| 摘要 |
(A) extension of the fuel element lifetime in a PWR is effected by the following steps, not necessarily carried out in the given order, (a) after a preset operating time, withdrawing the fuel element (1) from the reactor core, the connectors between the element lead (6) and one end of the control rod guide tubes (4) and between the element foot (7) and the other end of the control rod guide tubes (4) having compatible designs; (b) detaching the control rod guide tubes (4) from the head and the foot; (c) placing the fuel rod bundle (2) on the head (6) and connecting the ends of the guide tubes (4), which were previously connected to the foot (7), to the head (6) and vice-versa; and (d) introducing the fuel element (1) into a suitable location in the core, the foot (7) being at the bottom as previously. (B) Also claimed are similar processes and appts. for carrying out the processes. ADVANTAGE - Inversion of the fuel bundle, usually carried out after 3 operating cycles, provides more uniform corrosion along the fuel rods so that fuel element lifetime can be extended by 4 to 5 operating cycles. |
