***Until recently there has been very little srv setpoint testing failures at Hope Creek. The last three operating periods sit outside the normal. The first two operating period consist of three or four SRV setpoint testing failures, while the last setpoint testing failures has 10 failed SRVs. Why are the failures skyrocketing? What has changed to cause this.
You can't do a SRV lift setpoints accuracy test up at power. You have to shutdown to test these valve. If one of Pilgrims SRV valves was known to be outside their plus or minus 3% tech spec limit, they would be required to shutdown within 24 hours.
This exact problem with repeated two stage Target Rock inaccuracy setpoint testing problems at Hope Creek...the ones in the Pilgrim plant now... is the reason why Pilgrim dumped their two stage SRV valves and jumped into their defective three stage SRVs valves.
You get it, Target Rock hasn't made nuclear plant grade two or three stage safety relief valves for many decades. They are out of manufacturing for decades. Currently the whole USA nuclear fleet (BWRs) gets their reliefs from canceled or decommissioning plant junk yards.
***There is a fix to corrosion bonding or welding with inaccurate setpoint testing with the safety relief valves. You open and shut them once for a bi monthly or monthly bases during the operating period. The problem of this duty of monthly testing is really the two or three stage Safety Relief Valve are too delicate for the installation in these nuclear plants. They are a obsolete technology. They would quickly start to leak much like Pilgrim and then leakage would drive the valves into breaking and not operating when called upon. These utilities would begin to lie to stay up power with leaking valves saying they will definitely operative...then they won't. Then you got regulatory issues like Pilgrim today. As for today, we make believe this valves are operational when they are not. Lying, cheating and not telling the whole truth has a high probability of damaging the whole safety culture in a nuclear plant.***
***We really need a new bullet proof design for safety relief valves. We could beat the hell out of these valves without them degrading and not passing setpoint testing for many years. We can keep these valves in the plant for many operating cycles without excessive burdens with testing and maintenance.***
LER: As-Found Values for Safety Relief Valve Lift Set Points Exceed Technical Specification Allowable Limit
On June 2, 2015, Hope Creek
Generating Station (HCGS) received initial results of the 'as-found' setpoint
testing for the safety relief valve (SRV) pilot stage assemblies. The initial
results indicated that three SRV pilot stage assemblies had exceeded the lift
settings prescribed in Technical Specification (TS) 3.4.2.1. The TS requires
the SRV lift settings to be within +/- 3% of the nominal setpoint value. During
the nineteenth refueling outage (H1R19),
all fourteen SRV pilot stage
assemblies were removed for testing at an offsite facility. Between June 2 and June
1 O,
2015,
HCGS received the test results for the remainder of the SRV pilot valve
assemblies. A total of ten of the fourteen SRV pilot stage assemblies
experienced setpoint drift outside of the TS 3.4.2.1 specified values. All of the
valves failing to meet the limits were Target Rock Model 7567F two-stage SRVs.
This is a condition reportable under 1 O CFR 50. 73{a)(2)(i)(B) as an Operation
or Condition Prohibited by Technical Specifications.
The cause of the setpoint drift
for the ten SRV pilot stage assemblies is attributed to corrosion bonding
between the pilot disc and seating surfaces, which is consistent with industry
experience. This conclusion is based on previous cause evaluations and the
repetitive nature of this condition at HCGS and within the BWR industry.
Technical evaluations performed
to assess the aggregate safety significance of ten SRVs with out of tolerance initial
lift setpoints concluded that this condition had no safety significance.
DESCRIPTION OF OCCURRRENCE
During the nineteenth refueling
outage (H1R19) at Hope Creek Generating Station (HCGS), all 14 Main Steam
Safety Relief Valves (SRV) pilot stage assemblies {SB/RV} were removed and
tested at NWS Technologies. The SRVs are Target Rock Model 7567F two-stage
SRVs. During the period from June 2, 2015 through June 10. 2015, HCGS received
the results of the 'as-found' set pressure testing required by Technical Specification
(TS) Surveillance Requirement (SR) 4.4.2.2. A total of ten of the 14 SRV pilot
stage assemblies had setpoint drift outside of the required
TS 3.4.2.1 tolerance values of
+/-3% of nominal value. The 'as-found' test results for the ten SRVs not
meeting the TS requirements are as follows:
Valve ID As Found TS Lift
Setting Acceptable Band % Difference
(psig) (psig) (psig) Actual
F013C 1216 1130 1096.1 -1163.9
7.61%
F013F 1240 1108 1074.8 -1141.2
11.90%
F013G 1208 1120 1086.4 - 1153.6
7.86%
F013H 1148 1108 1074.8-1141.2
3.60%
F013J 1161 1120 1086.4 -1153.6
3.66%
F013K 1161 1108 107 4.8 -1141.2
4.80%
F013 L 1165 1120 1086.4 -1153.6
4.00%
F013 M 1207 1108 1074.8 -1141.2
8.90%
F013P 1221 1120 1086.4 -1153.6
9.00%
F013R 1169 1120 1086.4 -1153.6 4.38%
CAUSE OF EVENT
The cause of the setpoint drift
for the ten SRV pilot stage assemblies is attributed to corrosion bonding
between the pilot disc and seating surfaces, which is consistent with industry
experience. This conclusion is based on previous cause evaluations and the
repetitive nature of this condition at HCGS and within the BWR industry.
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