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81. 发明专利

JPS63298193A FAST BREEDER REACTOR 失效
公开(公告)号：JPS63298193A
公开(公告)日：1988-12-05
申请号：JP13390287
申请日：1987-05-29
申请人： NIPPON ATOMIC IND GROUP CO , TOSHIBA CORP
发明人： KAWASHIMA MASATOSHI
IPC分类号： G21C3/60 , G21C7/00
摘要： PURPOSE:To improve safety in regard to a reactor core operation by regarding a part of start-up rods operated in the time of start-up in control rods as ones for neutron moderation and so reducing influence by Doppler effect. CONSTITUTION:Start-up rods indicated by mark N, operating rods indicated by mark P and safety rods indicated by mark S are arranged in a reactor core part 11. The start-up rods N is the control rods for neutron moderation constituted of neutron moderators such as Be and ZrH. The operating rods P is the control rods for neutron absorption composed of neutron absorbers such as B4C. Thus, a neutron spectrum in the reactor core is shifted to a low energy side by the neutron moderation effect of the start-up rods N. Therefore, negative reactivity application is heightened by Doppler effect, and inherent safety of a reactor can be secured.

82. 发明专利

JPS63293487A FUEL ASSEMBLY 失效
公开(公告)号：JPS63293487A
公开(公告)日：1988-11-30
申请号：JP13036987
申请日：1987-05-27
申请人： NIPPON ATOMIC IND GROUP CO , TOSHIBA CORP
发明人： KAWASHIMA MASATOSHI
IPC分类号： G21C3/28
摘要： PURPOSE:To improve the safety of a reactor core operation by providing neutron moderating layers into the upper part of the metal fuel elements in fuel rods in a part of a fuel assembly. CONSTITUTION:The neutron moderating layers are provided on the upper part of a part of the fuel rods sealed therein with the metal fuel elements 3 by disposing a material 4 contg. a neutron moderating material such as beryllium to said upper part. The neutron spectra in the upper part of the reactor core where a fuel temp. is high and a Doppler effect is large are thereby softened and the impression of the negative reactivity by the Doppler effect is enhanced. The negative feedback effect in isothermal coefft. and output coefft. is, therefore, intensified and the safety with the reactor core operation is improved.

83. 发明专利

JPS63277995A FUEL ASSEMBLY 失效
公开(公告)号：JPS63277995A
公开(公告)日：1988-11-15
申请号：JP11227987
申请日：1987-05-11
申请人： NIPPON ATOMIC IND GROUP CO , TOSHIBA CORP
发明人： KAWASHIMA MASATOSHI
IPC分类号： G21C3/60
摘要： PURPOSE:To enhance bleedability and to prolong the period of operation cycles by decreasing the amt. of the additive metals to be added to metallic fuel while preventing generation of an eutectic phenomenon. CONSTITUTION:The content of the additive metals such as zirconium, molybdenum and titanium to be added to the metallic fuel 12 consisting of metallic uranium, uranium-plutonium alloy, etc., is so specified that the content of the zirconium is decreased to 10% in the half part on a coolant outlet side and to 5% in the half part on the coolant inlet side. The content distribution may be the reversal stepped or curved shape. Since the content of the additive metals can be thereby made lower than the fuel assembly having the content of the additive metals uniform over the entire part, the density of fissionable atoms can be increased and the bleedability is improved; in addition, the period of the operation cycles is prolonged. The content is made lower on the coolant inlet side than on the coolant outlet side where the temp. distribution of fuel clad pipes is high and, therefore, the generation of the eutectic phenomenon is prevented as well.

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