05000341/LER-2012-002, Regarding Reactor Scram During Reactor Pressure Vessel Hydrostatic Test
| ML12174A159 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 06/21/2012 |
| From: | Plona J DTE Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NRC-12-0040 LER 12-002-00 | |
| Download: ML12174A159 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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)(iii) 10 CFR 50.73(a)(2)(ix)(A) 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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3412012002R00 - NRC Website | |
text
Joseph H. Plona Site Vice President 6400 N. Dixie Highway, Newport, MI 48166 Tel: 734,586.5910 Fax: 734.586.4172 DTE Energy-10 CFR 50.73 June 21, 2012 NRC-12-0040 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington D C 20555-0001
Reference:
Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43
Subject:
Licensee Event Report (LER) No. 2012-002 Pursuant to 10 CFR 50.73(a)(2)(iv)(A), Detroit Edison is submitting the enclosed LER No. 2012-002, Reactor Scram During Reactor Pressure Vessel Hydrostatic Test.
No commitments are being made in this LER.
Should you have any questions or require additional information, please contact Mr. Rodney W. Johnson of my staff at (734) 586-5076.
Sincerely, Enclosure cc: NRC Project Manager NRC Resident Office Reactor Projects Chief, Branch 4, Region III Regional Administrator, Region III Supervisor, Electric Operators, Michigan Public Service Commission
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: No. 3150-0104 Expires 10/31/2013 (10-2010)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Fermi2 05000341 1 OF 3
- 4. TITLE Reactor Scram During Reactor Pressure Vessel Hydrostatic Test
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEUNIL RVFACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR 05000 NUMBER NO.05 0
04 26 2012 2012 002 00 06 21 2012 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT SUBMITTED PURSU ANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
E 20.2201(b) 0 20.2203(a)(3)(i)
I 50.73(a)(2)(i)(C) 0 50.73(a)(2)(vii) 4 20.2201(d) 20.2203(a)(3)(ii)
E 50.73(a)(2)(ii)(A)
Q 50.73(a)(2)(viii)(A) 20.2203(a)(1) 020.2203(a)(4) 0 50.73(a)(2)(ii)(B) 050.73(a)(2)(viii)(B)
E 20.2203(a)(2)(i)
E 50.36(c)(1)(i)(A) 0 50.73(a)(2)(iii)
E 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL jJ20.2203(a)(2)(ii) 0 50.36(c)(1)(ii)(A) x 50.73(a)(2)(iv)(A) 050.73(a)(2)(x) 0 20.2203(a)(2)(iii) j 50.36(c)(2)
Q 50.73(a)(2)(v)(A) 073.71(a)(4) 0 Percent E 20.2203(a)(2)(iv) 050.46(a)(3)(ii) 0 50.73(a)(2)(v)(B) 073.71(a)(5)
E 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C) 0 OTHER 20.2203(a)(2)(vi)
Q 50.73(a)(2)(i)(B)
J 50.73(a)(2)(v)(D)
Specify in abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THS LER FACILITY NAME rELEPHONE NUMBER (Include Area Code)
Fermi 2 / Archana Manoharan - Engineer, Nuclear Licensing (734) 586 - 5204CAUSE SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX I
FACTURER TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION L YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
X NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On April 26, 2012, at 10:12 am EDT, during Refueling Outage 15 with the Reactor Pressure Vessel Hydrostatic Pressure Test, in progress, a high pressure reactor scram occurred. The control room operator was monitoring reactor pressure using an indication that was invalid due to excess flow check valve testing that was in progress.
This resulted in a lowering of indicated reactor pressure while actual pressure was rising. All control rods were already fully inserted in the reactor core at the time of the scram. The Reactor Protection System and other plant equipment responded as expected to the high pressure condition and reactor pressure was lowered to 600 psig. The operating staff identified all control room instruments affected by the excess flow check valve testing, ensured they were monitoring valid signals prior to restarting the hydrostatic test, provided a dedicated operator for monitoring pressure, and communicated reactor pressure conditions to the staff. Long term corrective actions include revisions to procedural requirements and inclusion of the event in operator requalification training as part of refuel outage preparation.
NRC FORM 366 10-2010)
Initial Plant Conditions
Mode 4
Reactor Power 0 percent Description of the Event On April 26, 2012, at 10:12 am EDT, during Refueling Outage 15 (RF15) with the Reactor Pressure Vessel (RPV) Hydrostatic Pressure Test, in progress, a high pressure reactor scram occurred. The test was being conducted in accordance with Infrequently Performed Test and Evolution (IPTE) 12-03, RPV Hydrostatic Test.
Operators were monitoring RPV pressure using an Integrated Plant Computer System (IPCS) [CPU] average pressure point. However, one input of the average pressure point was valved out for scheduled excess flow check valve (EFCV) testing. This resulted in a lowering of indicated pressure while actual pressure was rising. When actual pressure reached the scram setpoint, a valid scram occurred. The Reactor Protection System (RPS) RPV high pressure signals for trip system A, channel 1 and trip system B, channel 1 came in on a RPV high pressure.
All control rods were already fully inserted in the reactor core at the time of the scram. The RPS and other plant equipment responded as expected to the RPV high pressure condition.
The IPCS pressure indication selected by the Licensed Control Room Staff became inaccurate because of the EFCV testing. The inaccuracy was not recognized prior to RPV pressure reaching the high pressure setpoint.
RPV pressure lowered to 600 psig as expected following the scram. The plant was stable and the scram was reset at 10:13 am.
Significant Safety Consequences and Implications
The plant was in Mode 4 "Cold Shutdown," at the time of the Reactor Scram. All Control Rods were already fully inserted in the Reactor Core. The RPS and other plant equipment responded as expected to the RPV high pressure condition.
RPV Steam Dome Pressure Transmitters [PIT] B21N078A and B21N078B remained in service during the pressure transient. Both transmitters detected the increase in RPV pressure accurately. When the pressure reached the trip setpoint of 1093 psig, a valid scram signal was initiated. Transmitter B21N078A provides input to the RPS trip system A and transmitter B21N078B provides input to the RPS trip system B. With a half scram signal in both RPS A and B trip systems, a full scram occurred as expected.
The plant responded as expected to the RPV high pressure condition and no safety limits were exceeded.
Therefore, there were no safety consequences and no effect on public health and safety as a result of this event.
This event was reported as an 8-hour non-emergency notification for a valid RPS system actuation per 10CFR50.72(b)(3)(iv)(A) as documented in event notification 47868. This report is provided in accordance with 10 CFR 50.73 (a)(2)(iv)(A), "Any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B)."U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE YEAR SEQUENTIAL REVISION Fermi 2 05000341 2012 NUMBER NUMBER 3 OF 3 201 05004 002 00
Cause of the Event
When the EFCV testing was released, the control room operators failed to recognize that one of the IPCS points being monitored would become invalid as part of the EFCV test. Inadequate impact evaluation for EFCV testing led to a failure to properly monitor a critical parameter. The IPCS point being monitored indicated a lowering pressure while actual RPV pressure was rising. The Control Room staff allowed the pressure to increase based on an IPCS computer point that averaged RPV pressure inputs where one of the inputs did not reflect the actual RPV pressure. The Licensed Operator did not use the indications specified in the RPV system leakage test procedure to validate reactor pressure.
Corrective Actions
This event was entered into the Fermi 2 Corrective Actions Program. The scram was reset and prior to resumption of the RPV hydrostatic pressure test (1) All instruments affected by EFCV testing were identified on the main control room panels, (2) A dedicated operator monitored reactor pressure on a wide range pressure recorder unaffected by EFCV testing and communicate pressure changes with shift personnel, and (3) IPCS screens were updated to display redundant RPV Pressure instruments not affected by EFCV testing.
Long term corrective actions include revisions to procedural requirements and inclusion of the event in operator requalification training as part of refuel outage preparation.
Additional Information
A.
Failed Component:
None identified.
B.
Previous Licensee Event Reports (LERs) on Similar Problems:
No similar events were identified.