05000353/LER-1917-005, Regarding Condition Prohibited by TS Due to Non-Conservative APRM and Control Rod Block Setpoints
| ML17208A301 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/27/2017 |
| From: | Libra R Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LG-17-106 LER 17-005-00 | |
| Download: ML17208A301 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3531917005R00 - NRC Website | |
text
Exelon Generation LG-17-106 July 27, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 2 Renewed Facility Operating License No. NPF-85 NRC Docket No. 50-353 10 CFR 50.73
Subject:
LER 2017-005-00, Condition Prohibited by Technical Specifications due to Non-conservative APRM and Control Rod Block Setpoints Enclosed is a Licensee Event Report (LER) which addresses a Condition Prohibited by Technical Specifications (TS) due to Non-Conservative Average Power Range Monitor (APRM) and Control Rod Block Setpoints as a result of inaccurate flow indication from a degraded jet pump at Limerick Generating Station (LGS) Unit 2.
This LER is being submitted pursuant to the requirements 1 O CFR 50.73(a)(2)(i)(B), Operation or Condition Prohibited by Technical Specifications.
There are no commitments contained in this letter.
If you have any questions, please contact Robert B. Dickinson at (61 O) 718-3400.
Respectfully,
-* ~"- R. L*Sf.4 Richard W. Libra Vice President - Limerick Generating Station Exelon Generation Company, LLC cc: Administrator Region I, USNRC USNRC Senior Resident Inspector, LGS
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)
, the http://www.nrc.qov/readinq-rm/doc-collections/nureqs/staff/sr1022/r3/)
NRC may not conduct or sponsor, and a person is not required to respond to, the information coOect1on.
- 3. PAGE Limerick Generating Station, Unit 2 05000353 1 OF 4
- 4. TITLE Condition Prohibited by TS due to Non-Conservative APRM and Control Rod Block Setpoints
- 5. EVENT DATE
- 6. LEA NUMBER
- 7. REPORT DATE B. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.
MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05 31 17 2017 - 005
- - 00 07 31 17
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITIED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201 (bl D 20.2203(a)(3Hil D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A) 1 D 20.2201 (dl D 20.2203(aH3Hiil D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1 i D 20.2203(aH4l D so.13(a)(2)(iiil D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(il D 50.36(c)(1 )(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(iil D 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(v)(A)
D 13.11(a)(4J D 20.2203(a)(2)(iiil D so.36(c)(2J D 50.73(a)(2)(v)(B)
D 13_11(aHsi D 20.2203(a)(2)(iv)
D so.4s(aH3Hiil D 50.73(a)(2)(v)(C)
D 13.11(aJ(1J 100 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 13.11(a)(2)(il D 20.2203(a)(2)(vi)
[8J 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(iil D 50.73(a)(2)(i)(C)
D OTHER Specify in Abstract below or 1n The condition with Jet Pump 9 affects the flow biased Reactor Protection System (RPS) Trip and Rod Block setpoints which depend on an accurate flow input. The higher indicated flow ultimately impacted compliance with TS Tables 2.2.1-1 and 3.3.6-2 (APRM STP and Control Rod block). The TS requirements are as follows:
APRM - TS 2.2.1, Reactor Protection System Instrumentation Setpoints "The reactor protection system instrumentation setpoints shall be set consistent with the Trip Setpoint values shown in Table 2.2.1-1."
Table 2.2.1-1. 2.b for Simulated Thermal Power - Upscale Two Recirculation Loop Operation provides a Trip Setpoint of: s 0.65W + 61.7% ands 116.6% of Rated Thermal Power.
Action: With a reactor protection system instrumentation setpoint less conservative than the value shown in the Allowable Values column of Table 2.2.1-1, declare the channel inoperable*
and apply the applicable ACTION statement requirement of Specification 3.3.1 until the channel is restored to OPERABLE status with its setpoint adjusted consistent with the Trip Setpoint value.
TS Table 3.3.1-1, REACTOR PROTECTION SYSTEM INSTRUMENTATION, provides the action for Simulated Thermal Power - Upscale, which states, "Be in at least STARTUP within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />."
Control Rod Block - TS 3.3.6, Control Rod Block Instrumentation "The control rod block instrumentation channels shown in Table 3.3.6-1 shall be OPERABLE with their trip setpoints set consistent with the values shown in the Trip Setpoint column of Table 3.3.6-2.
Table 3.3.6-2.2.a for APRM Simulated Thermal Power - Upscale provides a trip setpoint of s0.65W +54.3% ands 108.0% Rated Thermal Power.
Action:
a. With a control rod block instrumentation channel trip setpoint less conservative than the value shown in the Allowable Values column of Table 3.3.6-2, declare the channel inoperable until the channel is restored to OPERABLE status with its trip setpoint adjusted consistent with the Trip Setpoint value.
b. With the number of OPERABLE channels less than required by the Minimum OPERABLE Channels per Trip Function requirement, take the ACTION required by Table 3.3.6-1.
Table 3.3.6-1 states, "One less than required by the Minimum OPERABLE Channels per Trip Function requirement, restore the inoperable channel to OPERABLE status within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or place the inoperable channel in the tripped condition."
NAC SEQUENTIAL NUMBER 005 REV NO.
00 The APRM, and the Control Rod Block TS setpoint values discussed above were not met or exceeded. The TS actions were not entered, as the condition was not recognized until after the fact.
IV.
Cause of the Event
The low differential pressure in Jet Pump 9 was not recognized until plant startup was in progress.
The condition with Jet Pump 9 affected the flow biased Reactor Protection System (RPS) Trip and Rod Block setpoints which depend on an accurate flow input. The higher indicated flow ultimately impacted compliance with TS Tables 2.2.1-1and3.3.6-2 (APRM STP and Control Rod Block).
V.
Corrective Actions
A Temporary Change Configuration Package (TCCP) Engineering Change (EC) was completed for changes to the flow biased SCRAM and Rod Block setpoints. The APRM Scram and Rod Block setpoints were adjusted to the Single Loop Operation (SLO) values.
Additionally, the performance monitoring program for the jet pumps will be modified in order to identify issues sooner.
VI.
Previous Similar Occurrences There have been no previous similar occurrences in the last five years of APRM and Control Rod Block setpoint values not being met at LGS.
VII.
Component data:
System:
IG Component:
FOR lncore/Excore Monitoring System Flow Recorder (Totalized)
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