9-13 When a spent fuel rod is removed from a reactor core, it is stored in an on-site storage pool of water so that the most intense, short-lived radioactive fission products decay, and the rod is safe for further handling and possible shipment to a reprocessing plant

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Rate of decay = d X N ( N = no . of atoms) where I = decay constant = on 2 ty ty = 5.27 days = 5.27 x 24 x 3600 sec ( given) Now, wer wish the rate of decay to be < 300 mle J Rate of decay < < 3x 3.7 x 10" decays/ sec On 2 AN *0 . 3 X 3 7 x 10 10 5-27 X24X3600 NS 7.29 x 10", atoms This should be the number of atoms of yo' in the sample after storage in the pool of water 7 No of males n = N = 7:29 *10's NA 6.022 X1023 n = 1.21 x 10-8 m = M (M= 133 (et Xe 123) M When fuel rod is placed in water, mass of Xe" was 0. 1% of 30 kg. ) my = 30 g Radioactive decay lane - N = No Q- At = On (m A In 2 t= 5.27 k In 30X106 1.61 In 2 ~ 127.28 days