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Title: The influence of low dose neutron irradiation on the thermal conductivity of Allcomp carbon foam

Oak Ridge National Laboratory was contracted via a Work for Others Agreement with Allcomp Inc. (NFE-14-05011-MSOF: Carbon Foam for Beam Stop Applications ) to determine the influence of low irradiation dose on the thermal conductivity of Allcomp Carbon Foam. Samples (6 mm dia. x 5 mm thick) were successfully irradiated in a rabbit capsule in a hydraulic tube in the target region of the High Flux Isotope Reactor at the Oak Ridge National Laboratory. The specimens were irradiated at Tirr = 747.5 C to a neutron damage dose of 0.2 dpa. There is a small dimensional and volume shrinkage and the mass and density appear reduced (we would expect density to increase as volume reduces at constant mass). The small changes in density, dimensions or volume are not of concern. At 0.2 dpa the irradiation shrinkage rate difference between the glassy carbon skeleton and the CVD coating was not sufficient to cause a large enough irradiation-induced strain to create any mechanical degradation. Similarly differential thermal expansion was not a problem. It appears that only the thermal conductivity was affected by 0.2 dpa. For the intended application conditions, i.e. @ 400 C and 0 DPA (start- up) the foam thermal conductivitymore » is about 57 W/m.K and at 700 C and 0.2 DPA (end of life) the foam thermal conductivity is approx. 30.7 W/m.K. The room temp thermal conductivity drops from 100-120 W/m.K to approximately 30 W/m.K after 0.2 dpa of neutron irradiation.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1244203
Report Number(s):
ORNL/TM--2016/103
453060031; TRN: US1601040
DOE Contract Number:
AC05-00OR22725
Resource Type:
Technical Report
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; THERMAL CONDUCTIVITY; ATOMIC DISPLACEMENTS; NEUTRONS; RADIATION DOSES; FOAMS; CARBON; IRRADIATION; DENSITY; THERMAL EXPANSION; MASS; SHRINKAGE; STRAINS; TEMPERATURE RANGE 1000-4000 K; TEMPERATURE RANGE 0400-1000 K; PHYSICAL RADIATION EFFECTS carbon foam; radiation damage