Radiological Safety Experience in the Fabrication of Alloy Plate Fuels Bearing<sup>233</sup>U/Pu

Bhagwat, A.M.; Kamath, K. V.; Kutty, K. Narayan; Naik, G. R.; Narayan, K. K.; Pillai, Prakash Rajappan; Prasad, G.; Ganguly, C.

doi:10.13182/nt93-a34846

Cited by 1 publication

(1 citation statement)

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“…7 In the meantime, a 1993 article from the Bhabba Atomic Research Center in Bombay reported a 6.7 person-rem summed dose incurred by workers fabricating a research-reactor core containing 0.6 kg "clean" U-233 containing 3 ppm U-232. 8 Interest in U-233 as a Reactor Fuel One reason for interest in U-233 as a reactor fuel is the superior conversion ratios Cp that can be achieved with it in slow-neutron reactors. 9 It will be seen from Table 1 that about 0.2 more neutrons are produced on average per "thermal" (20 °C or 0.025 eV) neutron absorbed on U-233 than for absorption in Pu-239.…”

Section: U-232 Radiation Hazardmentioning

confidence: 99%

U‐232 and the proliferation‐resistance of U‐233 in spent fuel

Kang¹,

Hippel²

2001

Science & Global Security

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The factors influencing the level of U-232 contamination in U-233 are examined for heavy-water-moderated, light-water-moderated and liquid-metal cooled fast breeder reactors fueled with natural or low-enriched uranium and containing thorium mixed with the uranium or in separate target channels. U-232 decays with a 69-year half-life through 1.9-year half-life Th-228 to T1-208, which emits a 2.6 MeV gamma ray upon decay.We find that pressurized light-water-reactors fueled with LEU-thorium fuel at high burnup (70 MWd/kg) produce U-233 with U-232 contamination levels of about 0.4 percent. At this contamination level, a 5 kg sphere of U-233 would produce a gammaray dose rate of 13 and 38 rem/hr at 1 meter one and ten years after chemical purification respectively. The associated plutonium contains 7.5 percent of the undesirable heat-generating 88-year half-life isotope Pu-238.However, just as it is possible to produce weapon-grade plutonium in low-burnup fuel, it is also practical to use heavy-water reactors to produce U-233 containing only a few ppm of U-232 if the thorium is segregated in "target" channels and discharged a few times more frequently than the natural-uranium "driver" fuel. The dose rate from a 5-kg solid sphere of U-233 containing 5 ppm U-232 could be reduced by a further factor of 30, to about 2 mrem/hr, with a close-fitting lead sphere weighing about 100 kg.Thus the proliferation resistance of thorium fuel cycles depends very much upon how they are implemented.

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Section: U-232 Radiation Hazardmentioning

confidence: 99%