MITI prepares for standardization of LWR plants

Feasibility studies on the standardization of LWR plants, aiming at minimizing the radiation exposure of workers and at improving workability, were reported by MITI (the Ministry of International Trade and Industry). The studies cover the improvements to the shape of reactor containments and the increased space within containments as well as equipment arrangement. The radiation exposure of workers in a standardized plant can be reduced by some 35% in BWRs and 25% in PWRs. Further reduction can be expected if preventive measures are taken against the corrosion in piping systems. The time required for regular inspection could be reduced. MITI plans to prepare the first stage of standard specifications in FY-77, and calls for utilities and suppliers to incorporate these results in all future LWR plants now under planning, including Sendai-I (PWR 800 MW) of Kyushu Electric Power Company and No. 2 unit (BWR 1,100 MW) of Fukushima-II of Tokyo Electric Power Company. At the first stage, the standardization is mainly focussed on reactor steam supply systems, and the arrangement of equipments and building design will be left to future studies. At the second stage, improvement and standardization will require relatively long term technological assessments, for which MITI plans to set targets after FY-77, aiming at completing the standard plant specifications of LWRs in Japan around FY-80. (Iwakiri, K.)