Nine Mile Point: I Approve Reduction Of Testing Frequency On SRVs

 “Clinton 2009 safety evaluation: Dikkers Model G-471 SRVs have shown exemplary test history.

If we take it at face value the NWS testing facility is ethical, I thinking maybe Nine Mile Point deserves the reduction in SRV testing. I am surprised I am coming to this conclusion. It’s surprising there was no corrosion bonding of the seat and disc.

See what I say, if saying drastically changes, something has changed to create the different outcome. The site has tested the SRVs onsite and they used nitrogen as the testing medium. Now its tested at NWS and they use saturated steam.

I am disappointed the NRC used an incomplete framework with this safety evaluation. They didn’t explicitly state NMP had inaccuracies in the past and they solved the problem. I am just concern bad actor plants would use the safety evaluation to loosen testing without making a change that solves the problem.

What the hell:  “Clinton 2009 safety evaluation: The installed Dikkers Model G-471 SRVs have shown exemplary test history.” So we know there are companies and valves out there.

Jesus, the miracle SRV and MSSV…the Dikker valves

NMP: Supplement 1 to Licensee Event Report 2011-001, As-Found Safety Relief Valve Lift Setpoints Exceed Technical Specification Allowable Values 

On April 1, 2011, Nine Mile Point Nuclear Station, LLC (NMPNS) determined that, based on the results of completed as-found testing, four (4) of eighteen (18) Main Steam Safety Relief Valves (SRVs) mechanically actuated at pressures that exceeded the allowable Technical Specification (TS) limit, which is the TS specified setpoint plus or minus 3 percent. These 18 SRVs had been removed and replaced with pre-tested, certified SRVs during the 2010 Nine Mile Point Unit 2 (NMP2) refueling outage. NMP2 TS 3.4.4 requires the safety function of sixteen (16) SRVs to be operable in reactor operating modes 1, 2, and 3. Since the as found testing determined that 4 of the 18 SRVs were inoperable for an indefinite period of time during the operating cycle that preceded the 2010 refueling outage, it is probable that NMP2 operated longer than the TS allowed Completion Time. 

The immediate cause for this reportable condition is out-of-tolerance lift pressures that exceeded the TS-allowed values for 4 of 18 SRVs, and which existed for longer than the TS allowed Completion Time. The 4 SRVs that failed the as-found test were disassembled and inspected at NWS Technologies in Spartanburg, SC, using the guidance provided in the Dikkers instruction manual and Electric Power Research Institute (EPRI) TR-1 05872, "Safety and Relief Valve Testing and Maintenance Guide." There was no evidence of degradation, corrosion, binding, rubbing, foreign material intrusion, or parts out of adjustment noted during the inspections, and no test method irregularities at the NWS test facility were identified that would account for the test failures. The cause for the 4 as-found test failures is attributed to inaccurate as-left lift pressure settings that resulted from the use of nitrogen as the test medium for SRV testing performed prior to the 2010 refueling outage. Onsite nitrogen testing of the NMP2 SRVs was conducted from 1997 to 2008. Prior to commencing nitrogen testing, NMPNS performed analyses to establish a nitrogen-steam correlation that, when combined with a 95% confidence limit, would provide conservative nitrogen pressure limits for establishing an equivalent SRV steam set pressure within the TS as-left set pressure tolerance limit of plus or minus 1 percent. The analyses considered the concerns expressed in General Electric Service Information Letter (SIL) No. 577, "Nitrogen Setting of the Dikkers SRV," and incorporated the implementation considerations described in the SIL. The testing of the 18 SRVs removed during the 2010 refueling outage, performed at NWS Technologies using saturated steam as the test medium, indicates that all of the lift pressures were greater than the nominal TS setpoint values; therefore, it appears that the nitrogen-steam correlation was not sufficiently conservative. Onsite nitrogen testing of the NMP2 SRVs is no longer being performed.