Research Manager, AB åkers Styckebruk, åkers Styckebruk,
Research Metallurgist, Structural Materials Laboratory, Aktiebolaget Atomenergi, Studsvik, Nyköping
Pages: 24 Published: Jan 1969
Steam-cooled fast reactor pressure vessels must withstand high pressures (130–230 atm) and high neutron doses, for example, 5 × 10 20 n/cm 2 (>1 MeV). Two new steels have been investigated, a 16 Cr-5 Ni-1 Mo steel (Avesta 248 SV) and a 13 Cr-6 Ni-1.5 Mo steel (Bofors 2 RMO). Their tensile strengh is above 70 kg/mm2 at 300 C. The steels are unusually tough at low temperatures, and there is no sharp brittle-to-ductile transition. Various properties of the steels are described.
Impact and tension specimens have been irradiated in two thermal reactors at 60 to 550 C. After 3.2 × 1019 n/cm2 (>1 MeV) at 265 C, the temperature at 4.2 kg-m impact energy has been increased 100 C to —90 C. Tension tests show a small decrease or an increase in ductility because of irradiation.
To draw conclusions from these experiments the differences in neutron spectra between the materials testing reactors and the fast reactor vessel have to be taken into account. This problem is discussed for two types of damage: displacement damage and transmutation damage. In the former case, an attempt is made to use different damage theories for an engineering type of estimate of the maximum difference between irradiation effects in the two types of spectra. In the later case, an analysis of the transmutation reactions is made.
irradiation, steel, pressure vessel, fast reactors (nuclear), tension test, impact test, fracture, displacement damage, transmutations, evaluation
Paper ID: STP41847S