05000397/LER-2015-001, Re Non-Conservative Compensatory Measure for Flooding Barriers
| ML15120A642 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 04/30/2015 |
| From: | Hettel W Energy Northwest |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GO2-15-069 LER 15-001-00 | |
| Download: ML15120A642 (4) | |
| 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)(B), Unanalyzed Condition 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) 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)(viii)(B) 10 CFR 50.73(a)(2)(iii) 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)(i)(A), Completion of TS Shutdown |
| LER closed by | |
| IR 05000397/2015000 (7 August 2015) IR 05000397/2015002 (7 August 2015) | |
| 3972015001R00 - NRC Website | |
text
ENERGY NORTHWEST APR 3 O 2015 G02-15-069 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 W. Grover Hettel Columbia Generating Station P.O. Box 968, PE23 Richland, WA 99352-0968 Ph. 509.377.8311 I F. 509.377.4150 wghettel@energy-northwest.com 10 CFR 50.73
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 LICENSEE EVENT REPORT NO. 2015-001-00
Dear Sir or Madam:
Transmitted herewith is Licensee Event Report No. 2015-001-00 for Columbia Generating Station. This report is submitted pursuant to 1 O CFR 50.73(a)(2)(i)(B), 1 O CFR 50.73(a)(2)(ii)(B), 10 CFR 50.73(a)(2)(v)(B), and 10 CFR 50.73(a)(2)(v)(D).
There are no commitments being made to the NRC by this letter. If you have any questions or require additional information, please contact Mr. J.R. Trautvetter, Regulatory Compliance Supervisor, at (509) 377-4337.
Executed on i/ I ~c /,c;;,
Respectfully, w
W. G. Hettel Vice President, Operations
Enclosure:
Licensee Event Report 2015-001-00 cc: NRC Region IV Administrator NRC NRA Project Manager NRC Senior Resident lnspector/988C CD Sonoda - BP A/1399 WA Horin - Winston & Strawn
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (01-2014)
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block).
APPROVED BY OMB: NO. 3150-0104 EXPIRES 01/31//2017 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Columbia Generating Station
- 2. DOCKET NUMBER 05000 397
- 3. PAGE 1
OF 3
- 4. TITLE Non-Conservative Compensatory Measure for Flooding Barriers
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05000 03 02 2015 2015 001 00 04 30 2015 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203 (a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 100 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)
OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in Abstract below or in
Plant Conditions
At the time of the event reactor power was 100% from December 3, 2014, to December 19, 2014, except from December 13, 2014, 23:05 until December 14, 2014, 00:20 when it was 97% for Main Steam Bypass Testing. There were no structures, systems, or components that were inoperable at the start of the event which contributed to the event.
Event Description
On March 2, 2015, it was identified that Columbia Generating Stations (Columbia) barrier impairment procedure which allowed for floor plugs over the Emergency Core Cooling System (ECCS) and Reactor Core Isolation Cooling (RCIC) [BN]
System pump [P] rooms to be removed with a one hour flood tour to maintain operability of the system was non-conservative and Columbia had been non-compliant with Technical Specifications (TS).
On December 3, 2014, a floor plug for the Residual Heat Removal (RHR) [BO] System B on the Reactor Building (RB)
[NG] 471 elevation was removed per the barrier impairment process. A one hour flood tour was initiated for this barrier impairment, and a berm was erected; however, the one hour flood tour was non-conservative and the berm did not meet procedural requirements for flood height nor was it a continuous berm. On December 18, 2014, the NRC Resident questioned the adequacy of the installed berm and its non-compliance with the barrier impairment procedure. On December 19, 2014, a berm was erected which met procedural requirements to protect against flooding in the RHR System B pump room below.
Cause
The cause of the non-compliance with TS occurred because the flood tour was allowed by the barrier impairment procedure as a compensatory measure to support operability based on engineering judgement without a thorough technical evaluation. The inadequate compensatory measure was allowed because specific guidance for the evaluation of compensatory measures for barrier impairments was not available.
Extent of Condition Extent of condition was examined for all of the ECCS and RCIC Systems during the past three years when floor plugs were removed. Floor plugs were removed from above 5 of the 6 ECCS and RCIC System pump rooms 7 times during the modes of applicability, Modes 1, 2, and 3. Below is a list of the dates of times when a floor plug was removed and additional conditions prohibited by TS were found to exist.
- 1. March 5, 2012 - RHR A - 14 days inoperability time - TS 3.5.1, 3.6.1.5, and 3.6.2.3 completion times were exceeded
- 2. May 2, 2013 - RHR B - 9 days inoperability time - TS 3.5.1, 3.6.1.5, and 3.6.2.3 completion times were exceeded.
- 3. December 3, 2014 - RHR B - 16 days inoperability time - TS 3.5.1, 3.6.1.5, and 3.6.2.3 completion times were exceeded
- 4. December 17, 2014 - RHR A, RHR B, and Low Pressure Core Spray (LPCS) [BM] - 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 42 minutes of inoperability time - TS 3.5.1 completion times were exceeded and LCO 3.0.3 was not entered 26158A R3
Immediate Corrective Action
When it was discovered on December 18, 2014, that the installed berm was inadequate, actions were taken to erect a berm which is compliant with the barrier impairment procedure. This was completed on December 19, 2014. An operations standing order was put in place to ensure that floor plugs would not be removed without either declaring the affected system inoperable or erecting a berm which can maintain operability.
Operating Experience & Previous Occurrences A previous occurrence has been found to have a similar cause. A NRC violation from 2013 was found against the same barrier impairment procedure for failure to translate flooding design and calculation into procedures. An extent of condition was performed which reviewed the barrier impairment procedure for compensatory measures which were based on calculations or quantitative analysis. Floor plug removal was identified as having no quantitative analysis, however based upon engineering judgement an hourly flood tour which had been in place since 2002 was determined to be adequate.
Further Corrective Actions A revision to the barrier impairment procedure has been completed which removes the option for an hourly flood tour to maintain operability of the ECCS and RCIC systems when floor plugs are removed.
Planned corrective actions include further enhancement to the barrier impairment procedure and creation of a procedure for proper berm installation.
Assessment of Safety Consequences
There were no actual safety consequences of the event. There was no equipment damage, injuries or dose exposure to station personnel. There was no change in plant status or operating condition and there was no actual risk to the public at any time. The floor plugs are designed to protect the ECCS and RCIC systems during a medium energy line crack (MELC). During each instance where floor plugs were removed, although systems were not declared inoperable, no actual MELC occurred.
There was a potential safety consequence if a MELC were to have occurred while the floor plugs were removed. Flooding procedures direct operators to physically render the ECCS and RCIC pumps inoperable upon flooding in the respective pump room; therefore, the pump with the floor plugs removed would not have been available to perform its safety function.
During the period of time when floor plugs were removed there was a period of inoperability of other ECCS systems which resulted in a loss of safety function. This was due to inoperability of three ECCS Systems, RHR A, RHR B, and LPCS.
On December 17, 2014, with RHR B floor plugs removed and RHR A, and LPCS systems declared inoperable, the RHR A and LPCS systems were maintained available to provide cooling to the reactor since they were operating in suppression pool cooling mode and suppression pool mixing mode, respectively, during this time period. The High Pressure Core Spray (HPCS) [BG] system was also operable and available to support ECCS injection/spray. The normal method of heat removal from the reactor, the condenser, was also available for heat removal. At no period of time, with the provision of operating the pumps, was there more than one pump, RHR B, incapable of providing cooling to the reactor.
Energy Industry Identification System Information Energy Industry Identification System Information codes from IEEE Standards 805-1984 and 803-1983 are represented in brackets as [X] and [XX] throughout the body of the narrative.
26158A R3