduced MgO crystals doped with lithium impurities

    International Nuclear Information System (INIS)

    Gonzalez, R.; Pareja, R.; Chen, Y.

    1992-01-01

    H - (hydride) ions have been observed in lithium-doped MgO crystals which have been neutron irradiated or thermochemically reduced (TCR). Infrared-absorption measurements have been used to identify the local modes of the H - ions in these crystals. The concentration of the H - ions in the neutron-irradiated crystals is found to be far less than that found in the TCR crystals. The thermal stability of H - and oxygen vacancies in both oxidizing and reducing atmospheres are investigated. The emergence of sharp structures due to OH - ions is attributed to the displacements of substitutional Li + ions, leaving behind unperturbed OH - ions, via a mechanism of rapid radiation-induced diffusion during irradiation in a reactor. Results of neutron-irradiated MgO:Li, which had previously been oxidized at high temperature, are also presented

  6. Positron annihilation spectroscopy of vacancy aggregates in neutron-irradiated MgO crystals

    International Nuclear Information System (INIS)

    Pareja, R.; De La Cruz, R.M.; Gonzalez, R.; Chen, Y.; Department of Energy, Washington, DC

    1992-01-01

    Positron annihilation measurements in neutron-irradiated MgO crystals show that the positron lifetime is shorter than in as-grown crystals, suggesting that most of the defects produced by neutron irradiations are positively charged. The concentration of the neutral anion vacancy (possibly also the neutral anion divacancy) is estimated to be no more than ∼ 10 16 cm -3 for samples irradiated to a dose of 10 17 to 10 19 n cm -2 . Annealing experiments on the neutron-irradiated crystals show a significant increase in the positron lifetime after anneals at 900 K. The increase is attributed to positron trapping by anion-vacancy aggregates. A lifetime of (284±15)ps is tentatively assigned to positrons trapped in these aggregates. (Author)

  7. Micro-Raman and photoluminescence studies of neutron-irradiated gallium nitride epilayers

    International Nuclear Information System (INIS)

    Wang, R.X.; Xu, S.J.; Fung, S.; Beling, C.D.; Wang, K.; Li, S.; Wei, Z.F.; Zhou, T.J.; Zhang, J.D.; Huang Ying; Gong, M.

    2005-01-01

    GaN epilayers grown on sapphire substrate were irradiated with various dosages of neutrons and were characterized using Micro-Raman and photoluminescence. It was found that the A 1 (LO) peak in the Raman spectra clearly shifted with neutron irradiation dosage. Careful curve fitting of the Raman data was carried out to obtain the carrier concentration which was found to vary with the neutron irradiation dosage. The variation of the full width at half maximum height of the photoluminescence was consistent with the Raman results. The neutron irradiation-induced structural defects (likely to be Ge Ga ) give rise to carrier trap centers which are responsible for the observed reduction in carrier concentration of the irradiated GaN

  8. Deuterium Depth Profile in Neutron-Irradiated Tungsten Exposed to Plasma

    International Nuclear Information System (INIS)

    Shimada, Masashi; Cao, G.; Hatano, Y.; Oda, T.; Oya, Y.; Hara, M.; Calderoni, P.

    2011-01-01

    The effect of radiation damage has been mainly simulated using high-energy ion bombardment. The ions, however, are limited in range to only a few microns into the surface. Hence, some uncertainty remains about the increase of trapping at radiation damage produced by 14 MeV fusion neutrons, which penetrate much farther into the bulk material. With the Japan-US joint research project: Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), the tungsten samples (99.99 % pure from A.L.M.T., 6mm in diameter, 0.2mm in thickness) were irradiated to high flux neutrons at 50 C and to 0.025 dpa in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Subsequently, the neutron-irradiated tungsten samples were exposed to a high-flux deuterium plasma (ion flux: 1021-1022 m-2s-1, ion fluence: 1025-1026 m-2) in the Tritium Plasma Experiment (TPE) at the Idaho National Laboratory (INL). First results of deuterium retention in neutron-irradiated tungsten exposed in TPE have been reported previously. This paper presents the latest results in our on-going work of deuterium depth profiling in neutron-irradiated tungsten via nuclear reaction analysis. The experimental data is compared with the result from non neutron-irradiated tungsten, and is analyzed with the Tritium Migration Analysis Program (TMAP) to elucidate the hydrogen isotope behavior such as retention and depth distribution in neutron-irradiated and non neutron-irradiated tungsten.

  9. Fracture behavior and deformation mechanisms under fast neutron irradiation

    International Nuclear Information System (INIS)

    Boutard, J.L.; Dupouy, J.M.

    1980-09-01

    We have established the out-of-pile and in-pile deformation mechanism maps of a 316 stainless steel irradiated in a fast reactor. The knowledge of the dominating deformation mechanism either in post irradiation creep experiments or during the in-pile steady state operating conditions allows to rationalize the apparent discrepancy between the very low out-of-pile ductility and the rather high plastic diametral strains which are obtained in the fast reactor environment without fracture

  10. Inhomogeneous strain induced by fast neutron irradiation in NaKSO4 crystals

    International Nuclear Information System (INIS)

    Kandil, S.H.; El Gamal, M.A.; El Khatib, A.; El Wahidy, E.F.

    1987-06-01

    The effect of fast neutron irradiation on the thermal properties of NaKSO 4 crystals was studied around the phase transition temperature T c =453 K. The thermal expansion coefficient as well as the phase transition temperature were found to be dependent upon the irradiation dose. The specific heat, C p , showed multiple peaks in the phase transition temperature region. An explanation of this behaviour was based on the induced inhomogeneous strain in the crystal casued by the neutron irradiation process. (author). 10 refs, 3 figs

  11. Influence of neutron irradiation on the stability of recipitates in zircaloy: a critical review

    International Nuclear Information System (INIS)

    Lobo, Raquel M.; Andrade, Arnaldo H. P.

    2013-01-01

    The realization of RMB enterprise (Brazilian Multipurpose Reactor) will give the country a powerful tool to investigate the behavior materials subjected to irradiation. Among them, zirconium alloys, used as cladding of nuclear fuel in reactors type LWR. It is know that neutron irradiation can affect the stability of precipitates in zircaloys, generating as a result changes in theirs mechanical properties, important application of this alloys. This paper present a critical review of neutron irradiation effects on microstructural stability of zircaloys (2 and 4). (author)

  12. Microstructural evolution of neutron-irradiated Ni-Si and Ni-Al alloys

    Science.gov (United States)

    Takahashi, H.; Garner, F. A.

    1992-10-01

    Additions of silicon and aluminum suppress the neutron-induced swelling of pure nickel but to different degrees. Silicon is much more effective initially when compared to aluminum on a per atom basis but silicon exhibits a nonmonotonic influence on swelling with increasing concentration. Silicon tends to segregate toward grain boundaries while aluminum segregates away from these boundaries. Whereas the formation of the Ni 3Si phase is frequently observed in charged particle irradiation experiments conducted at much higher displacement rates, it did not occur during neutron irradiation in this study. Precipitation also did not occur in Ni-5Al during neutron irradiation, nor has it been reported to occur during ion irradiation.

  13. Surface damage in the small intestine of the mouse after X - or neutron irradiation

    International Nuclear Information System (INIS)

    Hamlet, R.; Carr, K.E.; Nias, A.H.; Watt, C.

    1981-01-01

    Damage after X-irradiation includes lateral villous collapse, progressing after 3 - 5 days to villi which sometimes show signs of vertical collapse. After neutron irradiation vertical villous collapse is established earlier, with less swelling of villous tips. It seems, therefore, that at radiobiologically equivalent doses, neutron and X-irradiation produce different levels of surface damage, with neutron irradiation being the more destructive. Early villous tip damage may perhaps be due to disruption of susceptible cells already at the extrusion zone, or to stromal damage

  14. Superconducting and normal state properties of carbon doped and neutron irradiated MgB2

    International Nuclear Information System (INIS)

    Wilke, R.H.T.; Samuely, P.; Szabo, P.; Holanova, Z.; Bud'ko, S.L.; Canfield, P.C.; Finnemore, D.K.

    2007-01-01

    Current research in MgB 2 focuses on the effects various types of perturbations have on the superconducting properties of this novel two-gap superconductor. In this article we summarize the effects of carbon doping and neutron irradiation in bulk MgB 2 . Low levels of carbon doping and light neutron irradiation result in significant enhancements in H c2 . At high fluences, where superconductivity is nearly fully suppressed, superconductivity can be restored through post exposure annealing. However, this results in a change in the interdependencies of the normal state and superconducting properties (ρ 0 , T c , H c2 ), with little or no enhancement in H c2

  15. Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling

    International Nuclear Information System (INIS)

    Bloom, E.E.; Stiegler, J.O.; Rowcliffe, A.F.; Leitnaker, J.M.

    1977-01-01

    The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels. 3 figures, 3 tables

  16. Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling

    International Nuclear Information System (INIS)

    Bloom, E.E.; Stiegler, J.O.; Rowcliffe, A.F.; Leitnaker, J.M.

    1979-01-01

    The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels

  17. Evaluation of neutron irradiation embrittlement in the Korean reactor pressure vessel steels (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, J. H.; Lee, B. S.; Chi, S. H.; Kim, J. H.; Oh, Y. J.; Yoon, J. H.; Kwon, S. C.; Park, D. G.; Kang, Y. H.; Choo, K. N.; Oh, J. M.; Park, S. J.; Kim, B. K.; Shin, Y. T.; Cho, M. S.; Sohn, J. M.; Kim, D. S.; Choo, Y. S.; Ahn, S. B.; Oh, W. H. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-05-01

    Reactor pressure vessel materials, which were produced by a domestic company, Doosan Heavy Industries and construction Co., Ltd., have been evaluated using the neutron irradiation facility HANARO. For this evaluation, instrumented capsules were used for neutron irradiation of various kinds of specimens made of different heats of steels, which are VCD(Y4), VCD+Al(U4), Si+Al(Y5), U4 weld metal, and U4 HAZ, respectively. The fast neutron fluence levels ranged 1 to 5 (x10{sup 19} n/cm{sup 2}, E>1MeV) depending on the specimens and the irradiation temperature was controlled within 290{+-}10 deg C. The test results showed that, in the ranking of the material properties of the base metals, both before and after neutron irradiation, Y5 is the best, U4 the next and Y4 the last. Y4 showed a substantial change by neutron irradiation as well as the properties was worse than others in the unirradiated state. However, Y5, which showed the best properties in unirradiated state, was also the best in the resistance for irradiation embrittlement and one can hardly detect the property change after irradiation. The weldment showed a reasonably good resistance to irradiation embrittlement while the unirradiated properties were worse than base metals. The RPV steels are all expected to meet the screening criteria of the USNRC codes and regulations during the end of plant life. 39 refs., 42 figs., 27 tabs. (Author)

  18. Scanning tunneling spectroscopy on neutron irradiated MgB2 thin films

    International Nuclear Information System (INIS)

    Di Capua, Roberto; Salluzzo, Marco; Vaglio, Ruggero; Ferdeghini, Carlo; Ferrando, Valeria; Putti, Marina; Xi Xiaoxing; Aebersold, Hans U.

    2007-01-01

    Neutron irradiation was performed on MgB 2 thin films grown by hybrid physical chemical vapor deposition. Samples irradiated with different neutron fluences, having different critical temperatures, were studied by scanning tunneling spectroscopy in order to investigate the effect of the introduced disorder on the superconducting and spectroscopic properties. A monotonic increase of the π gap with increasing disorder was found

  19. Scanning tunneling spectroscopy on neutron irradiated MgB{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Di Capua, Roberto [University of Napoli and CNR-INFM/Coherentia, Via Cinthia, Naples I-80126 (Italy)], E-mail: rdicapua@na.infn.it; Salluzzo, Marco; Vaglio, Ruggero [University of Napoli and CNR-INFM/Coherentia, Via Cinthia, Naples I-80126 (Italy); Ferdeghini, Carlo [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Ferrando, Valeria [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Pennsylvania State University, University Park, PA 16802 (United States); Putti, Marina [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Xi Xiaoxing [Pennsylvania State University, University Park, PA 16802 (United States); Aebersold, Hans U. [Paul Scherrer Institut, Villigen CH-5232 (Switzerland)

    2007-09-01

    Neutron irradiation was performed on MgB{sub 2} thin films grown by hybrid physical chemical vapor deposition. Samples irradiated with different neutron fluences, having different critical temperatures, were studied by scanning tunneling spectroscopy in order to investigate the effect of the introduced disorder on the superconducting and spectroscopic properties. A monotonic increase of the {pi} gap with increasing disorder was found.

  20. Physical model of evolution of oxygen subsystem of PLZT-ceramics at neutron irradiation and annealing

    CERN Document Server

    Kulikov, D V; Trushin, Y V; Veber, K V; Khumer, K; Bitner, R; Shternberg, A R

    2001-01-01

    The physical model of evolution of the oxygen subsystem defects of the ferroelectric PLZT-ceramics by the neutron irradiation and isochrone annealing is proposed. The model accounts for the effect the lanthanum content on the material properties. The changes in the oxygen vacancies concentration, calculated by the proposed model, agree well with the polarization experimental behavior by the irradiated material annealing

  1. Chemical consequences of the neutron irradiation of ionic antimony oxides and Fe Sb2O4

    Energy Technology Data Exchange (ETDEWEB)

    Facetti, J F [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

    1970-01-01

    The chemical consequences fo the neutron irradiation of ionic antimony oxides and Fe Sb2O4 are studied. The nature of the Sb-O2 bond effects the yield of SbV the higher the yield the more covalent the bond. In addition, the Fe Sb2O4 obeys the Maddock's rule.

  2. Neutron irradiation effects on in situ Nb3Sn superconducting wires

    International Nuclear Information System (INIS)

    Hirano, Y.; Fukumoto, M.; Kodaka, H.; Nishijima, S.; Okada, T.; Yoshida, H.

    1985-01-01

    Three types of ''in situ'' Nb 3 Sn conductors have been studied to determine the detrimental effects of neutron irradiation on critical temperature, critical current and AC losses. It was found that at fluences of 10 18 n/cm 2 , the critical temperature is degraded by approximately 10%. Degradation of AC loss is discussed in comparison with that of critical current density

  3. Neutron irradiation effects on magnetic properties of iron-nickel Invar alloys

    International Nuclear Information System (INIS)

    Morita, H.; Tanji, Y.; Hiroyoshi, H.; Nakagawa, Y.

    1983-01-01

    The Curie temperature of fcc Fe-Ni containing 30-50% Ni is reaised by neutron irradiation, although no appreciable change is detected in the X-ray diffraction pattern. These results are related to a tendency to two-phase separation of the fcc phase. (orig.)

  4. Effect of Neutron Irradiation on Beam-Column Interaction of Reinforced Concrete

    International Nuclear Information System (INIS)

    Kwon, Tae-Hyun; Park, Jiho; Kim, Jun Yeon; Kim, HyungTae; Park, Kyoungsoo; Kim, Sang-Ho

    2015-01-01

    Age-related effects on such RC structures have been extensively studied in detail. However, the effect of neutron irradiation requires further studies from its limited database. Most of RC structures have been regarded as sound as the neutron fluence below 1.0x10 19 n/cm 2 . The reduction of strength is not considered in a periodic inspection program at aging NPPs. However, RC structures, such as biological shields and supports for a reactor vessel, could be exposed to see the critical level of neutron fluence at years of operation. In this regard, beam-column interaction of a typical RC member is numerically investigated as a result of neutron irradiation. The effect of neutron irradiation on beam-column interaction is evaluated. ACI318 requires the strength reduction factor, ϕ=0.70, for the compression controlled area and the higher up to 0.9 as the tensile strain in steel reinforcement goes higher. This concept works well with this example. However, this does not take into account the energy dissipation capacity of the member but it only expresses the ultimate strength. Therefore, the current strength evaluation concept may be misleading when the material behavior of steel reinforcement becomes brittle due to the neutron irradiation. In such case, even for the transient and tension controlled area, the strength reduction factor needs to be modified to account for the potential ductility loss

  5. Analysis of microstress in neutron irradiated polyester fibre by X-ray ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Microstresses developed in the crystallites of polymeric material due to irradiation of high-energy particle causes peak broadening and shifting of X-ray diffraction lines to lower angle. Neutron irradiation significantly changes the material properties by displacement of lattice atoms and the generation of helium.

  6. Characterization of the fast neutron irradiation facility of the Portuguese Research Reactor after core conversion

    International Nuclear Information System (INIS)

    Marques, J.G.; Sousa, M.; Santos, J.P.; Fernandes, A.C.

    2011-01-01

    The fast neutron irradiation facility of the Portuguese Research Reactor was characterized after the reduction in uranium enrichment and rearrangement of the core configuration. In this work we report on the determination of the hardness parameter and the 1 MeV equivalent neutron flux along the facility, in the new irradiation conditions, following ASTM E722 standard.

  7. Influence of interstitial impurity atoms on point defect relaxation in neutron irradiated iron

    International Nuclear Information System (INIS)

    Weller, M.; Diehl, J.

    1975-01-01

    The aim of the investigation was to study the combined influence of neutron irradiation and interstitial impurities on the low temperature internal friction peaks as well as on those appearing at higher temperatures after annealing, in a more systematic manner, using irradiations at [de

  8. Report of the Working Group on low-temperature neutron irradiation

    International Nuclear Information System (INIS)

    1982-07-01

    This report summarizes deliberations at a Working Group meeting sponsored by the Department of Energy, Division of Materials Sciences for the purpose of: (1) assessing the need for maintaining a low temperature neutron irradiation program in the United States; and (2) recommending a course of action based on this assessment

  9. Investigation of hydrogen isotopes interaction processes with lithium under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zaurbekova, Zhanna, E-mail: zaurbekova@nnc.kz [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Skakov, Mazhyn; Ponkratov, Yuriy; Kulsartov, Timur; Gordienko, Yuriy; Tazhibayeva, Irina; Baklanov, Viktor; Barsukov, Nikolay [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Chikhray, Yevgen [Institute of Experimental and Theoretical Physics of Kazakh National University, Almaty (Kazakhstan)

    2016-11-01

    Highlights: • The experiments on study of helium and tritium generation and release processes under neutron irradiation from lithium saturated with deuterium are described in paper. ​ • The values of relative tritium and helium yield from lithium sample at different levels of neutron irradiation is calculated. • It was concluded that the main affecting process on tritium release from lithium is its interaction with lithium atoms with formation of lithium tritide. - Abstract: The paper describes the experiments on study of helium and tritium generation and release processes from lithium saturated with deuterium under neutron irradiation (in temperature range from 473 to 773 K). The diagrams of two reactor experiments show the time dependences of helium, DT, T{sub 2}, and tritium water partial pressures changes in experimental chamber with investigated lithium sample. According to experimental results, the values of relative tritium and helium yield from lithium sample at different levels of neutron irradiation were calculated. The time dependences of relative tritium and helium yield from lithium sample were plotted. It was concluded that the main affecting process on tritium release from lithium is its interaction with lithium atoms with formation of lithium tritide.

  10. DT fusion neutron irradiation of ORNL magnesium oxide crystals and BNL--LASL superconductor wires

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1978-01-01

    The DT fusion neutron irradiation of two ORNL magnesium oxide crystals and eleven BNL-LASL superconductor wires is described. The sample position and neutron dose record are given. The maximum neutron fluence on any sample was 2.16 x 10 16 neutrons/cm 2

  11. Effect of neutron irradiation on the cellular stage of Ni-Be alloy decomposition

    International Nuclear Information System (INIS)

    Larikov, L.N.; Borimskaya, S.T.

    1981-01-01

    Effects of neutron irradiation on the cellular stage of decomposition are investigated in deformed supersaturated solid solution Ni-1.92%Be by the X-ray structural and metallographic analyses. Radiation-initiated stimulation of the recovery properties in the deformed alloy and a lower rate of the cellular decomposition in irradiated samples are discovered [ru

  12. Time factor of BSH from intravenous infusion to neutron irradiation for BNCT in patients with glioblastoma

    International Nuclear Information System (INIS)

    Kageji, T.; Nagahiro, S.; Kitamura, K.; Nakagawa, Y.; Hatanaka, H.; Haritz, D.; Grochulla, F.; Haselsberger, K.; Gabel, D.

    2000-01-01

    The present report evaluates the time factor of BSH from infusion to irradiation in patients with glioblastoma as a cooperative study in Europe and Japan. For BNCT with BSH after intravenous infusion, this work confirms that the planned neutron irradiation after intravenous BSH infusion appears to be optimal around 12-19 hours after the infusion. (author)

  13. Theoretical description of the influence of neutron irradiation on viscoplastic properties of mild steel

    International Nuclear Information System (INIS)

    Pecherski, R.

    1978-01-01

    The physical bases of plastic deformation of mild steel are described. The influence of neutron irradiation on the change of mechanisms of plastic deformation is discussed in detail. Constitutive equations of viscoplasticity for irradiated mild steel are given. The problem of thickwalled viscoplastic spherical tank irradiated by neutrons is studied. (Z.R.)

  14. Neutronic irradiation effect in FeNi alloys, observed by magnetic measurements

    International Nuclear Information System (INIS)

    Sciani, V.; Lucki, G.

    1986-01-01

    In this work some aspects of radiation damage are analysed through the influence of neutron irradiation on magnetic properties of FeNi alloys. The main points emphasized are: radiation enhanced diffusion, determination of the activation energy for diffusion process and vacancies supersaturation, which is an important parameter from technological point of view and a necessary condition for the void formation. (Author) [pt

  15. Impurity effects in neutron-irradiated simple oxides: Implications for fusion devices

    International Nuclear Information System (INIS)

    Gonzalez, R.; Chen, Y.; Caceres, D.; Vergara, I.

    2006-01-01

    Radiation damage induced by neutron irradiation was studied in undoped MgO crystals and in MgO doped with either iron, hydrogen or lithium impurities. The oxygen-vacancy concentration produced by irradiation increases with neutron fluence. The net production rates resulting from irradiations with 14.8 MeV neutrons are about twice those produced by fission neutrons. In nominally pure crystals, the oxygen-vacancy concentration incurred by the fission-neutron irradiation is higher in crystals with a larger number of inherent impurities (such as iron) due to trapping of interstitials by impurities. Suppression of these defects is observed in MgO:H crystals and attributed to migration of oxygen vacancies to microcavities filled with H 2 gas. In MgO:Li crystals irradiated with neutron fluences below 10 18 n/cm 2 , most of the oxygen vacancies are camouflaged as hydride ions. Nanoindentation experiments show that hardness increases with neutron fluence and is independent of the presence of lithium in the crystal. Comparison between a neutron-irradiated and a thermochemically reduced crystal containing similar concentrations of oxygen vacancies shows that 70% of the neutron-irradiation hardening is produced by interstitials, 30% by oxygen vacancies and a negligible amount by higher-order point defects

  16. Neutron irradiation of sapphire for compressive strengthening. II. Physical properties changes

    Energy Technology Data Exchange (ETDEWEB)

    Regan, Thomas M. E-mail: thomas_regan@uml.edu; Harris, Daniel C. E-mail: harrisdc@navair.navy.mil; Blodgett, David W.; Baldwin, Kevin C.; Miragliotta, Joseph A.; Thomas, Michael E.; Linevsky, Milton J.; Giles, John W.; Kennedy, Thomas A.; Fatemi, Mohammad; Black, David R.; Lagerloef, K. Peter D

    2002-01-01

    Irradiation of sapphire with fast neutrons (0.8-10 MeV) at a fluence of 10{sup 22}/m{sup 2} increased the c-axis compressive strength and the c-plane biaxial flexure strength at 600 deg. C by a factor of {approx}2.5. Both effects are attributed to inhibition of r-plane twin propagation by damage clusters resulting from neutron impact. The a-plane biaxial flexure strength and four-point flexure strength in the c- and m-directions decreased by 10-23% at 600 deg. C after neutron irradiation. Neutron irradiation had little or no effect on thermal conductivity, infrared absorption, elastic constants, hardness, and fracture toughness. A featureless electron paramagnetic resonance signal at g=2.02 was correlated with the strength increase: This signal grew in amplitude with increasing neutron irradiation, which also increased the compressive strength. Annealing conditions that reversed the strengthening also annihilated the g=2.02 signal. A signal associated with a paramagnetic center containing two Al nuclei was not correlated with strength. Ultraviolet and visible color centers also were not correlated with strength in that they could be removed by annealing at temperatures that were too low to reverse the compressive strengthening effect of neutron irradiation.

  17. Fiscal year 1976 DT fusion neutron irradiations and dosimetry at the LLL rotating target neutron source

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1977-01-01

    The DT fusion neutron irradiation of 319 samples during 19 irradiation periods (beam-on time of more than 1026 hours) is described. Experiments from 24 individuals representing 11 institutions are summarized. The numbers of the UCID dosimetry reports detailing each of the irradiations are given

  18. Study of irradiation damage structures in austenitic stainless steels

    International Nuclear Information System (INIS)

    Hamada, Shozo

    1997-08-01

    The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs

  19. Study of irradiation damage structures in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Shozo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-08-01

    The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs.

  20. Effect of preliminary neutron irradiation on helium blistering of 0Kh16N15M3B steel

    International Nuclear Information System (INIS)

    Chernov, I.I.; Kalin, B.A.; Skorov, D.M.; Shishkin, G.N.; Ivanov, M.V.

    1982-01-01

    The method of electron microscopy has been applied to investigate the effect of preliminary neutron irradiation on the OKh16N15M3B steel blistering under irradiation by 20 keV helium ions with (1-10)x10 21 ion/m 2 doses at the temperature below 373 K. It is shown that neutron irradiation shifts critical doses of blister formation and intense scaling towards higher doses. But after the incubation period the erosion of steel preliminary neutron irradiated grows with the increase of helium ion dose above 7x10 21 ion/m 2 . Short-term heating of neutron irradiated samples during 15 min at 1173 K does not practically affect the beginning of intense scaling of the surface

  1. Deuterium trapping at vacancy clusters in electron/neutron-irradiated tungsten studied by positron annihilation spectroscopy

    Science.gov (United States)

    Toyama, T.; Ami, K.; Inoue, K.; Nagai, Y.; Sato, K.; Xu, Q.; Hatano, Y.

    2018-02-01

    Deuterium trapping at irradiation-induced defects in tungsten, a candidate material for plasma facing components in fusion reactors, was revealed by positron annihilation spectroscopy. Pure tungsten was electron-irradiated (8.5 MeV at ∼373 K and to a dose of ∼1 × 10-3 dpa) or neutron-irradiated (at 573 K to a dose of ∼0.3 dpa), followed by post-irradiation annealing at 573 K for 100 h in deuterium gas of ∼0.1 MPa. In both cases of electron- or neutron-irradiation, vacancy clusters were found by positron lifetime measurements. In addition, positron annihilation with deuterium electrons was demonstrated by coincidence Doppler broadening measurements, directly indicating deuterium trapping at vacancy-type defects. This is expected to cause significant increase in deuterium retention in irradiated-tungsten.

  2. Study on changes of sperm count and testis tissue in black mouse after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Ki Jung; Seo, Won Sook [KAERI, Daejeon (Korea, Republic of); Son, Hwa Young [Chungnam National Univ., Daejeon (Korea, Republic of)

    2006-03-15

    For the purpose of the biological effect in black mouse by neutron irradiation, mice were irradiated with 16 or 32 Gy neutron (flux: 1.036739E+09) by lying flat pose at BNCT facility on HANARO Reactors. And 90 days later of irradiation, physical changes of testis and testis tissue were examined. There were no weight changes but a little bit volume changes and sperm counts in the tests. Atrophy of seminiferous tubules irradiated with 32 Gy neutron is increased in number and severity and those in stage VI showed depletion of spermatogonia and pachytene spermatocytes compared to the non-irradiated control group. Testis damage of black mouse was not recovered after long time by 32 Gy neutron irradiation.

  3. Study on changes of sperm count and testis tissue in black mouse after neutron irradiation

    International Nuclear Information System (INIS)

    Chun, Ki Jung; Seo, Won Sook; Son, Hwa Young

    2006-01-01

    For the purpose of the biological effect in black mouse by neutron irradiation, mice were irradiated with 16 or 32 Gy neutron (flux: 1.036739E+09) by lying flat pose at BNCT facility on HANARO Reactors. And 90 days later of irradiation, physical changes of testis and testis tissue were examined. There were no weight changes but a little bit volume changes and sperm counts in the tests. Atrophy of seminiferous tubules irradiated with 32 Gy neutron is increased in number and severity and those in stage VI showed depletion of spermatogonia and pachytene spermatocytes compared to the non-irradiated control group. Testis damage of black mouse was not recovered after long time by 32 Gy neutron irradiation

  4. Extra spots in the electron diffraction patterns of neutron irradiated zirconium and its alloys

    International Nuclear Information System (INIS)

    Madden, P.K.

    1977-01-01

    Specimens of neutron irradiated zirconium and its alloys were examined in the transmission electron microscope. Groups of extra spots, often exhibiting four-fold symmetry, were observed in thin foil electron diffraction patterns of these specimens. The 'extra-spot' structure, like the expected black-dot/small scale dislocation loop neutron irradiated damage, is approximately 100 A in size. Its nature is uncertain. It may be related to irradiation damage or to some artefact introduced during specimen preparation. If it is the latter, then published irradiation damage defect size distributions and determined irradiation growth strains of other investigators, may require modification. The present inconclusive results indicate that extra-spot structure is likely to consist of oxide particles, but may correspond to hydride precipitation or decoration effects, or even, to electron beam effects. (author)

  5. Phase stability of oxide dispersion-strengthened ferritic steels in neutron irradiation

    International Nuclear Information System (INIS)

    Yamashita, S.; Oka, K.; Ohnuki, S.; Akasaka, N.; Ukai, S.

    2002-01-01

    Oxide dispersion-strengthened ferritic steels were irradiated by neutrons up to 21 dpa and studied by microstructural observation and microchemical analysis. The original high dislocation density did not change after neutron irradiation, indicating that the dispersed oxide particles have high stability under neutron irradiation. However, there is potential for recoil resolution of the oxide particles due to ballistic ejection at high dose. From the microchemical analysis, it was implied that some of the complex oxides have a double-layer structure, such that TiO 2 occupied the core region and Y 2 O 3 the outer layer. Such a structure may be more stable than the simple mono-oxides. Under high-temperature irradiation, Laves phase was the predominant precipitate occurring at grain boundaries α phase and χ phase were not observed in this study

  6. Irradiation hardening and localized deformation of neutron-irradiated α-iron single crystals

    International Nuclear Information System (INIS)

    Mughrabi, H.; Stroehle, D.; Wilkens, M.

    1981-01-01

    The early yielding behaviour of neutron-irradiated α iron single crystals orientated for single slip was investigated as a function of neutron dose. In the range of neutron doses between approx. equal to 10 18 and approx. equal to 10 19 n/cm 2 , the irradiation hardening increment was found to be almost constant. Qualitative modifications of this behaviour were observed in the case of predeformed specimens. The localized deformation of the neutron-irradiated specimens by dislocation channelling was investigated by slip-line observations, transmission electron microscopy and X-ray topography. A model of localized deformation is proposed in order to explain the development of the observed asymmetric dislocation double layers which bound the channels and transmit characteristic misorientations. (orig.)

  7. Neutron irradiation effects on the ductile-brittle transition of ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1997-08-01

    Ferritic/martensitic steels such as the conventional 9Cr-1MoVNb (Fe-9Cr-1Mo-0.25V-0.06Nb-0.1C) and 12Cr-1MoVW (Fe-12Cr-1Mo-0.25V-0.5W-0.5Ni-0.2C) steels have been considered potential structural materials for future fusion power plants. The major obstacle to their use is embrittlement caused by neutron irradiation. Observations on this irradiation embrittlement is reviewed. Below 425-450{degrees}C, neutron irradiation hardens the steels. Hardening reduces ductility, but the major effect is an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy, as measured by a Charpy impact test. After irradiation, DBTT values can increase to well above room temperature, thus increasing the chances of brittle rather than ductile fracture.

  8. Model of defect reactions and the influence of clustering in pulse-neutron-irradiated Si

    International Nuclear Information System (INIS)

    Myers, S. M.; Cooper, P. J.; Wampler, W. R.

    2008-01-01

    Transient reactions among irradiation defects, dopants, impurities, and carriers in pulse-neutron-irradiated Si were modeled taking into account the clustering of the primal defects in recoil cascades. Continuum equations describing the diffusion, field drift, and reactions of relevant species were numerically solved for a submicrometer spherical volume, within which the starting radial distributions of defects could be varied in accord with the degree of clustering. The radial profiles corresponding to neutron irradiation were chosen through pair-correlation-function analysis of vacancy and interstitial distributions obtained from the binary-collision code MARLOWE, using a spectrum of primary recoil energies computed for a fast-burst fission reactor. Model predictions of transient behavior were compared with a variety of experimental results from irradiated bulk Si, solar cells, and bipolar-junction transistors. The influence of defect clustering during neutron bombardment was further distinguished through contrast with electron irradiation, where the primal point defects are more uniformly dispersed

  9. Spallation and 14-MeV neutron irradiation of stabilized NbTi superconductors

    International Nuclear Information System (INIS)

    Hahn, P.; Brown, B.S.; Weber, H.W.; Guinan, M.W.

    1983-08-01

    The results on 5 K irradiation available so far may be summarized as follows. (1) Increases of j/sub c/ following neutron irradiation occur only in conductors which are far from the optimal metallurgical treatments. (2) The changes of j/sub c/ following neutron irradiation and a thermal cycle to room temperature are small and in most cases comparable to the results obtained after 77 K irradiation. (3) The data available so far indicate that the degradation of j/sub c/ at 8 T is larger by about 5 to 10% than the corresponding changes at 5 T at a neutron fluence of 1.3 x 10 22 m -2 (E > 0.1 MeV). (4) The increase of Cu-resistivity is significant even after a thermal cycle to room temperature and requires design changes for a stable magnet operation

  10. Characterization of phosphorus segregation in neutron-irradiated Russian pressure vessel steel weld

    International Nuclear Information System (INIS)

    Miller, M.K.; Jayaram, R.; Russell, K.F.

    1995-01-01

    An atom probe field ion microscopy characterization of three Russian pressure vessel steels has been performed. Field ion micrographs of several lath boundaries have indicated that they are decorated with a semicontinuous film of discrete brightly-imaging precipitates that were identified as molybdenum carbonitrides. In addition, extremely high phosphorus levels were measured at the lath boundaries. The phosphorus was found to be confined to an extremely narrow region indicative of monolayer type segregation. The phosphorus coverage determined from the atom probe results of the unirradiated materials agree with predictions based on McLean's equilibrium model of grain boundary segregation. The boundary phosphorus coverage of a neutron-irradiated weld material was significantly higher than in the unirradiated material. Ultrafine darkly-imaging copper- and phosphorus-enriched precipitates were also observed in the matrix of the neutron-irradiated material. (orig.)

  11. Microstructural evolution of neutron-irradiated Ni-Si and Ni-Al alloys

    International Nuclear Information System (INIS)

    Takahashi, H.; Garner, F.A.

    1992-01-01

    Additions of silicon and aluminium suppress the neutron-induced swelling of pure nickel but to different degrees. Silicon is much more effective initially when compared to aluminium on a per atom basis but silicon exhibits a nonmonotonic influence on swelling with increasing concentration. Silicon tends to segregate toward grain boundaries while aluminium segregates away from these boundaries. Whereas the formation of the Ni 3 Si phase is frequently observed in charged particle irradiation experiments conducted at much higher displacement rates, it did not occur during neutron irradiation in this study. Precipitation also did not occur in Ni-5Al during neutron irradiation, nor has it been reported to occur during ion irradiation. (orig.)

  12. Fast neutron irradiation induced changes in the optical and thermal properties of modified polyvinyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Abou Taleb, W.M. [Alexandria Univ. (Egypt); Madi, N.K.; Kassem, M.E.; El-Khatib, A.M. [Alexandria Univ. (Egypt). Dept. of Physics

    1996-05-01

    The effect of both dopant and neutron radiation on the optical and thermal properties of polyvinyl chloride (PVC) has been studied. The doped samples with Pb and Cd were irradiated with a 14 MeV-neutron fluence in the range 7-28.8 x 10{sup 9} n/cm{sup 2}. The optical energy gap E{sub op} exhibits a significant dependence on the type of additive and the neutron irradiation fluence. The specific heat at constant pressure C{sub p} showed a nonmonotonical change with radiation fluence. The results of this study show that PVC:Pb behaves as a crystalline structure which is only slightly affected by neutron irradiation, while PVC:Cd is highly affected. (author).

  13. Fast neutron irradiation induced changes in the optical and thermal properties of modified polyvinyl chloride

    International Nuclear Information System (INIS)

    Abou Taleb, W.M.; Madi, N.K.; Kassem, M.E.; El-Khatib, A.M.

    1996-01-01

    The effect of both dopant and neutron radiation on the optical and thermal properties of polyvinyl chloride (PVC) has been studied. The doped samples with Pb and Cd were irradiated with a 14 MeV-neutron fluence in the range 7-28.8 x 10 9 n/cm 2 . The optical energy gap E op exhibits a significant dependence on the type of additive and the neutron irradiation fluence. The specific heat at constant pressure C p showed a nonmonotonical change with radiation fluence. The results of this study show that PVC:Pb behaves as a crystalline structure which is only slightly affected by neutron irradiation, while PVC:Cd is highly affected. (author)

  14. Point defects and magnetic properties of neutron irradiated MgO single crystal

    Directory of Open Access Journals (Sweden)

    Mengxiong Cao

    2017-05-01

    Full Text Available (100-oriented MgO single crystals were irradiated to introduce point defects with different neutron doses ranging from 1.0×1016 to 1.0×1020 cm-2. The point defect configurations were studied with X-ray diffuse scattering and UV-Vis absorption spectra. The isointensity profiles of X-ray diffuse scattering caused by the cubic and double-force point defects in MgO were theoretically calculated based on the Huang scattering theory. The magnetic properties at different temperature were measured with superconducting quantum interference device (SQUID. The reciprocal space mappings (RSMs of irradiated MgO revealed notable diffuse scattering. The UV-Vis spectra indicated the presence of O Frenkel defects in irradiated MgO. Neutron-irradiated MgO was diamagnetic at room temperature and became ferromagnetic at low temperature due to O Frenkel defects induced by neutron-irradiation.

  15. DAMAGE IN MOLYBDENUM ASSOCIATED WITH NEUTRON IRRADIATION AND SUBSEQUENT POST-IRRADIATION ANNEALING

    Energy Technology Data Exchange (ETDEWEB)

    Mastel, B.

    1963-07-23

    Molybdemum containing carbon was studied in an attempt to establish the combined effect of impurity content and neutron irradiation on the properties and structure of specific metals. Molybdenum foils were punched into discs and heat treated in vacuum. They were then slow-cooled and irradiated. After irradiation and subsequent decay of radioactivity to a low level the foils were subjected to x-ray diffraction measurements. Cold-worked foils with less than 10 ppm carbon showed no change in microstructure due to irradiation. Molybdenum foils that were annealed prior to irradiation showed spot defects. In foils containing up to 500 ppm carbon, it was concluded that the small loops present after irradiation are due to the clustering of point defects at interstitial carbon atoms, followed by collapse to form a dislocation loop. The amount of lattice expansion after irradiation was strongly dependent on impurity content. Neutron irradiation was found to reduce the number of active slip systems. (M.C.G.)

  16. A design study on hyper-thermal neutron irradiation field for neutron capture therapy at Kyoto University Reactor

    International Nuclear Information System (INIS)

    Sakurai, Y.; Kobayashi, T.

    2000-01-01

    A study about the installation of a hyper-thermal neutron converter to a clinical collimator was performed, as a series of the design study on a hyper-thermal neutron irradiation field at the Heavy Water Neutron Irradiation Facility of Kyoto University Reactor. From the parametric-surveys by Monte Carlo calculation, it was confirmed that the practical irradiation field of hyper-thermal neutrons would be feasible by the modifications of the clinical collimator and the bismuth-layer structure. (author)

  17. Characteristics of neutron irradiation facility and dose estimation method for neutron capture therapy at Kyoto University research reactor institute

    International Nuclear Information System (INIS)

    Kobayashi, T.; Sakurai, Y.; Kanda, K.

    2001-01-01

    The neutron irradiation characteristics of the Heavy Water Neutron Irradiation Facility (HWNIF) at the Kyoto University Research Reactor Institute (KIJRRI) for boron neutron capture therapy (BNCT), is described. The present method of dose measurement and its evaluation at the KURRI, is explained. Especially, the special feature and noticeable matters were expounded for the BNCT with craniotomy, which has been applied at present only in Japan. (author)

  18. Increase of the electrical resistance of thin aluminium film due to 14 MeV neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, S K; Kumar, U; Singh, S P; Bhattacharya, S; Nigam, A K [Banaras Hindu Univ. (India). Dept. of Physics

    1978-01-01

    The effect of 14 MeV neutron bombardment on the electrical resistance of 500 A thick vacuum-coated Al film is investigated. In the beginning, a slow, then sharp and finally again slow increase is observed in the electrical resistance of the film. Transmission electron micrographs of the film after the same dose of neutron irradiation show a large number of defects produced in the film due to neutron irradiation, which seems to be the cause of this increase.

  19. Resistivity recovery of neutron-irradiated and cold-worked thorium

    International Nuclear Information System (INIS)

    Tang, J.T.

    1977-02-01

    Results from a study of the resistivity recovery of neutron-irradiated and cold-worked thorium on isochronal annealing, activation energies, and isothermal annealing and kinetics are discussed. The nature and extent of radiation effects on the resistivity of thorium at 80 0 K, interpretation of stage II recovery above 80 0 K, and activation energy and interpretation of stage III recovery are also discussed. There are 79 references

  20. Comparison of damage microstructures in neutron-irradiated vanadium and iron

    International Nuclear Information System (INIS)

    Horton, L.L.; Farrell, K.

    1983-01-01

    The cavity morphology and dislocation loop geometry in bcc vanadium are compared with the previously reported observations for neutron-irradiated iron. The specimens were vanadium (V) with 100 wppM of interstitial impurities and vanadium with boron carbide additions (V-B 4 C) which were irradiated to approx. 1 dpa in the same Oak Ridge Research Reactor capsules as the iron specimens

  1. Contribution to the study of recoil species produced by potassium ferrocyanide neutron irradiation

    International Nuclear Information System (INIS)

    Meriadec Vernier de Byans, B.

    1969-04-01

    The chemical species produced by potassium ferrocyanide neutron irradiation were separated and identified. The study of their behaviour upon thermal annealing has allowed to establish a scheme of reaction as well as a kinetic treatment of the data. Activation energies are determined in different conditions and the effects of radiation dose, oxygen and water of crystallisation upon the activation energies were studied. Preliminary E.S.R. data and its relevance to the decomposition process is also discussed. (authors) [fr

  2. Anisotropy variation of crystallographic orientation in pyrocarbon coatings of fuel particles by annealing and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Koizlik, K.

    1973-04-15

    This document is a translation of those parts of the German report Jul-868-RW concerned with changes in anisotropy as determined using an optical technique on pyrocarbon coatings on fuel particles resulting from annealing and neutron irradiations. Two lists of contents are included, one is for the present document and the other is the full contents of the original report and is included for the generl interest of users.

  3. Short-range order of amorphous FeNiB alloy after neutron irradiation

    International Nuclear Information System (INIS)

    Miglierini, M.; Sitek, J.; Baluch, S.; Cirak, J.; Lipka, J.

    1990-01-01

    Transmission Moessbauer spectroscopy was used to study irradiation-induced changes in the short-range order of an amorphous Fe 80-x Ni x B 20 alloy. Neutron irradiation led to an increase of the width of a hyperfine field distribution implying atomic rearrangement towards disordering. Changes in a mean value of a HFD and Moessbauer line areas can be associated with a reorientation of spins due to radiation damage. (orig.)

  4. Investigation of the combined effect of neutron irradiation and electron beam exposure on pure tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Van Renterghem, W., E-mail: wvrenter@sckcen.be; Uytdenhouwen, I., E-mail: iuytdenh@sckcen.be

    2016-08-15

    Pure tungsten samples were neutron irradiated in the BR2 reactor of SCK·CEN to fluences of 1.47 × 10{sup 20} n/cm{sup 2} and 4.74 × 10{sup 20} n/cm{sup 2} at 300 °C under Helium atmosphere and exposed to the electron beam of the Judith 1 installation The effect of these treatments on the defect structure was studied with transmission electron microscopy. In the irradiated samples the defect structure in the bulk is compared to the structure at the surface. The neutron irradiation created a large amount of a/2‹111› type dislocation loops forming dislocation rafts. The loop density increased from 8.5 × 10{sup 21}/m³ to 9 × 10{sup 22}/m³ with increasing dose, while the loop size decreased from 5.2 nm to 3.5 nm. The electron beam exposure induced significant annealing of the defects and almost all of the dislocation loops were removed. The number of line dislocations in that area increased as a result of the thermal stresses from the thermal shock. - Highlights: • Neutron irradiated and electron beam exposed tungsten samples were studied with transmission electron microscopy. • Neutron irradiation creates dislocation loops and rafts, while voids are created at higher irradiation dose. • No precipitates of transmutation products were found under these low dose irradiation conditions. • Electron beam exposure annihilates the dislocation loops and rafts.

  5. Effect of fast neutron irradiation on the thermal and electrical properties of acrylic resin

    International Nuclear Information System (INIS)

    Madi, N.K.; El-Khatib, A.M.; Kassem, M.E.; Ammar, E.A.

    1993-01-01

    Infrared technique was used to elucidate the effect of neutron irradiation on the structure of the polymethyl methacrylate (PMMA). It was found that PMMA resists large doses of irradiation at room temperature. The thermo-mechanical and electrical conductivity experiments have been applied to confirm the chemical results. The results show that the physical properties were slightly improved. The observations are correlated with the crystallinity produced by the accumulation of stable radiation defects. (author). 12 refs., 5 figs

  6. Correlative Microscopy of Alpha Prime Precipitation in Neutron-Irradiated Fe-Cr-Al Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Samuel A. [Univ. of Wisconsin, Madison, WI (United States)

    2016-12-01

    Fe-Cr-Al alloys are currently being considered for accident tolerant light water reactor fuel cladding applications due to their superior high temperature oxidation and corrosion resistance compared to Zr-based alloys. This work represents the current state-of-the-art on both techniques for analysis of α' precipitate microstructures and the processes and mechanisms governing its formation in neutron-irradiated Fe-Cr-Al alloys.

  7. Spontaneous recombination volumes of Frenkel defects in neutron-irradiated non-fcc metals

    International Nuclear Information System (INIS)

    Nakagawa, M.; Mansel, W.; Boening, K.; Rosner, P.; Vogl, G.

    1979-01-01

    Production and production-rate curves for the non-fcc metals Fe, Mo, Ta, W, Zr, and Sn are obtained by electrical-resistivity measurements taken at 4.6 K during reactor neutron irradiations. The saturation concentration of Frenkel defects, c/sub s/, and the recombination volume v/sub o/ are evaluated. A parabolic relation between the spontaneous recombination volume v 0 and the compressibility kappa for a series of bcc metals is found

  8. Efigie: a computer program for calculating end-isotope accumulation by neutron irradiation and radioactive decay

    International Nuclear Information System (INIS)

    Ropero, M.

    1978-01-01

    Efigie is a program written in Fortran V which can calculate the concentration of radionuclides produced by neutron irradiation of a target made of either a single isotope or several isotopes. The program includes optimization criteria that can be applied when the goal is the production of a single nuclide. The effect of a cooling time before chemical processing of the target is also accounted for.(author) [es

  9. The Edinburgh experience of treating sarcomas of soft tissues and bone with neutron irradiation

    International Nuclear Information System (INIS)

    Duncan, W.; Arnott, S.J.; Jack, W.J.L.

    1986-01-01

    The experience of treating 30 patients with sarcomas of soft tissue and bone with d(15)+Be neutron irradiation is reported. The local control of measurable soft-tissue sarcomas was 38.5% (minimum follow-up 2 years), which is similar to that expected after photon therapy. The radiation morbidity was unacceptably high (50%). Bone tumours did not respond well; in only one out of nine was lasting local tumour control achieved. (author)

  10. Low cycle fatigue properties of neutron irradiated solid HIP 316L(N). ITER Task T214, NET deliverable GB6 ECN-5

    International Nuclear Information System (INIS)

    Rensman, J.; Van Osch, E.V.; Tjoa, G.L.; Boskeljon, J.; Van Hoepen, J.

    1998-05-01

    The Low Cycle Fatigue (LCF) properties of neutron irradiated Hot Isostatically Pressed (HIP) joints of type 316L(N) stainless steel (heat PM-130) have been measured, as well as the LCF properties of reference 316L(N)-ERHII. Cylindrical LCF test specimens of 3 mm diameter were irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands, simulating the first wall conditions of future fusion reactors by a combination of high displacement damage with proportional amounts of helium. The solid HIP specimens were irradiated up to a target dose level of 5 dpa at a temperature of 550K. The damage levels realised range from 3.0 to 4.4 dpa, with helium contents up to 41 appm. Testing temperature was equal to the irradiation temperature: 550K. The report contains the experimental conditions and summarises the results, which are given in terms of first cycle stress, the peak stress, the number of cycles where the peak stress is reached, the stress at half life and the plastic strain at half life, and the total number of cycles to failure, N f . The main conclusions are that the unirradiated solid-HIP materials has the same LCF properties as unirradiated 316L(N)-ERHII plate material. The neutron irradiation induces both hardening and reduction of fatigue life. The bond does not seem to have any effect on the fatigue properties for the unirradiated solid HIP 316L(N), whereas a combined effect of irradiation and the bond cannot be established. No failures related to debonding of the joint were observed for the tests. 7 refs

  11. Apoptosis of nasopharyngeal carcinoma cell line (CNE-2) induced by neutron irradiation

    International Nuclear Information System (INIS)

    Liang Ke; He Shaoqin; Feng Yan; Tang Jinhua; Feng Qinfu; Shen Yu; Yin Weibo; Xu Guozhen; Liu Xinfan; Wang Luhua; Gao Li

    1999-01-01

    Objective: To study the apoptotic response of the nasopharyngeal carcinoma cell line (CNE-2) induced by neutron irradiation. Methods: CNE-2 cells were cultured as usual. Using the techniques of DNA agarose gel electrophoresis and DNA special fluorescent staining, the status of apoptosis in CNE-2 cells after neutron irradiation was detected. Results: It was shown that the apoptosis can be induced in CNE-2 cell after neutron radiation. Six hrs, after different doses of neutron (0/0.667/1.333/2.000/2.667/3.333 Gy) and X-ray 0/2/4/6/8/10 Gy) irradiation the apoptotic rates were 2.4%, 6.3%, 7.1%, 9.5%, 13.5%, 14.6% and 2.4%, 3.8%, 5.7%, 7.8%, 10.4%, 11.7%, respectively; at 48 hrs they were 18.3%, 21.5%, 22.8%, 29.3%, 34.2% and 13.7%, 17.6%, 21.3%, 25.6%, 28.9%, respectively. At 10 hrs after neutron irradiation the DNA ladder of apoptosis could be detected between 0.667-3.333 Gy doses in CNE-2 cells by DNA agarose gel electrophoresis. Conclusion: Neutron radiation can induce apoptosis in tumor cells. Compared with the X-ray, neutron induces apoptosis in larger extent than X-ray in the same condition; meanwhile, apoptosis after irradiation is dose and time dependent

  12. Determination of tritium generation and release parameters at lithium CPS under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ponkratov, Yuriy, E-mail: ponkratov@nnc.kz [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Baklanov, Viktor; Skakov, Mazhyn; Kulsartov, Timur; Tazhibayeva, Irina; Gordienko, Yuriy; Zaurbekova, Zhanna; Tulubayev, Yevgeniy [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Chikhray, Yevgeniy [Institute of Experimental and Theoretical Physics of Kazakh National University, Almaty (Kazakhstan); Lyublinski, Igor [JSC “Star”, Moscow (Russian Federation); NRNU “MEPhI”, Moscow (Russian Federation); Vertkov, Alexey [JSC “Star”, Moscow (Russian Federation)

    2016-11-01

    Highlights: • The main parameters of tritium generation and release from lithium capillary-porous system (CPS) under neutron irradiation at the IVG.1 M research reactor is described in paper. • In the experiments a very small tritium release was fixed likely due to its high solubility in liquid lithium. • If the lithium CPS will be used as a plasma facing material in temperature range up to 773 K under neutron irradiation only helium will release from lithium CPS into a vacuum chamber. - Abstract: This paper describes the main parameters of tritium generation and release from lithium capillary-porous system (CPS) under neutron irradiation at the IVG.1 M research reactor. The experiments were carried out using the method of mass-spectrometric registration of released gases and using a specially constructed ampoule device. Irradiation was carried out at different reactor thermal powers (1, 2 and 6 MW) and sample temperatures from 473 to 773 K. In the experiments a very small tritium release was detected likely due to its high solubility in liquid lithium. It can be caused by formation of lithium tritide during tritium diffusion to the lithium surface.

  13. The effect of low-dose neutron irradiation on extracellular matrix

    International Nuclear Information System (INIS)

    Chen Tiehe; Lu Yongjie; Chai Mingsheng; Peng Wulin; Yang Yifang; Pan Yan; Chen Jinguo

    2003-01-01

    Projective: To study the effect of neutron irradiation on extracellular matrix. Methods: 120 male wistar rats were divided into four groups at random, and then exposed to neutron of 252 Cf-source at the doses of 0, 0.29, 0.62 and 1.20 Gy, respectively. After the exposure of 3 days, 1 month and 2 months, the rats were sacrificed and lung tissue specimens stored at -30 degree C. Hyaluronan, laminin, type III procollagen and type IV collagen in the lung tissue were detected by the method of radioimmunoassay. Results: The differences of the levels of hyaluronan in lung tissue among the groups were unsignificant. The levels of laminin in 0.29, 0.62 and 1.20 Gy groups after the 3-day exposure were remarkably different to those of the control group, and unable to recover completely even 2 months after the exposure. The levels of type IV collagen in higher three irradiated groups were all higher, but not significantly. The levels of type III procollagen in the early stage after exposure were higher, and later they lowered. Conclusion: The levels of some components of extracellular matrix in the lung tissue of rat can be changed by low-dose of neutron irradiation, but their variational modes and degrees depend on the dose of neutron irradiation and the length of period after exposure

  14. Large lattice relaxation deep levels in neutron-irradiated GaN

    International Nuclear Information System (INIS)

    Li, S.; Zhang, J.D.; Beling, C.D.; Wang, K.; Wang, R.X.; Gong, M.; Sarkar, C.K.

    2005-01-01

    Deep level transient spectroscopy (DLTS) and deep level optical spectroscopy (DLOS) measurements have been carried out in neutron-irradiated n-type hydride-vapor-phase-epitaxy-grown GaN. A defect center characterized by a DLTS line, labeled as N1, is observed at E C -E T =0.17 eV. Another line, labeled as N2, at E C -E T =0.23 eV, seems to be induced at the same rate as N1 under irradiation and may be identified with E1. Other defects native to wurtzite GaN such as the C and E2 lines appear to enhance under neutron irradiation. The DLOS results show that the defects N1 and N2 have large Frank-Condon shifts of 0.64 and 0.67 eV, respectively, and hence large lattice relaxations. The as-grown and neutron-irradiated samples all exhibit the persistent photoconductivity effect commonly seen in GaN that may be attributed to DX centers. The concentration of the DX centers increases significantly with neutron dosage and is helpful in sustaining sample conductivity at low temperatures, thus making possible DLTS measurements on N1 an N2 in the radiation-induced deep-donor defect compensated material which otherwise are prevented by carrier freeze-out

  15. Installation and measurement capacity of 3 x 592 GBq 241Am-Be neutron irradiation cell

    International Nuclear Information System (INIS)

    Bulut, Serdar; Celenk, I.

    2013-01-01

    In this study, the installation and measurement capacity of the neutron irradiation system are investigated. First of all an irradiation geometry enabling optimum irradiation was designed for three 241 Am-Be sources each of it having 592 GBq activity. Neutron irradiation system was installed after design and optimization of the system including the design of appropriate moderator and shielding were completed. Radiation safety standards of the Neutron Research Laboratory fulfilling the requirements of national regulation were achieved with unique configuration of the shielding materials. In this study the results of qualitative and quantitative detection limits obtained for Na, Al, Cl, K, Ti, V, Mn, Fe, Co, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Mo, Ru, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Yb, Lu, Hf, W, Pt, Au, Th and U elements by using the neutron irradiation cell comprising 3 x 592 GBq 241 Am-Be isotopic neutron source are presented and discussed. (orig.)

  16. Swelling and swelling resistance possibilities of austenitic stainless steels in fusion reactors

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1983-01-01

    Fusion reactor helium generation rates in stainless steels are intermediate to those found in EBR-II and HFIR, and swelling in fusion reactors may differ from the fission swelling behavior. Advanced titanium-modified austenitic stainless steels exhibit much better void swelling resistance than AISI 316 under EBR-II (up to approx. 120 dpa) and HFIR (up to approx. 44 dpa) irradiations. The stability of fine titanium carbide (MC) precipitates plays an important role in void swelling resistance for the cold-worked titanium-modified steels irradiated in EBR-II. Futhermore, increased helium generation in these steels can (a) suppress void conversion, (b) suppress radiation-induced solute segregation (RIS), and (c) stabilize fine MC particles, if sufficient bubble nucleation occurs early in the irradation. The combined effects of helium-enhanced MC stability and helium-suppressed RIS suggest better void swelling resistance in these steels for fusion service than under EBR-II irradiation

  17. Cracking behavior of thermally aged and irradiated CF-8 cast austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y., E-mail: Yiren_Chen@anl.gov [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Alexandreanu, B.; Chen, W.-Y.; Natesan, K. [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Li, Z.; Yang, Y. [University of Florida, Gainesville, FL 32611 (United States); Rao, A.S. [US Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2015-11-15

    To assess the combined effect of thermal aging and neutron irradiation on the cracking behavior of CF-8 cast austenitic stainless steel, crack growth rate (CGR) and fracture toughness J-R curve tests were carried out on compact-tension specimens in high-purity water with low dissolved oxygen. Both unaged and thermally aged specimens were irradiated at ∼320 °C to 0.08 dpa. Thermal aging at 400 °C for 10,000 h apparently had no effect on the corrosion fatigue and stress corrosion cracking behavior in the test environment. The cracking susceptibility of CF-8 was not elevated significantly by neutron irradiation at 0.08 dpa. Transgranular cleavage-like cracking was the main fracture mode during the CGR tests, and a brittle morphology of delta ferrite was often seen on the fracture surfaces at the end of CGR tests. The fracture toughness J-R curve tests showed that both thermal aging and neutron irradiation can induce significant embrittlement. The loss of fracture toughness due to neutron irradiation was more pronounced in the unaged than aged specimens. After neutron irradiation, the fracture toughness values of the unaged and aged specimens were reduced to a similar level. G-phase precipitates were observed in the aged and irradiated specimens with or without prior aging. The similar microstructural changes resulting from thermal aging and irradiation suggest a common microstructural mechanism of inducing embrittlement in CF-8.

  18. Crystallography and Morphology of MC Carbides in Niobium-Titanium Modified As-Cast HP Alloys

    Science.gov (United States)

    Buchanan, Karl G.; Kral, Milo V.; Bishop, Catherine M.

    2014-07-01

    The microstructures of two as-cast heats of HP alloy stainless steels modified with niobium and titanium were examined with particular attention paid to the interdendritic niobium-titanium-rich carbides formed during solidification of these alloys. Generally, these precipitates obtain a blocky morphology in the as-cast condition. However, the (NbTi)C precipitates may obtain a nodular morphology. To provide further insight to the origin of the two different morphologies obtained by the (NbTi)C precipitates in the HP-NbTi alloy, the microstructure and crystallography of each have been studied in detail using scanning electron microscopy, transmission electron microscopy, various electron diffraction methods (EBSD, SAD, and CBED), and energy-dispersive X-ray spectroscopy.

  19. Recent status of studies on the neutron irradiation effect focusing on Nb3Sn and Nb3Al strands

    International Nuclear Information System (INIS)

    Nishimura, Arata

    2011-01-01

    A fusion reactor generates a lot of 14 MeV neutrons, some of which penetrate shielding blankets, stream out of ports and reach superconducting magnets. Some important studies were performed in the 1970s and a basic understanding of the mechanisms of neutron irradiation effect was established. Advances in the design concept of nuclear fusion reactors led to the need for consistent studies on the neutron irradiation effect of A-15 strands such as Nb 3 Sn and Nb 3 Al, which are strong candidates for fusion reactors. In the early 2000s, a progressive attempt to organize the collaborative research of universities and national institutes was started using a 14 MeV neutron source at Japan Atomic Energy Agency. This paper outlines the neutron irradiation issues related to superconducting magnets for fusion, and a brief history of research on the neutron irradiation effect is provided. In addition, experimental results regarding changes in the superconducting properties of Nb 3 Sn and Nb 3 Al strands by neutron irradiation obtained in the newly established collaborative framework are presented, and general mechanisms for the property changes are introduced. (author)

  20. Energy spectra of primary knock-on atoms under neutron irradiation

    International Nuclear Information System (INIS)

    Gilbert, M.R.; Marian, J.; Sublet, J.-Ch.

    2015-01-01

    Materials subjected to neutron irradiation will suffer from a build-up of damage caused by the displacement cascades initiated by nuclear reactions. Previously, the main “measure” of this damage accumulation has been through the displacements per atom (dpa) index, which has known limitations. This paper describes a rigorous methodology to calculate the primary atomic recoil events (often called the primary knock-on atoms or PKAs) that lead to cascade damage events as a function of energy and recoiling species. A new processing code SPECTRA-PKA combines a neutron irradiation spectrum with nuclear recoil data obtained from the latest nuclear data libraries to produce PKA spectra for any material composition. Via examples of fusion relevant materials, it is shown that these PKA spectra can be complex, involving many different recoiling species, potentially differing in both proton and neutron number from the original target nuclei, including high energy recoils of light emitted particles such as α-particles and protons. The variations in PKA spectra as a function of time, neutron field, and material are explored. The application of PKA spectra to the quantification of radiation damage is exemplified using two approaches: the binary collision approximation and stochastic cluster dynamics, and the results from these different models are discussed and compared. - Highlights: • Recoil cross-section matrices under neutron irradiation are generated. • Primary knock-on atoms (PKA) spectra are calculated for fusion relevant materials. • Variation in PKA spectra due to changes in geometry are considered. • Inventory simulations to consider time-evolution in PKA spectra. • Damage quantification using damage functions from different approximations.

  1. Histological studies in developing brain after 0.5 Gy neutron irradiation in utero

    International Nuclear Information System (INIS)

    Antal, S.; Fueloep, Z.

    1986-01-01

    Pregnant mice were irradiated with 0.5 Gy neutrons on day 13, 15 or 18 of gestation. There was no significant difference in number of living young born per litter between in neutron irradiated mice and controls. Mortality of irradiated offspings increased in the first 3 days after birth. The brain weight of 21-day old animals after neutron irradiation averaged only 55, 56 and 69% of controls, resp. At six hours after irradiation morphological analysis showed nuclear pyknosis in the central nervous system. On day 13 the telencephalon was severely affected. The 30% cells were pyknotic in the wall of the cerebral hemisphere and 20% of cells in corpus striatum. In the metencephalon marked pyknosis was established in the tectal lamina of mesencephalon (16%) and in the cerebellar anlage (21%). The olfactory plate (24%), the ventricular zone of cerebral hemisphere (30%) and colliculus ganglionaris were damaged mostly (40%) after radiation on day 15 of gestation. The tectum of the mesencephali and in metencephalon the external granular layer of cerebellum and area of the rhombic lip were affected by irradiation (17-20%). The telencephalon found pyknotic but to a less extent in group irradiated on day 18 than it was on day 15. In the olfactory bulb 10% of pyknotic cells were seen and 16% of primary cortex of cerebral hemisphere more over 30% of nucleus caudatus/putamen were affected. In metencephalon 19% of external granular layer of cerebellum and 13% of trigonum cerebelli were pyknotic. In general, lesions of irradiation were rather mild in diencephalon and myelencephalon at all examined ages. Histological examinations support that defined parts of brain are damaged after neutron irradiation in utero and it may lead to the described physiological 18-20 and biochemical consequences 20,23 . (orig.)

  2. Nano-scale chemical evolution in a proton-and neutron-irradiated Zr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Harte, Allan, E-mail: allan.harte@manchester.ac.uk [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Topping, M.; Frankel, P. [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Jädernäs, D. [Studsvik Nuclear AB, SE 611 82, Nyköping (Sweden); Romero, J. [Westinghouse Electric Company, Columbia, SC (United States); Hallstadius, L. [Westinghouse Electric Sweden AB, SE 72163 Västerås (Sweden); Darby, E.C. [Rolls Royce Plc., Nuclear Materials, Derby (United Kingdom); Preuss, M. [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

    2017-04-15

    Proton-and neutron-irradiated Zircaloy-2 are compared in terms of the nano-scale chemical evolution within second phase particles (SPPs) Zr(Fe,Cr){sub 2} and Zr{sub 2}(Fe,Ni). This is accomplished through ultra-high spatial resolution scanning transmission electron microscopy and the use of energy-dispersive X-ray spectroscopic methods. Fe-depletion is observed from both SPP types after irradiation with both irradiative species, but is heterogeneous in the case of Zr(Fe,Cr){sub 2}, predominantly from the edge region, and homogeneously in the case of Zr{sub 2}(Fe,Ni). Further, there is evidence of a delay in the dissolution of the Zr{sub 2}(Fe,Ni) SPP with respect to the Zr(Fe,Cr){sub 2}. As such, SPP dissolution results in matrix supersaturation with solute under both irradiative species and proton irradiation is considered well suited to emulate the effects of neutron irradiation in this context. The mechanisms of solute redistribution processes from SPPs and the consequences for irradiation-induced growth phenomena are discussed. - Highlights: •Protons emulate the effects of neutron irradiation in the evolution of chemistry and morphology of second phase particles. •Detailed energy-dispersive X-ray spectroscopy reveals heterogeneity in Zr-Fe-Cr SPPs both before and after irradiation. •Zr-Fe-Ni SPPs are delayed in irradiation-induced dissolution due to their better self-solubility with respect to Zr-Fe-Cr.

  3. Characterisation of neutron irradiation damage in zirconium alloys - a 'Round Robin' experiment

    International Nuclear Information System (INIS)

    Kelly, P.M.; Blake, R.G.; Jostsons, A.

    1977-01-01

    The nature of the damage structure in the neutron-irradiated zirconium specimens supplied as part of an international 'Round Robin' experiment has been studied using transmission electron microscopy. The damage structure consists entirely of a/3 dislocation loops and no evidence has been found for c component loops. Both vacancy and interstitial loops were found in specimens where inside/outside contrast analysis was possible. Quantitative measurements of loop size distributions and loop concentrations are reported. All specimens exhibited corduroy contrast to varying degress. (author)

  4. Evolution of cleared channels in neutron-irradiated pure copper as a function of tensile strain

    DEFF Research Database (Denmark)

    Edwards, D.J.; Singh, B.N.

    2004-01-01

    Tensile specimens of pure copper were neutron irradiated at similar to323 K to a displacement dose of 0.3 dpa (displacement per atom). Five irradiated specimens were tensile tested at 300 K, but four of the specimens were stopped at specific strains -just before the yield point at similar to90......% of the macroscopic yield, at 1.5% and 5% elongation, and near the ultimate tensile strength at 14.5% elongation, with the 5th specimen tested to failure (e(T) = 22%). SEM and TEM characterization of the deformed specimens revealed that the plastic strain was confined primarily to the 'cleared' channels only...

  5. Internal friction study of neutron-irradiation effects on an amorphous Cu40Ti60 alloy

    International Nuclear Information System (INIS)

    Dong, Y.; Wu, G.; Xiao, K.; Li, X.; He, Y.

    1988-01-01

    Effects of neutron irradiation on the structure of an amorphous Cu 40 Ti 60 alloy have been studied by internal friction measurements. After irradiation, the position of the first internal friction peak remains almost unchanged and the shoulder position shifts towards a higher temperature by about 5 K, which indicates that the Cu 40 Ti 60 glass becomes more stable. These results are finally discussed based on the concept of changes of chemical short-range ordering and geometrical short-range ordering due to radiation damage

  6. Utilization of shear stress for determination of activation energy of the defects created by neutron irradiation

    International Nuclear Information System (INIS)

    Gonzalez, Hector C.; Miralles, Monica

    1996-01-01

    This paper describes an experimental technique used for the determination thermodynamical parameters such as activation energy using the thermal annealing of increments of Critical resolved Shear Stress of the defects created by neutron irradiation at 77 K. The doses chosen for this work was 3.1 x 10 16 n/cm 2 since the defects are stable to plastic deformation and the cascades of atomic displacements do not overlap. Specimens without any prior deformation were used allowing then the single addition of the initial stress to that due to the created defects. (author)

  7. Investigation of impact of neutron irradiation on properties of InSb-based hall plates

    Czech Academy of Sciences Publication Activity Database

    Ďuran, Ivan; Oszwaldowski, M.; Kovařík, Karel; Jankowski, J.; El-Ahmar, S.; Viererbl, L.; Lahodová, Z.

    2011-01-01

    Roč. 417, 1-3 (2011), s. 846-849 ISSN 0022-3115. [International Conference on Fusion Reactor Materials (ICFRM)/14./. Sapporo, 07.09.2009-12.09.2009] R&D Projects: GA MPO 2A-1TP1/101 Institutional research plan: CEZ:AV0Z20430508 Keywords : tokamak * Hall sensors * magnetic measurements * neutron irradiation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.052, year: 2011 http://www.sciencedirect.com/science/article/pii/S0022311510009712

  8. Studies on neutron irradiation effects of iron alloys and nickel-base heat resistant alloys

    International Nuclear Information System (INIS)

    Watanabe, Katsutoshi

    1987-09-01

    The present paper describes the results of neutron irradiation effects on iron alloys and nickel-base heat resistant alloys. As for the iron alloys, irradiation hardening and embrittlement were investigated using internal friction measurement, electron microscopy and tensile testings. The role of alloying elements was also investigated to understand the irradiation behavior of iron alloys. The essential factors affecting irradiation hardening and embrittlement were thus clarified. On the other hand, postirradiation tensile and creep properties were measured of Hastelloy X alloy. Irradiation behavior at elevated temperatures is discussed. (author)

  9. A 14 MeV neutron irradiation facility with an automated fast cyclic pneumatic

    International Nuclear Information System (INIS)

    Montgomery, M.T.; Yoho, M.D.; Biegalski, S.R.; Landsberger, S.; Welch, L.

    2016-01-01

    This work details the design criteria, construction, controls, and optimization of the 14 MeV neutron irradiation facility at the University of Texas, built with the motivation of performing neutron activation analysis on samples with short half-lives. The facility couples a D-T neutron generator with a pneumatic transfer system capable of transit of approximately one second between source and detector, while the cyclic automated nature allows for many irradiation/count trials with any number of samples, translating to significantly improved counting statistics. (author)

  10. Measurements and characterization of a hole trap in neutron-irradiated silicon

    International Nuclear Information System (INIS)

    Avset, B.S.

    1996-04-01

    The report describes measurements on a hole trap in neutron irradiated silicon diodes made one high resistivity phosphorus doped floatzone silicon. The hole trap was detected by Deep Level Transient Spectroscopy. This measurement gave a trap activation energy of 0.475 MeV. Other measurements showed that the trap has very small capture cross sections for both holes and electrons (10 -18 to 10 -20 cm 2 ) and that the hole capture cross section is temperature dependent. The energy level position of the trap has been estimated to be between 0.25 and 0.29 eV from the valence band. 25 refs., 21 figs., 4 tabs

  11. Ultrasonic attenuation measurements in neutron-irradiated quartz: a microscopic model for the tunneling states

    International Nuclear Information System (INIS)

    Keppens, V.; Laermans, C.; Coeck, M.

    1996-01-01

    Ultrasonic attenuation measurements are carried out in neutron-irradiated z-cut quartz for three different doses, in a frequency range from 70 to 320 MHz. The data are analyzed using the tunneling model, and the typical TS-parameters are derived. A comparison with the results obtained from similar x-cut samples shows that the coupling of the tunneling states with the longitudinal phonons is direction-dependent. This confirms the anisotropic behaviour of the tunneling states and gives support to the microscopic picture of the TS as a rotation of coupled SiO 4 tetrahedra. (orig.)

  12. Fatigue crack propagation in neutron-irradiated ferritic pressure-vessel steels

    International Nuclear Information System (INIS)

    James, L.A.

    1977-01-01

    The results of a number of experiments dealing with fatigue crack propagation in irradiated reactor pressure-vessel steels are reviewed. The steels included ASTM alloys A302B, A533B, A508-2, and A543, as well as weldments in A543 steel. Fluences and irradiation conditions were generally typical of those experienced by most power reactors. In general, the effect of neutron irradiation on the fatigue crack propagation behavior of these steels was neither significantly beneficial nor significantly detrimental

  13. DLTS and capacitance transients study of defects induced by neutron irradiation in MOS structures CCD process

    International Nuclear Information System (INIS)

    Ahaitouf, A.; Losson, E.; Charles, J.P.

    1999-01-01

    The aim of this paper is to study neutron irradiation effects on PMOS capacitors and NMOSFETs transistors. The characterization of induced defects was made by capacitance transients C(t) measurements, DLTS spectroscopy, and optical DLTS (ODLTS). DLTS spectra present three peaks due to deep levels created in the semiconductor and two peaks due to minority carrier generation. Two levels are reported in the literature. Two other minority carrier traps have been observed on ODLTS spectra after irradiation. This can explain the decrease of the minority carrier generation lifetime observed by capacitance transients measurements. (authors)

  14. Use of L-cysteine for minimization of inorganic Hg loss during thermal neutron irradiation

    International Nuclear Information System (INIS)

    Anderson, D.L.

    2009-01-01

    Thermal neutron irradiation experiments performed with cellulose-based L-cysteine-treated and untreated Hg standards showed Hg losses of 59-81% for untreated standards but only about a 0.2% loss for treated standards. These results and others for multielement standards showed that Hg loss is highly dependent on total mass and placement of materials in the irradiation vessel and that distribution of volatilized Hg was fairly uniform throughout the sample-containing region of the vessel. Polyethylene trapped volatile Hg much more efficiently than cellulose and a multielement standard containing inorganic Se selectively trapped Hg lost from a co-irradiated multielement standard containing Hg. (author)

  15. Concerning the problem of the plastic deformation mechanism changeover in neutron-irradiated metals and alloys

    International Nuclear Information System (INIS)

    Kolesnikov, A.N.; Krasnoselov, V.A.; Prokhorov, V.I.

    1982-01-01

    With a phenomenological model of plastic deformation instability as a basis, an analysis was made of the neutron irradition effects on the characteristics of strength and plasticity vs. structural parameters and radiation damage morphology. It was demonstrated that the enchanced plasticity in the initial stage of neutron irradiation has to do with the solid solution disintegration. Introduction of indestructible strengthening barriers enhances the stress-resistance of the neck-formation by 1.22 times. The ''big grain'' effect is observable during the deformation channel production only. Both the deformation twinning and deformation-induced martensite transformation raise the plastic flow stability

  16. The influence of fast neutron irradiation on the noise properties of silicon surface-barrier detectors

    International Nuclear Information System (INIS)

    Dabrowski, W.; Korbel, K.

    1988-01-01

    The susceptibility to the fast neutron irradiation of silicon surface-barrier detectors has been investigated. It was shown that the 1/f-noise decreases substantially with increasing fluence in the range from 10 10 n/cm 2 to 10 11 n/cm 2 . The deterioration of the detector performance is caused mainly by the positively-charged defects induced by the radiation. The critical value of the neutron fluence, at which the detector performance begins to be worsened was also determined. 5 refs., 5 figs. (author)

  17. Influence of neutron irradiation on etching of SiC in KOH

    Science.gov (United States)

    Mokhov, E. N.; Kazarova, O. P.; Soltamov, V. A.; Nagalyuk, S. S.

    2017-07-01

    The effect of reactor neutron irradiation on the etch rate of SiC in potassium hydroxide has been studied. In the case of high irradiation doses (1019-1021 cm-2), the etch rate of silicon carbide has been shown to drastically rise, especially in the [0001]Si direction. This considerably mitigates the orientation anisotropy of polar face etching. After high-temperature annealing (up to 1200-1400°C), a higher etch rate of irradiated crystals persists. The results have been explained by the high concentration of radiation-induced (partially clustered) defects they contain.

  18. Study of Fe-Ni-Cr-Mo-Si-B metallic glasses after neutron irradiation

    International Nuclear Information System (INIS)

    Sitek, J.; Miglierini, M.; Lipka, J.; Toth, I.

    1992-01-01

    Chromium containing metallic glasses are studied by transmission 57 Fe Moessbauer spectroscopy after neutron irradiation. Increasing number of non-magnetic chromium atoms causes a compositional dependence of Curie temperature. The unirradiated samples are fully paramagnetic for x≥10 at.% Cr at room temperature. Radiation induced changes in the magnetic structure imply a decrease of the Curie temperature. Ferromagnetic-to-paramagnetic transition is observed at room temperature for 8 at.% Cr after the exposure with 10 19 n/cm 2 . Using low temperature measurements, the Curie temperature for the sample containing 10 at.% Cr is estimated to be about 270 K. (orig.)

  19. Uses of AES and RGA to study neutron-irradiation-enhanced segregation to internal surfaces

    International Nuclear Information System (INIS)

    Gessel, G.R.; White, C.L.

    1980-01-01

    The high flux of point defects to sinks during neutron irradiation can result in segregation of impurity or alloy additions to metals. Such segregants can be preexisting or produced by neutron-induced transmutations. This segregation is known to strongly influence swelling and mechanical properties. Over a period of years, facilities have been developed at ORNL incorporating AES and RGA to examine irradiated materials. Capabilities of this system include in situ tensile fracture at elevated temperatures under ultrahigh vacuum 10 -10 torr and helium release monitoring. AES and normal incidence inert ion sputtering are exploited to examine segregation at the fracture surface and chemical gradients near the surface

  20. Superconductivity in irradiated A-15 compounds at low fluences. I. Neutron-irradiated V3Si

    International Nuclear Information System (INIS)

    Viswanathan, R.; Caton, R.; Pande, C.S.

    1978-01-01

    The behavior of the superconducting transition temperature T/sub c/ of single-crystal and polycrystalline V 3 Si was investigated as a function of low-fluence neutron irradiation. It is found that the initial degradation of T/sub c/ is sample-dependent, some specimens showing no degradation in T/sub c/ up to a fluence of 2 x 10 18 n/cm 2 . This and many other earlier observations on low-fluence behavior are explained in terms of a recently proposed model of radiation damage in A-15 compounds

  1. Alloys of nickel-iron and nickel-silicon do not swell under fast neutron irradiation

    International Nuclear Information System (INIS)

    Silvestre, G.; Silvent, A.; Regnard, C.; Sainfort, G.

    1975-01-01

    This research is concerned with the effect of fast-neutron irradiation on the swelling of nickel and nickel alloys. Ni-Fe (0-60at%Fe) and Ni-Si (0-8at%Si) were studied, and the fluences were in the range 10 20 -4.3x10 22 n/cm 2 . In dilute alloys, the added elements are dissolved and reduce swelling, silicon being particularly effective. In more concentrated alloys, irradiation of Ni-Fe and Ni-Si alloys brings about the formation of plate-shaped precipitates of Ni 3 X and these alloys do not swell. (Auth.)

  2. Defect cascades produced by neutron irradiation in YBa2Cu3O7-δ superconductors

    International Nuclear Information System (INIS)

    Frischherz, M.C.; Kirk, M.A.; Farmer, J.

    1994-02-01

    The defect cascades produced by fast neutron irradiation of YBa 2 Cu 3 O 7-δ single crystals were studied by transmission electron microscopy. The visible defects were found to have sizes between 1 and 5 rim. Defect densities were obtained as a function of neutron fluence between 2 and 8x 10 21 m -2 (E>0.1 MeV). The measured defect density scales linearly with fluence and amounts to 1x10 22 m -3 at a neutron fluence of 2x10 2l m -2 . The defect stability was studied at room temperature and through annealing to 400 degrees C

  3. Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source

    International Nuclear Information System (INIS)

    Andreani, C.; Pietropaolo, A.; Salsano, A.; Gorini, G.; Tardocchi, M.; Paccagnella, A.; Gerardin, S.; Frost, C. D.; Ansell, S.; Platt, S. P.

    2008-01-01

    The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 10 7 . Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays

  4. α′ precipitation in neutron-irradiated Fe–Cr alloys

    International Nuclear Information System (INIS)

    Bachhav, Mukesh; Robert Odette, G.; Marquis, Emmanuelle A.

    2014-01-01

    Graphical abstract: -- A series of model Fe–Cr alloys containing 3–18 at.% Cr was neutron irradiated at a nominal temperature of 563 K to 1.82 dpa. Solute distributions were analyzed by atom probe tomography, which revealed α′ precipitation for alloys containing more than 9 at.% Cr. Both the Cr concentration dependence of α′ precipitation and the measured matrix compositions are in agreement with the recently published Fe–Cr phase diagrams. An irradiation-accelerated precipitation process is strongly suggested

  5. Concentration dependence of solute atoms on vacancy cluster formation in neutron irradiated Ni alloy

    International Nuclear Information System (INIS)

    Sato, K.; Itoh, D.; Yoshiie, T.; Xu, Q.

    2007-01-01

    Full text of publication follows: One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. The movement of interstitial clusters was often observed in neutron irradiated metals by transmission electron microscopy (TEM). Alloying elements are expected to affect the motion of interstitial clusters. Yoshiie et al. have studied the effect of alloying elements in Ni. For example, in neutron irradiated pure Ni, well-developed dislocation networks and voids were observed at 573 K at a dose of 0.026 dpa by TEM. After the addition of 2at.%Si (-5.81% volume size factor to Ni) and Sn (74.08% volume size factor), no voids were detected by TEM observation and positron lifetime measurement. Alloying elements of Si and Sn were expected to prevent the 1-D motion of the interstitial clusters. In this study, the concentration dependence of alloying elements on the 1-D motion of the interstitial clusters was investigated by positron annihilation lifetime measurements, and the microstructural evolution was discussed. Specimens irradiated were 99.99 pure Ni (Johnson Matthey) and Ni based binary alloys, which contain Si, Cu, Ge and Sn as solute atoms. The concentration of solute atoms was 0.05at.%o, 0.3at.% and 2at.%. Neutron irradiation was performed with the Kyoto University Reactor (KUR) and Japan materials testing reactor (JMTR) at Japan Atomic Energy Agency. Neutron dose was 6x10 -5 -1x10 -2 dpa at KUR, and 8x10 -3 -0.3 dpa at JMTR. Irradiation temperature was 573 K at KUR and 563 K at JMTR. After the neutron irradiation, positron annihilation lifetime measurements were performed at room temperature. Microvoids were detected in pure Ni, Ni-0.05%Si, Ni-0.05%Sn, Ni-Cu and Ni-Ge alloys. In Ni-Si and Ni-Sn alloys, the size of microvoids decreased as the concentration of solute atoms increased. This is because the frequency of 1-D motion of the interstitial clusters depends on the alloy concentration. High concentration of alloying

  6. Concentration dependence of solute atoms on vacancy cluster formation in neutron irradiated Ni alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sato, K.; Itoh, D.; Yoshiie, T.; Xu, Q. [Kyoto Univ., Research Reactor Institute, Osaka (Japan)

    2007-07-01

    Full text of publication follows: One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. The movement of interstitial clusters was often observed in neutron irradiated metals by transmission electron microscopy (TEM). Alloying elements are expected to affect the motion of interstitial clusters. Yoshiie et al. have studied the effect of alloying elements in Ni. For example, in neutron irradiated pure Ni, well-developed dislocation networks and voids were observed at 573 K at a dose of 0.026 dpa by TEM. After the addition of 2at.%Si (-5.81% volume size factor to Ni) and Sn (74.08% volume size factor), no voids were detected by TEM observation and positron lifetime measurement. Alloying elements of Si and Sn were expected to prevent the 1-D motion of the interstitial clusters. In this study, the concentration dependence of alloying elements on the 1-D motion of the interstitial clusters was investigated by positron annihilation lifetime measurements, and the microstructural evolution was discussed. Specimens irradiated were 99.99 pure Ni (Johnson Matthey) and Ni based binary alloys, which contain Si, Cu, Ge and Sn as solute atoms. The concentration of solute atoms was 0.05at.%o, 0.3at.% and 2at.%. Neutron irradiation was performed with the Kyoto University Reactor (KUR) and Japan materials testing reactor (JMTR) at Japan Atomic Energy Agency. Neutron dose was 6x10{sup -5}-1x10{sup -2} dpa at KUR, and 8x10{sup -3} -0.3 dpa at JMTR. Irradiation temperature was 573 K at KUR and 563 K at JMTR. After the neutron irradiation, positron annihilation lifetime measurements were performed at room temperature. Microvoids were detected in pure Ni, Ni-0.05%Si, Ni-0.05%Sn, Ni-Cu and Ni-Ge alloys. In Ni-Si and Ni-Sn alloys, the size of microvoids decreased as the concentration of solute atoms increased. This is because the frequency of 1-D motion of the interstitial clusters depends on the alloy concentration. High

  7. Fabrication of thin cadmium cylinder coated with aluminum for neutron irradiation capsules

    International Nuclear Information System (INIS)

    Takeyama, Tomonori; Chiba, Masaaki

    2001-03-01

    In order to fabricate the irradiation capsule screened thermal neutron, a thin cadmium cylinder coated with aluminum was developed. The capsule is used for the fast neutron irradiation test. Requested specification of the cylinder are the thickness of 5.5 mm, the inner diameter of 23 mm, the length of 750 mm and the coated thickness of aluminum of 0.75 mm. Moreover, cadmium and aluminum adhere to each other. The cylinder was developed and fabricated by means of casting. The a new vacuum chamber in which solving and casting work is possible was fabricated to prevent cadmium oxidation and work safely from poison of cadmium. (author)

  8. Fast neutron irradiation and thermal properties of doped nonstoichiometric lithium potassium sulphate crystals

    International Nuclear Information System (INIS)

    Kassem, M.E.; Gomaa, N.G.; El-Khatib, A.M.

    1990-01-01

    The influence of point defects introduced by fast neutron irradiations with neutron fluences up to 1.08 x 10 10 n/cm 2 on the thermal properties of pure and doped Li 1.4 K 0.6 SO 4 single crystals are studied in the vicinity of high temperature phase transition at 705 K. The temperature dependence of specific heat is found to be shifted towards lower temperature with the increase of neutron fluence, and can be affected by the presence of Cu 2+ dopant. The change in the value of the specific heat can be attributed to the presence of internal strain generated inside the crystal. (author)

  9. Electron-microscopic investigation of a pressure vessel steel after neutron irradiation

    International Nuclear Information System (INIS)

    Klaar, H.J.

    1975-01-01

    As an introduction, changes in the mechanical properties of pressure vessel steels on neutron irradiation and the causes of radiation embrittlement are discussed. After this, the author describes his own experiments with steel of the composition 0.19% C; 3.88% Ni; 1.57% Cr; 0.51% Mo; 0.2% V. Samples of this material were irradiated in-pile at 300 0 C with various neutron doses. To study the influence of neutron dose, irradiation temperature, and heat treatment on the mechanical properties, tensile tests, notched bar impact bending tests, hardness tests and structural analyses were carried out. The findings are reported. (GSC) [de

  10. Annealing of dislocation loops in neutron-irradiated copper investigated by positron annihilation

    International Nuclear Information System (INIS)

    Gauster, W.B.; Mantl, S.; Schober, T.; Triftshauser, W.

    1975-01-01

    Positron annihilation angular correlation measurements were carried out on neutron-irradiated copper as a function of annealing temperature. Two types of specimens were used: single crystals irradiated with fast neutrons, and 10 B-doped polycrystalline samples irradiated with thermal neutrons. All irradiations were at approximately 320 0 K. A structure in the annealing curve, not previously observed by other techniques, indicates that between 460 and 600 0 K the dislocation loops present after irradiation dissociate and more effective positron trapping sites are formed. (auth)

  11. Neutron irradiation results for the LHCb silicon tracker data readout system components

    CERN Document Server

    Vollhardt, A

    2003-01-01

    This note reports irradiation data for different components of the LHCb Silicon Tracker data readout system, which will be exposed to neutron fluences due to their location in the readout link service box on the tracking station frame. The components were part of a neutron irradiation campaign in April 2003 at the Prospero reactor at CEA Valduc (France) and were exposed to fluences 5 to 100 times higher than the expected fluences at the experiment. For all tested components, minor or no influence on device performance was measured. We therefore consider the tested components to be compatible with the expected neutron fluences at the foreseen locations in the LHCb experiment.

  12. Evidence for shallow positron traps in a neutron-irradiated Al single crystal

    International Nuclear Information System (INIS)

    Schultz, P.J.; MacKenzie, I.K.; Lynn, K.G.; West, R.N.; Snead, C.L. Jr.

    1982-01-01

    Variable energy positrons have been used to determine the dependence on temperature of positron diffusion out of a neutron-irradiated single crystal of Al. The results are interpreted in the context of a one-dimensional diffusion model which includes bulk annihilations as well as trapping at voids and other microstructural defects in the bulk material by way of a removal rate kappa/sub eff/ of freely diffusing positrons. The data show a strongly negative dependence on temperature below 125 0 K for kappa/sub eff/, indicating the presence of some additional phenomenon which we attribute to positron localization in shallow, presumably radiation-induced, traps in the crystal

  13. First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

    International Nuclear Information System (INIS)

    Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J.P.

    2011-01-01

    With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 x 10 21 m -2 s -1 , ion fluence: 4 x 10 25 m -2 ) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

  14. First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

    Science.gov (United States)

    Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J. P.

    2011-08-01

    With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 × 1021 m-2 s-1, ion fluence: 4 × 1025 m-2) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

  15. Survival of mouse testicular stem cells after γ or neutron irradiation

    International Nuclear Information System (INIS)

    Lu, C.C.; Meistrich, M.L.; Thames, H.D. Jr.

    1980-01-01

    The survival of mouse testicular stem cells after γ or neutron irradiation was measured by counts of repopulated tubular cross sections and by the numbers of differentiated spermatogenic cells produced. The numbers of such cells were determined either by sperm head counts of the X-isozyme of lactate dehydrogenase enzyme levels. Qualitatively similar results were obtained with all three assays. The results have confirmed that, with C3H mice, stem-cell survival is higher when the γ-radiation dose is fractionated by a 24-h interval. Single-dose γ-radiaton survival curves for the stem cell had large shoulders and also showed the presence of a radioresistant subpopulation which predominated after doses greater than 600 rad. Part of the shoulder must have resulted from repair of sublethal damage since neutron irradiation produced survival curves with smaller shoulders. The relative biological effectiveness for stem-cell killing for these neutrons (mean energy, 22 MeV) varied from about 2.9 at 10 rad of γ radiation to 2.2 at 600 rad

  16. Fracture toughness and strength change of neutron-irradiated ceramic materials

    International Nuclear Information System (INIS)

    Dienst, W.; Zimmermann, H.

    1994-01-01

    In order to analyse the results of bending strength measurements on neutron-irradiated samples of Al 2 O 3 , AlN and SiC, fracture toughness measurements were additionally conducted. The neutron fluences concerned were mostly in the range of 0.6 to 3.2x10 26 n/m 2 at irradiation temperatures of 400 to 550 C. A fracture toughness decrease was generally observed for polycrystalline materials which, however, was considerably smaller than the reduction of the fracture strength. Exceptional increase of the fracture toughness seems typical for the effect of rather coarse irradiation defects. The irradiation-induced change of the fracture toughness of single crystal Al 2 O 3 appeared dependent on the crystallographic orientation; both reduced and increased fracture toughness after irradiation was observed. Recent results of neutron irradiation to about 2x10 25 n/m 2 at 100 C showed, that the strength decrease of various Al 2 O 3 grades sets in at (3-5)x10 24 n/m 2 and seems to be little dependent on the irradiation temperature. ((orig.))

  17. Effect of neutron irradiation on the breakdown voltage of power MOSFET's

    International Nuclear Information System (INIS)

    Hasan, S.M.Y.; Kosier, S.L.; Schrimpf, R.D.; Galloway, K.F.

    1994-01-01

    The effect of neutron irradiation on power metal-oxide-semiconductor field effect transistor (power MOSFET) breakdown voltage has been investigated. Transistors with various breakdown voltage ratings were irradiated in a TRIGA nuclear reactor with cumulative fluence levels up to 5 x 10 14 neutrons/cm 2 (1 MeV equivalent). Noticeable increases in the breakdown voltages are observed in n-type MOSFET's after 10 13 neutrons/cm 2 and in p-type MOSFETs after 10 12 neutrons/cm 2 . An increase in breakdown voltage of as much as 30% is observed after 5 x 10 14 neutrons/cm 2 . The increase in breakdown voltage is attributed to the neutron-irradiation-induced defects which decrease the mean free path and trap majority carriers in the space charge region. The effect of positive trapped oxide charge due to concomitant gamma radiation and the effect of the termination structure on the increase in breakdown voltage are considered. An empirical model is presented to predict the value of the breakdown voltage as a function of neutron fluence

  18. Review of recent studies on neutron irradiation embrittlement in light water reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Sudo, Akira; Miyazono, Shohachiro

    1983-06-01

    Recent studies in foreign countries (USA, France, FRG and UK) on neutron irradiation embrittlement have been reviewed. These studies are classified into four areas, such as 1) effect of chemical composition on irradiation embrittlement sensitivity, 2) postirradiation heat treatment for embrittlement relief, 3) fracture toughness evaluation of irradiated materials based on fracture mechanics analysis, and 4) effect of irradiation on fatigue crack propagation behavior. The first area mainly includes the studies related to the effects of copper, phosphorus impurities and nickel alloying and synergistic effect of these components, and furthermore, evaluation of Regulatory Guide 1.99 Rev.l. Studies in the second area show the effects of annealing condition (temperature and time) and metallugical condition on embrittlement relief, and evaluation of periodic annealing in the period of irradiation as a promising method for embrittlement control. Studies in the third area show the correlation between fracture toughness and Cv notch ductility changes with neutron irradiation, and J-R curves of irradiated materials based on the elasto-plastic fracture mechanics. In the forth area, most of studies are investigated in air condition but a few studies in reactor-grade water at high temperature and pressure. (author)

  19. Cell cycle of spermatogonial colony forming stem cells in the CBA mouse after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bootsma, A.L. (Rijksuniversiteit Utrecht (Netherlands). Academisch Ziekenhuis); Davids, J.A.G. (Netherlands Energy Research Foundation, Petten (Netherlands))

    1988-03-01

    In the CBA mouse testis, about 10% of the stem cell population is highly resistant to neutron irradiation (D/sub 0/, 0.75 Gy). Following a dose of 1.50 Gy these cells rapidly increase their sensitivity towards a second neutron dose and progress fairly synchronously through their first post-irradiation cell cycle. From experiments in which neutron irradiation was combined with hydroxyurea, it appeared that in this cycle the S-phase is less radiosensitive (D/sub 0/, 0.43 Gy) than the other phases of the cell cycle (D/sub 0/, 0.25 Gy). From experiments in which hydroxyurea was injected twice after irradiation, the speed of inflow of cells in S and the duration of S and the cell cycle could be calculated. Between 32 and 36 hr after irradiation cells start to enter the S-phase at a speed of 30% of the population every 12 hr. At 60 hr 50% of the population has already passed the S-phase while 30% is still in S. The data point to a cell cycle time of about 36 hr, while the S-phase lasts 12 hr at the most. (author).

  20. An investigation of neutron irradiation test on superplastic zirconia-ceramic materials

    International Nuclear Information System (INIS)

    Shibata, Taiju; Ishihara, Masahiro; Baba, Shinichi; Hayashi, Kimio

    2000-05-01

    A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). For the effective execution of the test, we reviewed the superplastic deformation mechanism of ceramic materials and discussed neutron irradiation effects on the superplastic deformation process of stabilized Tetragonal Zirconia Polycrystal (TZP), which is a representative superplastic ceramic material. As a result, we pointed out that the decrease in the activation energy for superplastic deformation is expected by the radiation-enhanced diffusion. We selected a fast neutron fluence of 5x10 20 n/cm 2 and an irradiation temperature of about 600degC as test conditions for the first irradiation test on TZP and decided to perform a preliminary irradiation test by the Japan Materials Testing Reactor (JMTR). Moreover, we estimated the radioactivity of irradiated TZP and indicated that it is in the order of 10 10 Bq/g (about 0.3 Ci/g) immediately after irradiation to a thermal neutron fluence of 3x10 20 n/cm 2 and that it decays to about 1/100 in a year. (author)

  1. Study of the chemical species of fluorine 18 produced by neutron irradiation of lithium aluminate

    International Nuclear Information System (INIS)

    Jimenez-Becerril, J.

    1990-01-01

    In the present work, the chemical form of fluorine-18 obtained by means of the neutron irradiated lithium aluminate was studied, in order to know its chemical behavior and to observe if it volatilizes and adheres to the walls of a tritium distillation system; for this matter paper chromatography and high voltage electrophoresis techniques were used. Lithium aluminate was synthetized, being characterized as LiAlO 2 which was irradiated with neutrons in order to produce fluorine-18. Lithium aluminate is a non-soluble solid, therefore fluorine produced may not be extracted, unless it is dissolved or extracted through the solid. So as not affect in a drastic way the chemical form, it was submitted to extraction processes, agitating the irradiated samples with different acids and basic solutions in order to analyze fluorine-18. The best extraction agent was found to be HCl, where two forms of fluorine-18 were found, one at the point of application, probably as a complex hexafluoride-aluminate and the other as a characteristic Rf of the fluorine ion. In the tritium distillation with helium as a carrier of a sample irradiated and heated up to 220-250 o C, no volatile types of fluorine-18 were found, thus it can be considered that in commercial production of tritium by means of neutron irradiation of lithium aluminate, fluorine-18 is not a damaging pollutant of the equipment pipe system. (Author)

  2. Study of supersaturation of defects under neutron irradiation by Zener relaxation

    International Nuclear Information System (INIS)

    Gonzalez, Hector C.; Justus, Francisco J.W.

    2004-01-01

    Vacancy supersaturation in dynamic equilibrium under fast neutron irradiation could be determined by anelastic relaxation. This phenomenon is particularly noticeable in some substitutional binary alloys. Relaxation is due to the reordering of atoms pairs under a stress, being a local reordering at the atomic scale. Relaxation time (τ) is inversely proportional to the vacancy concentration (Cv) and decreases under irradiation because a dynamical equilibrium of vacancy concentration, higher than thermodynamic equilibrium, is established. Theoretical models allow estimating the magnitude of that supersaturation. Determinations of τ at different temperatures, with and without fast neutron irradiations, were made with an 'in situ' device placed in the high temperature loop in the RA1 CAC-CNEA reactor. An alloy Au-30% Ni was used, since it presents an appreciable Zener effect. The measurements were performed in a spring-shaped specimen in order to minimize temperature and flux gradients. An Arrhenius plot of τ was obtained, and it was observed that for temperatures lower than 220 C degrees a vacancy supersaturation exists. The lowest temperature of our experiments was 190 C degrees. A value of τ at this temperature was three times lower under irradiations. A plot of τ vs. fast neutron fluence (φ f t) at the irradiation temperature T= 203 C degrees was obtained. An increase of τ was observed. After an annealing at T = 280 C degrees, the value of τ recovers the value corresponding to the unirradiated case. This fact suggests that the loops produced by irradiation act as defect sinks. (author) [es

  3. Tritium release and retention properties of highly neutron-irradiated beryllium pebbles from HIDOBE-01 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, V., E-mail: vladimir.chakin@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rolli, R.; Moeslang, A.; Klimenkov, M.; Kolb, M.; Vladimirov, P.; Kurinskiy, P.; Schneider, H.-C. [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Til, S. van; Magielsen, A.J. [Nuclear Research and Consultancy Group, Westerduinweg 3, Postbus 25, 1755 ZG Petten (Netherlands); Zmitko, M. [The European Joint Undertaking for ITER and the Development of Fusion Energy, c/Josep Pla, no. 2, Torres Diagonal Litoral, Edificio B3, 08019 Barcelona (Spain)

    2013-11-15

    The current helium cooled pebble bed (HCPB) tritium breeding blanket concept for fusion reactors includes a bed of 1 mm diameter beryllium pebbles to act as a neutron multiplier. Beryllium pebbles, fabricated by the rotating electrode method, were neutron irradiated in the HFR in Petten within the HIDOBE-01 experiment. This study presents tritium release and retention properties and data on microstructure evolution of beryllium pebbles irradiated at 630, 740, 873, 948 K up to a damage dose of 18 dpa, corresponding to a helium accumulation of about 3000 appm. The measured cumulative released activity from the beryllium pebbles irradiated at 948 K was found to be significantly lower than the calculated value. After irradiation at 873 and 948 K scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed large pores or bubbles in the bulk and oxide films with a thickness of up to 8 μm at the surface of the beryllium pebbles. The radiation-enhanced diffusion of tritium and the formation of open porosity networks accelerate the tritium release from the beryllium pebbles during the high-flux neutron irradiation.

  4. Fundamental study of polonium contamination by neutron irradiated lead-bismuth eutectic

    International Nuclear Information System (INIS)

    Obara, T.; Miura, T.; Sekimoto, H.

    2005-01-01

    As a fundamental study of polonium contamination by neutron irradiated LBE, it was investigated to remove polonium surface contamination by baking method. The baking experiments were performed using quartz glass plates contaminated by material evaporated from neutron irradiated LBE liquid. The contaminated quartz glass plates were baked in vacuum (2 Pa) at various temperatures. The experimental results clearly show that polonium evaporated from LBE can be removed by baking samples at temperatures 300 deg. C and above. It is of note that the decrease in the weight of deposited materials baked at 300 deg. C differed from that observed at 400 deg. C or higher temperatures. At temperature of 300 deg. C, no change in weight was observed. The mass of polonium in the LBE samples was so small that no weight change could be observed by release of polonium. Thus, it might show that only the polonium among the adherent materials was removed by baking at 300 deg. C without removing other adhered material. The method is rather simple, so it is easy to apply the method for practical application. One of the expected applications may be the removal of polonium contamination in a primary loop before maintenance work of the loop. Also it shows that this method can be used to avoid the release of polonium from contaminated material, in case of an accident, by keeping the contaminated material at low temperature

  5. Microstructure and mechanical behavior of neutron irradiated ultrafine grained ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Alsabbagh, Ahmad, E-mail: ahalsabb@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Sarkar, Apu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Miller, Brandon [ATR National Scientific User Facility, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Burns, Jatuporn [Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Squires, Leah; Porter, Douglas; Cole, James I. [ATR National Scientific User Facility, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Murty, K.L. [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2014-10-06

    Neutron irradiation effects on ultra-fine grain (UFG) low carbon steel prepared by equal channel angular pressing (ECAP) have been examined. Counterpart samples with conventional grain (CG) sizes have been irradiated alongside with the UFG ones for comparison. Samples were irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to 1.37 dpa. Atom probe tomography revealed manganese and silicon-enriched clusters in both UFG and CG steel after neutron irradiation. Mechanical properties were characterized using microhardness and tensile tests, and irradiation of UFG carbon steel revealed minute radiation effects in contrast to the distinct radiation hardening and reduction of ductility in its CG counterpart. After irradiation, micro hardness indicated increases of around 9% for UFG versus 62% for CG steel. Similarly, tensile strength revealed increases of 8% and 94% respectively for UFG and CG steels while corresponding decreases in ductility were 56% versus 82%. X-ray quantitative analysis showed that dislocation density in CG increased after irradiation while no significant change was observed in UFG steel, revealing better radiation tolerance. Quantitative correlations between experimental results and modeling were demonstrated based on irradiation induced precipitate strengthening and dislocation forest hardening mechanisms.

  6. Mechanical compression tests of beryllium pebbles after neutron irradiation up to 3000 appm helium production

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, V., E-mail: vladimir.chakin@kit.edu [Karlsruhe Institute of Technology, Institite for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rolli, R.; Moeslang, A. [Karlsruhe Institute of Technology, Institite for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Zmitko, M. [The European Joint Undertaking for ITER and the Development of Fusion Energy, c/Josep Pla, no. 2, Torres Diagonal Litoral, Edificio B3, 08019 Barcelona (Spain)

    2015-04-15

    Highlights: • Compression tests of highly neutron irradiated beryllium pebbles have been performed. • Irradiation hardening of beryllium pebbles decreases the steady-state strain-rates. • The steady-state strain-rates of irradiated beryllium pebbles exceed their swelling rates. - Abstract: Results: of mechanical compression tests of irradiated and non-irradiated beryllium pebbles with diameters of 1 and 2 mm are presented. The neutron irradiation was performed in the HFR in Petten, The Netherlands at 686–968 K up to 1890–2950 appm helium production. The irradiation at 686 and 753 K cause irradiation hardening due to the gas bubble formation in beryllium. The irradiation-induced hardening leads to decrease of steady-state strain-rates of irradiated beryllium pebbles compared to non-irradiated ones. In contrary, after irradiation at higher temperatures of 861 and 968 K, the steady-state strain-rates of the pebbles increase because annealing of irradiation defects and softening of the material take place. It was shown that the steady-state strain-rates of irradiated beryllium pebbles always exceed their swelling rates.

  7. The Role of Grain Size on Neutron Irradiation Response of Nanocrystalline Copper

    Directory of Open Access Journals (Sweden)

    Walid Mohamed

    2016-03-01

    Full Text Available The role of grain size on the developed microstructure and mechanical properties of neutron irradiated nanocrystalline copper was investigated by comparing the radiation response of material to the conventional micrograined counterpart. Nanocrystalline (nc and micrograined (MG copper samples were subjected to a range of neutron exposure levels from 0.0034 to 2 dpa. At all damage levels, the response of MG-copper was governed by radiation hardening manifested by an increase in strength with accompanying ductility loss. Conversely, the response of nc-copper to neutron irradiation exhibited a dependence on the damage level. At low damage levels, grain growth was the primary response, with radiation hardening and embrittlement becoming the dominant responses with increasing damage levels. Annealing experiments revealed that grain growth in nc-copper is composed of both thermally-activated and irradiation-induced components. Tensile tests revealed minimal change in the source hardening component of the yield stress in MG-copper, while the source hardening component was found to decrease with increasing radiation exposure in nc-copper.

  8. Neutron irradiation effects on intermetallic precipitates in Zircaloy as a function of fluence

    International Nuclear Information System (INIS)

    Etoh, Y.; Shimada, S.

    1993-01-01

    Intermetallic precipitates in Zircaloy-2 and -4, recrystallized at the α-phase temperature, have been examined using analytical electron microscopy. The specimens were irradiated in BWRs up to a fast neutron fluence of 1.4x10 26 n/m 2 (E>1 MeV). Neutron irradiation induces a crystalline-to-amorphous transition, depleting Fe in the amorphous phase of Zr(Fe, Cr) 2 precipitates in the alloys. Amorphization starts from the periphery of the precipitates and all of them are totally amorphized at higher fluences than 1.2x10 26 n/m 2 . The width of the Fe-depleted zone increases in proportion to the 0.45 power of fluence. This result indicates that diffusion of Fe is the rate-controlling process for Fe depletion in Zr(Fe, Cr) 2 precipitates. Dissolution of Zr 2 (Fe, Ni) precipitates in Zircaloy-2 occurs during neutron irradiation. At a high fluence, such as 1.2x10 26 n/m 2 , Zr 2 (Fe, Ni) precipitates are almost completely dissolved into the matrix and the dissolution rate of Fe is faster than that of Ni. (orig.)

  9. Neutron irradiation control in the neutron transmutation doping process in HANARO using SPND

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Gi-Doo; Kim, Myong-Seop [Korea Atomic Energy Research Institute, Yuseong, Daejeon, 305-353, (Korea, Republic of)

    2015-07-01

    The neutron irradiation control method by using self-powered neutron detector (SPND) is developed for the neutron transmutation doping (NTD) application in HANARO. An SPND is installed at a fixed position of the upper part of the sleeve in HANARO NTD hole for real-time monitoring of the neutron irradiation. It is confirmed that the SPND is significantly affected by the in-core condition and surroundings of the facility. Furthermore, the SPND signal changes about 15% throughout a whole cycle according to the change of the control rod position. But, it is also confirmed that the variation of the neutron flux on the silicon ingots inside the irradiation can is not so big while moving of the control rod. Accordingly, the relationship between the ratio of the neutron flux to the SPND signal output and the control rod position is established. In this procedure, the neutron flux measurement by using zirconium foil is utilized. The real NTD irradiation experiments are performed using the established relationship. The irradiated neutron fluence can be controlled within ±1.3% of the target one. The mean value of the irradiation/target ratio of the fluence is 0.9992, and the standard deviation is 0.0071. Thus, it is confirmed that the extremely accurate irradiation would be accomplished. This procedure can be useful for the SPND application installed at the fixed position to the field requiring the extremely high accuracy. (authors)

  10. Evaluation of toughness degradation by small punch (SP) tests for neutron irradiated structural steels

    International Nuclear Information System (INIS)

    Misawa, Toshihei; Hamaguchi, Yoshikazu; Kimura, Akihiko; Eto, Motokuni; Suzuki, Masahide; Nakajima, Nobuya.

    1992-01-01

    The small punch (SP) test as one of the useful small specimen testing technique (SSTT) has been developed to evaluate the fracture toughness, ductile-brittle transition temperature (DBTT) and tensile properties for neutron irradiated structural materials. The SP tests using the miniaturized specimens of φ3 mm TEM disk and 10 mm 2 coupon were performed for six kinds of ferritic steels of F-82, F-82H, HT-9, JFMS, 2.25-1Mo and SQV2A. It was shown that the temperature dependence of SP fracture energies with scatter in miniaturized testing can give reliable information on the DBTT by use of the statistical analysis based on the Weibull distribution. A good correlation between the DBTT of the SP tests and that of the standard CVN test has been obtained for the various nuclear ferritic steels. The SP test was performed for cryogenic austenitic steels as a way of evaluating elastic-plastic fracture toughness, J IC , on the basis of a universal empirical relationship between J IC and SP equivalent fracture strain, ε-bar qf . The SP testing using the neutron irradiated specimens of 2.25Cr-1Mo, F-82, F-82H and HT-9 steels was successfully applied and presented the neutron radiation induced changes on the DBTT, fracture toughness and tensile properties. (author)

  11. Neutron irradiation effects on silicon detectors structure, electrical and mechanical characteristics

    International Nuclear Information System (INIS)

    Rabinovich, E.; Golan, G.; Axelevich, A.; Inberg, A.; Oksman, M.; Rosenwaks, I.; Lubarsky, G.; Seidman, A.; Croitoru, N.; Rancoita, P.G.; Rattaggi, M.

    1999-01-01

    Neutron irradiation effects on (p-n) and Schottky-junction silicon detectors were studied. It was shown that neutron interactions with monocrystalline silicon create specific types of microstructure defects with morphology differing according to the level of neutron fluences (Φ). The isolated dislocation loops, formed by interstitial atoms were observed in microstructure images for 10 10 ≤ Φ ≤ 10 12 n/cm 2 . A strong change in the dislocation loops density and a cluster formation was observed for Φ ≥ 10 13 n/cm 2 . A drastic silicon damage was found for fluences over 10 14 n/cm 2 . These fluences created zones enriched with all types of dislocations, covering more than 50 % of the total surface area. A mechanical fragility appeared in that fluence range in a form of microcracks. 10 14 n/cm 2 appears to be a critical value of neutron irradiation because of the radiation damage described above and because the characteristics I f -V f of silicon detectors can be differentiated from those obtained at low fluences. (A.C.)

  12. Perspectives for online analysis of raw material by pulsed neutron irradiation

    Science.gov (United States)

    Bach, Pierre; Le Tourneur, P.; Poumarede, B.

    1997-02-01

    On-line analysis by pulsed neutron irradiation is an example of an advanced technology application of nuclear techniques, concerning real problems in the cement, mineral and coal industries. The most significant of these nuclear techniques is their capability of continuous measurement without contact and without sampling, which can lead to improved control of processes and resultant large financial savings. Compared to Californium neutron sources, the use of electrical pulsed neutron generators allows to obtain a higher signal/noise ratio for a more sensitive measurement, and allows to overcome a number of safety problems concerning transportation, installation and maintenance. An experiment related to a possible new on-line raw material analyzer is described, using a pulsed neutron generator. The key factors contributing to an accurate measurement are related to a suitable generator, to a high count rate gamma ray spectroscopy electronics, and to computational tools. Calculation and results for the optimization of the neutron irradiation time diagram are reported. One of the operational characteristics of such an equipment is related to neutron flux available: it is possible to adjust it to the requested accuracy, i.e. for a high accuracy during a few hours/day and for a lower accuracy the rest of the time. This feature allows to operate the neutron tube during a longer time, and then to reduce the cost of analysis.

  13. Practice of adding value to materials by a neutron irradiation in research reactors

    International Nuclear Information System (INIS)

    Oh, Soo Youl; Jun, Byung Jin

    2008-01-01

    Adding more value to materials by a neutron irradiation is one of the utilization areas of research reactors. A neutron transmutation doping (NTD) of Si, a gemstone coloration, and a track etched membrane production are the three important subjects and these are being serviced on a commercial basis. Nevertheless, a further enhancement of the technologies is necessary, and the IAEA/RCA has supported the development and dissemination of the relevant technologies. This article reports on what was achieved during the IAEA/RCA Regional Training Course on the Design and Operation of Neutron Irradiation Facilities which was held in Korea in April 2008 for two weeks. The Course, which was open to the Asian RCA member states, consisted of lectures, presentations from each country, and design and experiment exercises concerning the above three subjects. The lectures covered not only the principles but also the practice in every detail. The experience of Korea on the NTD and those of Indonesia and Thailand on the gemstone coloration drew concentrated attention of the participants. Meanwhile, as one of the exercises the participants designed a device for the NTD or the gemstone irradiation and analyzed its performance from the neutronics point of view. The Course was successful in deepening the understanding on the practice of value adding technologies and also in sharing some ideas for their enhancement

  14. Practice of adding value to materials by a neutron irradiation in research reactors

    International Nuclear Information System (INIS)

    Oh, Soo-Youl; Jun, Byung Jin

    2008-01-01

    Adding more value to materials by a neutron irradiation is one of the utilization areas of research reactors. A neutron transmutation doping (NTD) of Si, a gemstone coloration, and a track-etched membrane production are the three important subjects and these are being serviced on a commercial basis. Nevertheless, a further enhancement of the technologies is necessary, and the IAEA/RCA has supported the development and dissemination of the relevant technologies. This article reports on what was achieved during the IAEA/RCA Regional Training Course on the Design and Operation of Neutron Irradiation Facilities which was held in Korea in April 2008 for two weeks. The Course, which was open to the Asian RCA member states, consisted of lectures, presentations from each country, and design and experiment exercises concerning the above three subjects. The lectures covered not only the principles but also the practice in every detail. The experience of Korea on the NTD and those of Indonesia and Thailand on the gemstone coloration drew concentrated attention of the participants. Meanwhile, as one of the exercises the participants designed a device for the NTD or the gemstone irradiation and analyzed its performance from the neutronics point of view. The Course was successful in deepening the understanding on the practice of value-adding technologies and also in sharing some ideas for their enhancement. (author)

  15. Practice of adding value to materials by a neutron irradiation in research reactors

    International Nuclear Information System (INIS)

    Oh, Soo Youl; Jun, Byung Jin

    2008-01-01

    Adding value to materials by a neutron irradiation is one of the utilization areas of research reactors. A neutron transmutation doping (NTD) of Si, a gemstone coloration, and a track-etched membrane production are the three important subjects and these are being serviced on a commercial basis. Nevertheless, a further enhancement of the technologies is necessary, and the IAEA/RCA has supported the development and dissemination of the relevant technologies. This article report on what was achieved during the IAEA/RCA regional Training Course on the Design and Operation of Neutron Irradiation Facilities which was held in Korea in April 2008 for two weeks. The Course, which was open to the Asian RCA member states, consisted of lectures, presentations from each country, and design and experiment exercises concerning the above three subjects. The lectures covered not only the principles but also the practice in every detail. The experience of Korea on the NTD and those of indonesia and Thailand on the gemstone coloration drew concentrated attention of the participants. Meanwhile, as one of the exercises the participants designed a device for the NTD or the gemstone irradiation and analyzed its performance from the neutronics point of view. The Course was successful in deepening the understanding on the practice of value-adding technologies and also in sharing some ideas for their enhancement

  16. Reticuloendothelial neoplasms in C57 black mice after fast-neutron irradiation at low dosage

    International Nuclear Information System (INIS)

    Mewissen, D.J.; Rust, J.H.

    1976-01-01

    In many inbred strains of mice the modulation of the basic control tumor pattern by ionizing radiation is operative primarily on the reticular tissue. This phenomenon seems more productive with high linear energy transfer radiation, particularly neutrons. The results reported in this paper are based on a total of 1963 C57 Black mice, subline 6, of either sex. From each litter animals were randomly assigned to control and treatment groups and were neutron-irradiated at 3.2, 4.5, 6.3, 8.8, and 12.3 rads of single exposure. In male and female irradiation groups, incidence rates for lymphocytic lymphomas were sharply decreased by neutron irradiation at all dose levels. In reticulum-cell sarcomas an interesting contrast was observed. First, the tumor type shifted almost entirely from type A to type B. Second, all specific incidence rates were markedly increased by radiation, both for male and female mice at all dose levels. Our data suggest the existence of an intercompetitive process triggered or accelerated by radiation

  17. Evaluation of neutron irradiated near-stoichiometric silicon carbide fiber composites

    International Nuclear Information System (INIS)

    Snead, L.L.; Katoh, Y.; Kohyama, A.; Bailey, J.L.; Vaughn, N.L.; Lowden, R.A.

    2000-01-01

    Composites have been fabricated by chemical vapor infiltration of silicon carbide (SiC) into SiC-based fiber preforms. Fibers were Ceramic Grade Nicalon TM , Hi-Nicalon TM and Hi-Nicalon TM Type-S. Results are presented for two parallel studies on the effects of neutron irradiation on these materials. In the first study, neutron irradiation induced changes in mechanical properties, as measured by bend testing, for Hi-Nicalon TM fiber materials of varied interphase structures is measured. Results indicate that both the Ceramic Grade Nicalon TM and Hi-Nicalon TM materials degrade substantially under irradiation, though the higher oxygen content Ceramic Grade fiber degrades more rapidly and more substantially. Of the three interfaces studied in the Hi-Nicalon TM system, the multilayer SiC is the most radiation resistant. At a dose of ∼1 dpa the mechanical property degradation of the Hi-Nicalon TM composite is consistent with a fiber densification-induced debonding. At a dose of 10 dpa the properties continue to degrade raising the question of degradation in the CVD SiC matrix as well. Low-dose results on the Hi-Nicalon TM Type-S fabricated material are encouraging, as they appear to not lose, and perhaps slightly increase, in ultimate bend strength. This result is consistent with the supposition that as the oxygen content in SiC-based fibers is reduced, the irradiation stability and hence composite performance under irradiation will improve

  18. Nanostructure evolution of neutron-irradiated reactor pressure vessel steels: Revised Object kinetic Monte Carlo model

    Energy Technology Data Exchange (ETDEWEB)

    Chiapetto, M., E-mail: mchiapet@sckcen.be [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium); Unité Matériaux Et Transformations (UMET), UMR 8207, Université de Lille 1, ENSCL, F-59600 Villeneuve d’Ascq Cedex (France); Messina, L. [DEN-Service de Recherches de Métallurgie Physique, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); KTH Royal Institute of Technology, Roslagstullsbacken 21, SE-114 21 Stockholm (Sweden); Becquart, C.S. [Unité Matériaux Et Transformations (UMET), UMR 8207, Université de Lille 1, ENSCL, F-59600 Villeneuve d’Ascq Cedex (France); Olsson, P. [KTH Royal Institute of Technology, Roslagstullsbacken 21, SE-114 21 Stockholm (Sweden); Malerba, L. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium)

    2017-02-15

    This work presents a revised set of parameters to be used in an Object kinetic Monte Carlo model to simulate the microstructure evolution under neutron irradiation of reactor pressure vessel steels at the operational temperature of light water reactors (∼300 °C). Within a “grey-alloy” approach, a more physical description than in a previous work is used to translate the effect of Mn and Ni solute atoms on the defect cluster diffusivity reduction. The slowing down of self-interstitial clusters, due to the interaction between solutes and crowdions in Fe is now parameterized using binding energies from the latest DFT calculations and the solute concentration in the matrix from atom-probe experiments. The mobility of vacancy clusters in the presence of Mn and Ni solute atoms was also modified on the basis of recent DFT results, thereby removing some previous approximations. The same set of parameters was seen to predict the correct microstructure evolution for two different types of alloys, under very different irradiation conditions: an Fe-C-MnNi model alloy, neutron irradiated at a relatively high flux, and a high-Mn, high-Ni RPV steel from the Swedish Ringhals reactor surveillance program. In both cases, the predicted self-interstitial loop density matches the experimental solute cluster density, further corroborating the surmise that the MnNi-rich nanofeatures form by solute enrichment of immobilized small interstitial loops, which are invisible to the electron microscope.

  19. Modification of the mesoscopic structure in neutron irradiated EPDM viewed through positron annihilation spectroscopy and dynamic mechanical analysis

    International Nuclear Information System (INIS)

    Lambri, O.A.; Plazaola, F.; Axpe, E.; Mocellini, R.R.; Zelada-Lambri, G.I.; Garcia, J.A.; Matteo, C.L.; Sorichetti, P.A.

    2011-01-01

    This article focuses on the study of the mesoscopic structure in neutron irradiated EPDM both from experimental and theoretical points of view. In this work we reveal completely the modification of the mesostructure of the EPDM due to neutron irradiation, resolving volume fraction, size and distribution of the crystalline zones as a function of the irradiation dose. Positron annihilation spectroscopy and dynamic mechanical analysis techniques are applied and the results are discussed by means of new theoretical results for describing the interaction process between the crystals and amorphous zones in EPDM.

  20. Evolution of stainless steels in nuclear industry

    International Nuclear Information System (INIS)

    Tavassoli, Farhad

    2010-01-01

    Starting with the stainless steels used in the conventional industry, their adoption and successive evolutions in the nuclear industry, from one generation of nuclear reactors to another, is presented. Specific examples for several steels are given, covering fabrication procedures, qualification methods, property databases and design allowable stresses, to show how the ever-increasing demands for better performance and reliability, in particular under neutron irradiation, have been met. Particular attention is paid to the austenitic stainless steels types 304L, 316L, 316L(N), 316L(N)-IG, titanium stabilized grade 321, precipitation strengthened alloy 800, conventional and low activation ferritic/martensitic steels and their oxygen dispersion strengthening (ODS) derivatives. For each material, the evolution of the associated filler metal and welding techniques are also presented. (author)

  1. Atomic structure of radiation damages in FCC-metals after neutron irradiation

    International Nuclear Information System (INIS)

    Popova, E.V.; Ivchenko, V.A.; Kozlov, A.V.

    2005-01-01

    Full text: Radiation clusters, formed at a neutron irradiation, are a product of evolution of cascade areas. The quantitative information about clusters can be used for verification of calculations of cascade damage ability, in particular, cascade efficiency. Data about concentration clusters and an average of the vacancies containing in them, allow to receive total of the vacancies reserved in them and to use them for comparison to results of calculations of cascade damage ability. A correctness of such comparison by that above, than below temperature of a neutron irradiation. The purpose of work was experimental studying radiation clusters formed in FCC-metals at a low temperature neutron irradiation methods of dilatometry, field ion (FIM) and transmission electronic microscopy (TEM). Radiation clusters were studied: in industrial austenite steel C0.05Crl6Nil5Mo2Mnl, irradiated in reactor Rw-2a at temperature 310 K up to fluence intermediate and fast neutrons (with E > 0,1 MeV) 6.7·l0 21 m -2 ; in a modelling material - Pt (cleanliness of 99.99 %) with the same - FCC-structure in an initial condition and after an irradiation in reactor RWW-2M at temperature 310 K up to fluence intermediate and fast neutrons (with E > 0.1 MeV) 3.5·10 22 m -2 . As a result of an irradiation of steel and pure Pt, in these materials by methods FIM and TEM many radiation clusters, the accelerated neutrons initiated by interaction with substance was revealed. It is established that these damage areas represent the depleted zones containing separate vacancies, and also small vacancy complexes, with the 'belt' interstitial atoms. The quantitative estimation of the sizes of such radiating defects is lead and their density in volume is experimentally established. So the neutron irradiation of steel at temperature 310 K up to fluence 6.7·10 21 m -2 causes formation radiation clusters which average diameter according to TEM makes 3 nanometers. Observable by methods FIM clusters have the

  2. Formation of ultra-fine grained SUS316L steels by ball-milling and their mechanical properties after neutron irradiation

    International Nuclear Information System (INIS)

    Zheng, Y.J.; Yamasaki, T.; Fukami, T.; Terasawa, M.; Mitamura, T.

    2003-01-01

    In order to overcome the irradiation embrittlement in austenitic stainless steels, ultra-fine grained SUS316L steels with very fine TiC particles have been developed. The SUS316L-TiC nanocomposite powders having 1.0 to 2.0 mass% TiC were prepared by ball-milling SUS316L-TiC powder mixtures for 125 h in an argon gas atmosphere. The milled powders were consolidated by hot isostatic pressing (HIP) under a pressure of 200 MPa at temperatures between 700 and 1000 C, and the bulk materials with grain sizes between 100 and 400 nm have been produced. The possibility of using fine-grained TiC particles to pin grain boundaries and thereby maintain the ultra-fine grained structures has been discussed. In order to clarify the effects of the neutron irradiation on mechanical properties of the ultra-fine grained SUS316L steels, Vickers microhardness measurements were performed before and after the irradiation of 1.14 x 10 23 n/m 2 and 1.14 x 10 24 n/m 2 . The hardness increased with increasing the dose of the irradiation. However, these increasing rates of the ultra-fine grained steels were much smaller than those of the coarse-grained SUS316L steels having grain sizes between 13 and 50 μm. (orig.)

  3. Influence of LBE long term exposure and simultaneous fast neutron irradiation on the mechanical properties of T91 and 316L

    Energy Technology Data Exchange (ETDEWEB)

    Stergar, E., E-mail: estergar@sckcen.be [SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Eremin, S.G. [RIAR, Research Institute of Atomic Reactors, Dimitrovgrad (Russian Federation); Gavrilov, S.; Lambrecht, M. [SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Makarov, O.; Iakovlev, V. [RIAR, Research Institute of Atomic Reactors, Dimitrovgrad (Russian Federation)

    2016-05-15

    The LEXUR–II–LBE irradiation campaign was conducted from 2011 to 2012 and was aimed to investigate the combined influence of irradiation and LBE environment. In this irradiation campaign tensile test samples, pressurized tubes and corrosion samples were irradiated in LBE filled capsules. To separate the effect of exposure to LBE and neutron irradiation a parallel furnace experiment where the samples were exposed to LBE at the irradiation temperature for the corresponding time was conducted. Here we report results of the first extracted capsule which was irradiated about 6 months and dismantled after a cooling phase to decrease activity. The results of SSRT tests for irradiated T91 show that the exposure to LBE at 350 °C for a long time leads to the appearance of liquid metal embrittlement without any pre-treatment which is usually necessary to promote LME. Irradiation increases the effect of LME on the ductility of T91. In contrast to the findings for T91 the gained results also show that tensile tests on irradiated austenitic stainless steel 316L show no influence of LBE environment on the tensile properties.

  4. Thermal creep and stress-affected precipitation of 20% cold-worked 316 stainless steel

    International Nuclear Information System (INIS)

    Puigh, R.J.; Lovell, A.J.; Garner, F.A.

    1984-01-01

    Measurements of the thermal creep of 20% cold-worked 316 stainless steel have been performed for temperatures from 593 to 760 0 C, stress levels as high as 138 MPa and exposure times as long as 15,000 hours. The creep strains exhibit a complex behavior arising from the combined action of true creep and stress-affected precipitation of intermetallic phases. The latter process is suspected to be altered by neutron irradiation. (orig.)

  5. The effect of neutron irradiation on the mechanical properties of welded zircaloy-2

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D G

    1962-07-15

    Zircaloy-2 tensile specimens, subsize impact bars and representative spigot welds were subjected to three NRX cycles in the X-5 loop. Average loop temperature was 260{sup o}C over the three cycles. One group of tensile specimens was heat-treated in vacuum at 900{sup o}C for 40 minutes, another group contained welded areas in the centre of the gauge length and a third group was hydrided after welding. Notches of the impact specimens were located in the fusion zone of the weld, Spigot welds were made on autoclaved and unautoclaved simulated production assemblies. The transition temperature of Zircaloy-2 increased appreciably upon welding. This was accompanied by a decrease in absorbed energy values for all temperatures between 0{sup o} and 300{sup o}C. Neutron irradiation had no effect on the impact properties of welded. Zircaloy-2. Welding decreased the uniform and total elongation at room temperature and at 260{sup o}C, and increased the 260{sup o}C PL, YS and UTS. Hydriding to a nominal 100 ppm hydrogen had no effect on the unirradiated tensile properties at either test temperature. The heat treatment decreased the strength properties but did not affect the ductility. Neutron irradiation increased the YS of the welded and hydrided material by 20% and the heat treated YS by 40%. Irradiation also increased the 260{sup o}C strength properties of the as-welded material. It was found that the unautoclaved spigot welds had a generally higher tensile strength than the autoclaved and welded specimens. For specimens welded in either condition, the outer welds of the 19-element bundle had a lower average breaking load than the inner welds. Neutron irradiation had no effect on the tensile strength of these welds. It was also demonstrated that a cup-and-cone type of fracture could be produced in a bend test. These fractures were similar to those observed in irradiated fuel bundles which had been damaged during transfer operations. A large amount of scatter rendered some

  6. Influence of impurities on the evolution of vacancy-type defects in neutron-irradiated nickel

    International Nuclear Information System (INIS)

    Druzhkov, A.P.; Perminov, D.A.; Arbuzov, V.L.

    2012-01-01

    Highlights: ► We study, by means of PAS, the effects of purity on damage evolution in neutron-irradiated Ni at 330 K. ► Impurity carbon atoms in solution decrease the cascade efficiency during irradiation. ► C–V complexes are formed on the recovery stage III in impure Ni irradiated with 10 −4 dpa. ► The formation of V-loops and SFTs dominate on stage III with increasing dose level. ► The thermal stability of SFTs in impure Ni is similar to that in pure Ni. - Abstract: In order to investigate the effect of impurities on vacancy defect evolution in nickel, specimens with high (5N) and technical (3N) purity were neutron-irradiated at ∼330 K in the IVV-2M reactor (Russia) to fluencies in the range of 1 × 10 21 –1 × 10 23 n/m 2 (E > 0.1 MeV) corresponding to displacement dose levels in the range of about 0.0001–0.01 dpa and subsequently stepwise annealed to about 900 K. The specimens of Ni with different purities were characterized both in as-irradiated state as well as after post-irradiation annealing by positron annihilation spectroscopy. The formation of three-dimensional vacancy clusters (3D-VCs) in cascades was observed under neutron irradiation. The density and size of 3D-VCs depended not only on dose level, but also on purity. The population of 3D-VCs in the technical Ni is lower than that in the high-purity Ni. 3D-VCs collapse into secondary-type clusters (stacking fault tetrahedra (SFTs) and vacancy loops) during stepwise annealing at 350–450 K (stage III in Ni). The suppression of secondary cluster formation in 3N Ni is attributed to an effective vacancy interaction with impurity carbon atoms, which based on a relatively large vacancy–carbon atom binding energy (0.32–0.35 eV). The trapping of vacancies released at the collapse of 3D-VCs by the interstitial impurity atoms dominates at low irradiation dose level (10 −4 dpa). Thus, we found that carbon impurity atoms have strong effects both on the primary vacancy-type defect

  7. Investigations on neutron irradiated 3D carbon fibre reinforced carbon composite material

    Science.gov (United States)

    Venugopalan, Ramani; Alur, V. D.; Patra, A. K.; Acharya, R.; Srivastava, D.

    2018-04-01

    As against conventional graphite materials carbon-carbon (C/C) composite materials are now being contemplated as the promising candidate materials for the high temperature and fusion reactor owing to their high thermal conductivity and high thermal resistance, better mechanical/thermal properties and irradiation stability. The current need is for focused research on novel carbon materials for future new generation nuclear reactors. The advantage of carbon-carbon composite is that the microstructure and the properties can be tailor made. The present study encompasses the irradiation of 3D carbon composite prepared by reinforcement using PAN carbon fibers for nuclear application. The carbon fiber reinforced composite was subjected to neutron irradiation in the research reactor DHRUVA. The irradiated samples were characterized by Differential Scanning Calorimetry (DSC), small angle neutron scattering (SANS), XRD and Raman spectroscopy. The DSC scans were taken in argon atmosphere under a linear heating program. The scanning was carried out at temperature range from 30 °C to 700 °C at different heating rates in argon atmosphere along with reference as unirradiated carbon composite. The Wigner energy spectrum of irradiated composite showed two peaks corresponding to 200 °C and 600 °C. The stored energy data for the samples were in the range 110-170 J/g for temperature ranging from 30 °C to 700 °C. The Wigner energy spectrum of irradiated carbon composite did not indicate spontaneous temperature rise during thermal annealing. Small angle neutron scattering (SANS) experiments have been carried out to investigate neutron irradiation induced changes in porosity of the composite samples. SANS data were recorded in the scattering wave vector range of 0.17 nm-1 to 3.5 nm-1. Comparison of SANS profiles of irradiated and unirradiated samples indicates significant change in pore morphology. Pore size distributions of the samples follow power law size distribution with

  8. Comparison of four NDT methods for indication of reactor steel degradation by high fluences of neutron irradiation

    Czech Academy of Sciences Publication Activity Database

    Tomáš, Ivan; Vértesy, G.; Pirfo Barroso, S.; Kobayashi, S.

    2013-01-01

    Roč. 265, DEC (2013), s. 201-209 ISSN 0029-5493 Institutional support: RVO:68378271 Keywords : neutron irradiation * steel degradation * nuclear reactor pressure vessel * magnetic NDT * magnetic minor hysteresis loops * Magnetic Barkhausen Emission Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.972, year: 2013 http://www.sciencedirect.com/science/article/pii/S0029549313004664

  9. The investigation of the magnetic after-effect in iron-alpha after neutron irradiation at low temperature

    International Nuclear Information System (INIS)

    Mensch, W.

    1986-01-01

    The present thesis investigates the magnetic after-effect for neutron irradiated, polycrystalline iron-alpha for the temperature range 10 to 400 K by means of susceptibility measurements. 24 maxima of magnetic after-effect are found, which are related to different classes of defects. (BHO)

  10. DT fusion neutron irradiation of LLL Nb3Sn and LLL superconductor wires at 4.20K

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1977-01-01

    The DT fusion neutron irradiation of one LLL superconductor wire and one LLL Nb 3 Sn foil at 4.2 0 K is described. The sample position, beam-on time, and neutron dose record are given. The results from two ''profile'' dosimetry foils measuring the lateral variation in neutron flux are included

  11. Antiradiation Vaccine: Technology Development Of Prophylaxis, Prevention And Treatment Of Biological Consequences And Complications After Neutron Irradiation.

    Science.gov (United States)

    Popov, Dmitri; Maliev, Slava; Jones, Jeffrey

    Introduction: Neutrons irradiation produce a unique biological effectiveness compare to different types of radiation because their ability to create a denser trail of ionized atoms in biological living tissues[Straume 1982; Latif et al.2010; Katz 1978; Bogatyrev 1982]. The efficacy of an Anti-Radiation Vaccine for the prophylaxis, prevention and therapy of acute radiation pathology was studied in a neutron exposure facility. The biological effects of fast neutrons include damage of central nervous system and cardiovascular system with development of Acute Cerebrovascular and Cardiovascular forms of acute radiation pathology. After irradiation by high doses of fast neutron, formation of neurotoxins, hematotoxins,cytotoxins forming from cell's or tissue structures. High doses of Neutron Irradiation generate general and specific toxicity, inflammation reactions. Current Acute Medical Management and Methods of Radiation Protection are not effective against moderate and high doses of neutron irradiation. Our experiments demonstrate that Antiradiation Vaccine is the most effective radioprotectant against high doses of neutron-radiation. Radiation Toxins(biological substances with radio-mimetic properties) isolated from central lymph of gamma-irradiated animals could be working substance with specific antigenic properties for vaccination against neutron irradiation. Methods: Antiradiation Vaccine preparation standard - mixture of a toxoid form of Radiation Toxins - include Cerebrovascular RT Neurotoxin, Cardiovascular RT Neurotoxin, Gastrointestinal RT Neurotoxin, Hematopoietic RT Hematotoxin. Radiation Toxins were isolated from the central lymph of gamma-irradiated animals with different forms of Acute Radiation Syndromes - Cerebrovascular, Cardiovascular, Gastrointestinal, Hematopoietic forms. Devices for Y-radiation were "Panorama","Puma". Neutron exposure was accomplished at the Department of Research Institute of Nuclear Physics, Dubna, Russia. The neutrons

  12. Internal friction in Al alloys after neutron irradiation at low temperature

    International Nuclear Information System (INIS)

    Takamura, S.; Kobiyama, M.

    1985-01-01

    Internal friction and elastic modulus of dilute Al alloys have been measured after fast neutron irradiation at about 5 K. The internal friction spectra in Al-Pb, Al-Si, Al-Zn, Al-Ag, Al-Sn and Al-In are very similar. This result suggests that the configuration of the interstitial-solute atom complex in these alloys is very similar. In Al-Mg, the main complexes have the configuration with nearly symmetry, but its internal friction spectrum is different from that of the above-mentioned alloys. The internal friction spectra and their annealing behavior in Al-Be, Al-Mn, Al-Fe and Al-Cu demonstrate that the configuration of their interstitial-solute atom complex seems to be different from each other and the main complex in these alloys is immobile until stage III. (author)

  13. Defect cascades produced by neutron irradiation in YBa2Cu3O7-δ

    International Nuclear Information System (INIS)

    Frischherz, M.C.; Kirk, M.A.; Farmer, J.; Greenwood, L.R.; Weber, H.W.

    1992-12-01

    The defect cascades produced by fast neutron irradiation of YBa 2 Cu 3 O 7-δ single crystals were studied by transmission electron microscopy. The visible defects were found to have sizes between 1 and 5 nm. Defect densities were obtained as a function of neutron fluence between 2 and 8 x 10 21 m -2 (E>0.1 MeV) and compared to damage calculations. The measured defect density was found to scale linearly with fluence and to be 1 x 10 22 m -3 at 2 x 10 21 m -2 . The defect stability was studied at room temperature and through annealing to 400 degrees C. The high fluence regime (∼10 22 m -2 ) was investigated as well

  14. High dose effects in neutron irradiated face-centered cubic metals

    International Nuclear Information System (INIS)

    Garner, F.A.; Toloczko, M.B.

    1993-06-01

    During neutron irradiation, most face-centered cubic metals and alloys develop saturation or quasi-steady state microstructures. This, in turn, leads to saturation levels in mechanical properties and quasi-steady state rates of swelling and creep deformation. Swelling initially plays only a small role in determining these saturation states, but as swelling rises to higher levels, it exerts strong feedback on the microstructure and its response to environmental variables. The influence of swelling, either directly or indirectly via second order mechanisms, such as elemental segregation to void surfaces, eventually causes major changes, not only in irradiation creep and mechanical properties, but also on swelling itself. The feedback effects of swelling on irradiation creep are particularly complex and lead to problems in applying creep data derived from highly pressurized creep tubes to low stress situations, such as fuel pins in liquid metal reactors

  15. Use of the National Low-Temperature Neutron Irradiation Facility (NLTNIF) for fusion materials research

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Kerchner, H.R.; Klabunde, C.E.

    1986-01-01

    In May 1983 the Division of Materials Sciences, Office of Basic Energy Sciences of the Department of Energy authorized the establishment of a National Low-Temperature Neutron Irradiation Facility (NLTNIF) at ORNL's Bulk Shielding Reactor (BSR). The NLTNIF, which will be available for qualified experiments at no cost to users, will provide a combination of high radiation intensities and special environmental and testing conditions that have not been previously available in the US. Since the DOE authorization, work has proceeded on the design and construction of the new facility without interruption. This report describes the present status of the development of NLTNIF and, for the information of new candidate users, a recounting of the major specifications and capabilities is also given

  16. Fusion neutron irradiation of Ni(Si) alloys at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.S.; Guinan, M.W.; Hahn, P.A.

    1987-09-01

    Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab.

  17. Studies of frequency dependent C-V characteristics of neutron irradiated p+-n silicon detectors

    International Nuclear Information System (INIS)

    Li, Zheng; Kraner, H.W.

    1990-10-01

    Frequency-dependent capacitance-voltage fluence (C-V) characteristics of neutron irradiated high resistivity silicon p + -n detectors have been observed up to a fluence of 8.0 x 10 12 n/cm 2 . It has been found that frequency dependence of the deviation of the C-V characteristic (from its normal V -1/2 dependence), is strongly dependent on the ratio of the defect density and the effective doping density N t /N' d . As the defect density approaches the effective dopant density, or N t /N' d → 1, the junction capacitance eventually assumes the value of the detector geometry capacitance at high frequencies (f ≤ 10 5 Hz), independent of voltage. A two-trap-level model using the concept of quasi-fermi levels has been developed, which predicts both the effects of C-V frequency dependence and dopant compensation observed in this study

  18. Annealing effects on resistivity and Hall coefficient of neutron irradiated silicon

    International Nuclear Information System (INIS)

    Biggeri, U.

    1995-01-01

    High Temperature Annealing (HTA) treatment has been carried out on fast-neutron irradiated silicon samples with temperatures up to 300 C. Fluences of irradiation up to 1x10 14 n/cm 2 were used. Before annealing, samples irradiated with fluences higher than 1x10 13 n/cm 2 suffered the type conductivity inversion from n-type to p-type. The changes in the resisitivity and Hall coefficient during each annealing step have been measured by Hall effect analysis. Results indicate the possible creation of acceptors for low temperature annealing up to 150 C and the phosphorous release by E centres at annealing temperatures among 150 C and 200 C. Heating samples up to 300 C allows the recovering of the sample resistivity to its value before irradiation, with the peculiarity that bulks inverted to p-type after irradiation does not come back to n-type after annealing. (orig.)

  19. HEINBE; the calculation program for helium production in beryllium under neutron irradiation

    International Nuclear Information System (INIS)

    Shimakawa, Satoshi; Ishitsuka, Etsuo; Sato, Minoru

    1992-11-01

    HEINBE is a program on personal computer for calculating helium production in beryllium under neutron irradiation. The program can also calculate the tritium production in beryllium. Considering many nuclear reactions and their multi-step reactions, helium and tritium productions in beryllium materials irradiated at fusion reactor or fission reactor may be calculated with high accuracy. The calculation method, user's manual, calculated examples and comparison with experimental data were described. This report also describes a neutronics simulation method to generate additional data on swelling of beryllium, 3,000-15,000 appm helium range, for end-of-life of the proposed design for fusion blanket of the ITER. The calculation results indicate that helium production for beryllium sample doped lithium by 50 days irradiation in the fission reactor, such as the JMTR, could be achieved to 2,000-8,000 appm. (author)

  20. PCC-ring induction in human lymphocytes exposed to gamma and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lamadrid Boada, Ana I; Garcia Lima, Omar [Centro de Proteccion e Higiene de las Radiaciones (CPHR), La Habana (Cuba); Delbos, Martine; Voisin, Philipe; Roy, Laurence [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses (France)

    2008-07-01

    Dose-effect curves for dose assessment in Gamma and neutron overexposures to high doses are presented in this paper for the first time in literature. The relationships were obtained by plotting the Premature Chromosome Condensation -rings (PCC-R) frequencies in PCC lymphocytes obtained by chemical induction with Calyculin A in vitro, with radiation doses between 5 to 25 Gy. For the elaboration of these curves 9 676 PCC cells in G1 G2 and M stages were analyzed. The results were fitted to a lineal quadratic model in Gamma irradiation and showed saturation starting from 20 Gy. For neutron irradiation the data was fitted to a lineal quadratic model up to 10 Gy, and then a markedly cell cycle arrest and saturation was observed. These curves are of particular interest for victims exposed to doses exceeding 5 Gy where it is always very difficult to estimate a dose using the conventional technique. (author)

  1. PCC-ring induction in human lymphocytes exposed to gamma and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lamadrid B, A I; Garcia L, O [CPHR, Calle 20 No. 4113 e/41 y 47, Playa, La Habana 11300 (Cuba); Delbos, M; Voisin, P; Roy, L [Institut de Radioprotection et de Surete Nucleaire, BP 17, 92262 Fontenay-aux-Roses (France)

    2006-07-01

    Dose-effect curves for dose assessment in Gamma and neutron overexposures to high doses are presented in this paper for the first time in literature. The relationships were obtained by plotting the Premature Chromosome Condensation -rings (PCC-R) frequencies in PCC Iymphocytes obtained by chemical induction with Calyculin A in vitro, with radiation doses between 5 to 25 Gy. For the elaboration of these curves 9 676 PCC cells in Gl G2 and M stages were analyzed. The results were fitted to a lineal quadratic model in Gamma irradiation. For neutron irradiation the data was fitted to a lineal quadratic model up to 10 Gy and then a markedly cell cycle arrest and saturation was observed. These curves are of particular interest for victims exposed to doses exceeding 5 Gy where it is always very difficult to estimate a dose using the conventional technique. (Author)

  2. PCC-ring induction in human lymphocytes exposed to gamma and neutron irradiation

    International Nuclear Information System (INIS)

    Lamadrid B, A.I.; Garcia L, O.; Delbos, M.; Voisin, P.; Roy, L.

    2006-01-01

    Dose-effect curves for dose assessment in Gamma and neutron overexposures to high doses are presented in this paper for the first time in literature. The relationships were obtained by plotting the Premature Chromosome Condensation -rings (PCC-R) frequencies in PCC Iymphocytes obtained by chemical induction with Calyculin A in vitro, with radiation doses between 5 to 25 Gy. For the elaboration of these curves 9 676 PCC cells in Gl G2 and M stages were analyzed. The results were fitted to a lineal quadratic model in Gamma irradiation. For neutron irradiation the data was fitted to a lineal quadratic model up to 10 Gy and then a markedly cell cycle arrest and saturation was observed. These curves are of particular interest for victims exposed to doses exceeding 5 Gy where it is always very difficult to estimate a dose using the conventional technique. (Author)

  3. PCC-ring induction in human lymphocytes exposed to gamma and neutron irradiation

    International Nuclear Information System (INIS)

    Lamadrid Boada, Ana I.; Garcia Lima, Omar; Delbos, Martine; Voisin, Philipe; Roy, Laurence

    2008-01-01

    Dose-effect curves for dose assessment in Gamma and neutron overexposures to high doses are presented in this paper for the first time in literature. The relationships were obtained by plotting the Premature Chromosome Condensation -rings (PCC-R) frequencies in PCC lymphocytes obtained by chemical induction with Calyculin A in vitro, with radiation doses between 5 to 25 Gy. For the elaboration of these curves 9 676 PCC cells in G1 G2 and M stages were analyzed. The results were fitted to a lineal quadratic model in Gamma irradiation and showed saturation starting from 20 Gy. For neutron irradiation the data was fitted to a lineal quadratic model up to 10 Gy, and then a markedly cell cycle arrest and saturation was observed. These curves are of particular interest for victims exposed to doses exceeding 5 Gy where it is always very difficult to estimate a dose using the conventional technique. (author)

  4. Neutron irradiation effects on superconducting and stabilizing materials for fusion magnets

    International Nuclear Information System (INIS)

    Maurer, W.

    1984-05-01

    Available low-temperature neutron irradiation data for the superconductors NbTi and Nb 3 Sn and the stabilization materials Cu and Al are collected and maximum tolerable doses for these materials are defined. A neutron flux in a reactor of about 10 9 n/cm 2 s at the magnet position is expected. However, in fusion experiments the flux can be higher by an order of magnitude or more. The energy spectrum is similar to a fission reactor. A fluence of about 10 18 n/cm 2 results during the lifetime of a fusion magnet (about 20 full power years). At this fluence and energy spectrum no severe degradation of the superconducting properties of NbTi and Nb 3 Sn will occur. But the radiation-induced resistivity is for Cu about a twentieth of the room temperature resistivity and a tenth for Al. (orig.) [de

  5. Neutron irradiation effects on the mechanical properties of thorium and thorium--carbon alloy

    International Nuclear Information System (INIS)

    Wang, S.C.P.

    1978-04-01

    The effects of neutron exposure to 3.0 x 10 18 neutrons/cm 2 on the mechanical properties of thorium and thorium-carbon alloy are described. Tensile measurements were done at six different test temperatures from 4 0 K to 503 0 K and at two strain rates. Thorium and thorium-carbon alloy are shown to display typical radiation hardening like other face-centered cubic metals. The yield drop phenomenon of the thorium-carbon alloy is unchanged after irradiation. The variation of shear stress and effective shear stress with test temperature was fitted to Seeger's and Fleischer's equations for irradiated and unirradiated thorium and thorium-carbon alloy. Neutron irradiation apparently contributes an athermal component to the yield strength. However, some thermal component is detected in the low temperature range. Strain-rate parameter is increased and activation volume is decreased slightly for both kinds of metal after irradiation

  6. Neutron irradiation effects in reactor pressure vessel steels and weldments. Working document

    International Nuclear Information System (INIS)

    1998-10-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. A separate abstract was prepared for the introduction and for each of the eleven chapters, which are: 1. Reactor Pressure Vessel Design, 2. Reactor Pressure Materials, 3. WWER Pressure Vessels, 4. Determination of Mechanical Properties, 5. Neutron Exposure, 6. Methodology of Irradiation Experiments, 7. Effect of Irradiation on Mechanical Properties, 8. Mechanisms of Irradiation Embrittlement, 9. Modelling of Irradiation Damage, 10. Annealing of Irradiation Damage, 11. Safety Assessment using Surveillance Programmes and Data Bases

  7. Improvement of radiation response characteristic on CdTe detectors using fast neutron irradiation

    International Nuclear Information System (INIS)

    Miyamaru, Hiroyuki; Takahashi, Akito; Iida, Toshiyuki

    1999-01-01

    The treatment of fast neutron pre-irradiation was applied to a CdTe radiation detector in order to improve radiation response characteristic. Electron transport property of the detector was changed by the irradiation effect to suppress pulse amplitude fluctuation in risetime. Spectroscopic performance of the pre-irradiated detector was compared with the original. Additionally, the pre-irradiated detector was employed with a detection system using electrical signal processing of risetime discrimination (RTD). Pulse height spectra of 241 Am, 133 Ba, and 137 Cs gamma rays were measured to examine the change of the detector performance. The experimental results indicated that response characteristic for high-energy photons was improved by the pre-irradiation. The combination of the pre-irradiated detector and the RTD processing was found to provide further enhancement of the energy resolution. Application of fast neutron irradiation effect to the CdTe detector was demonstrated. (author)

  8. Structure and Spatial Distribution of Ge Nanocrystals Subjected to Fast Neutron Irradiation

    Directory of Open Access Journals (Sweden)

    Alexander N. Ionov

    2011-07-01

    Full Text Available The influence of fast neutron irradiation on the structure and spatial distribution of Ge nanocrystals (NC embedded in an amorphous SiO2 matrix has been studied. The investigation was conducted by means of laser Raman Scattering (RS, High Resolution Transmission Electron Microscopy (HR-TEM and X-ray photoelectron spectroscopy (XPS. The irradiation of Ge- NC samples by a high dose of fast neutrons lead to a partial destruction of the nanocrystals. Full reconstruction of crystallinity was achieved after annealing the radiation damage at 8000C, which resulted in full restoration of the RS spectrum. HR-TEM images show, however, that the spatial distributions of Ge-NC changed as a result of irradiation and annealing. A sharp decrease in NC distribution towards the SiO2 surface has been observed. This was accompanied by XPS detection of Ge oxides and elemental Ge within both the surface and subsurface region.

  9. 'In situ' straining in the HVEM of neutron irradiated copper crystals

    International Nuclear Information System (INIS)

    Johnson, E.; Hirsch, P.B.

    1976-01-01

    High energy neutron irradiated copper single crystals strained 'in situ' in the high voltage electron microscope are observed to yield in relatively few strongly developed slip bands. The deformation in the slip bands is caused by glide of inclined dislocations close to screw orientation belonging to the primary slip system. Radiation induced point defect clusters are swept up by the dislocations whereby superjogs are formed. Some of the jogs will be sessile and act as pinning points for the gliding dislocations, which bow out under the applied stress to form perfect dipoles mainly of edge nature, as well as faulted dipoles, which are finally pinched off. The effective stress measured from the radius of curvature of the bowed-out dislocations is in agreement with resolved flow stress measurements from irradiated bulk crystals. (Auth.)

  10. Structure of compensating centers in neutron irradiated n-type germanium

    International Nuclear Information System (INIS)

    Erchak, D.P.; Kosobutskij, V.S.; Stel'makh, V.F.

    1989-01-01

    Structural model of one of the main compensating defects of Ge-M1, Ge-M5, Ge-M6 in neutron irradiated (10 18 -10 20 cm -2 ) germanium, strongly alloyed (2x10 18 -3x10 19 cm -3 ) with antimony, phosphorus and arsenic respectively, is suggested. The above mentioned compensating centers are paramagnetic in a positive charge state and represent a vacancy, two nearby germanium atoms of which are replaced with two atoms of corresponding fine donor impurity. It is mainly contributed (63%- for Ge-M5 centers, 56% - for Ge-M6 centers) by orbitals of two germanium atoms neighbouring the vacancy. The angle of the bonds of each of two mentioned germanium atoms with its three neighbours and orientation of maximum electron density of hybride orbital, binding both germanium atoms, is approximately by 5 deg greater the tetrahedral one

  11. Study of the temperature evolution of defect agglomerates in neutron irradiated molybdenum single crystals

    International Nuclear Information System (INIS)

    Lambri, O.A.; Zelada-Lambri, G.I.; Cuello, G.J.; Bozzano, P.B.; Garcia, J.A.

    2009-01-01

    Small angle neutron scattering as a function of temperature, differential thermal analysis, electrical resistivity and transmission electron microscopy studies have been performed in low rate neutron irradiated single crystalline molybdenum, at room temperature, for checking the evolution of the defects agglomerates in the temperature interval between room temperature and 1200 K. The onset of vacancies mobility was found to happen in temperatures within the stage III of recovery. At around 550 K, the agglomerates of vacancies achieve the largest size, as determined from the Guinier approximation for spherical particles. In addition, the decrease of the vacancy concentration together with the dissolution of the agglomerates at temperatures higher than around 920 K was observed, which produce the release of internal stresses in the structure.

  12. Study of the temperature evolution of defect agglomerates in neutron irradiated molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lambri, O.A. [Instituto de Fisica Rosario. Member of the CONICET' s Research Staff, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina); Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina)], E-mail: olambri@fceia.unr.edu.ar; Zelada-Lambri, G.I. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina); Cuello, G.J. [Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble (France); Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain); Bozzano, P.B. [Laboratorio de Microscopia Electronica. Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499, (1650) San Martin (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2009-04-15

    Small angle neutron scattering as a function of temperature, differential thermal analysis, electrical resistivity and transmission electron microscopy studies have been performed in low rate neutron irradiated single crystalline molybdenum, at room temperature, for checking the evolution of the defects agglomerates in the temperature interval between room temperature and 1200 K. The onset of vacancies mobility was found to happen in temperatures within the stage III of recovery. At around 550 K, the agglomerates of vacancies achieve the largest size, as determined from the Guinier approximation for spherical particles. In addition, the decrease of the vacancy concentration together with the dissolution of the agglomerates at temperatures higher than around 920 K was observed, which produce the release of internal stresses in the structure.

  13. Modeling of helium bubble nucleation and growth in neutron irradiated boron doped RAFM steels

    International Nuclear Information System (INIS)

    Dethloff, Christian; Gaganidze, Ermile; Svetukhin, Vyacheslav V.; Aktaa, Jarir

    2012-01-01

    Reduced activation ferritic/martensitic (RAFM) steels are promising candidates for structural materials in future fusion technology. In addition to other irradiation defects, the transmuted helium is believed to strongly influence material hardening and embrittlement behavior. A phenomenological model based on kinetic rate equations is developed to describe homogeneous nucleation and growth of helium bubbles in neutron irradiated RAFM steels. The model is adapted to different 10 B doped EUROFER97 based heats, which already had been studied in past irradiation experiments. Simulations yield bubble size distributions, whereby effects of helium generation rate, surface energy, helium sinks and helium density are investigated. Peak bubble diameters under different conditions are compared to preliminary microstructural results on irradiated specimens. Helium induced hardening was calculated by applying the Dispersed Barrier Hardening model to simulated cluster size distributions. Quantitative microstructural investigations of unirradiated and irradiated specimens will be used to support and verify the model.

  14. Modeling of helium bubble nucleation and growth in neutron irradiated boron doped RAFM steels

    Energy Technology Data Exchange (ETDEWEB)

    Dethloff, Christian, E-mail: christian.dethloff@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Gaganidze, Ermile [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Svetukhin, Vyacheslav V. [Ulyanovsk State University, Leo Tolstoy Str. 42, 432970 Ulyanovsk (Russian Federation); Aktaa, Jarir [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-07-15

    Reduced activation ferritic/martensitic (RAFM) steels are promising candidates for structural materials in future fusion technology. In addition to other irradiation defects, the transmuted helium is believed to strongly influence material hardening and embrittlement behavior. A phenomenological model based on kinetic rate equations is developed to describe homogeneous nucleation and growth of helium bubbles in neutron irradiated RAFM steels. The model is adapted to different {sup 10}B doped EUROFER97 based heats, which already had been studied in past irradiation experiments. Simulations yield bubble size distributions, whereby effects of helium generation rate, surface energy, helium sinks and helium density are investigated. Peak bubble diameters under different conditions are compared to preliminary microstructural results on irradiated specimens. Helium induced hardening was calculated by applying the Dispersed Barrier Hardening model to simulated cluster size distributions. Quantitative microstructural investigations of unirradiated and irradiated specimens will be used to support and verify the model.

  15. Fusion neutron irradiation of Ni(Si) alloys at high temperature

    International Nuclear Information System (INIS)

    Huang, J.S.; Guinan, M.W.; Hahn, P.A.

    1987-09-01

    Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab

  16. Microstructural evolution of pure tungsten neutron irradiated with a mixed energy spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Takaaki, E-mail: koyanagit@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kumar, N.A.P. Kiran [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hwang, Taehyun [Tohoku University, Sendai, 980-8579 (Japan); Garrison, Lauren M.; Hu, Xunxiang [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2017-07-15

    Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90–800 °C to 0.03–4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.

  17. Photoconversion of F+ centers in neutron-irradiated MgO

    International Nuclear Information System (INIS)

    Monge, M.A.; Gonzalez, R.; Munoz Santiuste, J.E.; Pareja, R.; Chen, Y.; Kotomin, E.A.; Popov, A.I.

    2000-01-01

    In neutron-irradiated MgO crystals, experiments and theory demonstrate that photon excitation of the positively charged anion vacancies (F + centers) at 5.0 eV releases holes that are subsequently trapped at V-type centers, which are cation vacancies charge-compensated by impurities, such as Al 3+ , F - , and OH - ions. A photoconversion mechanism occurs very likely via electron transfer to F + centers from the quasi-local states which are induced in the valence band. INDO quantum chemical simulations of F + centers confirmed the appearance of two induced quasi-local states located at 1.2 and 2.0 eV below the top of the valence band

  18. National Low-Temperature Neutron Irradiation Facility (NLTNIF). The status of development

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Kerchner, H.R.; Klabunde, C.E.; Young, F.W. Jr.

    1985-12-01

    In May 1983, the Department of Energy authorized the establishment of a National Low-Temperature Neutron Irradiation Facility (NLTNIF) at ORNL's Bulk Shielding Reactor (BSR). The NLTNIF, which will be available for qualified experiments at no cost to users, will provide a combination of high radiation intensities and special environmental and testing conditions that have not been previously available in the US. Since the DOE authorization, work has proceeded on the design and construction of the new facility without interruption. This report describes the present status of the development of the NLTNIF and the anticipated schedule for completion and performance testing. There is a table of the major specifications and capabilities and a schematic layout of the irradiation cryostate for design and dimensioning of test and experiment assemblies

  19. Comparative study of neutron irradiation and carbon doping in MgB2 single crystals

    International Nuclear Information System (INIS)

    Krutzler, C.; Zehetmayer, M.; Eisterer, M.; Weber, H. W.; Zhigadlo, N. D.; Karpinski, J.

    2007-01-01

    We compare the reversible and irreversible magnetic properties of superconducting carbon doped and undoped MgB 2 single crystals before and after neutron irradiation. A large number of samples with transition temperatures between 38.3 and 22.8 K allows us to study the effects of disorder systematically. Striking similarities are found in the modification of the reversible parameters by irradiation and doping, which are discussed in terms of impurity scattering and changes of the Fermi surface. The irreversible properties are influenced by two counteracting mechanisms: they are enhanced by the newly introduced pinning centers but degraded by changes in the thermodynamic properties. Accordingly, the large neutron induced defects and the small defects from carbon doping lead to significantly different effects on the irreversible properties. Finally, the fishtail effect caused by all kinds of disorder is discussed in terms of an order-disorder transition of the flux-line lattice

  20. Synergies Between ' and Cavity Formation in HT-9 Following High Dose Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Saleh, Tarik A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eftink, Benjamin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Candidate cladding materials for advanced nuclear power reactors including fast reactor designs require materials capable of withstanding high dose neutron irradiation at elevated temperatures. One candidate material, HT-9, through various research programs have demonstrated the ability to withstand significant swelling and other radiation-induced degradation mechanisms in the high dose regime (>50 displacements per atom, dpa) at elevated temperatures (>300 C). Here, high efficiency multi-dimensional scanning transmission electron microscopy (STEM) acquisition with the aid of a three-dimensional (3D) reconstruction and modeling technique is used to probe the microstructural features that contribute to the exceptional swelling resistance of HT-9. In particular, the synergies between ' and fine-scale and moderate-scale cavity formation is investigated.

  1. Effect of Fast Neutron Irradiation on Current Transport Properties of HTS Materials

    CERN Document Server

    Ballarino, A; Kruglov, V S; Latushkin, S T; Lubimov, A N; Ryazanov, A I; Shavkin, S V; Taylor, T M; Volkov, P V

    2004-01-01

    The effect of fast neutron irradiation with energy up to 35 MeV and integrated fluence of up to 5 x 10**15 cm-2 on the current transport properties of HTS materials Bi-2212 and Bi-2223 has been studied, both at liquid nitrogen and at room temperatures. The samples irradiated were selected after verification of the stability of their superconducting properties after temperature cycling in the range of 77 K - 293 K. It has been found that the irradiation by fast neutrons up to the above dose does not produce a significant degradation of critical current. The effect of room temperature annealing on the recovery of transport properties of the irradiated samples is also reported, as is a preliminary microstructure investigation of the effect of irradiation on the soldered contacts.

  2. Glass-like, low-energy excitations in neutron-irradiated quartz

    International Nuclear Information System (INIS)

    Gardner, J.W.

    1980-01-01

    The specific heat and thermal conductivity of neutron-irradiated crystalline quartz have been measured for temperatures approx. = 0.1 to 5 K. Four types of low-energy excitations are observed in the irradiated samples, two of which can be removed selectively by heat treatment. One set of remaining excitations gives rise to low-temperature thermal behavior characteristic of glassy (amorphous) solids. The density of these glass-like excitations can be 50% the density observed in vitreous silica, yet the sample still retains long-range atomic order. In a less-irradiated sample, glass-like excitations may be present with a density only approx. = 2.5% that observed in vitreous silica and possess a similar broad energy spectrum over 0.1 to 1 K

  3. Relationship of microstructure and tensile properties for neutron-irradiated vanadium alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Smith, D.L.

    1990-01-01

    The microstructures in V-15Cr-5Ti, V-10Cr-5RTi, V-3Ti-1Si, V-15Ti-7.5Cr, and V-20Ti alloys were examined by transmission electron microscopy after neutron irradiation at 600 degree C to 21--84 atom displacements per atom in the Materials Open Test Assembly of the Fast Flux Test Facility. The microstructures in these irradiated alloys were analyzed to determine the radiation-produced dislocation density, precipitate number density and size, and void number density and size. The results of these analyses were used to compute increases in yield stress and swelling of the irradiated alloys. The computed increase in yield stress was compared with the increase in yield stress determined from tensile tests on these irradiated alloys. This comparison made it possible to evaluate the influence of alloy composition on the evolution of radiation-damaged microstructures and the resulting tensile properties. 11 refs

  4. Fusion neutron irradiation of Ni-Si alloys at high temperature*1

    Science.gov (United States)

    Huang, J. S.; Guinan, M. W.; Hahn, P. A.

    1988-07-01

    Two Ni-4% Si alloys, with different cold work levels, have been irradiated with 14-MeV fusion neutrons at 623 K, and their Curie temperatures have been monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2-MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14-MeV fusion neutrons is only 6-7% of that for an identical alloy irradiated by 2-MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6-7% for the fusion neutron irradiated sample.

  5. Defects in SiO2 crystals after neutron irradiations at 20 K and 360 K

    International Nuclear Information System (INIS)

    Nakagawa, M.; Okada, M.; Kawabata, Y.; Atobe, K.; Itoh, H.; Nakanishi, S.

    1994-01-01

    The synthetic silicon dioxide (SiO 2 ), cut parallel (x-plate) or perpendicular (z-plate) to c-axis, are irradiated by reactor neutrons at 360 K (2.8x10 18 n/cm 2 ) or at 20 K (8.0x10 16 n/cm 2 ). After neutron irradiation at 360 K, the main absorption peak can be observed at 212 nm (5.84 eV) for z-plate and 217 nm (5.71 eV) for x-plate. After irradiation at 20 K a new band at 250 nm (4.96 eV) can be observed in addition to the band at about 220 nm. The 250 nm band having FWHM similar 0.44 eV disappears at 300-340 K. Thermoluminescences are also observed between 80 to 400 K; which show some difference between x-plate and z-plate. ((orig.))

  6. Void formation by annealing of neutron-irradiated plastically deformed molybdenum

    International Nuclear Information System (INIS)

    Petersen, K.; Nielsen, B.; Thrane, N.

    1976-01-01

    The positron annihilation technique has been used in order to study the influence of plastic deformation on the formation and growth of voids in neutron irradiated molybdenum single crystals treated by isochronal annealing. Samples were prepared in three ways: deformed 12-19% before irradiation, deformed 12-19% after irradiation, and - for reference purposes -non-deformed. In addition a polycrystalline sample was prepared in order to study the influence of the grain boundaries. All samples were irradiated at 60 0 C with a flux of 2.5 x 10 18 fast neutrons/cm 2 . After irradiation the samples were subjected to isochronal annealing. It was found that deformation before irradiation probably enhanced the formation of voids slightly. Deformation after irradiation strongly reduced the void formation. The presence of grain boundaries in the polycrystalline sample had a reducing influence on the growth of voids. (author)

  7. Temperature dependence of the thermal expansion of neutron-irradiated pyrolytic carbon and graphite

    International Nuclear Information System (INIS)

    Matsuo, Hideto

    1988-01-01

    The effects of neutron irradiation and annealing on the temperature dependence of the linear thermal expansion of pyrolytic carbon and graphite were investigated after irradiation at 930-1280 0 C to a maximum neutron fluence of 2.84 x 10 25 m -2 (E > 29 fJ). After irradiation, little change in the thermal expansion of pyrolytic graphite was observed. However, as-deposited pyrolytic carbon showed an increase in thermal expansion in the perpendicular direction, a decrease in the direction parallel to the deposition plane, and also an increase in the anisotropy of the thermal expansion. Annealing at 2000 0 C did not cause any effective changes for irradiated specimens of either as-deposited pyrolytic carbon or pyrolytic graphite. (author)

  8. Preparation of 227Ac/223Ra by neutron irradiation of 226Ra

    International Nuclear Information System (INIS)

    Ekaterina Kukleva; Jan Kozempel; Martin Vlk; Petra Micolova; Dusan Vopalka

    2015-01-01

    Radium-223 is a prospective alpha-emitter for targeted radionuclide therapy. Although 223 Ra is formed naturally by the decay of 235 U, for practical reasons its preparation involves neutron irradiation of 226 Ra. The β - decay of the 227 Ra (T ½ = 43 min) produced via 226 Ra(n,γ) 227 Ra reaction leads to 227 Ac, a mother nuclide of 227 Th and subsequently 223 Ra. Radium target material is generally available in multigram quantities from historical stock. The main aim of this study was to experimentally as well as theoretically evaluate and verify the available literature data on production of 227 Ac/ 223 Ra. According to the data obtained from the γ-spectra, the approximate yield values were determined and effective cross section value for the 227 Ac production was calculated to 14 ± 4 b. (author)

  9. Decommissioning of an Irradiator MPX-γ - 25M and a neutron Irradiator

    International Nuclear Information System (INIS)

    Soguero, Dania; Guerra, Mercedes; Prieto, Enrique; Desdin, Luis

    2013-01-01

    In this paper a technology is developed with its procedures in radiation protection to ensure the safety of the process of decommissioning of two irradiators. Both processes are described, the process of decommissioning of a neutron Irradiator 4. 44·10 11 Bq, employed in the vegetal radio mutagenesis, and disassembling of an installation of gamma irradiation of 3.33 * 10 12 Bq, self-shielded of category I, model MPX - γ - 25 M. The specific objectives are: a) identify aspects of the contractual assurance, of human and technical resources, b) to evaluate the radiological situation of the process and c) analyze the potential radiological extraordinary events in each of the steps of the process, ensuring the right answers. Evaluation of radiological successful events described can be considered as reference to address the process of disassembling of other similar irradiators

  10. Reduction of beta-interference in gamma-spectrometric measurements of neutron-irradiated geological material

    International Nuclear Information System (INIS)

    Garmann, L.B.

    1986-01-01

    The analytical technique for INAA, when applied to geological materials, is improved by introducing an electromagnetic field between sample and detector. This field lowers the bremsstrahlung background intensity in the gamma-spectrum by reducing the number of beta-particles reaching the detector. Thus precision, accuracy and lower detection limit are improved. The technique was used on alkalisyenite and on meteoritic material, rocks containing high quantities of sodium and iron, respectively. After neutron irradiation, the induced nuclides sup(24)Na and sup(59)Fe are responsible for high bremsstrahlung interference, which under normal analyitical conditions would mask any x-ray or gamma-ray peaks of interest. The technique is easily applied to multielement analysis of geological and biological materials. It can be combined with sophisticated spectrum-treating techniques such as spectrum stripping and spectrum smoothing, or coincidence-anticoincidence circuits. (author)

  11. Behavior of radioisotope in liquid neutron irradiated Pb-17Li eutectic

    International Nuclear Information System (INIS)

    Tebus, V.N.; Aksenov, B.S.; Klabukov, U.G.

    1994-01-01

    Investigation of radioisotope 210 Po evaporation from liquid neutron irradiated Pb- 17 Li eutectic has been performed by Knudsen method. Equilibrium 210 Po vapor pressures at temperatures 250-700 degrees C were found about 3-4 orders of magnitude less than that for pure Po and were closed to equilibrium vapor pressures of Po-Pb compound. It was proposed Po forms stable Po-Pb compounds in eutectic at temperatures up to 750-800 degrees C. But disintegrates during long storage owing to self irradiation. It was determined Po aerosol transfer with radio gases takes place at the melting period. Contamination is happened also under irradiated eutectic storage at room temperature owing to aggregate recoil characteristic of Po

  12. Neutron irradiation effects on grain-refined W and W-alloys

    International Nuclear Information System (INIS)

    Hasegawa, A.; Fukuda, M.; Tanno, T.; Nogami, S.; Yabuuchi, K.; Tanaka, T.; Muroga, T.

    2014-10-01

    Microstructural data of neutron irradiated Tungsten (W) such as size and number density of voids and precipitates obtained by W up to 1.5dpa irradiation in the temperature range of 400-800degC were compiled quantitatively. Nucleation and growth process of these defects were clarified and a qualitative prediction of the damage structure development and hardening of W in fusion reactor environments were made taking into account the solid transmutation effects for the first time. To improve recrystallization behavior and low temperature embrittlement, grain refined-W alloys were fabricated by K- or La-doping method. Rhenium addition to the grain refining process was also examined to improve mechanical properties. Characterizations of unirradiated materials were performed. (author)

  13. Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, B.N.

    1998-01-01

    The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al(2)O(3) as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post......-irradiation annealing has been carried out. The results are discussed with reference to equivalent Transmission Electron Microscopy results on the microstructure of the materials. The CuNiBe has the lowest conductivity (less than or equal to 55% of that of pure Cu), and Cu-Al(2)O(3) the highest (75-90% of pure Cu). (C...

  14. Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

    Science.gov (United States)

    Eldrup, M.; Singh, B. N.

    1998-10-01

    The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al 2O 3 as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post-irradiation annealing has been carried out. The results are discussed with reference to equivalent Transmission Electron Microscopy results on the microstructure of the materials. The CuNiBe has the lowest conductivity (⩽55% of that of pure Cu), and Cu-Al 2O 3 the highest (75-90% of pure Cu).

  15. The effect of low-temperature neutron irradiation on the critical current of some superconducting materials

    International Nuclear Information System (INIS)

    Takamura, S.; Okuda, S.

    1978-01-01

    The critical current densities of pure V and Nb single crystals, single core Nb-50 wt% Ti coated with Cu and Nb 3 Sn were measured after fast neutron irradiation at about 5 K and during subsequent annealings. The peak effect was observed in V and Nb single cyrstals immediately after irradiation. In V, the peak effect disappeared after subsequent annealing above 200 K (in the so-called stage III recovery where vacancies are considered to anneal out in V). In contrast, in Nb the peak effect did not disappear even after annealing at 300 K (above the stage III recovery of Nb). Furthermore, in V the peak effect showed a remarkable recovery at 120 K where about 50% of the resistivity increase recovered. The elementary force of the fluxoid-defect interaction was estimated in V single crystals. (Auth.)

  16. Fast neutron irradiation deteriorates hippocampus-related memory ability in adult mice.

    Science.gov (United States)

    Yang, Miyoung; Kim, Hwanseong; Kim, Juhwan; Kim, Sung-Ho; Kim, Jong-Choon; Bae, Chun-Sik; Kim, Joong-Sun; Shin, Taekyun; Moon, Changjong

    2012-03-01

    Object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice exposed to cranial fast neutron irradiation (0.8 Gy) were examined to evaluate hippocampus-related behavioral dysfunction following acute exposure to relatively low doses of fast neutrons. In addition, hippocampal neurogenesis changes in adult murine brain after cranial irradiation were analyzed using the neurogenesis immunohistochemical markers Ki-67 and doublecortin (DCX). In the object recognition memory test and contextual fear conditioning, mice trained 1 and 7 days after irradiation displayed significant memory deficits compared to the sham-irradiated controls. The number of Ki-67- and DCX-positive cells decreased significantly 24 h post-irradiation. These results indicate that acute exposure of the adult mouse brain to a relatively low dose of fast neutrons interrupts hippocampal functions, including learning and memory, possibly by inhibiting neurogenesis.

  17. Age-dependent conversion coefficients for organ doses and effective doses for external neutron irradiation

    International Nuclear Information System (INIS)

    Nishizaki, Chihiro; Endo, Akira; Takahashi, Fumiaki

    2006-06-01

    To utilize dose assessment of the public for external neutron irradiation, conversion coefficients of absorbed doses of organs and effective doses were calculated using the numerical simulation technique for six different ages (adult, 15, 10, 5 and 1 years and newborn), which represent the member of the public. Calculations were performed using six age-specific anthropomorphic phantoms and a Monte Carlo radiation transport code for two irradiation geometries, anterior-posterior and rotational geometries, for 20 incident energies from thermal to 20 MeV. Effective doses defined by the 1990 Recommendation of ICRP were calculated from the absorbed doses in 21 organs. The calculated results were tabulated in the form of absorbed doses and effective doses per unit neutron fluence. The calculated conversion coefficients are used for dose assessment of the public around nuclear facilities and accelerator facilities. (author)

  18. Monovacancy paramagnetism in neutron-irradiated graphite probed by 13C NMR.

    Science.gov (United States)

    Zhang, Z T; Xu, C; Dmytriieva, D; Molatta, S; Wosnitza, J; Wang, Y T; Helm, M; Zhou, Shengqiang; Kühne, H

    2017-10-20

    We report on the magnetic properties of monovacancy defects in neutron-irradiated graphite, probed by 13 C nuclear magnetic resonance spectroscopy. The bulk paramagnetism of the defect moments is revealed by the temperature dependence of the NMR frequency shift and spectral linewidth, both of which follow a Curie behavior, in agreement with measurements of the macroscopic magnetization. Compared to pristine graphite, the fluctuating hyperfine fields generated by the defect moments lead to an enhancement of the 13 C nuclear spin-lattice relaxation rate [Formula: see text] by about two orders of magnitude. With an applied magnetic field of 7.1 T, the temperature dependence of [Formula: see text] below about 10 K can well be described by a thermally activated form, [Formula: see text], yielding a singular Zeeman energy of ([Formula: see text]) meV, in excellent agreement with the sole presence of polarized, non-interacting defect moments.

  19. Evaluation of gamma and neutron irradiation effects on the properties of mica film capacitors

    International Nuclear Information System (INIS)

    Roy, Rajesh; Pandya, Arun

    2005-01-01

    We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view. We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40 μm (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm 2 . The capacitance has been measured at room temperature in the frequency range 100 Hz-10 MHz. Negligible change in the capacitance due to high gamma dose of 60 Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 X 10 7 neutrons/cm 2 h from 252 Cf neutron source of fluence, 2.5 x 10 7 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10 kHz, These results show that the mica capacitors do not show any radiation response below 10 kHz. The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by gamma source and only few cGy dose has been given by fast neutron source. (author)

  20. On the Thermal Conductivity Change of Matrix Graphite Materials after Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Woo; Yeo, Seunghwan; Kim, Eung-Seon; Sah, Injin; Park, Daegyu; Kim, Youngjun; Cho, Moon Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this work, the variations of the thermal conductivity of the A3-3 matrix graphite after neutron irradiation is discussed as well as of the IG-110 graphite for comparison. Neutron irradiation of the graphite specimens was carried out as a part of the first irradiation test of KAERI's coated particle fuel specimens by use of Hanaro research reactor. This work can be summarized as follows: 1) In the evaluation of the specific heat of the graphite materials, various literature data were used and the variations of the specific heat data of all the graphite specimens are observed well agreed, irrespectively of the difference in specimens (graphite and matrix graphite and irradiated and un-irradiated). 2) This implies that it should be reasonable that for both structural graphite and fuel matrix graphite, and even for the neuron-irradiated graphite, any of these specific heat data set be used in the calculation of the thermal conductivity. 3) For the irradiated A3-3 matrix graphite specimens, the thermal conductivity decreased on both directions. On the radial direction, the tendency of variation upon temperature is similar to that of unirradiated specimen, i.e., decreasing as the temperature increases. 4) In the German irradiation experiments with A3-27 matrix graphite specimens, the thermal conductivity of the un-irradiated specimen shows a decrease and that of irradiated specimen is nearly constant as the temperature increases. 5) The thermal conductivity of the irradiated IG-110 was considerably decreased compared with that of un-irradiated specimens The difference of the thermal conductivity of un-irradiated and irradiated IG-110 graphite specimens is much larger than that of un-irradiated and irradiated A3-3 matrix graphite specimens.

  1. Posterior magnetic effect on the pure and doped Fe-Ni alloy under neutron irradiation

    International Nuclear Information System (INIS)

    Ferreira, Iris

    1974-01-01

    Polycrystalline specimens of unirradiated and neutron irradiated Fe-Ni alloys have been studied in the temperature range RT - 500 deg C. The study was carried out in pure (50-50) as well as in Si, A1, Cr and Mo doped samples. Initial magnetic permeability was measured in unirradiated (virgin)and in neutron irradiated samples, during isochronal and linear thermal treatments. The main results are: a magnetic After Effect (MAE) is detected in the temperature range 370 deg C - Tc, where Tc is the Curie Temperature. In this range an activation energy of 3.2 ± 0.2 eV was determined for the Cr doped Fe-Ni alloy (impurity content: 0.1%); measurements made in the irradiated samples, during a linear temperature treatment, show the existence of several MAE zones in the temperature range RT - Tc. The isochronal annealing experiments show that these MAE zones are accompanied by a decrease in the room temperature value of the magnetic permeability, for zones between RT and a certain temperature T 1 . Above this range there is a steep increase in the room temperature permeability. Activation energies were determined for pure and Mo-doped (0.1%) samples for the first MAE zone (50 deg C - 120 deg C). The values obtained 1.25 - 0.08 eV and 1.42 ± 0.09 eV, respectively; the impurity - doped samples show a different behaviour relative to the pure ones: samples with low impurity content (0.1% and 0.5% of Si, Al or Mo) present an enhancement in the amplitude and also an overlapping of the diffusion stages. On the other hand, samples with higher impurity content (2 and 4% of Mo) show a decrease in these amplitudes. (author)

  2. Mechanical Properties and Microstructure of Neutron Irradiated Cold-worked Al-1050 and Al-6063 Alloys

    International Nuclear Information System (INIS)

    Munitz, A.; Cotler, A; Talianker, M.

    1998-01-01

    The impact of neutron irradiation on the internal microstructure, mechanical properties and fracture morphology of cold-worked Al-1050 and Al-6063 alloys was studied, using scanning and transmission electron microscopy, and tensile measurements. Specimens consisting of 50 mm long and 6 mm wide gauge sections, were punched out from Al-1050 and Al-6063 23% cold-worked tubes. They were exposed to prolonged neutron irradiation of up to 4.5x10 25 and 8x10 25 thermal neutrons/m 2 (E -3 s -1 . In general, the uniform and total elongation, the yield stress, and the ultimate tensile strength increase as functions of fluence. However, for Al-1050 a decrease in the ultimate tensile strength and yield stress was observed up to a fluence of 1x10 25 thermal neutrons/m 2 which then increase with thermal neutrons fluence. Metallographic examination and fractography for Al-6063 revealed a decrease in the local area reduction of the final fracture necking. This reduction is accompanied by a morphology transition from ductile transgranular shear rupture to a combination of transgranular shear with intergranular dimpled rupture. The intergranular rupture area increases with fluence. In contrast, for Al-1050, fracture morphology remains ductile transgranular shear rupture and the final local area reduction remains almost constant No voids could be observed in either alloy up to the maximum fluence. The dislocation density of cold-worked Al was found to decrease with the thermal neutron fluence. Prolonged annealing of unirradiated cold-worked Al-6063 at 52 degree led to similar results. Thus, it appears that, under our irradiation conditions, whereby the temperature encompassing the samples increases the exposure to this thermal field is the major factor influencing the mechanical properties and microstructure of aluminum alloys

  3. Superconductivity degradation in Gd-containing high temperature superconductors (HTSC) under thermal neutron irradiation

    International Nuclear Information System (INIS)

    Petrov, A.; Kudrenitskis, I.; Makletsov, A.; Arhipov, A.; Karklin, N.

    1999-01-01

    The physical properties of ordered crystals are extremely sensitive to the degree of order in the distribution of the various kinds of atoms over the corresponding sites in the crystal lattice. An increasingly popular means of creating disordered states is to use nuclear radiation. The type of radiation defects which appear and the nature and degree of the structural changes in ordered crystals depend on the kind of radiation and the fluence level, the irradiation temperature, the type of crystal structure, the composition and initial disorder of the material, the character of the interatomic forces, etc. There are many such scientific publications where the effects of fast neutron irradiation on high temperature superconductors (HTSC) have been studied in both polycrystalline and single crystalline superconductors. It is known also that the role of thermal neutrons in structural defects forming is negligible in comparison with fast neutrons because of their small (∼0.025 eV) energy. But it is evident enough that in superconductors containing isotopes with large thermal neutron cross sections the important results concerning the role of point defects could be obtained. Such point defects are creating due to soft displacements of isotopes having interacted with thermal neutrons. Such the possibility of creating point defects in solids including HTSC is investigating by several groups (Austria, USA, China, Latvia) and these investigations have found the support in the person of IAEA. In this review the authors consider the changes brought about by thermal-neutron irradiation (E∼0.025 eV) in the structure, superconducting and magnetic properties of gadolinium containing ordered HTSC with the structure 123, whose extreme electric and magnetic properties continue to attract both research and practical interest. All of the studies reviewed have been done on bulk polycrystalline samples RBa 2 Cu 3 O 7-δ (where R - natural mixture of Gd isotopes, 155 Gd, 157 Gd, 160

  4. The comparison of microstructure and nanocluster evolution in proton and neutron irradiated Fe–9%Cr ODS steel to 3 dpa at 500 °C

    Energy Technology Data Exchange (ETDEWEB)

    Swenson, M.J., E-mail: matthewswenson1@u.boisestate.edu; Wharry, J.P.

    2015-12-15

    A model Fe–9%Cr oxide dispersion strengthened (ODS) steel was irradiated with protons or neutrons to a dose of 3 displacements per atom (dpa) at a temperature of 500 °C, enabling a direct comparison of ion to neutron irradiation effects at otherwise fixed irradiation conditions. The irradiated microstructures were characterized using transmission electron microscopy and atom probe tomography including cluster analysis. Both proton and neutron irradiations produced a comparable void and dislocation loop microstructure. However, the irradiation response of the Ti–Y–O oxide nanoclusters varied. Oxides remained stable under proton irradiation, but exhibited dissolution and an increase in Y:Ti composition ratio under neutron irradiation. Both proton and neutron irradiation also induced varying extents of Si, Ni, and Mn clustering at existing oxide nanoclusters. Protons are able to reproduce the void and loop microstructure of neutron irradiation carried out to the same dose and temperature. However, since nanocluster evolution is controlled by both diffusion and ballistic impacts, protons are rendered unable to reproduce the nanocluster evolution of neutron irradiation at the same dose and temperature. - Highlights: • Fe–9% Cr ODS was irradiated with protons and neutrons to 3 dpa at 500 °C. • Dislocation loop size and density were similar upon proton and neutron irradiation. • Oxide nanocluster size and density decreased more with neutron irradiation. • Oxide Y:Ti ratio increased from 0.54 to 0.97 upon neutron irradiation. • Irradiation induced enrichment of Si, Mn, and Ni at oxide locations.

  5. 57Fe Moessbauer study of amorphous and nanocrystalline Fe73.5Nb3Cu1Si13.5B9 after neutron irradiation

    International Nuclear Information System (INIS)

    Miglierini, M.; Sitek, J.; Szasz, Z.; Vitazek, K.

    1994-01-01

    57 Fe Moessbauer spectroscopy is used to study neutron irradiation induced changes in the short-range order of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 alloy. The samples are investigated in both amorphous and nanocrystalline states. Neutron irradiation leads to an increase of the standard deviation of a hyperfine field distribution (HFD), implying rearrangement of the atoms towards disordering. Simultaneously, changes in the average value of the hyperfine field and a net magnetic moment position occur as a consequence of a spin reorientation, atom mixing and microscopic stress centres which are introduced by neutron irradiation. (orig.)

  6. Temper-bead repair-welding of neutron-irradiated reactor (pressure) vessel by low-heat-input TIG and YAG laser welding

    International Nuclear Information System (INIS)

    Nakata, Kiyotomo; Ozawa, Masayoshi; Kamo, Kazuhiko

    2006-01-01

    Weldability in neutron-irradiated low alloy steel for reactor (pressure) vessel has been studied by temper-bead repair-welding of low-heat-input TIG and YAG laser welding. A low alloy steel and its weld, and stainless steel clad and nickel (Ni)-based alloy clad were irradiated in a materials test reactor (LVR-15, Czech Republic) up to 1.4 x 10 24 n/m 2 (>1 MeV) at 290degC, which approximately corresponds to the maximum neutron fluence of 60-year-operation plants' vessels. The He concentration in the irradiated specimens was estimated to be up to 12.9 appm. The repair-welding was carried out by TIG and YAG laser welding at a heat input from 0.06 to 0.86 MJ/m. The mechanical tests of tensile, impact, side bend and hardness were carried out after the repair-welding. Cracks were not observed in the irradiated low alloy steel and its weld by temper-bead repair-welding. Small porosities were formed in the first and second layers of the repair-welds of low alloy steel (base metal). However, only a few porosities were found in the repair-welds of the weld of low alloy steel. From the results of mechanical tests, the repair-welding could be done in the irradiated weld of low alloy steel containing a He concentration up to 12.9 appm, although repair-welding could be done in base metal of low alloy steel containing up to only 1.7 appmHe. On the other hand, cracks occurred in the heat affected zones of stainless steel and Ni-based alloy clads by repair-welding, except by YAG laser repair-welding at a heat input of 0.06 MJ/m in stainless steel clad containing 1.7 appmHe. Based on these results, the determination processes were proposed for optimum parameters of repair-welding of low alloy steel and clad used for reactor (pressure) vessel. (author)

  7. Precipitation and cavity formation in austenitic stainless steels during irradiation

    International Nuclear Information System (INIS)

    Lee, E.H.; Rowcliffe, A.F.; Mansur, L.K.

    1982-01-01

    Microstructural evolution in austenitic stainless steels subjected to displacement damage at high temperature is strongly influenced by the interaction between helium atoms and second phase particles. Cavity nucleation occurs by the trapping of helium at partially coherent particle-matrix interfaces. The recent precipitate point defect collector theory describes the more rapid growth of precipitate-attached cavities compared to matrix cavities where the precipitate-matrix interface collects point defects to augment the normal point deflect flux to the cavity. Data are presented which support these ideas. It is shown that during nickel ion irradiation of a titanium-modified stainless steel at 675 0 C the rate of injection of helium has a strong effect on the total swelling and also on the nature and distribution of precipitate phases. (orig.)

  8. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady

  9. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    International Nuclear Information System (INIS)

    Rapp, Juergen; Aaron, A. M.; Bell, Gary L.; Burgess, Thomas W.; Ellis, Ronald James; Giuliano, D.; Howard, R.; Kiggans, James O.; Lessard, Timothy L.; Ohriner, Evan Keith; Perkins, Dale E.; Varma, Venugopal Koikal

    2015-01-01

    Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma-material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a ''. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.'' The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma-material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL's proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL's strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the ''signature facility'' FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material-Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady-state heat fluxes of

  10. Final Report on Investigations of the influence of Helium concentration and implantation rate on Cavity Nucleation and Growth during neutron irradiation of Fe and EUROFER 97

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, Bachu Narain; Golubov, S.

    This report presents results of investigations of damage accumulation during neutron irradiation of pure iron and EUROFER 97 steel with or without prior helium implantation. The defect microstructure, in particular the cavities, was characterized using Positron Annihilation Spectroscopy (PAS) and...

  11. Investigation of the agglomeration and amorphous transformation effects of neutron irradiation on the nanocrystalline silicon carbide (3C-SiC) using TEM and SEM methods

    Energy Technology Data Exchange (ETDEWEB)

    Huseynov, Elchin M., E-mail: elchin.h@yahoo.com [Department of Nanotechnology and Radiation Material Science, National Nuclear Research Center, Inshaatchilar pr. 4, AZ 1073 Baku (Azerbaijan); Institute of Radiation Problems of Azerbaijan National Academy of Sciences, B.Vahabzade 9, AZ 1143 Baku (Azerbaijan)

    2017-04-01

    Nanocrystalline 3C-SiC particles irradiated by neutron flux during 20 h in TRIGA Mark II light water pool type research reactor. Silicon carbide nanoparticles were analyzed by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) devices before and after neutron irradiation. The agglomeration of nanoparticles was studied comparatively before and after neutron irradiation. After neutron irradiation the amorphous layer surrounding the nanoparticles was analyzed in TEM device. Neutron irradiation defects in the 3C-SiC nanoparticles and other effects investigated by TEM device. The effect of irradiation on the crystal structure of the nanomaterial was studied by selected area electron diffraction (SAED) and electron diffraction patterns (EDP) analysis.

  12. Ion irradiation to simulate neutron irradiation in model graphites: Consequences for nuclear graphite

    Science.gov (United States)

    Galy, N.; Toulhoat, N.; Moncoffre, N.; Pipon, Y.; Bérerd, N.; Ammar, M. R.; Simon, P.; Deldicque, D.; Sainsot, P.

    2017-10-01

    Due to its excellent moderator and reflector qualities, graphite was used in CO2-cooled nuclear reactors such as UNGG (Uranium Naturel-Graphite-Gaz). Neutron irradiation of graphite resulted in the production of 14C which is a key issue radionuclide for the management of the irradiated graphite waste. In order to elucidate the impact of neutron irradiation on 14C behavior, we carried out a systematic investigation of irradiation and its synergistic effects with temperature in Highly Oriented Pyrolitic Graphite (HOPG) model graphite used to simulate the coke grains of nuclear graphite. We used 13C implantation in order to simulate 14C displaced from its original structural site through recoil. The collision of the impinging neutrons with the graphite matrix carbon atoms induces mainly ballistic damage. However, a part of the recoil carbon atom energy is also transferred to the graphite lattice through electronic excitation. The effects of the different irradiation regimes in synergy with temperature were simulated using ion irradiation by varying Sn(nuclear)/Se(electronic) stopping power. Thus, the samples were irradiated with different ions of different energies. The structure modifications were followed by High Resolution Transmission Electron Microscopy (HRTEM) and Raman microspectrometry. The results show that temperature generally counteracts the disordering effects of irradiation but the achieved reordering level strongly depends on the initial structural state of the graphite matrix. Thus, extrapolating to reactor conditions, for an initially highly disordered structure, irradiation at reactor temperatures (200 - 500 °C) should induce almost no change of the initial structure. On the contrary, when the structure is initially less disordered, there should be a "zoning" of the reordering: In "cold" high flux irradiated zones where the ballistic damage is important, the structure should be poorly reordered; In "hot" low flux irradiated zones where the ballistic

  13. On the design of a cold neutron irradiator (CNI) for quantitative materials characterization

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, Alexander Grover [Cornell Univ., Ithaca, NY (United States)

    1997-08-01

    A design study of a cold neutron irradiator (CNI) for materials characterization using prompt gamma-ray neutron activation analysis (PGNAA) is presented. Using 252Cf neutron sources in a block of moderator, a portion of which is maintained at a cryogenic temperature, the CNI employs cold neutrons instead of thermal neutrons to enhance the neutron capture reaction rate in a sample. Capture gamma rays are detected in an HPGe photon detector. Optimization of the CNI with respect to elemental sensitivity (counts per mg) is the primary goal of this design study. Monte Carlo simulation of radiation transport, by means of the MCNP code and the ENDF/B cross-section libraries, is used to model the CNI. A combination of solid methane at 22 K, room-temperature polyethylene, and room-temperature beryllium has been chosen for the neutron delivery subsystem of the CNI. Using four 250-microgram 252Cf neutron sources, with a total neutron emission rate of 2.3 x 109 neutrons/s, a thermal-equivalent neutron flux of 1.7 x 107 neutrons/cm2-s in an internally located cylindrical sample space of diameter 6.5 cm and height 6.0 cm is predicted by MCNP calculations. A cylindrical port with an integral annular collimator composed of bismuth, lead, polyethylene, and lithium carbonate, is located between the sample and the detector. Calculations have been performed of gamma-ray and neutron transport in the port and integral collimator with the objective of optimizing the statistical precision with which one can measure elemental masses in the sample while also limiting the fast neutron flux incident upon the HPGe detector to a reasonable level. The statistical precision with which one can measure elemental masses can be enhanced by a factor of between 2.3 and 5.3 (depending on the origin of the background gamma rays) compared with a neutron irradiator identical to the CNI except for the replacement of the cryogenic solid methane by room

  14. Biological effects of fast neutron irradiation on callus tissues of Tecoma stans Juss. and Ammi visnaga Lam

    International Nuclear Information System (INIS)

    Supniewska, J.H.; Dohnal, B.; Cebulska Wasilewska, A.; Huczkowski, J.

    1982-01-01

    Callus tissues of Tecoma stans Juss. and Ammi visnaga Lam. were subjected to fast neutron irradiation. Nine doses were applied within the range of 100 - 10.000 cGy. Small doses caused growth stimulation. Intermediate and high doses caused morphological changes, reduced growth and biosynthesis of biologically active substances (monoterpene alkaloids in T. stans, furanochromones in A. visnaga). In A. visnaga neutron irradiation considerably decreased the chlorophyll content in callus tissues. The radiosensitivity of A. visnaga at 50% growth reduction level was 1.5 times higher than that of the callus of T. stans. The recovery of the tissues takes place during a subculturing course. Three to 7 months after neutron exposure growth and biosynthesis reach the control level. (author)

  15. Experimental study on 14 MeV neutron irradiation effects in FLASH ROM28F256 and 29C256

    International Nuclear Information System (INIS)

    He Chaohui; Chen Xiaohua; Li Guozheng; Wang Yanping; Ji Lin; Geng Bin; Yang Hailiang; Liu Enke

    2000-01-01

    Experimental results of neutron irradiation effects are given for FLASH ROM. New phenomena are observed. The 14 MeV neutron irradiation effects in 28F256 and 29C256 devices are different from the single event effects. Errors are only '0'→'1'. There is a neutron flux threshold. Errors occur when neutron flux is above the threshold, no error occurs when below the threshold. The errors go up with the increase of the neutron flux until all '0' change to '1'. Hard errors, that new data cannot be written in memory with programmer, occur in devices which are measured during irradiation and irradiated in power on mode. Errors rise with the increase of reading times. Under same neutron flux, there is no error in devices in power off mode, however, errors occur in all devices in power on mode, moreover, undefined errors occur

  16. Simultaneous impact of neutron irradiation and sputtering on the surface structure of self–damaged ITER–grade tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, A. I., E-mail: aibelyaeva@mail.ru; Savchenko, A. A. [National Technical University “Kharkov Politechnical Institute”, Kharkov, 61002 (Ukraine); Galuza, A. A.; Kolenov, I. V. [Institute of Electrophysics and Radiation Technologies, National Academy of Science of Ukraine, Kharkov, 61024 (Ukraine)

    2014-07-15

    Simultaneous effects of neutron irradiation and long–term sputtering on the surface relief of ITER–grade tungsten were studied. The effects of neutron–induced displacement damage have been simulated by irradiation of tungsten target with W{sup 6+} ions of 20 MeV energy. Ar{sup +} ions with energy 600 eV were used as imitation of charge exchange atoms in ITER. The surface relief was studied after each sputtering act. The singularity in the WJ–IG surface relief was ascertained experimentally at the first time, which determines the law of roughness extension under sputtering. As follows from the experimental data, the neutron irradiation has not to make a decisive additional contribution in the processes developing under impact of charge exchange atoms only.

  17. Ion-Neutron Irradiated BOR60 Sample Preparation and Characterization: Nuclear Science User Facility 2017 Milestone Report

    Energy Technology Data Exchange (ETDEWEB)

    Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Quinlan B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    This document outlines the results obtained by Oak Ridge National Laboratory (ORNL) in collaboration with the University of Michigan-led Consolidated Innovative Nuclear Research project, “Feasibility of combined ion-neutron irradiation for accessing high dose levels.” In this reporting period, neutron irradiated were prepared and shipped to the University of Michigan for subsequent ion irradiation. The specimens were returned to ORNL’s Low Activation Materials Development and Analysis facility, prepared via focused ion beam for examination using scanning/transmission electron microscopy (S/TEM), and then examined using S/TEM to measure the as-irradiated microstructure. This report briefly summarizes the S/TEM results obtained at ORNL’s Low Activation Materials Development and Analysis facility.

  18. Final report on neutron irradiation at low temperature to investigate plastic instability and at high temperature to study caviation

    DEFF Research Database (Denmark)

    Singh, B.N; Eldrup, Morten Mostgaard; Golubov, D.J.

    2005-01-01

    Effects of neutron irradiation on defect accumulation and physical and mechanical properties of pure iron and F82H and EUROFER 97 ferritic-martensitic steels have been investigated. Tensile specimens were neutron irradiated to a dose level of 0,23 dpa at333 and 573 K. Electrical resistivity......, based on the production bias model (PBM) were carried out to study the details of evolution of cavitieswith and without helium generation. The phenomena of dislocation decoration and raft formation, which are important for understanding radiation hardening and plastic flow localization, have been...... studied using the Kinetic Monte Carlo (KMC) code during arealistic dynamic irradiation of bcc iron at 300 K. Molecular dynamics (MD) simulations have been carried out to study the stress dependencies of dislocation velocity and drag coefficient for an edge dislocation decorated with small SIA loops...

  19. Mammary carcinogenesis induced by three consecutive 14 MeV neutron irradiations in Sprague-Dawley rats

    International Nuclear Information System (INIS)

    Jacrot, M.; Mouriquand, J.; Mouriquand, C.

    1978-01-01

    At high doses (400 to 800 rads) the relative biological effectiveness (R.B.E.) of neutrons is two or three times greater than that of X-rays or gamma radiation. The neutron irradiation-induced mammary carcinogenesis threshold, if any, is certainly very low in Sprague-Dawley females. The purpose of this work is to test the possibilities offered by three consecutive 14 MeV neutron irradiations in the mammary carcinogenesis region of Sprague-Dawley rats. The results of these experiments show a hormone-dependence of tumour promotion similar to that observed with chemical carcinogenetic agents. However these tumours, by their recurrences and possible metastases, bear some resemblance to breast cancers in women. Although the tumour induction frequencies seem modest in relation to those obtained with the DMBA model they should nevertheless prove very useful in the study of hormone effects liable to control the appearance of such radioinduced cancers [fr

  20. Effect of defects induced by doping and fast neutron irradiation on the thermal properties of lithium ammonium sulphate crystals

    International Nuclear Information System (INIS)

    Kandil, S.H.; Ramadan, T.A.; Darwish, M.M.; Kassem, M.E.; El-Khatib, A.M.

    1994-01-01

    Structural defects were introduced in lithium ammonium sulphate crystals (LAS) either in the process of crystal growth (in the form of foreign ions) or by neutron irradiation. The effect of such defects on the thermal properties of LAS crystals was studied in the temperature range 300-500 K. It was assumed that the doped LAS crystals are composed of a two-phase system having different thermal parameters in each phase. The specific heat at constant pressure, C p , of irradiated samples was found to decrease with increasing irradiation doses. The thermal expansion of LAS crystals was found to be dependent on neutron irradiation, and was attributed to two processes: the release of new species and the trapping process. (author)

  1. Effect of defects induced by doping and fast neutron irradiation on the thermal properties of lithium ammonium sulphate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, S.H.; Ramadan, T.A.; Darwish, M.M. (Alexandria Univ. (Egypt). Dept. of Materials Science); Kassem, M.E.; El-Khatib, A.M. (Alexandria Univ. (Egypt). Dept. of Physics)

    1994-05-01

    Structural defects were introduced in lithium ammonium sulphate crystals (LAS) either in the process of crystal growth (in the form of foreign ions) or by neutron irradiation. The effect of such defects on the thermal properties of LAS crystals was studied in the temperature range 300-500 K. It was assumed that the doped LAS crystals are composed of a two-phase system having different thermal parameters in each phase. The specific heat at constant pressure, C[sub p], of irradiated samples was found to decrease with increasing irradiation doses. The thermal expansion of LAS crystals was found to be dependent on neutron irradiation, and was attributed to two processes: the release of new species and the trapping process. (author).

  2. The effects of oxide evolution on mechanical properties in proton- and neutron-irradiated Fe-9%Cr ODS steel

    Energy Technology Data Exchange (ETDEWEB)

    Swenson, M.J., E-mail: matthewswenson1@u.boisestate.edu [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Dolph, C.K. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Wharry, J.P. [Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States)

    2016-10-15

    The objective of this study is to evaluate the effect of irradiation on the strengthening mechanisms of a model Fe-9%Cr oxide dispersion strengthened steel. The alloy was irradiated with protons or neutrons to a dose of 3 displacements per atoms at 500 °C. Nanoindentation was used to measure strengthening due to irradiation, with neutron irradiation causing a greater increase in yield strength than proton irradiation. The irradiated microstructures were characterized using transmission electron microscopy and atom probe tomography (APT). Cluster analysis reveals solute migration from the Y-Ti-O-rich nanoclusters to the surrounding matrix after both irradiations, though the effect is more pronounced in the neutron-irradiated specimen. Because the dissolved oxygen atoms occupy interstitial sites in the iron matrix, they contribute significantly to solid solution strengthening. The dispersed barrier hardening model relates microstructure evolution to the change in yield strength, but is only accurate if solid solution contributions to strengthening are considered simultaneously.

  3. EL2-related defects in neutron irradiated GaAs1/sub -x/P/sub x/ alloys

    International Nuclear Information System (INIS)

    Munoz, E.; Garcia, F.; Jimenez, B.; Calleja, E.; Gomez, A.; Alcober, V.

    1985-01-01

    The generation of EL2-related defects in GaAsP alloys by fast neutron irradiation has been studied through deep level transient spectroscopy and photocapacitance techniques. After irradiation p-n junctions were not annealed at high temperatures. In the composition range x>0.4, fast neutrons generate a broad center at E/sub c/-0.7 eV that it is suggested to belong to the EL2 family. The presence of photocapacitance quenching effects has been taken as a preliminary fingerprint to make the above assignment. From computer analysis of the nonexponential transient capacitance waveforms, evidence that neutron irradiation creates a family of midgap levels, EL2-related, is found

  4. Irradiation response in titanium modified austenitic stainless steels prepared by rapid solidification processing. Pt. 3. A model for the effect of titanium addition

    Energy Technology Data Exchange (ETDEWEB)

    Imeson, D.; Tong, C.H.; Parker, C.A.; Vander Sande, J.B.; Grant, N.J.; Harling, O.K. (Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Materials Science and Engineering; Massachusetts Inst. of Tech., Cambridge (USA). Nuclear Reactor Lab.)

    1984-05-01

    Titanium carbide precipitation on dislocations during irradiation and recoil-induced particle dissolution are considered. The outline analysis given indicates that complete swelling suppression may occur in favorable conditions due to a counterbalancing of the effective dislocation interstitial bias. The behavior is, however, not stable against a return to normal swelling levels for type 316 steels. A model is presented which may serve as a basis for the interpretation of some aspects of the irradiation response in this system.

  5. Study of short range order in alloy of glassy metals and effect of neutron irradiation on them

    International Nuclear Information System (INIS)

    Habibi, S.; Banaee, N.; Salman, M.; Gupta, A.; Principi, G.

    2000-04-01

    In this paper, we have studied a series of glassy metals with composition Fe 78-x Ni x Si 8 B 14 with x=0, 15, 25,38,53, 58. We have used Moessbauer spectroscopy to get information about short range order and local structure in these alloys. The specimens are exposed to neutron irradiation to perturb local structure and their short range order. The hyperfine parameters obtained from spectra before and after n-irradiation and are compared

  6. Effect of ion-beam gettering on the GaAs transistor structure parameters under neutron irradiation

    International Nuclear Information System (INIS)

    Obolenskij, S.V.; Skupov, V.D.

    2000-01-01

    It is established that the neutron irradiation negative effect on the parameters of the field transistors with the Schottky shut-off on the basis of the epitaxial gallium arsenide is essentially reduced when the argon ions are preliminary implanted into structure on the substrate side. The above effect is explained through remotely controlled gettering by ion irradiation of admixtures and defects in the transistor active areas related with origination of deep levels under the neutron fluence [ru

  7. Effects of neutron irradiation on microstructure and deformation behaviour of mono- and polycrystalline molybdenum and its alloys

    DEFF Research Database (Denmark)

    Singh, B.N.; Evans, J.H.; Horsewell, A.

    1998-01-01

    The influence of neutron irradiation on microstructural evolution and mechanical properties of mono- and polycrystalline molybdenum and its alloys has been investigated. Tensile specimens and 3 mm diameter discs of monocrystals of pure molybdenum and Mo-5%Re were irradiated with fission neutrons...... microscopy are presented and discussed in terms of intracascade clustering of self-interstitial atoms and the role of one-dimensional glide of these clusters in controlling microstructural evolution and the resulting mechanical properties....

  8. Separation of Protactinium from Neutron Irradiated Thorium Oxide; Separacion de Protactinio de Oxido de Torio Irradiado con Neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, G; Gutierrez, L; Ropero, M

    1983-07-01

    The chemical separation of thorium and protactinium can be carried out by leaching most of the last one, about 95%, with aqueous HF from neutron irradiated thorium oxide. This leaching reaction la highly favored by the transformation reaction of the ThO{sub 2} material into ThF{sub 4}. For both reactions, leaching and transformation, the reagents concentration, agitation speed and temperature influences were studied and the activation energies were found. (Author) 18 refs.

  9. Semiconducting lithium indium diselenide: Charge-carrier properties and the impacts of high flux thermal neutron irradiation

    Science.gov (United States)

    Hamm, Daniel S.; Rust, Mikah; Herrera, Elan H.; Matei, Liviu; Buliga, Vladimir; Groza, Michael; Burger, Arnold; Stowe, Ashley; Preston, Jeff; Lukosi, Eric D.

    2018-06-01

    This paper reports on the charge carrier properties of several lithium indium diselenide (LISe) semiconductors. It was found that the charge collection efficiency of LISe was improved after high flux thermal neutron irradiation including the presence of a typically unobservable alpha peak from hole-only collection. Charge carrier trap energies of the irradiated sample were measured using photo-induced current transient spectroscopy. Compared to previous studies of this material, no significant differences in trap energies were observed. Through trap-filled limited voltage measurements, neutron irradiation was found to increase the density of trap states within the bulk of the semiconductor, which created a polarization effect under alpha exposure but not neutron exposure. Further, the charge collection efficiency of the irradiated sample was higher (14-15 fC) than that of alpha particles (3-5 fC), indicating that an increase in hole signal contribution resulted from the neutron irradiation. Finally, it was observed that significant charge loss takes place near the point of generation, producing a significant scintillation response and artificially inflating the W-value of all semiconducting LISe crystals.

  10. Morphological differences in the response of mouse small intestine to radiobiologically equivalent doses of X and neutron irradiation

    International Nuclear Information System (INIS)

    Carr, K.E.; Hamlet, R.; Nias, A.H.; Watt, C.

    1984-01-01

    A scale has been developed to describe the effects of radiation on small intestinal villi. The scale has been used to compare the damage done to the villi in the period 0-5 days after irradiation by X-irradiation or neutron irradiation, using 10 Gy X-rays and 5 Gy neutrons, doses which are radiobiologically equivalent when assessed by the microcolony assay method. Use of the scale indicates that the damage done to the villi by neutrons is greater than that produced by X-rays. This has implications for the interpretation of radiobiological equivalent doses (R.B.E.). Resin light microscopy and transmission electron microscopy (T.E.M.) have also been used to examine small intestinal damage after 10 Gy X-irradiation and 5 Gy neutron irradiation. Differences include variations in crypt shape, mitotic activity and the proportion of crypts which are heavily parasitised. As well as the differences in villous shape which have been reflected in the different values on the scoring system, there are also variations in the response of the constituent cells of the epithelial compartment of the villi. In general, the effect of the neutron irradiation is more severe than that of the X-rays, particularly as would be suggested by a simple quantitation of crypt regeneration

  11. First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Masashi, E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Calderoni, P. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Oda, T. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-8656 (Japan); Oya, Y. [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka 422-8529 (Japan); Sokolov, M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhang, K. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Cao, G. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706 (United States); Kolasinski, R. [Hydrogen and Metallurgical Science Department, Sandia National Laboratories, Livermore, CA 94551 (United States); Sharpe, J.P. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2011-08-01

    With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 x 10{sup 21} m{sup -2} s{sup -1}, ion fluence: 4 x 10{sup 25} m{sup -2}) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

  12. Development of crack growth and crack initiation test units for stress corrosion cracking examinations in high-temperature water environments under neutron irradiation (1) (Contract research)

    International Nuclear Information System (INIS)

    Izumo, Hironobu; Ishida, Takuya; Kawamata, Kazuo; Inoue, Shuichi; Ide, Hiroshi; Saito, Takashi; Ishitsuka, Etsuo; Chimi, Yasuhiro; Ise, Hideo; Miwa, Yukio; Ugachi, Hirokazu; Nakano, Junichi; Kaji, Yoshiyuki; Tsukada, Takashi

    2009-04-01

    To evaluate integrity of irradiation-assisted stress corrosion cracking (IASCC) on in-core structural materials used in light water reactors (LWRs), useful knowledge regarding IASCC has been obtained mainly by post-irradiation examinations (PIEs). In the core of commercial LWRs, however, the actual IASCC occurs under the effects of irradiation on both materials and high-temperature water environment. Therefore, it is necessary to confirm the suitability of the knowledge by PIE with comparison to IASCC behaviors during in-core SCC tests. Fundamental techniques for in-core crack growth and crack initiation tests have been developed already at the Japan Materials Testing Reactor (JMTR) of the Japan Atomic Energy Agency (JAEA). For the in-core crack growth test technique, to evaluate the effects of neutron irradiation on stainless steels irradiated to low neutron fluences, it is indispensable to develop new loading technique which is applicable to compact tension (CT) specimens with thickness of 0.5 inch (0.5T), from the viewpoint of validity based on the fracture mechanics. Based on the present technical investigation for the in-core loading technique, it is expected that a target load of 7.6 kN approximately can apply to a 0.5T-CT specimen by adopting a loading unit of a lever type instead of the previous uni-axial tension type. For the in-core crack initiation test technique, moreover, construction of a loading unit adopting linear variable differential transformers (LVDTs) has been investigated and technical issues have examined. (author)

  13. Study of the microstructure of neutron irradiated beryllium for the validation of the ANFIBE code

    International Nuclear Information System (INIS)

    Rabaglino, E.; Ferrero, C.; Reimann, J.; Ronchi, C.; Schulenberg, T.

    2002-01-01

    The behaviour of beryllium under fast neutron irradiation is a key issue of the helium cooled pebble bed tritium breeding blanket, due to the production of large quantities of helium and of a non-negligible amount of tritium. To optimise the design, a reliable prediction of swelling due to helium bubbles and of tritium inventory during normal and off-normal operation of a fusion power reactor is needed. The ANFIBE code (ANalysis of Fusion Irradiated BEryllium) is being developed to meet this need. The code has to be applied in a range of irradiation conditions where no experimental data are available, therefore a detailed gas kinetics model, and a specific and particularly careful validation strategy are needed. The validation procedure of the first version of the code was based on macroscopic data of swelling and tritium release. This approach is, however, incomplete, since a verification of the microscopic behaviour of the gas in the metal is necessary to obtain a reliable description of swelling. This paper discusses a general strategy for a thorough validation of the gas kinetics models in ANFIBE. The microstructure characterisation of weakly irradiated beryllium pebbles, with different visual examination techniques, is then presented as an example of the application of this strategy. In particular, the advantage of developing 3D techniques, such as X-ray microtomography, is demonstrated

  14. Development of positron annihilation spectroscopy for investigating deuterium decorated voids in neutron-irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.N., E-mail: chase.taylor@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Shimada, M.; Merrill, B.J. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Akers, D.W. [Experimental Programs, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan)

    2015-08-15

    The present work is a continuation of a recent research to develop and optimize positron annihilation spectroscopy (PAS) for characterizing neutron-irradiated tungsten. Tungsten samples were exposed to neutrons in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory and damaged to 0.025 and 0.3 dpa. Subsequently, they were exposed to deuterium plasmas in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory. The implanted deuterium was desorbed through sample heating to 900 °C, and Doppler broadening (DB)-PAS was performed both before and after heating. Results show that deuterium impregnated tungsten is identified as having a smaller S-parameter. The S-parameter increases after deuterium desorption. Microstructural changes also occur during sample heating. These effects can be isolated from deuterium desorption by comparing the S-parameters from the deuterium-free back face with the deuterium-implanted front face. The application of using DB-PAS to examine deuterium retention in tungsten is examined.

  15. Development of positron annihilation spectroscopy for investigating deuterium decorated voids in neutron-irradiated tungsten

    Science.gov (United States)

    Taylor, C. N.; Shimada, M.; Merrill, B. J.; Akers, D. W.; Hatano, Y.

    2015-08-01

    The present work is a continuation of a recent research to develop and optimize positron annihilation spectroscopy (PAS) for characterizing neutron-irradiated tungsten. Tungsten samples were exposed to neutrons in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory and damaged to 0.025 and 0.3 dpa. Subsequently, they were exposed to deuterium plasmas in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory. The implanted deuterium was desorbed through sample heating to 900 °C, and Doppler broadening (DB)-PAS was performed both before and after heating. Results show that deuterium impregnated tungsten is identified as having a smaller S-parameter. The S-parameter increases after deuterium desorption. Microstructural changes also occur during sample heating. These effects can be isolated from deuterium desorption by comparing the S-parameters from the deuterium-free back face with the deuterium-implanted front face. The application of using DB-PAS to examine deuterium retention in tungsten is examined.

  16. Preparation of the Nanostructured Radioisotope Metallic Oxide by Neutron Irradiation for Use as Radiotracers

    Directory of Open Access Journals (Sweden)

    Sang-Ei Seo

    2017-10-01

    Full Text Available Metallic oxides manganese dioxide (MnO2, samarium oxide (Sm2O3, and dysprosium oxide (Dy2O3 with nanorod-like structures were synthesized by the hydrothermal synthesis method, respectively. Subsequently, the nanostructured radioisotopes MnO2 with Mn-56, Sm2O3 with Sm-153, and Dy2O3 with Dy-165 were prepared by neutron irradiation from the HANARO research reactor, respectively. The three different elements, Mn, Sm, and Dy, were selected as radiotracers because these elements can be easily gamma-activated from neutrons (activation limits: 1 picogram (Dy, 1–10 picogram (Mn, 10–100 picogram (Sm. Furthermore, the synthesized radioisotopes can be used as radiotracers in Prompt Gamma Neutron Activation Analysis as the rare earth metals Dy and Sm were not present in the Korean environment. The successful synthesis of the radioisotope metallic oxides was confirmed by Transmission Electron Microscopy (TEM, Energy Dispersive X-ray Spectrometry (EDS, X-ray Diffraction (XRD analysis, and gamma spectroscopy analysis. The synthesized nanostructured radioisotope metallic oxides may be used as radiotracers in scientific, environmental, engineering, and industrial fields.

  17. Structural and optical properties improvements of PVP/gelatin blends induced by neutron irradiation

    Science.gov (United States)

    Basha, Mohammad Ahmad-Fouad; Hassan, Mohamed Ahmed

    2018-05-01

    Blends of polyvinylpyrrolidone and gelatin were prepared in three different concentrations to study the modifications in their structural and optical properties induced by neutron irradiations with different neutron fluence values from 108 up to 1011 neutron/cm2. X-ray spectroscopy revealed that the irradiation has induced a recrystallization phenomenon in the studied blends and the crystallinity index increased by increasing the neutron fluence due to the breaking of the crystallites. Fourier-transform infrared spectroscopy came to confirm the existence of interactions between interchain groups and a higher compatibility for the irradiated blends. The irradiation induced defects inside the material were responsible for the change in their optical and structural properties. The creation of free radicals or ions inside the conduction bands has led to the increase in the number of carriers on localized states; this has caused the increase in optical conductivity of the irradiated blends as a result of decreasing the energy gaps by increasing the neutron fluence. Results may widen the applications of the gelatin based blends to include optoelectronic devices, organic light emitting devices, solar selective and anti-reflectance bio-coatings, optical organic glass and lenses.

  18. High heat flux components with Be armour before and after neutron irradiation

    International Nuclear Information System (INIS)

    Lodato, A.; Derz, H.; Duwe, R.; Linke, J.; Roedig, M.

    2000-01-01

    Beryllium/copper mock-ups produced by different joining techniques have been tested in the electron beam facility JUDITH (Juelich Divertor Test Facility in Hot Cells) at Forschungszentrum Juelich. The experiments described in this paper represent the conclusive part of a test program started in 1994. The properties of non-irradiated Be/Cu joints have been characterised in a previous test campaign. Post-irradiation tests are now being carried out to investigate the neutron damage on the joints. The neutron irradiation on selected mock-ups has been carried out in the High Flux Reactor (HFR) at Petten (The Netherlands). Parametric finite element thermal analyses have been carried out to establish the allowable heat flux value to be applied during the tests. Screening tests up to power densities of ∼7 MW/m 2 and thermal fatigue tests up to 1000 cycles have been performed. None of these mock-ups showed any indication of failure. Post-mortem analyses (metallography, SEM) have also been conducted

  19. Charge collection and space charge distribution in neutron-irradiated epitaxial silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Poehlsen, Thomas

    2010-04-15

    In this work epitaxial n-type silicon diodes with a thickness of 100 {mu}m and 150 {mu}m are investigated. After neutron irradiation with fluences between 10{sup 14} cm{sup -2} and 4 x 10{sup 15} cm{sup -2} annealing studies were performed. CV-IV curves were taken and the depletion voltage was determined for different annealing times. All investigated diodes with neutron fluences greater than 2 x 10{sup 14} cm{sup -2} showed type inversion due to irradiation. Measurements with the transient current technique (TCT) using a pulsed laser were performed to investigate charge collection effects for temperatures of -40 C, -10 C and 20 C. The charge correction method was used to determine the effective trapping time {tau}{sub eff}. Inconsistencies of the results could be explained by assuming field dependent trapping times. A simulation of charge collection could be used to determine the field dependent trapping time {tau}{sub eff}(E) and the space charge distribution in the detector bulk. Assuming a linear field dependence of the trapping times and a linear space charge distribution the data could be described. Indications of charge multiplication were seen in the irradiated 100 {mu}m thick diodes for all investigated fluences at voltages above 800 V. The space charge distribution extracted from TCT measurements was compared to the results of the CV measurements and showed good agreement. (orig.)

  20. APFIM investigation of clustering in neutron-irradiated Fe-Cu alloys and pressure vessel steels

    International Nuclear Information System (INIS)

    Auger, P.; Pareige, P.; Blavette, D.

    1996-01-01

    Pressure vessel steels used in PWRs are known to be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are commonly supposed to result from the formation of point defects, dislocation loops, voids and copper-rich precipitates. However, the real nature of the irradiation induced damage, in these particularly low copper steels (>0,1 wt%), has not been clearly identify yet. A new experimental work has been carried out thanks to atom probe and field ion microscopy (APFIM) facilities and, more particularly with a new generation of atom probe recently developed, namely the tomographic atom probe (TAP), in order to improve: the understanding of the complex behavior of copper precipitation which occurs when low-alloyed Fe-Cu model alloys are irradiated with neutrons; the microstructural characterization of the pressure vessel steel of the CHOOZ A reactor under various fluences (French Surveillance Programme). The investigations clearly reveal the precipitation of copper-rich clusters in irradiated Fe-Cu alloys while more complicated Si, Ni, Mn and Cu-solute 'clouds' were observed to develop in the low-copper ferritic solid solution of the pressure vessel steel. (authors)

  1. Comparison of the effect of neutron irradiation on high purity vanadium and vanadium oxygen alloys

    International Nuclear Information System (INIS)

    Arsenault, R.J.; Bressers, J.

    1977-01-01

    An investigation of the effect of neutron damage on the low temperature deformation characteristics of high purity vanadium (R/sub 300K//R/sub 4.2K/ = 1100) was undertaken for two purposes. One purpose was to determine if reducing the purity interstitial content to a lower level would result in a large difference in the effective stress between irradiated and non-irradiated samples. The present data along with previously obtained data does indicate that the difference increases as the impurity interstitial content is reduced. The explanation of this observation is based on the rapid increase of the non-irradiated yield stress at 77 0 K due to small increases in the oxygen content; however, the increase of the yield stress of the irradiated samples is much less with the same increase in oxygen content. A second purpose of this investigation was to determine the size and density of observable neutron produced defects as a function of oxygen content by transmission electron microscopy, and to relate the changes in density with changes in the yield stress. It was found that the density decreases and the size increases as the oxygen content decreases. There is qualitative agreement between the increase in yield stress at 300 0 K and the observable defect density. However, the change in the yield stress at 77 0 K due to neutron irradiation cannot be related to defect density and size

  2. Examination of the creep behaviour of ceramic fuel elements under neutron irradiation

    International Nuclear Information System (INIS)

    Brucklacher, D.

    1978-01-01

    This paper examines the creeping of UO 2 , UO 2 -PuO 2 and UN under neutron irradiation. It starts with the experimental results about the relation between the thermal creep rate and the load, the temperature, as well as characteristic material values, stoichiometry, grain size and porosity. These correlation are first qualitatively discussed and then compared with the statements of actual quantitative equations. From the models and theories on which these equations are based a modified Nabarro-Heering-equation results for the correlation between the creep rate of ceramic fuels, stress, temperature and the fission rate. In the experimental part of the examination, length-changes of creep samples of UO 2 , (U,Pu)O 2 and UN were measured in specially developed irradiation creep casings in different reactors. The measuring data were corrected and evaluated considering the thermal expansion effects, irregular temperature distribution and swelling effects in such a way that the dependences of the creep rate of UO 2 , UO 2 -PuO 2 and UN under irradiation on stress, temperature, fission rate, burn-up and porosity is obtained. It shows that creeping of fuels under irradiation at high temperatures is equivalent to thermally activated creeping, while at low temperature the creep rate induced by irradiation is much higher than the condition without irradiation. The increment of oxidic nuclear fuels is greater than in UN, the stress dependence on low burn-up is proportional in both cases, and the influence of temperature is quite small. (orig.) [de

  3. Kinetics that govern the release of tritium from neutron-irradiated lithium oxide

    International Nuclear Information System (INIS)

    Bertone, P.C.

    1986-01-01

    The Lithium Blanket Module (LBM) program being conducted at the Princeton Plasma Physics Laboratory requires that tritium concentrations as low as 0.1 nCi/g, bred in both LBM lithium oxide pellets and gram-size lithium samples, be measured with an uncertainty not exceeding +/-6%. This thesis reports two satisfactory methods of assaying LBM pellets and one satisfactory method of assaying lithium samples. Results of a fundamental kinetic investigation are also reported. The thermally driven release of tritium from neutron-irradiated lithium oxide pellets is studied between the temperatures of 300 and 400 0 C. The observed release clearly obeys first-order kinetics, and the governing activation energy appears to be 28.4 kcal/mole. Finally, a model is presented that may explain the thermally driven release of tritium from a lithium oxide crystal and assemblies thereof. It predicts that under most circumstances the release is controlled by either the diffusion of a tritiated species through the crystal, or by the desorption of tritiated water from it

  4. Dislocation Arrangements in Deformed and Neutron Irradiated Zirconium and Zircaloy-2

    International Nuclear Information System (INIS)

    Roy, R.B.

    1963-12-01

    Dislocation arrangements in deformed and neutron irradiated Zr and Zircaloy-2 have been studied by thin film transmission electron microscopy. Results indicate that the prominent slip system, in both Zr and Zircaloy-2, is the {1010} 1/3 type; no evidence for basal slip was observed. Attractive and repulsive dislocation interactions seem to be more important than the intersection jog reactions. Elongated loops and dipoles were seen at higher deformations and it is suspected that such loops or dipoles are formed due to interactions between dislocations lying in parallel planes. Stacking fault ribbons lying in {1010} plane have been found in 15% cold rolled Zircaloy-2: a rough estimate of stacking fault energy indicates that it is ∼ 65 ergs/cm 2 . Calculations show that the equilibrium separation of partials is ∼ 60 A and a stress as high as 19x10 -3 μ acting along {0010} direction is needed to separate them. It has been suggested that O 2 and N 2 in addition to their solid solution hardening effect may also cause a lowering of the stacking fault energy and Suzuki hardening

  5. Radiation-induced conductivity of doped silicon in response to photon, proton and neutron irradiation

    International Nuclear Information System (INIS)

    Kishimoto, N.; Amekura, H.; Plaksin, O.A.; Stepanov, V.A.

    2000-01-01

    The opto-electronic performance of semiconductors during reactor operation is restricted by radiation-induced conductivity (RIC) and the synergistic effects of neutrons/ions and photons. The RICs of Si due to photons, protons and pulsed neutrons have been evaluated, aiming at radiation correlation. Protons of 17 MeV with an ionizing dose rate of 10 3 Gy/s and/or photons (hν=1.3 eV) were used to irradiate impurity-doped Si (2x10 16 B atoms/cm 3 ) at 300 and 200 K. Proton-induced RIC (p-RIC) and photoconductivity (PC) were intermittently detected in an accelerator device. Neutron-induced RIC (n-RIC) was measured for the same Si in a pulsed fast-fission reactor, BARS-6, with a 70-μs pulse of 2x10 12 n/cm 2 (E>0.01 MeV) and a dose rate of up to 6x10 5 Gy/s. The neutron irradiation showed a saturation tendency in the flux dependence at 300 K due to the strong electronic excitation. Normalization of the electronic excitation, including the pulsed regime, gave a fair agreement among the different radiation environments. Detailed comparison among PC, p-RIC and n-RIC is discussed in terms of radiation correlation including the in-pile condition

  6. Charge collection and space charge distribution in neutron-irradiated epitaxial silicon detectors

    International Nuclear Information System (INIS)

    Poehlsen, Thomas

    2010-04-01

    In this work epitaxial n-type silicon diodes with a thickness of 100 μm and 150 μm are investigated. After neutron irradiation with fluences between 10 14 cm -2 and 4 x 10 15 cm -2 annealing studies were performed. CV-IV curves were taken and the depletion voltage was determined for different annealing times. All investigated diodes with neutron fluences greater than 2 x 10 14 cm -2 showed type inversion due to irradiation. Measurements with the transient current technique (TCT) using a pulsed laser were performed to investigate charge collection effects for temperatures of -40 C, -10 C and 20 C. The charge correction method was used to determine the effective trapping time τ eff . Inconsistencies of the results could be explained by assuming field dependent trapping times. A simulation of charge collection could be used to determine the field dependent trapping time τ eff (E) and the space charge distribution in the detector bulk. Assuming a linear field dependence of the trapping times and a linear space charge distribution the data could be described. Indications of charge multiplication were seen in the irradiated 100 μm thick diodes for all investigated fluences at voltages above 800 V. The space charge distribution extracted from TCT measurements was compared to the results of the CV measurements and showed good agreement. (orig.)

  7. Response of the MG-63 human osteosarcoma cell line grown as multicellular spheroids to neutron irradiation

    International Nuclear Information System (INIS)

    Kubota, Nobuo; Kakehi, Masae; Matsubara, Shou; Koike, Sachiko; Ando, Koichi.

    1993-01-01

    Multicellular tumor spheroids are composed of the mixed populations of cells with regard to cell proliferation, nutrition, oxygenation and radiosensitivity. Human osteogenic sarcoma is generally considered clinically radioresistant. However, the in vitro cell survival curves for human osteogenic sarcoma cell lines do not differ from those of other tumor cell lines. In this study, the responses of human osteogenic sarcoma cell line to gamma ray and neutrons were investigated by using spheroid system. The spheroids of the osteogenic sarcoma cell line are considered to be a good in vitro model of radioresistant tumors. The purpose of this study is to measure the response of the spheroids to fast neutron irradiation. MG-63 human osteogenic sarcoma cell line was used for this study. The cell line was cultured in alpha-MEM with supplement. Cell survival was estimated after the trypsinization of spheroids 24 hours after irradiation. The method of measuring spheroid cure is explained. The mean number of surviving cells per spheroid can be obtained from the mean clonogenic number and cell survival curve. The cell survival of MG-63 spheroids exposed to gamma ray and neutrons and the dose effect curves for spheroid cure after irradiation are shown. (K.I.)

  8. Change in properties of superconducting magnet materials by fusion neutron irradiation

    International Nuclear Information System (INIS)

    Nishimura, Arata; Nishijima, Shigehiro; Takeuchi, Takao; Nishitani, Takeo

    2007-01-01

    A fusion reactor will generate a lot of high energy neutron and much energy will be taken out of the neutrons by a blanket system. Since some neutrons will stream out of a plasma vacuum vessel through neutral beam injection ports and penetrate a blanket system, a superconducting magnet system, which provides high magnetic field to confirm high energy particles, will be irradiated by a certain amount of neutrons. By developing the new NBI system or by reducing the penetration, the neutron fluence to the superconducting magnet will be able to be reduced. However, it is not easy to achieve the lower streaming and penetration at the present. Therefore, investigations on irradiation behavior of superconducting magnet materials are desired and some novel researches have been performed from 1970s. In general, the critical current of the superconducting wire increases under fast neutron environment comparing with that of the non-irradiated wire, and then decreased to almost zero as an increase of neutron fluence. On the other hand, the critical temperature of the wire starts to get down around 10 22 n/m 2 of neutron fluence and the temperature margin will be decreased during the operation by the neutron irradiation. In this paper, some aspects of irradiated materials will be overviewed and general tendency will be discussed focussing on knock-on effect of fast neutron and long range ordering of A15 compounds

  9. Effect of neutron irradiation on the density of low-energy excitations in vitreous silica

    International Nuclear Information System (INIS)

    Smith, T.L.

    1979-01-01

    Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity were made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C/sub ex/, the thermal conductivity kappa, and the anomalous temperature dependence of the ultrasound velocity Δv/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that kappa and Δv/v are determined by the same localized excitations responsible for C/sub ex/, but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. A consistent account for the measured C/sub ex/, kappa, and Δv/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model

  10. The effect of neutron irradiation on the trapping of tritium in carbon-based materials

    International Nuclear Information System (INIS)

    Kwast, H.; Werle, H.; Glugla, M.; Wu, C.H.; Federici, G.

    1993-11-01

    Carbon-based materials are considered for protection of plasma facing components in the next step fusion device. To investigate the effects of neutron damage on the tritium behaviour an experimental study on the tritium retention of various neutron irradiated graphites and carbon/carbon fibre composites was started. The irradiation dose of the specimens ranges from 10 -3 to 3.5 dpa.g and the irradiation temperature from 390 C to 1500 C. A comparison of tritium retention in pre- and post-irradiated carbon-based materials as a function of the sample temperature is reported in this paper and the results are discussed. The first results indicate that the retention of tritium is higher in irradiated graphite than in unirradiated graphite and depends largely on the density and microstructure. The retention is also influenced by the tritium-loading temperature. Graphite of type S 1611, irradiated at 400 C and 600 C up to a damage of 0.1 dpa.g, retained about two times more tritium than the unirradiated material. (orig.)

  11. High Temperature Tensile Properties of Unirradiated and Neutron Irradiated 20 Cr-35 Ni Austenitic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R B; Solly, B

    1966-12-15

    The tensile properties of an unirradiated and neutron irradiated (at 40 deg C) 20 % Cr, 35 % Ni austenitic steel have been studied at 650 deg C, 750 deg C and 820 deg C. The tensile elongation and mode of fracture (transgranular) of unirradiated specimens tested at room temperature and 650 deg C are almost identical. At 750 deg C and 820 deg C the elongation decreases considerably and a large part of the total elongation is non-uniform. Furthermore, the mode of fracture at these temperatures is intergranular and microscopic evidence suggests that fracture is caused by formation and linkup of grain boundary cavities. YS and UTS decrease monotonically with temperature. Irradiated specimens show a further decrease in ductility and an increase in the tendency to grain boundary cracking. Irradiation has no significant effect on the YS, but the UTS are reduced. The embrittlement of the irradiated specimens is attributed to the presence of He and Li atoms produced during irradiation and the possible mechanisms are discussed. Prolonged annealing of irradiated and unirradiated specimens at 650 deg C appears to have no significant effect on tensile properties.

  12. Dislocation Arrangements in Deformed and Neutron Irradiated Zirconium and Zircaloy-2

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R B

    1963-12-15

    Dislocation arrangements in deformed and neutron irradiated Zr and Zircaloy-2 have been studied by thin film transmission electron microscopy. Results indicate that the prominent slip system, in both Zr and Zircaloy-2, is the {l_brace}1010{r_brace} 1/3 <1210> type; no evidence for basal slip was observed. Attractive and repulsive dislocation interactions seem to be more important than the intersection jog reactions. Elongated loops and dipoles were seen at higher deformations and it is suspected that such loops or dipoles are formed due to interactions between dislocations lying in parallel planes. Stacking fault ribbons lying in {l_brace}1010{r_brace} plane have been found in 15% cold rolled Zircaloy-2: a rough estimate of stacking fault energy indicates that it is {approx} 65 ergs/cm{sup 2}. Calculations show that the equilibrium separation of partials is {approx} 60 A and a stress as high as 19x10{sup -3} {mu} acting along {l_brace}0010{r_brace} direction is needed to separate them. It has been suggested that O{sub 2} and N{sub 2} in addition to their solid solution hardening effect may also cause a lowering of the stacking fault energy and Suzuki hardening.

  13. Electron trapping in neutron-irradiated very thin films of Al2O3

    International Nuclear Information System (INIS)

    Srivastava, P.C.; Bardhan, A.R.

    1979-01-01

    Oxide layers of thicknesses less than 100 A have been prepared by thermal-oxidation of a base metal electrode film of aluminium. These films were then neutron-irradiated from a laboratory Ra-Be source to a fluence of approximately 10 11 neutrons cm -2 and the sandwich structure, Al-Al 2 O 3 -Au, was completed by depositing a thin metal film of gold over the irradiated oxide layer. D.C. steady and transient flow through the sandwich structures have been studied. Results obtained in the experiments with irradiated sandwiches have been compared with unirradiated ones to show that traps are introduced because of the damage caused by the incident neutrons. Transient voltage measurement across the junction gives a trap density of approximately 10 18 cm -3 . A capture cross-section of the order 10 -28 cm 2 is estimated for the traps. It is found that the (identified) traps are uniformly distributed within an energy of 0.099 eV below the conduction band edge of aluminium oxide. The physical nature of the traps is discussed by comparing the capture cross-sections of the physically known trapping centres. The possibility of vacancies or F-centres acting as traps (for the identified ones) has been suggested. (author)

  14. Neutron irradiation embrittlement of reactor pressure vessel steel 20 MnMoNi55 weld

    International Nuclear Information System (INIS)

    Ghoneim, M.M.

    1987-05-01

    The effect of neutron irradiation on the mechanical and fracture properties of an 'improved' 20 MnMoNi 55 Pressure Vessel Steel (PVS) weld was investigated. In addition to very low residual element content, especially Cu (0.035 wt.%), and relatively higher Ni content (0.9 wt.%), this steel has higher strength (30% more) than the steels used currently in nuclear reactor pressure vessels. The material was irradiated to 3.5x10 19 and 7x10 19 n/cm 2 (E > 1 Mev) at 290 0 C and 2.5x10 19 n/cm 2 (E > 1 MeV) at 160 0 C in FRJ-1 and FRJ-2 research reactors at KFA, Juelich, F.R.G. Test methods used in the evaluation included instrumented impact testing of standard and precracked Charpy specimens, tensile, and fracture toughness testing. Instrumented impact testing provided load and energy vs. time (deflection) data in addition to energy absorption data. The results indicated that the investigated high strength improved steel is more resistant to irradiation induced embrittlement than conventional PVSs. (orig./IHOE)

  15. Prenatal exposure to gamma/neutron irradiation: Sensorimotor alterations and paradoxical effects on learning

    International Nuclear Information System (INIS)

    Di Cicco, D.; Antal, S.; Ammassari-Teule, M.

    1991-01-01

    The effects of prenatal exposure on gamma/neutron radiations (0.5 Gy at about the 18th day of fetal life) were studied in a hybrid strain of mice (DBA/Cne males x C57BL/Cne females). During ontogeny, measurements of sensorimotor reflexes revealed in prenatally irradiated mice (1) a delay in sensorial development, (2) deficits in tests involving body motor control, and (3) a reduction of both motility and locomotor activity scores. In adulthood, the behaviour of prenatally irradiated and control mice was examined in the open field test and in reactivity to novelty. Moreover, their learning performance was compared in several situations. The results show that, in the open field test, only rearings were more frequent in irradiated mice. In the presence of a novel object, significant sex x treatment interactions were observed since ambulation and leaning against the novel object increased in irradiated females but decreased in irradiated males. Finally, when submitted to different learning tasks, irradiated mice were impaired in the radial maze, but paradoxically exhibited higher avoidance scores than control mice, possibly because of their low pain thresholds. Taken together, these observations indicate that late prenatal gamma/neutron irradiation induces long lasting alterations at the sensorimotor level which, in turn, can influence learning abilities of adult mice

  16. On remarks by K. Guenther on the application of track theory to neutron irradiations

    International Nuclear Information System (INIS)

    Katz, R.

    1976-01-01

    The author is replying to criticisms of the application of track theory to neutron irradiation. (Guenther, K., 1976, Int. J. Radiat. Biol., vol. 30, 495). Guenther correctly pointed out that any success of the theory for high neutron energies depends on the neglect of the error made at the stopping end of the path of a secondary heavy ion in relation to the overall estimate of the damage produced by that ion. The identity, size and position within the nucleus of the sensitive element whose inactivation leads to cell-killing are all unknown, but any predictions made using the theory are still useful in that they should provoke further experimental investigations ascertaining the limits of the theory. The track theory has other problems at low particle velocities. Consideration is given to the justification for ignoring the error at the stopping end under various conditions. The extent to which the different errors and neglects of the theory may be self-compensating is not yet known. Even if the agreement in r.b.e.-dose relations between calculation from cell survival parameters and experiment for different tissues is fortuitous, the algorithm serves a useful purpose since r.b.e-dose relations can be calculated from a knowledge of the particle energy spectrum of the radiation. Radiotherapy can then be planned for fast neutrons, pions and ion beams, and radiation hazards evaluated in complex radiation environments. (U.K.)

  17. Neutron irradiation effect on the strength of jointed Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Ishiyama, Shintaro; Miya, Naoyuki

    2002-01-01

    In order to investigate applicability of Ti alloy to large scaled structural material for fusion reactors, irradiation effect on the mechanical properties of Ti-6Al-4V alloy and its TIG welded material was investigated after neutron irradiation (temperature: 746-788K, fluence: 2.8 x 10 23 n/m 2 (>0.18 MeV). The following results were obtained. (1) Irradiated Ti alloy shows about 20-30% increase of its tensile strength and large degradation of fracture elongation, comparing with those of unirradiated Ti alloy. (2) TIG welded material behaves as Ti alloy in its tensile test, however, shows 30% increase of area reduction in 373-473K, whereas 1/2 degradation of area reduction over 600K. (3) Irradiated TIG welded material behaves heavier embrittlement than that of irradiated Ti alloy. (4) Charpy impact properties of un- and irradiated Ti alloys shift to ductile from brittle fracture and transition temperature shift, ΔT was estimated as about 100K. (5) Remarkable increase of hardness was found, especially in HAZ of TIG welded material after irradiation. (author)

  18. Effect of fast neutron irradiation upon the omega transformation process in zirconium--niobium alloys

    International Nuclear Information System (INIS)

    Bremer, B.W.

    1974-01-01

    The effect of fast neutrons (E greater than 1 MeV) upon the beta-omega transformation was investigated. Irradiation-produced vacancies promoted the omega transformation by migrating to the regions of high compressive stress associated with the one-dimensional omega embryos, thereby allowing rearrangement of the strain fields. This rearrangement allows the omega embryos to attain large sizes. Growth of these embryos is diffusion controlled. However, irradiation produced no increase in growth rate. It is concluded the vacancies are effectively trapped by these strain fields even at the aging temperature, 400 0 C. The omega hardening mechanism is shown to be related solely to lattice misfit, independent of irradiation, and to saturate when the magnitude of the strain causes a breakdown of the coherent interface, thereby creating one or two interfacial dislocations. Aging at 400 0 C results in alpha growth into the interomega beta phase, producing an additional hardness increase additive to that resulting from the omega phase. At higher aging temperatures 500 0 C, the omega is rapidly replaced by alpha. The alpha microstructure consists of ultra-fine grains, 1000 A, each composed of one 12 interrelated crystallographic variants. Fast neutron irradiation has no effect upon the omega metastable equilibrium phase diagram

  19. Study of accelerated diffusion in gold and aluminium under neutron irradiation

    International Nuclear Information System (INIS)

    Acker, Denis.

    1977-09-01

    The speed-up of diffusion under neutron irradiation was studied. The experiments concern the self-diffusion of gold as a function of temperature and the heterodiffusion of copper and gold in aluminium against flux and temperature. In each of these systems the coefficients measured were 10 6 times higher than the expected extra-irradiation values for a flux of 6.10 12 n/cm 2 /s and at a temperature 0.33 Tsub(f), Tsub(f) being the matting point of the matrix expressed in Kelvins. The results obtained can be explained satisfactorily by assuming that, under irradiation: the activation energy of the diffusion coefficient is equal to half the hole migration energy (corrected for the hole-impurity interaction terms in the case of heterodiffusion); the diffusion coefficient under irradiation varies with the square root of the flux; defect wells eliminate interstitials much more efficient by than holes. The first two points agree well with theoretical predictions if the holes and interstitials are assumed to disappear essentially by mutual recombination, whereas the third can be interpreted in terms of a low efficiency of wells for holes and by supposing that the interstitial elimination reaction is limited only by the diffusion rate of these interstitials [fr

  20. Fast neutron irradiation effects on CR-39 nuclear track detector for dosimetric applications

    International Nuclear Information System (INIS)

    Kader, M.H.

    2005-01-01

    The effect of neutron irradiation on the dosimetric properties of CR-39 solid-state nuclear track detector have been investigated. CR-39 samples were irradiated with neutrons of energies follow a Maxwellian distribution centered about 2 MeV. These samples were irradiated with different doses in the range 0.1-1 Sv. The background and track density were measured as a function of etching time. In addition, the dependence of sensitivity of CR-39 detector on the neutrons dose has been investigated. The results show that the Sensitivity started to increase at 0.4 Sv neutrons dose, so this sample were chosen to be a subject for further study to investigate the effect of gamma dose on its properties. The sample irradiated with 0.4 Sv were exposed to different doses of gamma rays at levels between 10 and 80 kGy. The effect of gamma doses on the bulk etching rate VB, the track diameter and the sensitivity of the CR-39 samples was investigated. The results show that the dosimetric properties of CR-39 SSNTD are greatly affected by both neutron and gamma irradiation

  1. Neutron irradiation effects in Fe and Fe-Cr at 300 °C

    International Nuclear Information System (INIS)

    Chen, Wei-Ying; Miao, Yinbin; Gan, Jian; Okuniewski, Maria A.; Maloy, Stuart A.; Stubbins, James F.

    2016-01-01

    Fe and Fe-Cr (Cr = 10–16 at.%) specimens were neutron-irradiated at 300 °C to 0.01, 0.1 and 1 dpa. The TEM observations indicated that the Cr significantly reduced the mobility of dislocation loops and suppressed vacancy clustering, leading to distinct damage microstructures between Fe and Fe-Cr. Irradiation-induced dislocation loops in Fe were heterogeneously observed in the vicinity of grown-in dislocations, whereas the loop distribution observed in Fe-Cr is much more uniform. Voids were observed in the irradiated Fe samples, but not in irradiated Fe-Cr samples. Increasing Cr content in Fe-Cr results in a higher density, and a smaller size of irradiation-induced dislocation loops. Orowan mechanism was used to correlate the observed microstructure and hardening, which showed that the hardening in Fe-Cr can be attributed to the formation of dislocation loops and α′ precipitates. -- Graphical abstract: Addition of Cr in Fe suppressed the mobility of mobile 1/2<111> dislocation loops and increased the proportion of immobile <100> dislocation loops, leading to a transition of loop distribution from highly heterogeneous to uniform. Display Omitted

  2. Irradiation temperature dependence of production efficiency of lattice defects in some neutron-irradiated oxides

    International Nuclear Information System (INIS)

    Okada, Moritami; Atobe, Kozo; Nakagawa, Masuo

    2004-01-01

    Temperature dependence of production efficiency of irradiation-induced defects in neutron-irradiated oxides has been investigated. Some oxide single crystals, MgO, α-Al 2 O 3 (sapphire) and TiO 2 (rutile), were irradiated at several controlled temperatures, 10, 20, 50, 100, 150 and 200 K, using the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL), and at ambient temperature (∼370 K) in the same facility. Irradiation temperature dependence of production efficiency of a 1 μm band in TiO 2 differs greatly from that of anion vacancy (F-type centers) in MgO and α-Al 2 O 3 . Results for MgO and α-Al 2 O 3 show steep negative gradients from 10 to 370 K, whereas that for TiO 2 includes a valley between 40 and 60 K and a hump at about 130 K, and then disappear at about 200 K. In MgO and α-Al 2 O 3 , this behavior can be explained by the recombination of Frenkel pairs, which is activated at higher temperature. In TiO 2 , in addition to the recombination mechanism, a covalent bonding property is thought to be exerted strong influence, and it is suggested that a disappearance of the 1 μm band at above 200 K is due to the recombination process of Frenkel pairs which is caused by the irradiation-induced crystallization

  3. The effect of neutron irradiation on the recuperation and recristallization of the polycrystalline niobium

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1978-01-01

    Through the measurements in Transmission Electron Microscopy and Microhardness is studied the effect of fast neutron irradiation (E > or = 0,1 MeV) on the Recovery and Recrystallization in very pure grade Niobium. The range of temperature is 25 0 C - 1200 0 C for one hour. The sigmoidal curve of the Recovery in Niobium shows a initial increase in the microhardness in the range of temperature of 25 0 C - 300 0 C, who is related to the intersticial migration (impurity atoms) O, C and N to the dislocations and to the defects clusters produced by cold work and radiation. The Recrystallization in cold worked Niobium comes by subgrain growth (subgrains coalescence) and by strain induced grain boundary migration. The radiation with fast neutrons (O=1,3 x 10 18 nvt) acelerates the overall nucleation process of Recrystallization by about 150 0 C with respect to the only deformed Niobium. The activation energy for the Recrystallization process is obtained in both cases, in the rolling Niobium and in Nb deformed and irradiated by fast neutrons (1,2 x 10 17 nvt) [pt

  4. Effect of high fluence neutron irradiation on transport properties of thermoelectrics

    Science.gov (United States)

    Wang, H.; Leonard, K. J.

    2017-07-01

    Thermoelectric materials were subjected to high fluence neutron irradiation in order to understand the effect of radiation damage on transport properties. This study is relevant to the NASA Radioisotope Thermoelectric Generator (RTG) program in which thermoelectric elements are exposed to radiation over a long period of time in space missions. Selected n-type and p-type bismuth telluride materials were irradiated at the High Flux Isotope Reactor with a neutron fluence of 1.3 × 1018 n/cm2 (E > 0.1 MeV). The increase in the Seebeck coefficient in the n-type material was partially off-set by an increase in electrical resistivity, making the power factor higher at lower temperatures. For the p-type materials, although the Seebeck coefficient was not affected by irradiation, electrical resistivity decreased slightly. The figure of merit, zT, showed a clear drop in the 300-400 K range for the p-type material and an increase for the n-type material. Considering that the p-type and n-type materials are connected in series in a module, the overall irradiation damages at the device level were limited. These results, at neutron fluences exceeding a typical space mission, are significant to ensure that the radiation damage to thermoelectrics does not affect the performance of RTGs.

  5. Admittance studies of neutron-irradiated silicon p+-n diodes

    International Nuclear Information System (INIS)

    Tokuda, Y.; Usami, A.

    1977-01-01

    Defects introduced in n-type silicon by neutron irradiation were investigated by measuring the conductance (G) and the capacitance (C) of p + -n diodes. The method of the determination of the energy level, capture cross section, and concentration for each defect from the G-T and C-T curves for various frequencies was presented. Assuming that capture cross sections are independent of temperature, the energy levels of E/sub c/-0.15 eV, E/sub c/-0.22 eV, and E/sub c/-0.39 eV were obtained. For these defects, the calculated values of the electron capture cross section were 2.6 x 10 -14 , 3.7 x 10 -15 , and 2.0 x 10 -14 cm 2 , respectively. The introduction rate of defects for E/sub c/-0.39 eV was twice that for E/sub c/-0.22 eV which was twice that for E/sub c/-0.15 eV. Comparing with other published data, the energy levels of E/sub c/-0.15 eV and E/sub c/-0.39 eV were found to be correlated with the A center and the divacancy, respectively

  6. Radioactivity of neutron-irradiated cat's-eye chrysoberyls

    Energy Technology Data Exchange (ETDEWEB)

    Tang, S.M. E-mail: phytsm@leonis.nus.edu.sg; Tay, T.S

    1999-04-02

    The recent report of marketing of radioactive chrysoberyl cat's-eyes in South-East Asian markets has led us to use an indirect method to estimate the threat to health these color-enhanced gemstones may pose if worn close to skin. We determined the impurity content of several cat's-eye chrysoberyls from Indian States of Orissa and Kerala using PIXE, and calculated the radioactivity that would be generated from these impurities and the constitutional elements if a chrysoberyl was irradiated by neutrons in a nuclear reactor for color enhancement. Of all the radioactive nuclides that could be created by neutron irradiation, only four ({sup 46}Sc, {sup 51}Cr, {sup 54}Mn and {sup 59}Fe) would not have cooled down within a month after irradiation to the internationally accepted level of specific residual radioactivity of 2 nCi/g. The radioactivity of {sup 46}Sc, {sup 51}Cr and {sup 59}Fe would only fall to this safe limit after 15 months and that of {sup 54}Mn could remain above this limit for several years.

  7. Structural and chemical evolution in neutron irradiated and helium-injected ferritic ODS PM2000 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hee Joon [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Edwards, Dan J., E-mail: dan.edwards@pnnl.gov [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Kurtz, Richard J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Yamamoto, Takuya; Wu, Yuan [Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106 (United States); Odette, G. Robert [Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106 (United States); Materials Department, University of California, Santa Barbara, CA 93106 (United States)

    2017-02-15

    An investigation of the influence of helium on damage evolution under neutron irradiation of an 11 at% Al, 19 at% Cr ODS ferritic PM2000 alloy was carried out in the High Flux Isotope Reactor (HFIR) using a novel in situ helium injection (ISHI) technique. Helium was injected into adjacent TEM discs from thermal neutron {sup 58}Ni(n{sub th},γ) {sup 59}Ni(n{sub th},α) reactions in a thin NiAl layer. The PM2000 undergoes concurrent displacement damage from the high-energy neutrons. The ISHI technique allows direct comparisons of regions with and without high concentrations of helium since only the side coated with the NiAl experiences helium injection. The corresponding microstructural and microchemical evolutions were characterized using both conventional and scanning transmission electron microscopy techniques. The evolutions observed include formation of dislocation loops and associated helium bubbles, precipitation of a variety of phases, amorphization of the Al{sub 2}YO{sub 3} oxides (which also variously contained internal voids), and several manifestations of solute segregation. Notably, high concentrations of helium had a significant effect on many of these diverse phenomena. These results on PM2000 are compared and contrasted to the evolution of so-called nanostructured ferritic alloys (NFA).

  8. Absence of storage effects on radiation damage after thermal neutron irradiation of dry rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Kowyama, Y. [Mie Univ., Tsu (Japan); Saito, M.; Kawase, T.

    1987-09-15

    Storage effects on dry rice seeds equilibrated to 6.8% moisture content were examined after irradiation with X-rays of 5, 10, 20 and 40 kR and with thermal neutrons of 2.1, 4.2, 6.3 and 8.4×10{sup 13}N{sub th}/cm{sup 2}. Reduction in root growth was estimated from dose response curves after storage periods of 1 hr to 21 days. The longer the storage period, the greater enhancement of radiation damages in X-irradiated seeds. There were two components in the storage effect, i. e., a rapid increase of radiosensitivity within the first 24 hr and a slow increase up to 21 days. An almost complete absence of a storage effect was observed after thermal neutron exposure, in spite of considerably high radioactivities of the induced nuclides, {sup 56}Mn, {sup 42}K and {sup 24}Na, which were detected from gamma-ray spectrometry of the irradiated seeds. The present results suggest that the contributions of gamma-rays from the activated nuclides and of inherent contaminating gamma-rays are little or negligible against the neutron-induced damage, and that the main radiobiological effects of thermal neutrons are ascribed to in situ radiations, i, e., heavy particles resulting from neutron-capture reaction of atom. A mechanism underlying the absence of storage effect after thermal neutron irradiation was briefly discussed on the basis of radical formation and decay. (author)

  9. Mechanical Tests Plan after Neutron Irradiation for SMART SG Tube Materials in a Hot Cell

    International Nuclear Information System (INIS)

    Ahn, Sang Bok; Baik, Seung Jai; Kim, Do Sik; Yoo, Byung Ok; Jung, Yang Hong; Song, Woong Sub; Choo, Kee Nam; Park, Jin Seok; Lee, Yong Sun; Ryu, Woo Seog

    2010-01-01

    An advanced integral PWR, SMART (System- Integrated Modular Advanced ReacTor) is being developed in KAERI. It has compact size and a relatively small power rating compared to a conventional reactor. The main components such as the steam generators, main circulation pumps are located in the reactor vessel. Therefore they are damaged from neutron irradiations generated from nuclear fuel fissions during operation. The SMART SG tubes which are 17 mm in a diameter and 2.5 mm in a thickness will be made of Alloy 690. To ensure the operation safety the post irradiation examinations is necessary to evaluate the deterioration levels of various original properties. Specially the amount of mechanical properties change should be reflected and revised to design data. For that tensile, fracture, hardness test are planned and under preparations. In this paper the detailed plans are reviewed. Three kinds of materials having different heat treatment procedures are prepared to fabricate specimens. The capsules installed the specimens are going to be irradiated in HANARO. Finally the tests for them will be performed in IMEF, Irradiated Materials Examination Facility at KAERI

  10. Fusion neutron irradiation induced ordering and defect production in Cu3Au at high temperatures

    International Nuclear Information System (INIS)

    Huang, J.S.; Guinan, M.W.; Kirk, M.A.; Hahn, P.A.

    1987-08-01

    We irradiate three Cu 3 Au alloys different degrees of initial long-range order at temperatures between 300K and 434K. The resistivity of samples is monitored during irradiation and related to the long-term order parameter by the Muto relation. The results show that the ordering rate, which is proportional to the concentration of freely migrating vacancies, increases at the beginning and then decreases later with fluence. The decrease is a result of the continuous production of sinks in the form of dislocation loops. The effect of sinks on vacancy annihilation in some cases causes a reversed temperature dependence of ordering rate. The free vacancy production rate and the rate of sink production are determined using an ordering kinetics theory. The results of the 14 MeV neutron irradiations are compared to those obtained in other neutron spectra and particle irradiations. The estimated free vacancy production rate is also compared to the primary defect production rate measured at 4.2K in disordered samples

  11. Importance diagrams - a novel presentation of the response of a material to neutron irradiation

    International Nuclear Information System (INIS)

    Forrest, R.A.

    1998-01-01

    Activation of fusion materials following neutron irradiation is of great technological importance, especially in the study of safety and environmental impacts. Currently, activation calculations are performed for a particular neutron spectrum, appropriate to a region in a particular fusion device, which makes it difficult to extract generic information. The present work gives details of a method to present the dominant nuclides for the radiological responses or an irradiated material in a fashion that is independent of the neutron spectrum and almost independent of the flux. The importance diagrams show regions in the decay time versus neutron energy space where a nuclide contributes >50% of the response. The importance diagrams for pure iron and SS316 are described, and it is noted that the shapes of the various regions vary very little with the total neutron flux. Variation of the diagrams with irradiation time occurs at short decay times in a systematic fashion. The use of the diagrams in a realistic spectrum relies on an expansion, which while not generally true, does hold approximately for many of the nuclides of interest. The diagrams are therefore a valuable summary of the universal, device-independent, response of the materials, and when combined with pathway information give a comprehensive description of activation for that material. (orig.)

  12. Displacement damage effects on CMOS APS image sensors induced by neutron irradiation from a nuclear reactor

    International Nuclear Information System (INIS)

    Wang, Zujun; Huang, Shaoyan; Liu, Minbo; Xiao, Zhigang; He, Baoping; Yao, Zhibin; Sheng, Jiangkun

    2014-01-01

    The experiments of displacement damage effects on CMOS APS image sensors induced by neutron irradiation from a nuclear reactor are presented. The CMOS APS image sensors are manufactured in the standard 0.35 μm CMOS technology. The flux of neutron beams was about 1.33 × 10 8 n/cm 2 s. The three samples were exposed by 1 MeV neutron equivalent-fluence of 1 × 10 11 , 5 × 10 11 , and 1 × 10 12 n/cm 2 , respectively. The mean dark signal (K D ), dark signal spike, dark signal non-uniformity (DSNU), noise (V N ), saturation output signal voltage (V S ), and dynamic range (DR) versus neutron fluence are investigated. The degradation mechanisms of CMOS APS image sensors are analyzed. The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose. The dark images from CMOS APS image sensors irradiated by neutrons are presented to investigate the generation of dark signal spike

  13. Characterization of {sup 14}C in neutron irradiated NBG-25 nuclear graphite

    Energy Technology Data Exchange (ETDEWEB)

    LaBrier, Daniel, E-mail: labrdani@isu.edu; Dunzik-Gougar, Mary Lou

    2014-05-01

    Recent studies suggest that the highest concentration of {sup 14}C contamination present in reactor-irradiated graphite exists on the surfaces and within near-surface layers. Surface-sensitive analysis techniques (XPS, ToF-SIMS, SEM/EDS and Raman) were employed to determine the chemical nature of {sup 14}C on irradiated NBG-25 (nuclear grade) graphite surfaces. Several {sup 14}C precursor species are identified on the surfaces of irradiated NBG-25; the quantities of these species decrease at sub-surface depths, which further suggests that {sup 14}C formation is predominantly a surface-concentrated phenomenon. The elevated presence of several surface oxide complexes on irradiated NBG-25 surfaces are attributed directly to neutron irradiation. Larger numbers of oxide bonds were found on irradiated NBG-25 surfaces (when compared to unirradiated samples) in the form of interlattice (e.g. ether) and dangling (e.g. carboxylate and ketone) bonds; the quantities of these bond types also decrease with increasing sub-surface depths.

  14. Design of small-animal thermal neutron irradiation facility at the Brookhaven Medical Research Reactor

    International Nuclear Information System (INIS)

    Liu, H.B.

    1996-01-01

    The broad beam facility (BBF) at the Brookhaven Medical Research Reactor (BMRR) can provide a thermal neutron beam with flux intensity and quality comparable to the beam currently used for research on neutron capture therapy using cell-culture and small-animal irradiations. Monte Carlo computations were made, first, to compare with the dosimetric measurements at the existing BBF and, second, to calculate the neutron and gamma fluxes and doses expected at the proposed BBF. Multiple cell cultures or small animals could be irradiated simultaneously at the so-modified BBF under conditions similar to or better than those individual animals irradiated at the existing thermal neutron irradiation Facility (TNIF) of the BMRR. The flux intensity of the collimated thermal neutron beam at the proposed BBF would be 1.7 x 10 10 n/cm 2 ·s at 3-MW reactor power, the same as at the TNIF. However, the proposed collimated beam would have much lower gamma (0.89 x 10 -11 cGy·cm 2 /n th ) and fast neutron (0.58 x 10 -11 cGy·cm 2 /n th ) contaminations, 64 and 19% of those at the TNIF, respectively. The feasibility of remodeling the facility is discussed

  15. Effects of neutron irradiation to 63 dpa on the properties of various commercial copper alloys

    International Nuclear Information System (INIS)

    Brager, H.R.

    1985-04-01

    High purity copper and six commercial copper alloys were neutron irradiated to 47 and 63 dpa at about 450 0 C in the FFTF. Immersion density measurements showed a wide range of swelling behavior after irradiation to 63 dpa. At one extreme was CuBe in the aged and tempered (AT) condition which had densified slightly. At the other extreme was 20% CW Cu-0.1% Ag which swelled over 45%. Electrical resistivity measurements followed trends similar to previously published results for the same alloys irradiated to 16 dpa: a continued change in conductivity with fluence which appears to relate to void formation, transmutation products and coarsening of second phase precipitates. These results were compared with electrical conductivity of unirradiated alloys examined after aging for 10,000 hours. The most irradiation resistant high-conductivity copper alloys examined after 63 dpa are A125 and MZC. Cu-2.0Be, only a moderate-conductivity alloy, exhibits very consistent irradiation resistant properties

  16. Effect of whole body neutron irradiation on certain enzyme activities in different brain areas in mice

    International Nuclear Information System (INIS)

    Kotb, M.A.; Ashour, A.M.; El-Bassiouni, E.A.

    1994-01-01

    Male swiss albino mice were exposed to whole-body irradiation by fast neutrons of 14 MeV average energy. Two single doses of 0.08 sievert and 0.16 sievert were used, corresponding to fluences of 1.27 X 10 8 and 2.54 X 10 8 n/cm 2 respectively. Two enzymes were assessed in different layers of the cerebrum and cerebellum of mouse brain. Changes in the activities of acid phosphatase (ACP) and succinic dehydrogenase (SDH) were taken to measure alterations in lysosomal and mitochondrial functions respectively. The degrees of lysosomal affection in different layers of the cerebrum were not uniform, while changes in A activity were very prominent in certain layers (e.g. external pyramidal layer, polymorphous cells layer and white matter), they were practically absent in others (e.g. internal pyramidal layer). Stronger effect was noted in the tissue layers of the cerebellum. The activity of SDH decreased as result of fast neutron irradiation. The response was more apparent for this enzyme than for ACP. This indicates more liability for a decrease in energy metabolism with consequent effect on behavioural and physiological functions under central nervous system control. 4 figs., 4 tabs

  17. Dose field research of analysis room for in-hospital neutron irradiator

    International Nuclear Information System (INIS)

    Zhang Zizhu; Song Mingzhe; Li Wei; Chen Jun; Yang Yong; Li Yiguo

    2012-01-01

    Neutron equivalent dose rate and y ray dose rate inside the analysis room of the in-hospital neutron irradiator (IHNI) and outdoor were measured. The results show that γ ray dose rate inside the analysis room exceeds calculation value many times and γ/ ray dose rate outdoor is higher than supervision region dose limit of 7.5 μSv/h. According to the measurement results and the Monte Carlo simulation, the following shielding plan was adopted. Lead shielding with thickness of 16 cm was installed on the wall, which faces the neutron beam, to shield γ ray, and lithium polyethylene plate with thickness of l cm was installed on all the wall (not including ceiling and floor) to shield scattering neutron. After shielding transformation, the highest γ ray dose rate point inside the analysis room decreased 277 times, the neutron equivalent dose rate decreased 5.8 times, and the outdoor γ/ray dose rate decreased nearly 90 times. (authors)

  18. Monovacancy paramagnetism in neutron-irradiated graphite probed by 13C NMR.

    Science.gov (United States)

    Zhang, Zhi Tao; Xu, C; Dmytriieva, Daryna; Molatta, Sebastian; Wosnitza, J; Wang, Y T; Helm, Manfred; Zhou, Shengqiang; Kuehne, Hannes

    2017-09-18

    We report on the magnetic properties of monovacancy defects in neutron-irradiated graphite, probed by $^{13}$C nuclear magnetic resonance spectroscopy. The bulk paramagnetism of the defect moments is revealed by the temperature dependence of the NMR frequency shift and spectral linewidth, both of which follow a Curie behavior, in agreement with measurements of the macroscopic magnetization. Compared to pristine graphite, the fluctuating hyperfine fields generated by the defect moments lead to an enhancement of the $^{13}$C nuclear spin-lattice relaxation rate $1/T_{1}$ by about two orders of magnitude. With an applied magnetic field of 7.1 T, the temperature dependence of $1/T_{1}$ below about 10 K can well be described by a thermally activated form, $1/T_{1}\\propto\\exp(-\\Delta/k_{B}T)$, yielding a singular Zeeman energy of ($0.41\\pm0.01$) meV, in excellent agreement with the sole presence of polarized, non-interacting defect moments. © 2017 IOP Publishing Ltd.

  19. Fracture toughness of neutron irradiated solid and powder HIP 316L(N). ITER Task 214, NET deliverable GB6 ECN-5

    International Nuclear Information System (INIS)

    Rensman, J.; Van den Broek, F.P.; Jong, M.; Van Osch, E.V.

    1998-04-01

    The fracture toughness properties of unirradiated and neutron irradiated type 316L(N) stainless steel plate (European Reference Heat ERHII), conventional 316L(N) solid HIP joints (heat PM-130), and 316L(N)-1G powder HIP material have been measured. Compact tension specimens with a thickness of 12 and 5 mm were irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands, simulating the fusion reactor's first wall conditions by a combination of high displacement damage with proportional amounts of helium. The solid HIP (or HIP-bonded) CT-specimens were irradiated in two separate experiments: SIWAS-6 with 1.3 to 2.3 dpa (1.7 dpa av.) at 353 K, and CHARIOT-3 with 2.7 to 3.1 dpa (2.9 dpa av.) at 600 K. The plate material and powder HIP CT-specimens were irradiated in one experiment only, SIWAS-6. The helium content is up to 20 appm for the 2.9 dpa (av.) dose level. Testing temperatures of 353K and 573K have been used for the fracture toughness experiments. The report contains the experimental conditions and summarises the results, which are given in terms of J-resistance curve fits. The main conclusions are that all three materials have very high toughness in the unirradiated state with little difference between them; the solid HIP has the highest toughness, the powder HIP lowest. The toughness of all three materials is reduced significantly by irradiation, the reduction is the least for the plate material and the highest for the powder HIP material. However, many, but not all, of the solid HIP CT specimens showed debonding of the joint during testing. The machined notch of the CT specimens was not exactly on the joint interface, which could lead to unjustified interpretation of the measured values as being the toughness of the joint, the toughness of the joint being probably much lower. The reduction by irradiation of the fracture toughness of the powder HIP material is clearly larger than for plate material, which is confirmed by the observed early initiation

  20. Study of irradiation effects in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Etienne, A. [GPM UMR CNRS 6634, Universite et INSA de Rouen (France); Material Department, University of California, Santa Barbara (United States); Pareige, P.; Radiguet, B. [GPM UMR CNRS 6634, Universite et INSA de Rouen (France); Cunningham, N.J.; Odette, G.O. [Material Department, University of California, Santa Barbara (United States); Pokor, C. [EDF RD, departement MMC, site des Renardieres, Moret-sur-Loing (France)

    2011-07-01

    Chemical analyses using Atom Probe Tomography were performed on a bolt made of cold worked 316 austenitic stainless steel, extracted from the internal structures of a pressurized water reactor after seventeen years of reactor service. The irradiation temperature of these samples was 633 K and the irradiation dose was estimated to 12 dpa. These analyses have shown that neutron irradiation has a strong effect on the intragranular distribution of solute atoms. A very high number density (6.10{sup 23} m{sup -3}) of Ni-Si enriched and Cr-Fe depleted clusters was detected after irradiation. In order to bring complementary experimental results and to determine the mechanism of formation of these Ni-Si nano-clusters, Fe{sup 5+} ion irradiations have been performed on a 316 austenitic stainless steel. As after neutron irradiation, the formation of solute enriched features is observed. Linear features and two kinds of clusters, rounded and torus shaped, are present. Considering that solute enriched features are probably formed by radiation induced segregation on point defect sinks, these different shapes are due to the nature of the sinks where segregation occurs. (authors)

  1. Life span, testis damage and immune cell populations of spleen in C57BL mice with neutron irradiation by lying flat pose

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Ki Jung; kim, Myung Sup; Kyung, Yoo Bo [KAERI, Taejon (Korea)

    2003-10-01

    This study deals with the biological effects of black mouse (C57BL) irradiated with neutron irradiation by using Boron Neutron Capture Therapy facility in HANARO reactor. These include mortality, body wt., hair color, testis volume, sperm count and immune cell populations in mouse spleen after 80 days later by thermal neutron irradiation. Six week old C57BL male mice were irradiated with neutron irradiation for 1 hr or 2 hrs (flux : 1.036739E +09). These irradiat ion doses estimated 15Gy and 30Gy, respectively. Survival days and hair color in mice was checked. On day 80 after irradiation, testis were taken for volume and sperm count. Also spleen was taken for FACS and spleen cells were isolatd and discarded RBC by treating with lysising solution. These cells were placed on ice and immunofluorescence staining was performed. Phycoerythrin (PE )-anti-CD3e, fluorescein isothiocyanate (FITC)-anti-CD4, and FITC-anti-CD8 were added, then the immunostaining cells were incubated on ice for 40 min. The resulting cells were washed with a PBS buffer 3 times and analyzed using a Flow cytometer. All experimental animals survived over 90 days but in case of 30 Gy neutron irradiation, black mice hair were changed white color on the center of the back. Neutron irradiation of black mice show similar in damage of spleen immune cells by subpopulation of T helper and T cytotoxic cells compared to the control non - irradiated group. These results show that treatment of neutron irradiation without boron compounds for 2 hrs in mice can survive over 90 days with hair color change from black to white. Damaged spleen cells recover after long time by irradiation but testis volume and no. of sperm are not recover compared to the normal group in response to neutron irradiation.

  2. Life span, testis damage and immune cell populations of spleen in C57BL mice with neutron irradiation by lying flat pose

    International Nuclear Information System (INIS)

    Chun, Ki Jung; kim, Myung Sup; Kyung, Yoo Bo

    2003-01-01

    This study deals with the biological effects of black mouse (C57BL) irradiated with neutron irradiation by using Boron Neutron Capture Therapy facility in HANARO reactor. These include mortality, body wt., hair color, testis volume, sperm count and immune cell populations in mouse spleen after 80 days later by thermal neutron irradiation. Six week old C57BL male mice were irradiated with neutron irradiation for 1 hr or 2 hrs (flux : 1.036739E +09). These irradiat ion doses estimated 15Gy and 30Gy, respectively. Survival days and hair color in mice was checked. On day 80 after irradiation, testis were taken for volume and sperm count. Also spleen was taken for FACS and spleen cells were isolatd and discarded RBC by treating with lysising solution. These cells were placed on ice and immunofluorescence staining was performed. Phycoerythrin (PE )-anti-CD3e, fluorescein isothiocyanate (FITC)-anti-CD4, and FITC-anti-CD8 were added, then the immunostaining cells were incubated on ice for 40 min. The resulting cells were washed with a PBS buffer 3 times and analyzed using a Flow cytometer. All experimental animals survived over 90 days but in case of 30 Gy neutron irradiation, black mice hair were changed white color on the center of the back. Neutron irradiation of black mice show similar in damage of spleen immune cells by subpopulation of T helper and T cytotoxic cells compared to the control non - irradiated group. These results show that treatment of neutron irradiation without boron compounds for 2 hrs in mice can survive over 90 days with hair color change from black to white. Damaged spleen cells recover after long time by irradiation but testis volume and no. of sperm are not recover compared to the normal group in response to neutron irradiation

  3. Desorption of tritium and helium from high dose neutron irradiated beryllium

    Science.gov (United States)

    Kupriyanov, I. B.; Nikolaev, G. N.; Vlasov, V. V.; Kovalev, A. M.; Chakin, V. P.

    2007-08-01

    The effect of high dose neutron irradiation on tritium and helium desorption in beryllium is described. Beryllium samples were irradiated in the SM and BOR-60 reactors to a neutron fluences ( E > 0.1 MeV) of (5-16) × 10 22 cm -2 at 70-100 °C and 380-420 °C. A mass-spectrometry technique was used in out of pile tritium release experiments during stepped annealing in the 250-1300 °C temperature range. The total amount of helium accumulated in irradiated beryllium samples varied from 6000 to 7200 appm. The first signs of tritium and helium release were detected at temperature of 312-445 °C and 500-740 °C, respectively. It is shown that most tritium (˜82%) from sample irradiated at 70-100 °C releases in temperature range of 312-700 °C before the beginning of helium release (740 °C). In the case of beryllium sample irradiated at 380-420 °C, tritium release starts at a higher temperature ( Ts > Tann = 445 °C) and most of the tritium (˜99.8%) is released concurrently with helium which could be considered as evidence of co-existence of partial amounts of tritium and helium in common bubbles. Both the Be samples differ little in the upper temperatures of gas release: 745 and 775 °C for tritium; 1140 and 1160 °C for helium. Swelling of beryllium starts to play a key role in accelerating tritium release at Tann > 600 °C and in helium release - at Tann > 750 °C.

  4. Modeling of displacement damage in silicon carbide detectors resulting from neutron irradiation

    Science.gov (United States)

    Khorsandi, Behrooz

    There is considerable interest in developing a power monitor system for Generation IV reactors (for instance GT-MHR). A new type of semiconductor radiation detector is under development based on silicon carbide (SiC) technology for these reactors. SiC has been selected as the semiconductor material due to its superior thermal-electrical-neutronic properties. Compared to Si, SiC is a radiation hard material; however, like Si, the properties of SiC are changed by irradiation by a large fluence of energetic neutrons, as a consequence of displacement damage, and that irradiation decreases the life-time of detectors. Predictions of displacement damage and the concomitant radiation effects are important for deciding where the SiC detectors should be placed. The purpose of this dissertation is to develop computer simulation methods to estimate the number of various defects created in SiC detectors, because of neutron irradiation, and predict at what positions of a reactor, SiC detectors could monitor the neutron flux with high reliability. The simulation modeling includes several well-known---and commercial---codes (MCNP5, TRIM, MARLOWE and VASP), and two kinetic Monte Carlo codes written by the author (MCASIC and DCRSIC). My dissertation will highlight the displacement damage that may happen in SiC detectors located in available positions in the OSURR, GT-MHR and IRIS. As extra modeling output data, the count rates of SiC for the specified locations are calculated. A conclusion of this thesis is SiC detectors that are placed in the thermal neutron region of a graphite moderator-reflector reactor have a chance to survive at least one reactor refueling cycle, while their count rates are acceptably high.

  5. Flux effect on neutron irradiation embrittlement of reactor pressure vessel steels irradiated to high fluences

    International Nuclear Information System (INIS)

    Soneda, N.; Dohi, K.; Nishida, K.; Nomoto, A.; Iwasaki, M.; Tsuno, S.; Akiyama, T.; Watanabe, S.; Ohta, T.

    2011-01-01

    Neutron irradiation embrittlement of reactor pressure vessel (RPV) steels is of great concern for the long term operation of light water reactors. In particular, the embrittlement of the RPV steels of pressurized water reactors (PWRs) at very high fluences beyond 6*10 19 n/cm 2 , E > 1 MeV, needs to be understood in more depth because materials irradiated in material test reactors (MTRs) to such high fluences show larger shifts than predicted by current embrittlement correlation equations available worldwide. The primary difference between the irradiation conditions of MTRs and surveillance capsules is the neutron flux. The neutron flux of MTR is typically more than one order of magnitude higher than that of surveillance capsule, but it is not necessarily clear if this difference in neutron flux causes difference in mechanical properties of RPV. In this paper, we perform direct comparison, in terms of mechanical property and microstructure, between the materials irradiated in surveillance capsules and MTRs to clarify the effect of flux at very high fluences and fluxes. We irradiate the archive materials of some of the commercial reactors in Japan in the MTR, LVR-15, of NRI Rez, Czech Republic. Charpy impact test results of the MTR-irradiated materials are compared with the data from surveillance tests. The comparison of the results of microstructural analyses by means of atom probe tomography is also described to demonstrate the similarity / differences in surveillance and MTR-irradiated materials in terms of solute atom behavior. It appears that high Cu material irradiated in a MTR presents larger shifts than those of surveillance data, while low Cu materials present similar embrittlement. The microstructural changes caused by MTR irradiation and surveillance irradiation are clearly different

  6. Grain size effect on the mechanical properties of neutron irradiated niobium

    International Nuclear Information System (INIS)

    Gusev, M. N.; Maksimkin, O.P.

    2000-01-01

    Samples for mechanical tests were prepared from niobium of technical purity and have form of plates (10·3.5 ·0.3mm) with grain size from 2 to 100 mcm. Neutron irradiation was carried out at the reactor WWR-K to the fluence of 2·10 22 n/m 2 ( Angstroem >0.1 MeV). Tests on uniaxial tension at 293K were performed at the facility, evolving Calvet's microcalorimeter and miniature rapture machine. The developed technique enabled to record heat effects just during the deformation process. As experimental results the characteristics of strength and ductility were defined, as well as values of the latent energy E s , accumulated in material in the process of its deformation up to the moment of destruction. It was found that irradiation of niobium with large-grain structure by neutrons leads to increasing of strength characteristics (yield strength σ 0 .2 changes from 130 to 210 MPa, time-resistance σ b from 200 to 230 MPa) and decreasing of ductility from 36 to 28%. As this takes place the capability of the material to accumulate and dissipate energy of plastic deformation suffers substantial change. There were revealed some additional effects, for instance, the radiation annealing hardening (RAH) (i.e. additional change of properties of irradiated material at annealing), whose maximum takes place at 473K. Its temperature and kinetic parameters were determined in this work. Decreasing of grain size usually leads to decreasing of strengthening under irradiation and to decreasing of RAH effect intensity at subsequent annealing. At the same time decreasing of radiation embrittlement is observed. Consequently, creation of fine-grain structure for some cases can favored the stability of material's properties under irradiation. The obtained results are discussed in context of views on grain boundaries as a defect sink. The relation 'grain boundary volume - grain matrix volume', its influence on RAH-effect and value of latent energy are considered

  7. A Study on the Improvement of Switching Speed of NPT-IGBT by Fast Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Baek, H. N.; Sun, G. M.; Kim, J. S.; Hoang, S. M. T.; Jin, M. E.; Jin, S. B.; Ahn, S. H. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The insulated gate bipolar transistor (IGBT) has been widely used for high power switching devices due to low on-state forward voltage drop and fast switching speed. But, turn-off delay time occurs due to the tail current generated by the minority carrier existing in the n-drift region during turn-off, which reduces the switching speed. Recently, to mitigate this problem, studies on the control of the MCLT to improve the switching speed of IGBTs are carried out. A crystal defect is formed in the n-drift region of an IGBT to realize a deep energy level within the energy band. The deep level act as the recombination center of the minority carrier to reduce the turn-off delay time and control the lifetime by reducing the lifetime of the minority carrier injected during the device operation. The particle-beam irradiation method, such as electron, proton, fast neutron and others, has been used to control the lifetime of the minority carrier of a silicon power semiconductor device. To improve the switching speed of a IGBT, devices were produced by irradiating various doses of fast neutron, and electrical properties were comparatively analyzed with the IGBT device where before irradiated. The reduced in the lifetime of the minority carrier flowing into the n-drift region due to the crystal defect helps improve the switching speed of the IGBT. But, the resistance component increased due to the crystal defect generated by the fast neutron irradiation in the on-state, increasing of the forward voltage drop. So, to improve and optimize the IGBT performance, appropriate condition should be determined by trading off each electrical properties.

  8. Neutron irradiation effects on the mechanical properties of organic composite materials

    International Nuclear Information System (INIS)

    Egusa, S.; Kirk, M.A.; Birtcher, R.C.

    1984-01-01

    Neutron irradiations with low γ-ray flux in the Intense Pulsed Neutron Source were carried out on four kinds of cloth-filled organic composites (filler: E-glass or carbon fiber; matrix: epoxy or polyimide resin) and a unidirectional alumina fiber/epoxy composite. These composites were examined with regard to the mechanical properties at room temperature. Following irradiation at room temperature, the Young's (tensile) modulus of these composites remains practically unchanged up to a total neutron fluence of 5.0x10 18 n/cm 2 (1.4x10 18 n/cm 2 for E>0.1 MeV). The shear modulus and the ultimate strength, on the other hand, decrease significantly at this neutron fluence for the glass/epoxy and glass/polyimide composites, whereas for the other composites both properties do not degrade. This result is most likely ascribed to the radiation damage at fiber/matrix interface due to recoil particles produced by a 10 B(n,α) 7 Li reaction in the boron-containing E-glass fibers. Only for the E-glass fiber composites, in fact, the fracture propagation energy is appreciably increased by irradiation, while for the other composites the propagation energy is scarcely changed, thus confirming the significant contribution due to the 10 B reaction. As to the 5 K irradiation, degradation of the present composites was not observed up to a total neutron fluence of 1.0x10 18 n/cm 2 (7.0x10 17 n/cm 2 for E>0.1 MeV) when tested at room temperature. (orig.)

  9. Evolution of precipitation in reactor pressure vessel steel welds under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Kristina, E-mail: kristina.lindgren@chalmers.se [Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Boåsen, Magnus [Department of Solid Mechanics, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Stiller, Krystyna [Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Efsing, Pål [Department of Solid Mechanics, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Vattenfall Ringhals AB, SE-430 22 Väröbacka (Sweden); Thuvander, Mattias [Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden)

    2017-05-15

    Reactor pressure vessel steel welds are affected by irradiation during operation. The irradiation results in nanometre cluster formation, which in turn affects the mechanical properties of the material, e.g. the ductile-to-brittle transition temperature is shifted to higher levels. In this study, cluster formation is characterised in high Ni (1.58%) low Cu (0.04%) steel welds identical to Ringhals R4 welds, using atom probe tomography in both surveillance material and in material irradiated at accelerated dose rates. Clusters containing mainly Ni and Mn, but also some Si and Cu were observed in all of the irradiated materials. Their evolution did not change drastically during irradiation; the clusters grew and new clusters were nucleated. Hence, both the cluster number density and the average size increased with irradiation time. Some flux effects were observed when comparing the high flux material and the surveillance material. The surveillance material has a lower cluster number density, but larger clusters. The resulting impact on the mechanical properties of these two effects cancel out, resulting in a measured hardness that seems to be on the same trend as the high flux material. The dispersed barrier hardening model with an obstacle strength factor of 0.15 was found to reproduce the increase in hardness. In the investigated high flux materials, the clusters' Cu content was higher. - Highlights: •Clustering in a low Cu, high Ni reactor pressure vessel steel weld is studied. •The clusters nucleate and grow during irradiation, and consist of Ni, Mn, Si, and Cu. •High flux neutron irradiated material is compared to surveillance material. •High flux was found to result in smaller clusters with a larger number density. •Hardness follows the same dependence on fluence, independent of flux.

  10. Irradiation temperature dependence of production efficiency of lattice defects in some neutron-irradiated oxides

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Moritami [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 5900494 (Japan)]. E-mail: okada@rri.kyoto-u.ac.jp; Atobe, Kozo [Faculty of Science, Naruto University of Education, Naruto, Tokushima 7728502 (Japan); Nakagawa, Masuo [Faculty of Education, Kagawa University, Takamatsu, Kagawa 7608522 (Japan)

    2004-11-01

    Temperature dependence of production efficiency of irradiation-induced defects in neutron-irradiated oxides has been investigated. Some oxide single crystals, MgO, {alpha}-Al{sub 2}O{sub 3} (sapphire) and TiO{sub 2} (rutile), were irradiated at several controlled temperatures, 10, 20, 50, 100, 150 and 200 K, using the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL), and at ambient temperature ({approx}370 K) in the same facility. Irradiation temperature dependence of production efficiency of a 1 {mu}m band in TiO{sub 2} differs greatly from that of anion vacancy (F-type centers) in MgO and {alpha}-Al{sub 2}O{sub 3}. Results for MgO and {alpha}-Al{sub 2}O{sub 3} show steep negative gradients from 10 to 370 K, whereas that for TiO{sub 2} includes a valley between 40 and 60 K and a hump at about 130 K, and then disappear at about 200 K. In MgO and {alpha}-Al{sub 2}O{sub 3}, this behavior can be explained by the recombination of Frenkel pairs, which is activated at higher temperature. In TiO{sub 2}, in addition to the recombination mechanism, a covalent bonding property is thought to be exerted strong influence, and it is suggested that a disappearance of the 1 {mu}m band at above 200 K is due to the recombination process of Frenkel pairs which is caused by the irradiation-induced crystallization.

  11. Scanning electron microscopy of mouse intestinal mucosa after cobalt 60 and D-T neutron irradiation

    International Nuclear Information System (INIS)

    Hamlet, R.; Carr, K.R.; Toner, P.G.; Nias, A.H.W.

    1976-01-01

    The stem-cell population of the intestinal crypt is an important model system in experimental radiobiology. Standardized techniques have been developed to allow quantitation of the response of crypt cells to radiation injury following doses of 0 to 2 krad of D-T neutrons or 60 Co γ rays. These techniques rely on the identification of regenerating crypt cells three-and-a-half days after irradiation. The results were expressed as the number of regenerating crypts per circumference of small intestine, as determined by conventional histological examination; the more profound the injury, the smaller the the crypt count. The practical relevance of crypt-counting techniques to clinical radiotherapy is limited by their relative insensitivity; the dose levels commonly used in fractionated radiotherapy produced no detectable response. Scanning electron microscopy of the mucosal surface provided a more sensitive measure of radiation injury. The earliest detectable changes occurred at the level of 300 rad of γ radiation, well below the threshold of the crypt-counting technique. At around 1,000 rad, where the first drop in crypt counts occurred, there were well-marked morphological changes which became more severe with increasing dose levels. Some differences have been observed between the morphological effects of γ and neutron irradiation at points of radiobiological equivalence in terms of crypt counts (using RBE value of about 2). The changes observed may reflect more than the disruption of epithelial cell kinetics. Mucosal morphology is the total expression of many different biological parameters of which the regenerative ability of the crypt cells is only one. The surface microanatomy of the gut may be the most sensitive indicator of radiation injury which is conveniently available for study. (author)

  12. Resistivity recovery of neutron-irradiated and cold-worked thorium

    International Nuclear Information System (INIS)

    Tang, J.T.

    1976-01-01

    Recovery of neutron-irradiated and cold-worked thorium was studied using electrical resistivity measurements. Thorium wires containing 30 and 300 wt ppM carbon were irradiated to fast neutron fluence of 1.3 x 10 18 n/cm 2 (E greater than 0.1 MeV). Another group of thorium wires containing 45, 300 and 600 wt ppM carbon were laterally compressed 5 to 40 percent. Both irradiation and cold-working were performed at liquid nitrogen temperature. The induced resistivity was found to increase with carbon content for both treatments. Isochronal recovery studies were performed in the 120--420 0 K temperature range. Two recovery stages (II and III) were found for both cold-worked and irradiated samples. In all cases the activation energies were determined by use of the ratio-of-slope method. Consistent results were observed for both irradiated and cold-worked specimens within the experimental error in the two stages. Other methods were also used in determining the activation energy of stage III for irradiated samples. All analysis methods indicated that the activation energies decreased with increasing carbon content for differently treated specimens. Possible reasons for such behavior are discussed. The annealing data obtained do not fit a simple chemical rate equation but follow the empirical exponential equation proposed by Avrami. A model of detrapping of interstitials from impurities is suggested for stage II recovery. On the basis of the observed low activation energy and high retention of defects above stage III, a divacancy migration model is proposed for stage III recovery

  13. Vacancies supersaturation induced by fast neutron irradiation in FeNi alloys

    International Nuclear Information System (INIS)

    Lucki, G.; Chambron, W.; Watanabe, S.; Verdone, J.

    1975-01-01

    The void formation in metals and alloys during irradiation with high-energy particles is a problem of interest in physics and of paramount importance in nuclear technology. Voids are formed as a consequence of vacancy supersaturation and result in swelling as well as in changes of mechanical, electrical and magnetic properties of materials used in power reactors. Isothermal annealings were performed between 400 and 500 0 C with and without fast-neutron (1 MeV) irradiation. Pure Fe--Ni (50--50 at. percent) was irradiated in the Melousine reactor in Grenoble, and Fe--Ni(Mo) (50--50 at. percent + 50 ppM), in the IEAR-1 reactor at the Instituto de Energia Atomica in Sao Paulo. The toroidal-shaped specimens were fabricated from Johnson Mathey zone-refined ingots, and were initially annealed at 800 0 C during 1 h in hydrogen atmosphere and then slowly cooled (4 h) inside the furnace. Magnetic After Effect measurements (MAE) permitted the evaluation of activation energies during fast-neutron irradiation (1.54 eV) and without irradiation (3.14 eV) for pure Fe--Ni and respectively (1.36 eV) and (2.32 eV) for Fe--Ni(Mo). Since the time constants of the relaxation process are inversely proportional to the vacancy concentration, a quantitative evaluation of vacancy supersaturation was made; it decreases from the value 700 at 410 0 C to the value 40 at 490 0 C for pure Fe--Ni and from 765 to 121 for Fe--Ni(Mo) in the same temperature range. 3 figures, 5 tables

  14. Effect of low temperature neutron irradiation on the magnetoresistivity in stabilizer materials for a superconducting magnet

    International Nuclear Information System (INIS)

    Nakata, Kiyotomo; Tada, Naobumi; Masaoka, Isao; Takamura, Saburo.

    1985-01-01

    Magnetoresistivity changes caused by neutron irradiation at 5 K, annealing up to 300 K and cyclic irradiation are studied in copper and aluminuim stabilizer materials at 4.2 K. The radiation-induced resistivity in Al is about three times as large as that in Cu, and the resistivities in both Al and Cu are independent of the purity and the degree of cold-work of the samples. The radiation-induced magnetoresistivity of the high purity Cu with R.R.R. (R sub(298 K)/R sub(4.2 K)) of 1400 is larger than that of the impure Cu with R.R.R. of 300 and 280. The magnetoresistivities of the high purity Cu and Al with R.R.R. of 1500 increase with the magetic field. Magnetoresistivity change with the magnetic field in the irradiated Cu mostly follows Kohler's rule, and that in the irradiated Al does not follow the rule at high magnetic fields. By the annealing at 300 K after the irradiation, the radiation-induced resistivity is completely annihilated in the Al, but about 20 % of the resistivity retains in the full-annealed Cu and the retained resistivity is accumulated during the cyclic irradiation. Though the accumulated resistivity in the cold-worked Cu is smaller than that in the full-annealed one, the resistivity before irradiation in the cold-worked samples is very large. From the above results, the full-annealed Cu with R.R.R. of about 300 is considered to be the best material as a stabilizer used under irradiation. (author)

  15. Scanning electron microscopy of mouse intestinal mucosa after cobalt 60 and D-T neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hamlet, R [Belvidere Hospital, Glasgow (UK). Institute of Radiotherapeutics and Oncology; Carr, K R; Toner, P G; Nias, A H.W.

    1976-07-01

    The stem-cell population of the intestinal crypt is an important model system in experimental radiobiology. Standardized techniques have been developed to allow quantitation of the response of crypt cells to radiation injury following doses of 0 to 2 krad of D-T neutrons or /sup 60/Co ..gamma.. rays. These techniques rely on the identification of regenerating crypt cells three-and-a-half days after irradiation. The results were expressed as the number of regenerating crypts per circumference of small intestine, as determined by conventional histological examination; the more profound the injury, the smaller the the crypt count. The practical relevance of crypt-counting techniques to clinical radiotherapy is limited by their relative insensitivity; the dose levels commonly used in fractionated radiotherapy produced no detectable response. Scanning electron microscopy of the mucosal surface provided a more sensitive measure of radiation injury. The earliest detectable changes occurred at the level of 300 rad of ..gamma.. radiation, well below the threshold of the crypt-counting technique. At around 1,000 rad, where the first drop in crypt counts occurred, there were well-marked morphological changes which became more severe with increasing dose levels. Some differences have been observed between the morphological effects of ..gamma.. and neutron irradiation at points of radiobiological equivalence in terms ofCrypt counts (using RBE value of about 2). The changes observed may reflect more than the disruption of epithelial cell kinetics. Mucosal morphology is the total expression of many different biological parameters of which the regenerative ability of the crypt cells is only one. The surface microanatomy of the gut may be the most sensitive indicator of radiation injury which is conveniently available for study.

  16. The effect of helium generation and irradiation temperature on tritium release from neutron irradiated beryllium

    International Nuclear Information System (INIS)

    Kupriyanov, I.B.; Gorokhov, V.A.; Vlasov, V.V.; Kovalev, A.M.; Chakin, V.P.

    2004-01-01

    The effect of neutron irradiation condition on tritium release from beryllium is described in this paper. Beryllium samples were irradiated in the SM reactor with neutron fluence (E > 0.1 MeV) of (0.37-2.0) x 10 22 cm -2 at 70-100degC and 650-700degC. Mass-spectrometer technique was used in out of tritium release experiments during stepped-temperature anneal within a temperature range from 250 to 1300degC. The total amount of helium accumulated in irradiated beryllium samples varied from 521 appm to 3061 appm. The first signs of tritium release were detected at temperature of 406-553degC. It was shown that irradiation temperature and helium generation level significantly affect the tritium release. A fraction of 44 - 74 % of tritium content in samples irradiated at low temperature (70 - 100degC) is release from beryllium at an annealing temperature below 800degC, whereas for samples after high temperature irradiation (650 - 700 degC) tritium release did not exceed 14 %. Majority of tritium (∼68%) is released within a temperature range from 800 to 920 degC. The increase of helium generation from 521 appm to 3061 appm results in lowering the temperature of maximal tritium release rate and the upper temperature of tritium release from beryllium by 100-130degC and 200-240degC, correspondingly. On the basis of data obtained, the diffusion coefficients of tritium in beryllium were calculated. (author)

  17. A Study on the Improvement of Switching Speed of NPT-IGBT by Fast Neutron Irradiation

    International Nuclear Information System (INIS)

    Baek, H. N.; Sun, G. M.; Kim, J. S.; Hoang, S. M. T.; Jin, M. E.; Jin, S. B.; Ahn, S. H.

    2016-01-01

    The insulated gate bipolar transistor (IGBT) has been widely used for high power switching devices due to low on-state forward voltage drop and fast switching speed. But, turn-off delay time occurs due to the tail current generated by the minority carrier existing in the n-drift region during turn-off, which reduces the switching speed. Recently, to mitigate this problem, studies on the control of the MCLT to improve the switching speed of IGBTs are carried out. A crystal defect is formed in the n-drift region of an IGBT to realize a deep energy level within the energy band. The deep level act as the recombination center of the minority carrier to reduce the turn-off delay time and control the lifetime by reducing the lifetime of the minority carrier injected during the device operation. The particle-beam irradiation method, such as electron, proton, fast neutron and others, has been used to control the lifetime of the minority carrier of a silicon power semiconductor device. To improve the switching speed of a IGBT, devices were produced by irradiating various doses of fast neutron, and electrical properties were comparatively analyzed with the IGBT device where before irradiated. The reduced in the lifetime of the minority carrier flowing into the n-drift region due to the crystal defect helps improve the switching speed of the IGBT. But, the resistance component increased due to the crystal defect generated by the fast neutron irradiation in the on-state, increasing of the forward voltage drop. So, to improve and optimize the IGBT performance, appropriate condition should be determined by trading off each electrical properties

  18. The effects of thermal-neutron irradiation on platinum and dilute platinum-gold alloys

    International Nuclear Information System (INIS)

    Piani, C.S.B.

    1978-12-01

    The effect of varying defect concentrations on the recovery spectrum of thermal-neutron-irradiated pure platinum after isochronal anneals was investigated. The dose-independence of substages I(A), I(B) and I(C), and the dose dependence of substage I(D) and I(E), were observed to be in agreement with electron-irradiated studies. The 120 K substage in pure platinum was shown not to be due to interstitial-interstitial reactions, but could possibly be accounted for in terms of detrapping of interstitials from impurities or intrinsic immobile defects. The 360 K stage was shown to shift and was suppressed with increasing defect concentration. The possible conversion of the crowdion to a dumbbell near 160 K in Stage ll in platinum, as predicted by the two-interstitial model, was investigated by consideration of the initial slopes of the production curves between 80 K and 300 K. A minimum in these slopes was observed near 160 K and could be interpreted as due to the conversion of the highly mobile crowdion to an immobile dumbbell at this temperature. The influence of varying gold concentrations on the recovery spectrum of platinum was investigated in dilute platinum-gold alloys. The characteristics of several additional substages in Stage ll, due to the gold alloying were comparable to the results of electron-irradiation experiments. The observations made with regard to the impurity (gold) dependence of these substages could be interpreted in terms of the concentrations of the interstitials, vacancies and impurities present in the material. The interpretation of these substages was found to be consistent, if the recovery spectrum was investigated as a function of defect concentration [af

  19. Material property changes of stainless steels under PWR irradiation

    International Nuclear Information System (INIS)

    Fukuya, Koji; Nishioka, Hiromasa; Fujii, Katsuhiko; Kamaya, Masayuki; Miura, Terumitsu; Torimaru, Tadahiko

    2009-01-01

    Structural integrity of core structural materials is one of the key issues for long and safe operation of pressurized water reactors. The stainless steel components are exposed to neutron irradiation and high-temperature water, which cause significant property changes and irradiation assisted stress corrosion cracking (IASCC) in some cases. Understanding of irradiation induced material property changes is essential to predict integrity of core components. In the present study, microstructure and microchemistry, mechanical properties, and IASCC behavior were examined in 316 stainless steels irradiated to 1 - 73 dpa in a PWR. Dose-dependent changes of dislocation loops and cavities, grain boundary segregation, tensile properties and fracture mode, deformation behavior, and their interrelation were discussed. Tensile properties and deformation behavior were well coincident with microstructural changes. IASCC susceptibility under slow strain rate tensile tests, IASCC initiation under constant load tests in simulated PWR primary water, and their relationship to material changes were discussed. (author)

  20. Alterations in water and electrolyte absorption in the rat colon following neutron irradiation: influence of neutron component and irradiation dose.

    Science.gov (United States)

    Dublineau, I; Ksas, B; Joubert, C; Aigueperse, J; Gourmelon, P; Griffiths, N M

    2002-12-01

    To study the absorptive function of rat colon following whole-body exposure to neutron irradiation, either to the same total dose with varying proportion of neutrons or to the same neutron proportion with an increasing irradiation dose. Different proportions of neutron irradiation were produced from the reactor SILENE using a fissile solution of uranium nitrate (8, 47 and 87% neutron). Water and electrolyte fluxes were measured in the rat in vivo under anaesthesia by insertion into the descending colon of an agarose gel cylinder simulating the faeces. Functional studies were completed by histological analyses. In the first set of experiments, rats received 3.8 Gy with various neutron percentages and were studied from 1 to 14 days after exposure. In the second set of experiments, rats were exposed to increasing doses of irradiation (1-4Gy) with a high neutron percentage (87%n) and were studied at 4 days after exposure. The absorptive capacity of rat colon was diminished by irradiation at 3-5 days, with a nadir at 4 days. The results demonstrate that an increase in the neutron proportion is associated with an amplification of the effects. Furthermore, a delay in the re-establishment of normal absorption was observed with the high neutron proportion (87%n). A dose-dependent reduction of water absorption by rat colon was also observed following neutron irradiation (87%n), with a 50% reduction at 3 Gy. Comparison of this dose-effect curve with the curve obtained following gamma (60)Co-irradiation indicates an RBE of 2.2 for absorptive colonic function in rat calculated at 4 days after exposure.