Power stabilization and temporal performance of a peaceful nuclear explosion reactor with a mixture of 90% flibe +10% UF4 (or ThF4)

Abstract

This work investigated the power stabilization and the temporal neutronic behavior of a peaceful nuclear explosion reactor (PACER) with ThF 4 and UF 4 , which produces an electrical energy of 1.2 GW from fusion explosions of 8.13×10 12 J to be repeated every 40 min during the operation period of 30 year. The use of ThF 4 and UF 4 is realized by a mixture zone consisted of flibe and fuel, instead of full flibe zone. The mixture compositions determined by volume fraction are 90% flibe +10% UF 4 , 90% flibe +10% ThF 4 and 90% flibe +5% UF 4 +5% ThF 4 . The capacity factor of the reactor is 0.75. The cylindrical explosion chamber has a radius of 30 m and a height of 75 m. The mixture mass of 18,000 tonnes having a zone thickness of 5 m were circulated during the operation period. The mixture zone would be subdivided into jets so that the gas and the vapor bypasses the liquid as it vents and does not accelerate the liquid mixture to high velocities. The selected volume fraction is 75% void +25% mixture. The use of fuel materials in the PACER reactor resulted in high-energy production, sufficient tritium breeding and significant fissile fuel breeding. The averages of tritium breeding ratio (TBR) values over 30 years are between 1.1 and 1.17. Generally, the mixtures with UF 4 show better performance than the mixture with ThF 4 . For the mixtures with ThF 4 , ThF 4 +UF 4 and UF 4 , the energy production without the separation process reached from ≈1430 MW (electric), ≈1700 MW (electric) and ≈2000 MW (electric) to ≈1900 MW (electric), ≈2150 MW (electric) and ≈2320 MW (electric), respectively. The reached cumulative fissile fuel enrichments in the fuel (CFFE) in percentage are 1.8, 2.45 and 2.4%, respectively. The fuel obtained from the PACER could be used as a nuclear fuel only in the CANDU and the advanced CANDU. In addition, the stabilization process is performed by means of the plutonium or uranium fuel separation from the mixture, after the energy output of the reactor reaches 1600 MW (electric), 1800 MW (electric) and 2000 MW (electric) at the operation periods of 11, 6 years and 2 months, respectively. At the end of the separation process, the separated fuel amounts are about 15, 374 and 11 tonnes, respectively. The CFFE values of the separated fuel at the end and at the start up of the separation process are 99.36 and 99.23%, 1.13 and 3.9%, and 99.99 and 99.2%, respectively. The CFFE values of the remained fuel at the end of the separation process are ≈0.7, and 2.2%, ≈0.7%, respectively. Consequently, in the evaluation in terms of sufficient tritium breeding, high energy production, significant fissile fuel production and the nuclear weapon hazard of the fuel, the mixture of 90% flibe +5% ThF 4 +5% UF 4 exhibited the highest performance.