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U.S. Department of Energy
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Neutron exposure parameters for the fifth heavy section steel technology irradiation series

Technical Report ·
OSTI ID:5278294

The NRC's Heavy Section Steel Technology (HSST) Program is concerned with the investigation of cracklike flaws in reactor pressure vessel steels. In the fifth irradiation series, capsules containing a variety of metallurgical test specimens were irradiated to fluences in the range of 1 . 10/sup 19/ to 3 . 10/sup 19/ neutrons/cm/sup 2/ (E > 1.0 MeV). In order to correlate radiation embrittlement to damage fluences, accurate determination of the neutron fluence spectra at the critical location of the test specimen is needed. The part of the neutron spectrum which is responsible for the radiation damage is characterized as ''damage exposure parameter.'' Fluences for energies greater than 1.0 MeV (F > 1.0 MeV) is the most widely used parameter; however, current thinking favors displacements per atom (dpa) in iron as better related to the physical mechanism of radiation damage. Fluences for energies greater than 0.1 MeV (F > 0.1 MeV) are also considered since neutrons in the 0.1 and 1.0 MeV range are likely to contribute to the damage. In order not to prejudice future investigations, all three damage parameters F > 1.0, MeV F > 0.1 MeV, and dpa are listed in this report.

Research Organization:
Oak Ridge National Lab., TN (USA)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
5278294
Report Number(s):
NUREG/CR-4284; ORNL/TM-9664; ON: TI85014207
Country of Publication:
United States
Language:
English