Unit 2 at PSEG's Salem nuclear plant in New Jersey reentered service Monday after a maintenance outage that was extended following the discovery of damaged reactor coolant pump bolts.
Offline since April 12, the unit had reached 18 percent power as of Monday morning, according to the Nuclear Regulatory Commission. Eight turning vane bolt heads were removed from RCP piping and the reactor pressure vessel. PSEG told the South Jersey Times it believes they were weakened by intergranular stress corrosion cracking. Areva and Westinghouse inspected all four RCPs and made repairs using bolts with a different type of stainless steel.
The bolts were part of the original equipment at the Westinghouse reactor first licensed in 1981. An NRC spokesman told the paper the specific model of RCP affected was only installed at Salem and at the Surry plant in Virginia. Earlier, NRC officials wrote that PSEG had discovered a smaller number of bolt heads at unit 2 during previous outages. In the most recent case, most damaged bolt heads were held in place even after they failed by mechanical restraints and tack welds.