Measurement of carbon-14 activity in spent ion-exchange resin or Wolsong nuclear power plant

Measurement of spent resin activity was initiated in 2004 in order to develop the C-14 removal technology for safe disposal. As part of this program, spent resins were sampled and measured in the in-station resin storage tank 2 at Wolsong Nuclear Power Plant Unit 1. At the time of sampling, the resins had been in storage tank from 3 to 23 years. Total 72 resin samples were sampled, which were collected from both man-hole (68 samples) and test-hole (4 samples) in the in-station resin storage tank 2. They were separated into liquid, activated carbon, zeolite, and spent resin. The spent resins were oxidized with sample oxidizer and analyzed for C-14. Ten of collected mixed resin samples were separated by density into cation and anion resins using a sugar solution. The C-14 concentration in anion exchange resin was approximately 2 times higher than in the mixed resin. The average concentration of C-14 in the cation/anion mixed exchange resin was 460 GBq/m3 from test-hole and 53.1 GBq/m3 from man-hole. We have found that concentration of C-14 in the spent resin is about from 0.4 to 1,321 GBq/m3 So it could be a problem, when dispose of at a repository, since there is a disposal limit of 222 GBq/m3 This means we should develop the C-14 removal technology