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Title: High Conduction Neutron Absorber to Simulate Fast Reactor Environment in an Existing Test Reactor

A need was determined for a thermal neutron absorbing material that could be cooled in a gas reactor environment without using large amounts of a coolant that would thermalize the neutron flux. A new neutron absorbing material was developed that provided high conduction so a small amount of water would be sufficient for cooling thereby thermalizing the flux as little as possible. An irradiation experiment was performed to assess the effects of radiation and the performance of a new neutron absorbing material. Neutron fluence monitors were placed inside specially fabricated holders within a set of drop-in capsules and irradiated for up to four cycles in the Advanced Test Reactor. Following irradiation, the neutron fluence monitor wires were analyzed by gamma and x-ray spectrometry to determine the activities of the activation products. The adjusted neutron fluences were calculated and grouped into three bins – thermal, epithermal and fast to evaluate the spectral shift created by the new material. Fluence monitors were evaluated after four different irradiation periods to evaluate the effects of burn-up in the absorbing material. Additionally, activities of the three highest activity isotopes present in the specimens are given.
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0236-5731; 830403000
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Radioanalytical and Nuclear Chemistry; Journal Volume: 302; Journal Issue: 1
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
Country of Publication:
United States
Reactor dosimetry, advanced test reactor, Al3Hf shielding