▁P WR s , ▁the ▁neut ron ▁spectrum ▁is ▁not ▁fully ▁thermal ised . ▁The ▁goal ▁of ▁the ▁R M WR ▁is ▁to ▁depart ▁further ▁from ▁the ▁thermal ▁neut ron ▁spectrum ▁in ▁order ▁to ▁achieve ▁a ▁bre eder ▁ratio ▁of ▁slightly ▁greater ▁than ▁one , ▁so ▁that ▁after ▁the ▁initial ▁fuel ▁charge ▁no ▁en rich ment ▁of ▁the ▁u ran ium ▁input ▁to ▁the ▁fuel ▁cycle ▁is ▁required . ▁The ▁R M WR ▁concept ▁is ▁dependent ▁on ▁nuclear ▁fuel ▁re processing ▁in ▁order ▁to ▁achieve ▁its ▁objective ▁of ▁a ▁resource ▁renew able ▁fuel ▁cycle . ▁Hit achi ▁has ▁proposed ▁the ▁F L U O RE X ▁process ▁as ▁re processing ▁technology ▁for ▁this ▁purpose , ▁instead ▁of ▁the ▁more ▁conventional ▁P ure x ▁technology . ▁ ▁In ▁contrast ▁to ▁regular ▁light ▁water ▁react ors ▁and ▁in ▁order ▁to ▁achieve ▁a ▁harder ▁neut ron ▁spectrum , ▁which ▁is ▁optimal ▁for ▁bre eding ▁purposes , ▁the ▁R M WR ▁uses ▁hex ag onal ▁fuel ▁assemb lies ▁and ▁Y - sh aped ▁control ▁ro ds . ▁The ▁fuel ▁is ▁MO X ▁( M ixed ▁Ox ide ), ▁consisting ▁of ▁ 1 8 % ▁plut on ium , ▁which ▁is ▁surrounded ▁by ▁de ple ted ▁u ran ium ▁in ▁the ▁blank et ▁region . ▁ ▁Another ▁R M WR ▁bre eder ▁design ▁int ends ▁on ▁closing ▁the ▁nuclear ▁fuel ▁cycle ▁by ▁mixing ▁thor ium ▁with ▁re process ed ▁trans ur an ics , ▁which ▁include ▁plut on ium , ▁in ▁a ▁thor ium ▁containing ▁MO X ▁fuel