Tensile properties of modified 316 stainless steel (PNC316) after neutron irradiation over 100 dpa

Yano, Yasuhide; Uwaba, Tomoyuki; Tanno, Takashi; Yoshitake, Tsunemitsu; Otsuka, Satoshi; Kaito, Takeji

Journal of Nuclear Science and Technology, 9 Pages, 2023/00

https://doi.org/10.1080/00223131.2023.2243943

The effects of fast neutron irradiation on tensile properties of modified 316 stainless steel (PNC316) claddings and wrappers for fast reactors were investigated. PNC316 claddings and wrappers were irradiated in the experimental fast reactor Joyo at irradiation temperatures between 400 and 735 C to fast neutron doses ranging from 21 to 125 dpa. The post-irradiation tensile tests were carried out at room and irradiation temperatures. Elongations of PNC316 measured by the tensile tests were maintained at an engineering level, although the material incurred significant irradiation hardening and softening. The maximum swelling of PNC316 wrappers was about 2.5 vol.% at irradiation temperature between 400 and 500C up to 110 dpa. Japanese 20% cold-worked austenitic steels, PNC316 and 15Cr-20Ni, had sufficient ductility and work-hardenability even after above 10 vol.% swelling, while they had very weak plastic instabilities.

Post irradiation examination of (U,Pu) C and (U,Pu) N fuel for fast reactor; Non-destructive examination result of the fuel pin

; ; ; Matsumoto, Shinichiro

JNC TN9410 2000-009, 65 Pages, 2000/09

JNC-TN9410-2000-009.pdf:4.36MB

In order to evaluate irradiation behavior of(U, Pu) C and (U, Pu) N fuel using fast reactor, (U, Pu) C and (U, Pu) N fuel pins were irradiated in JOYO for the fist time in Japan. In this study, one (U, Pu) C fuel pin and two (U, Pu) N fuel pins were irradiated to maximum burn up about 40GWd/t. Post irradiation examination of (U, Pu) C and (U, Pu) N fuel pins started in Fuel Monitoring Facility (FMF) at JNC from October 1999, and it ended in March, 2000. The results of non-destructive post irradiation examination reported in this document. Main results are shown in the following. (1)The soundness of all (U,Pu) C and (U,Pu) N fuel pins were confirmed from the non-destructive examination result. (2)The fuel stack elongation of (U,Pu) C and (U,Pu) N is bigger than it of the MOX fuel for fast reactor. (3)The singular behavior from the gamma ray scanning measurement in the stack area was not confirmed. The migration of Cs137 to lower insulator pellet and outside of the pellet was confirmed in (U,Pu) N B9NO2 pin. In (U,Pu) C fuel, the migration of Cs137 was not confirmed. (4)In (U,Pu) C B9CO1 pin and (U,Pu) N B9NO2 pin in which the gap width was small, diameter of cladding increase around 50 m in the stack area which originates for FCMI was confirmed. In (U,Pu) N B9NO1 pin in which the gap width was wide, the ovality which originates from the relocation of the pellet was confirmed. (5)Fission gas release rate of (U,Pu) N were 3.3% and 5.2%, and the low value compared to the MOX fuel was shown.

Evaluation for the transient Burst property of austenitic steel fuel Claddings irradiated as the MONJU type Fuel Assemblies (MFA-1&MFA-2)in FFTF

; ; Sakamoto, Naoki; *; Akasaka, Naoaki;

JNC TN9400 2000-095, 110 Pages, 2000/07

JNC-TN9400-2000-095.pdf:13.57MB

The effects of high fluence irradiation and swelling on the transient burst properties of austenitic steel fuel claddings; PNC316 and 15Cr-20Ni stcel, which were irradiated as the MONJU type fuel assemblies (MFA-1&MFA-2) in the FFTF reactor, were investigated. The temperature-transient-to-burst tests were conducted on a total of eight irradiation conditions. Fractographic examination and TEM observation were performed in order to evaluate the effect of high dose irradiation on the transient burst property and the relation between failure mechanism and microstructural change during rapid (ramp) heating. The results of the PIE showed that there was no significant effect of irradiation on the transient burst properties of these fuel claddings under the irradiation conditions examined. the results obtained in this study are as follows; (1)The rupture temperature of the irradiated PNC316 fuel cladding of MFA-1 was as same as that of our previous works for the fluence range up to 2.1310 n/m. There was no noticeable decrease in rupture temperature with increasing fluence in lower hoop stress region(100MPa). (2)The rupture temperature of the irradiated 15Cr-20Ni fuel cladding of MFA-2 was almost as same as that of as-received cladding for the hoop stress range up to about 200MPa. The rupture temperature did not decrease significantly with fluence. (3)The rupture temperature of the irradiated PNC316 cladding tested at hoop stress 69MPa, which was the design hoop stress for MONJU fuel, was 1055.6C. This suggested that the design cladding maximum temperature limit for MONJU (830C) was conservative. (4)There was no obvious relation between rupture temperature, swelling and microstructural change during transient heating under the irradiation conditions examined.

JOYO MK-II core plant characteristics test data

JNC TN9410 2000-010, 72 Pages, 2000/03

JNC-TN9410-2000-010.pdf:2.14MB

The experimental fast reactor JOYO served as the MK-II irradiation bed core for testing fuel and material for FBR development for 16 years from 1982 to 1997. During the MK-II core operation, extensive data were accumulated from the plant characteristic tests. Tests conducted at JOYO included operating characteristic tests for confirming operational safety, performance tests for confirming design performance of the MK-II core, and special tests for research and development ofthe plant. In this report, the outline and the results of each test item are shown. These test data can be provided by the magnet-optical disk.

Development of JOYO plant operation management expert Tool (JOYPET)

; Terano, Toshihiro; ; ; Okubo, Toshiyuki

JNC TN9410 2000-004, 30 Pages, 2000/03

JNC-TN9410-2000-004.pdf:0.86MB

The Operation and Maintenance Support Systems for JOYO are being developed, with the aim of ensuring the stable and safe operation of JOYO and improving operational reliability of future FBR plants. Plant Operation Management Expert Tool named JOYPET had been developed as one of the Operation and Maintenance Support Systems, which helps plant operation management. The following functions were developed and applied. (1)Papers management (Plant status management) function for maintenance activities (2)Isolation management support function for plant operation (3)Automatically drawing function of plant operation schedule (4)Isolation judgment function for plant operation By use this system, the plant management of JOYO was able to improved reliability and reduced manpower.

Study on improvement of reactor physics analysis method for FBRs with various core concept

*; Kitada, Takanori*; Tagawa, Akihiro; *; Takeda, Toshikazu*

JNC TJ9400 2000-006, 272 Pages, 2000/02

JNC-TJ9400-2000-006.pdf:9.69MB

Investigation was made on the follwing three themes as a part of the improvement of reactor physics analysis method for FBR with various core concept. Part 1: Investigation of Error Estimation of Neutron Spectra in FBR and Suggestions to Improve the Accuracy. In order to improve the spectrum unfolding method used in fast experimental reactor JOYO, a trial was made to evaluate the error in the estimated neutron spectrum, cause by cause. And the evaluated errors were summed up to obtain the most probable and reasonable error as possible. The summed up error was found relatively small compared to the error caused by the uncertainty of cross section data: most of the error in the spectrum unfolding method can be attributed to the error in cross sections. It was also found that the error due to the fission spectrum causes a considerable error in the high energy neutron spectrum which is over several MeV. Part 2: Study on Reactor Physics Analysis Method for Gas-Cooled FBR. In gas-cooled FBR, the portion of coolant channels in core volume is larger than sodium-cooled FBR. This leads to strong neutron streaming effects. For sodium-cooled FBR, several methods were proposed to evaluate the neutron streaming effect, however, these methods can not be used directly to gas-cooled reactor because the direction dependent diffusion coefficient becomes infinitive along the direction pararel to the coolant chammel. In this study, a new method is proposed to evaluate the neutron streaming effect, based on the method taking the axial buckling into consideration, which method was originally proposed by Khler. Part 3: Study on Reactor Physics Analysis Method for Water-Cooled FBR An investigation was made on low-moderated water-cooled FBR, on the point that the ordinary used analysis method for FBR may give considerable difference in results in such core. In light water reactors, it is well known that the space dependence of self-shielding effect of heavy nuclides are considerably ...

Report of radiation exposure control on the 12th periodic inspection at experimental fast reactor JOYO

; Kano, Yutaka; ; Shindo, Katsutoshi

JNC TN9410 2000-001, 20 Pages, 1999/12

JNC-TN9410-2000-001.pdf:1.84MB

The 12th periodic inspection had been executed at the experimental fast reactor JOYO from February 24,1998 to June 28,1999. This inspection had been extended about three months because it was addtion to the work for the safety countermeasure. The result of collective dose equivalent was 263.92 man*mSv, whereas, the expected collective dose equivalent was about 407 man*mSv in the whole period of this inspection. It was confirmed that this inspection was carried out with the suitable radiation protection programmes. In this report, provided in 12th periodic inspection, were described with taking the results of the past periodic inspections into consideration.

Fabrication of uranium-plutonium mixed carbide and nitride fuel pins for the irradiation test in JOYO

Arai, Yasuo; Iwai, Takashi; ; Okamoto, Yoshihiro; Shiozawa, Kenichi;

JAERI-Research 96-009, 17 Pages, 1996/02

JAERI-Research-96-009.pdf:1.09MB

no abstracts in English

Operation experience report of experimental fast reactor JOYO; Operation expelience of primary main and auxiliary cooling systems of JOYO

Karube, Koji; ; ; ; Kawai, Masashi;

PNC TN9440 93-012, 83 Pages, 1993/04

PNC-TN9440-93-012.pdf:5.27MB

This report describes the operating experience of the primary main cooling system from January 1982 to March 1992, and of the primary auxiliary cooling system from october 1986 to March 1992. 0ut lines of the operating experience ale followings; There have been no serious troubles in this period. (1)The main system; Operation time of the circulation pumps are about 67675 hours. Accumulated operation time of the pumps are about 105970 hours. The pumps has been started 212 times. (2)The auxiliary system; Operation time of the circulation pump (EMP) is about 4767 hours. Accumulated operation time of the pump is about 8667 hours. The pump has been automatically started 31 times with the scheduled test.

Bowing reactivity analysis of FFTF core

Yamaoka, Mitsuaki; Hayashi, Hideyuki

PNC TN9410 92-368, 75 Pages, 1992/12

PNC-TN9410-92-368.pdf:1.49MB

A passive safety test phase IIB is planned at the FFTF (Fast Flux Test Facility) core to assess the reactivity feedback effect related to passive safety feature of FBRs, especially the effect due to core deformation. For pre-test analyses of the test, a bowing reactivity analysis has been carried out for FFTF core. The bowing reactivity is analyzed based on core displacement data evaluated postulating ULOF (Unprotected Loss of Flow) event at 30% rated flow. In the analysis, fuel reactivity worth distribution is expressed as function on the reference core without deformation and the bowing reactivity is calculated based on the first-order perturbation theory. This report summarizes the relationships between power to flow ratio and the bowing reactivity with clearance between subassembly load pads and that between the core and the core restraint system as parameters. Followings are main results. (1)As the power to flow ratio increases, a positive reactivity is added to the core by the core deformation until clearance between subassembly load pads doses. This is due to the inward displacement of active core caused by mechanical interactions of subassemblies. (2)After the closure of clearance between subassembly load pads, the active core begins to move outwards, and a negative reactivity is added to the core. (3)The deformation behavior of the outermost subassemblies of the core dominates the bowing reactivity since both the magnitude of deformation and the reactivity effect for unit displacement are large compared with those of others. For the analysis, a code for bowing reactivity calculation has been developed. The calculation method and the manual are also presented in this report.