Evaluation of gamma-ray transport effect on heating distribution in a fast reactor fuel subassembly

Chiba, Go

We evaluate a gamma-ray transport effect on a heating distribution in a fast reactor fuel subassembly by gamma-ray transport calculations. We carry out calculations by using a gamma cross section library UFGLIB.J40 based on the latest nuclear data file JENDL-4.0 and a radiation transport code system CBG which is under development at Japan Atomic Energy Agency. Numerical calculations with a Monju fuel subassembly model reveal that a heating rate in a fuel pin decreases about 1.35% by considering a gamma-ray transport. In addition, the uncertainty of this gamma-ray transport effect is estimated at 0.25%. It is also shown that a heating rate in a region inside of a wrapper tube decreases about 0.5% by considering the gamma-ray transport.