Fitzpatrick SRV Setpoint Testing: All But One Failed Testing Including The Experimental Valve

Reposted from 4/9

***The experimental 3 stage valve that failed testing, this exact designed valve is scheduled to replace the 2 stage valves next outage!!!!

Basically a total of ten Valves. Nine the 2 stage and one valve a experimental  3 stage valve.

Eight of the 2 stage valves failed their testing. These guys are notorious with failing their pressure setpoint testing. They are preparing to replace their 2 stage valve with the experimental 3 stage valve'

The only experimental 3 stage valve failed its setpoint testing.

They got to get rid of these dangerous valve across the industry. But nobody will supply these kinds of valves to the industry.

LER: 2017-004-01, Safety ReliefValves Out of Tolerance

Background The ASME Boiler and Pressure Vessel Code requires the reactor pressure vessel be protected from overpressure during upset conditions by self-actuated safety valves. As part of the nuclear pressure relief system, the size and number of SIRVs are selected such that peak pressure in the Reactor Coolant Pressure Boundary (RCPB) will not exceed the ASME Code limits.

The James A. FitzPatrick Nuclear Power Plant (JAF) used ten (10) two-stage and one (1) three-stage Target Rock Safety/Relief Valves (S/RV) [EIIS Identifier: SB] for emergency pressure relief during operating Cycle 22. These valves are located on the main steam lines between the reactor vessel, and the first isolation valve within the drywell. Each S/RV discharges steam through a discharge line to a point below the minimum water level in the suppression pool.

The pilots that are removed are sent to a vendor facility for testing, refurbishment, and certification. The test results for pilot assemblies removed in 2017, during Refueling Outage 22, identified ten (10) S/RV pilot assemblies that were out of allowable tolerance. Nine (9) of the pilots (all two-stage) lifted at greater than the allowable setpoint range, and one (three-stage) lifted at less than the allowable setpoint range.

In order to address the concerns with corrosion bonding, JAF will commence replacement of two-stage with three-stage Target Rock S/RVs in the next Refueling Outage (RO). Industry experience has shown that the three stage S/RVs are less susceptible to corrosion bonding. The design of the three-stage S/RVs produces a greater mechanical force on opening, resulting in a greater likelihood of overcoming any potential effects of corrosion bonding that might occur.

Event Description

As-Found testing was performed on all eleven main S/RV pilot assemblies removed in 2017, during R022. The testing was conducted by NWS Technologies. The TS setpoint for each S/RV is 1145 +1- 34.3. During the initial lift test, ten of the eleven pilot assemblies failed to open within the allowable range (1110.7 to 1179.3). Nine of the ten two-stage and the three-stage S/RV pilot failed high and low outside the allowable range, respectively. As-Found failed test results are tabulated below.