DOE-HDBK-1019/2-93Reactor Theory (Nuclear Parameters)SAMARIUM AND OTHER FISSION PRODUCT POISONSSAMARIUM AND OTHER FISSION PRODUCT POISONSThe fission product poison that has the most significant effect on reactoroperations other than xenon-135 is samarium-149. Samarium-149 behavessignificantly different from xenon-135 due to its different nuclear properties. EO 4.10DESCRIBE how samarium-149 is produced and removed fromthe reactor core during reactor operation.EO 4.11STATE the equation for equilibriumsamarium-149concentration.EO 4.12DESCRIBE how equilibrium samarium-149 concentrationvaries with reactor power level.EO 4.13DESCRIBE how samarium-149 concentration changes followinga reactor shutdown from steady-state conditions.EO 4.14DESCRIBE how samarium-149 concentration changes followinga reactor startup.EO 4.15STATE the conditions under which helium-3 will have asignificant effect on the reactivity of a reactor.Productionand Removalof Samarium-149Samarium-149 is the second most important fission-product poison because of its high thermalneutron absorption cross section of 4.1 x 104 barns. Samarium-149 is produced from the decayof the neodymium-149 fission fragment as shown in the decay chain below.14960Ndb1.72 hr14961Pmb53.1 hr14962Sm (stable)Rev. 0NP-03Page 43
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business