SEDL / STP / STP1170-EB / STP24764S

Surveillance Data on Neutron Embrittlement of Modern Low-Sensitivity Steel

Najžer, M
Research counselor; headresearch assistant; research associate; and research assistant, University of Ljubljana, “Jožef Stefan” Institute, Ljubljana

Glumac, B
Research counselor; headresearch assistant; research associate; and research assistant, University of Ljubljana, “Jožef Stefan” Institute, Ljubljana

Loose, A
Research counselor; headresearch assistant; research associate; and research assistant, University of Ljubljana, “Jožef Stefan” Institute, Ljubljana

Remec, I
Research counselor; headresearch assistant; research associate; and research assistant, University of Ljubljana, “Jožef Stefan” Institute, Ljubljana

Trandafir, A
Research counselor; headresearch assistant; research associate; and research assistant, University of Ljubljana, “Jožef Stefan” Institute, Ljubljana

Pages: 8    Published: Jan 1993

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Abstract

The reactor pressure vessel of the Krško Nuclear Power Plant, a two-loop 632-MWe pressurized water reactor, is made of SA 533 grade B class 1 steel plate welded by wire type B-4 Linde 0091. Copper content of both metals is low. Results of impact testing of reactor pressure vessel specimens from the first two withdrawn surveillance capsules are reported. Neutron exposure of the capsules was near 1 and 3 ⋅ 10¹⁹ ncm^-2 E > 1 MeV, respectively. The exposure rate was around 1.5 ⋅ 10¹¹ n s^-1 cm^-2 E > 1 MeV. Measured shifts in nil ductility temperature and impact upper shelf energy are compared with predictions of Nuclear Regulatory Commission (NRC) Regulatory Guide RG 1.99 Rev. 2. Nil ductility temperature shifts are in good agreement for base metal, whereas they are underpredicted for weld. Small or negligible upper shelf energy shifts were observed. Instrumented impact testing data are analyzed. Results are compared with a recent analysis of instrumented data from the power reactor embrittlement database.