SHIELDING PROPERTIES OF ORDINARY CONCRETE AS A FUNCTION OF TEMPERATURE
The effect of high temperature on neutron attenuation in concrete was determined. The fast neutron attenuation was exponential and could be adequately predicted using re moval theory. The calculated removal cross sections agreed with the measured values to within 3%. Tests indicated that even after penetrating 47.5 in. of concrete the thermal and resonance neutron fluxes had not reached equilibrium with the fast neutron flux. Significant changes in neutron flux values were observed after the concrete was baked at 100, 200, and 300 deg C. A combination of removal and age theories adequately predicted the increase in the fast, resonance, and thermal neutron fluxes. The measured relaxation lengths and removal cross sections are summarized. Changes in reflector and thermal shield thickness or composition from test values would affect the relaxation length. The shield facility was calibrated so that removal cross sections can be measured. The dose rate generated through the full thickness of the as-cured specimens was primarily due to the fast neutrons. After the concrete was baked at 300 deg C, the dose rate was a result of resonance neutron leakage. The gamma dose rate was measured through 47.5 in. in the 100 deg C test only. The data indicated that the biological dose rate through 47.5 in. of concrete is primarily due to gamma leakage at this temperature. (auth)
- Research Organization:
- General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
- DOE Contract Number:
- AT(45-1)-1350
- NSA Number:
- NSA-15-012407
- OSTI ID:
- 4073065
- Report Number(s):
- HW-65572
- Country of Publication:
- United States
- Language:
- English
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