Dresden's Broken Electromatic Relief Valves?

You get it, two different component manufacturers for parts in the same model valve: GE Hitachi and Dresser Industries. Two different components on the same model valve being defective and cause the safety valve not to work. One is on a actuator and the other is on the cutoff switch.

Seem like very similar problems...the component parts are defective or improper maintenance. Got tiny parts dimensional problems, alignment, spring force problems, vibration, bushing issues and guild post misalignment. It's is basically defective internal component problem.

Kinda sounds like Pilgrim SRVs and Oyster Creek electromatic relief valves small internal component or parts problems too? 

PART 21 REPORT - ELECTROMATIC RELIEF VALVE (EMRV) CUTOUT SWITCH

GENERAL ELECTRIC HITACHI

"Following the return of the actuator that failed bench testing to GEH, on 6/12/15 at 1804 [CDT], General Electric Hitachi (GEH) notified Dresden Station of a potential parts quality Potential Failure of the EMRV Cutout Switch. It has been determined the notification is applicable to DNPS [Dresden Nuclear Power Station], Units 2 and 3. "The GEH investigation concluded that the EMRV actuator assemblies failed to change state because of the

failure of the cutout switch to fully close and provide the appropriate current path. Multiple contributing factors were discovered which could have led to the presence of the gaps in the cutout switch. The most significant of these factors is a change in lever arm positioning causing increased forces in the tension spring which prevent roper closure of the cutout switch. Design changes to reduce wear caused by vibration on the actuators changed lever arm position and also allowed for additional dimensional tolerance which tended to increase force in the tension spring.

"Identification of Facility and Component: DNPS / EMRV Actuator, GEH Part Number 352B2632G001 "Safety Significance (e.g., substantial hazard that is or could be created): Identified condition is a Potential Substantial Safety Hazard since it could cause affected EMRVs to fail to operate as designed, which could result in a loss of safety function. Potential to affect the Minimum Critical Power Ratio (MCPR), Reactor Coolant System (RCS), Automatic Depressurization System (ADS), and Low Set Relief Function "Plants with similar GEH cutout switches: Quad Cities Nuclear Power Station."

LER 2015-002-02: 2C ERV Failed to Actuate duringExtent of Condition Testing

Dn February 7, 2015, with the reactor in mode 4, an Electromatic Relief Valve (ERV) actuator failed to open during the prerformance of an extent of condition test. The testing involved an operator manually actuating the ERV from the main control room with operators and engineers staged in the field. However, when the demand signal was given, the 20 actuator plunger did not move and the valve did not open. Th

The failed ERV actuator sub-components were inspected in the field and immediately following removal. Based upon the in-field inspection, the 2C ERV actuator's binding point was identified to be at the top of the guide post below the top of the top guide post bushing. PowerLabs performed a failure field inspection, the 2C ERV actuator's binding point was identified to be at the top of the guide post below the top of the top guide post bushing. PowerLabs performed a failure

NRC mechanical binding was determined to have been caused by preferential wear between the guide post and bushing due to an alignment issue. The 20 ERV actuator had measurable material loss on the bushing. The ERV actuator is normally open and de-energized. The bushings on the 20 were last replaced in 2005 per WO 636642. The wear due to actuation has been determined to be insignificant and is not related to the wear mechanism. The basis for the failure mechanism was determined by engineering inspection and a Powerlabs autopsy.

The preferential mechanical wear between ERV actuator sub components was determined to have been caused by the guide posts being in constant contact with the bushings during operation. The rigid guide post was noted to have been slightly angled away from the solenoid centerline, from the base of the post, with all base bolting completely intact and torqued, and interfering with the inside diameter of the bushing. These guide posts have sometimes been found slightly angled in previous WOs, requiring additional maintenance effort to bend the post into straight, concentric alignment with the bushing. Without this additional maintenance attention, the guide post and bushing would have had constant contact for the duration of cycle operation. The valve would have passed all as-left testing because the wear mechanism had not yet occurred.