Description. The inspectors performed an in-depth review of PSEG’s evaluation and corrective actions associated with continued failures of RCP TVBs. The RCPs at Salem Unit 2 are model 93A supplied by Westinghouse. The turning vane is attached to the thermal barrier, internal to the pump, by twenty 1.0 inch diameter bolts fabricated from alloy A286. This material is susceptible to IGSCC as identified by Westinghouse in technical bulletin NSD-TB-94-06-R0, issued on August 11, 1994. Since refueling outage 2R18 in 2011, a total of seventeen TVB heads have been discovered in the reactor coolant system. The issue was originally evaluated during refueling outage 2R18, when two separated bolt heads were identified in April 2011, under order number 70123042 and determined not to have an adverse effect on RCP operations. During refueling outage 2R19, five additional loose TVB heads were found in the reactor coolant system. The licensee again communicated with Westinghouse and evaluated the condition as documented in order 70144776. The evaluation stated that “Dropping of the stationary hydraulic will have no direct impact on the seal assembly, as little or no contact between stationary and rotating parts should occur.” Additionally, during refueling outage 2R20,
Little or no contact...why doesn't the engineering firm westinghouse know for sure? And it is safe.
more loose turning bolt heads were discovered as documented in notification 20647694. The NRC inspector reviewed this notification and previous evaluations and questioned the basis for acceptability of contact between stationary and rotating components.
The licensee conducted additional reviews in coordination with Westinghouse and documented in OTDM S-14-003, that in the event of a failure of the turning vane assembly, it was possible for machining between the rotating and stationary parts to occur. Or so now it is unsafe after after seeing the damage.
Based on this information, the licensee conducted a plant cooldown, defueled the reactor and shipped all four RCPs offsite for inspection and repair at two vendor facilities. These inspections found TVB failures on all four RCPs.
The NRC considers lying or being intentionally inaccurate to the agency as a safe practice according to risk perspectives.
An unresolved item (URI) was identified because additional NRC review and evaluation is needed to determine if the issue is more than minor and whether the issue of concern constitutes a violation. The inspectors will review PSEG’s evaluation and causal analysis of the as-found condition and the impact on safety components and accident analysis upon its completion. (URI 05000311/2014003-03, Repetitive Failures of Reactor Coolant Pump Turning Vane Bolts)
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