Analysis on isotopic plutonium barrier based on spent nuclear fuel of LWR

Recycling option of spent nuclear fuels (SFN) from the reactors is one of the hot issues in term of fuel utilization of recycling fuel for extending sustainability of nuclear fuel as well as nuclear non-proliferation because of plutonium utilization. The potential risk of plutonium utilization can be reduced by maintaining the isotopic plutonium barrier. Plutonium barrier can be increased by producing more even-mass plutonium isotopes or by increasing the irradiation time process which can burn much more fissile material in the reactors. The present study intends to analyze some important aspects of isotopic material barrier of plutonium composition based on the composition of spent nuclear fuel of light water reactors (LWRs). Some parameters of material barrier are evaluated such as decay heat (DH) and spontaneous fission neutron (SFN) which depends on plutonium isotopic compositions. The results show that increased production of even-mass plutonium (Pu-238, Pu-240 and Pu-242) can be easily achieved by increasing the burnup level, which also effectively reduces fissile Pu-239 production because more fissile material is consumed. Higher DH from even-mass plutonium can be achieved with higher burnup and longer cooling time because of high contribution of individual decay heat properties of even-mass plutonium especially from Pu-238 contribution. In addition, higher SFN composition can be obtained with a higher burnup level and longer cooling time, which is mainly due to the Pu-240 contribution. Higher burnup and longer cooling time are effective for increasing the even-mass plutonium composition. It is explained that higher irradiation process and cooling times are effective for increasing the proliferation resistance level of plutonium due to the level of even-mass plutonium as well as increasing the decay heat and spontaneous fission neutron as material barrier parameters.