Applicability Study of Pleated Filter to the Condensate Purification System in BWR

摘要

To maintain and enhance BWR plant operating reliabilities, it is required to reduce radiation exposure and generation of radioactive waste at the same time. To reduce crud intrusion into the reactor, many Japanese BWR plants adopt the precoat type condensate filter demineralizers (CFDs), which use powdered ion exchange resin as precoat material. The CFDs have a contradiction in crud removal efficiency and generation of radioactive waste. To keep high crud removal efficiency, the run length becomes shorter and radioactive waste will be generated more. In exchange for the CFDs, the pleated filters (PFs) are planning to retrofit in Japanese BWRs. Recently in United State and Europe, the PFs are used for condensate polisher system as retrofit to the CFD and additional new installation in BWRs and PWRs. The PFs seem to be desirable for retrofitting to the CFDs because of the PFs can be used without precoat material, less radioactive waste will be generated. The PFs have large surface areas for filtration. This means the linear velocity of filtration flow rate is very small and differential pressure may increase a little when crud will be loaded. Japanese BWR owners group is studying on the field trial of the PFs in an actual plant. This paper shows experience of a trial in a Japanese BWR.