Production of Np237 and Pu238 in Thermal Power Reactors

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PRODUCTION OF NP237A N D PU238 IN T H E R M A L POWER REACTORS D .

R . V O N D Y , J. A.

Onk Rid?? Yniionni Laboratory. O ak

L A N E , A N D A. T. G R E S K Y

RidqP. I mn.

The production of Np217and Pu23xwas calculated for present-generation reactors. Results indicate that Np2" production now averages about 3 kg. per year per 1000 Mw(th) (at 0.8 plant factor); it was estimated ~ cross section i s about three that 100 kg. per year would b e produced in 1975. Because the P u * ? capture times that of Np217,high efficiency for conversion of N p 2 " to Pu'ih requires removal of the product after relative short exposures. The maximum conversion of Np2j' to PuZJhin a single exposure i s about 20y0, but b y recycling the Np, over-all conversion of 50 to

60y0can b e realized.

~ b use . of Puzn8as a heat soiirce for space power applications temperature and fast-to-thermal flux ratio. T h e high fast Tis of interest because of its very desirable nuclear decay flux level is favorable because of resonance captures, especially properties relative to more conventional radioisotopes. hsn@ in L-23fi. .4 high thermal temperature is favorable because a t a emits 3.4 m.e.v. alpha particles a n d has a half life of 89.0years. given flux level the cT23fi resonance capture rate remains constant? \vhereas Lvith the lower thermal cross sections, the UZ3j 11 is Lvorth nearly as much per unit \