Calculation of Doppler Coefficient and Other Safety Parameters for a Large Fast Oxide Reactor

Several safety parameters are calculated for a large, fast, Na-cooled, oxide-fueled reactor. The Doppler coefficient is studied as regards its effect on the reactivity during a power excursion, and its dependence on the neutron spectrum, on the concentrations of U/sup 238/, Pu /sup 239/ , a nd Pu/sup 240/, on spatial temperature and power distributions, and on temperature. Other parameters studied include the Na temperature coefficient of reactivity, and the reactivity insertion caused by total Na loss; reactivity coefficients caused by thermal expansion of fuel and steel cladding; the excess operating reactivity; and the reactivity caused by a fuel slump. The effects of a Be reflector on neutron lifetimes are determined. The safety aspects are balanced against economic considerations. (T.F.H.

FAST OXIDE BREEDER-REACTOR. PART I. PARAMETRIC STUDY OF 300(e) MW REACTOR CORE

Physics scoping studies of a 300-Mw(e) PuO/sub 2/-UO/sub 2/-fueled fast- breeder reactor are reported. Physics design parameters that effect fuel costs, full conservation, and reactor safety were evaluated for use in the selection of parameters for a reference design. The total breeding ratio varied from 1.1 to 1.5 in the range of parameters corsidered. Plutonium core loading ranged from 500 to 1500 kg. Doubling time was found to be reduced by high-density fuel and low steel content. A compromise figure on fuel-rod range of sizes (about 100 mils) yields a 5 operating reactivity and a small, negative sodium temperature coefficient. (J.R.D.