Radiation embrittlement of Spanish nuclear reactor pressure vessel steels

Book · Wed Dec 01 04:00:00 EST 1993

OSTI ID:139990

Bros, J; Ballesteros, A; Lopez, A ^[1]

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1. Tecnatom, Madrid (Spain)

Commercial pressurized water reactor (PWR) and boiling water reactor (BWR) nuclear power plants contain a series of pressure vessel steel surveillance capsules as the principal means of monitoring radiation effects on the pressure vessel. Changes in fracture toughness are more severe in surveillance capsules than in reactor vessel materials because of their proximity of the reactor core. Therefore, it is possible to predict changes in fracture toughness of the reactor vessel materials. This paper describes the status of the reactor vessel surveillance program relating to Spanish nuclear power plants. To date, twelve capsules have been removed and analyzed from seven of the nine Spanish reactors in operation. The results obtained from the analysis of these capsules are compared with the predictions of the Nuclear Regulatory Commission (NRC) Regulatory Guide 1.99, Rev. 2, by means of measured and expected increase of the nil-ductility transition reference temperature (RT{sub NDT}). The comparison is made considering the different variables normally included in the studies of radiation response of reactor pressure vessel materials, such as copper content of steel, level of neutron fluence above 1 MeV, base metal or weld metal, and so forth. The surveillance data have been used for determining the adjusted reference temperatures and upper shelf energies at any time. The results have shown that the seven pressure vessels are in excellent condition to continue operating with safety against brittle fracture beyond the design life, without the need to recuperate the degraded properties of the materials by annealing of the vessel.

• OSTI ID: 139990
• Report Number(s): CONF-9009544--; ISBN 0-8031-1478-8
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
EMBRITTLEMENT
EXPERIMENTAL DATA
FRACTURE PROPERTIES
IRRADIATION CAPSULES
MONITORING
NEUTRON FLUX
NUCLEAR POWER PLANTS
PHYSICAL RADIATION EFFECTS
PRESSURE VESSELS
STEELS
SURVEILLANCE
WATER COOLED REACTORS