METHOD FOR WARMING PARTS OF REACTOR PRESSURE VESSEL

摘要

PROBLEM TO BE SOLVED: To make it possible to warm parts uniformly to the minimum operating temperature of a pressure vessel or higher in a short time without creating the unevenness in temperature distribution by heating a top cover with sheet heaters inserted into holes where stud bolts are inserted on a flange of the top cover. SOLUTION: In the warming of a top cover 1 for a reactor pressure vessel, sheet heaters 5 are wound cylindrically and are inserted into all holes where stud bolts are inserted and which are set up on a flange 3 of the top cover 1. Then, a control panel 12 is connected to a power source via a power source cable 13, power source cables 14 are linked to power source cables 10 through a connector 15 and the power source cables 10 are tied to cables 9 connected to the sheet heaters 5. Moreover, a temperature sensor 16 is mounted near the upper edge of a required one of the sheet heaters 5 and a hemispheric part 2 of the top cover 1 is covered with a heat insulation sheet 19. Many holes where the stud bolts are inserted are laid out toward the circumferential direction of the flange 3. The performance of this method eliminates losses in processes for restoring a reactor and makes it possible to shorten a period of construction work.