05000400/LER-2009-002, Regarding Potential for Residual Heat Removal Trains to Be Inoperable During Mode Change
| ML093580024 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 12/15/2009 |
| From: | Henderson K Progress Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| HNP-09-130 LER 09-002-00 | |
| Download: ML093580024 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(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 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4002009002R00 - NRC Website | |
text
Progress Energy DEC 1 5 2009 Serial: HNP-09-130 10 CFR 50.73 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 LICENSEE EVENT REPORT 2009-002-00 Ladies and Gentlemen:
The enclosed Licensee Event Report (LER) 2009-002-00 is submitted in accordance with 10 CFR 50.73, paragraph (a)(2)(i)(B) as a condition prohibited by the plant Technical Specifications, under 10 CFR 50.73(a)(2)(ii)(B) for being in an unanalyzed condition, and under 10 CFR 50.73(a)(2)(v)(B) as a condition that could potentially have prevented the fulfillment of a safety function. This report describes the potential for the Residual Heat Removal Trains to be inoperable during Mode changes. In accordance with 10 CFR 50.73(a) requirements, this LER is submitted within 60 days following discovery of the event.
This document contains no Regulatory Commitments.
Please refer any questions regarding this submittal to Mr. Dave Corlett, Supervisor -
Licensing/Regulatory Programs, at (919) 362-3137.
Sincerely Kelvin Henderson Plant General Manager Harris Nuclear Plant KH/jmd Enclosure cc:
Mr. J. D. Austin, NRC Senior Resident Inspector, HNP Mr. L. A. Reyes, NRC Regional Administrator, Region II Ms. M. G. Vaaler, NRC Project Manager, HNP Progress Energy Carolinas, Inc.
Harris Nuclear Plant P. 0. Box 165 New Hill, NC 27562 AJ(LI~
NRCFORM 366 U.S. NUCLEAR REGULATORY' COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)
,o
, the NRC may (See reverse for required number of not conduct or sponsor, and a person is not required to respond to, the diqits/characters for each block) information collection.
- 3. PAGE Harris Nuclear Plant'- Unit 1 05000 400 1
OF 4
- 4. TITLE Potential for Residual Heat Removal Trains to be Inoperable during Mode Change
- 5. EVENT DATE
- 6. LER NUMBER I
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR Y
S R
MFACILITY NAME DOCKET NUMBER NSEUENTIAL REV MONTH DAY YEAR N/A 05000 FACILITY NAME DOCKET NUMBER 10 16 2009 2009 2
0 12 1N/A 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1[
20.2201(b) j] 20.2203(a)(3)(i)
E] 50.73(a)(2)(i)(C) 50.73(a)(2)(vii)
EJ 20.2201(d)
[] 20.2203(a)(3)(ii)
E] 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 5 20.2203(a)(1)
E] 20.2203(a)(4)
[] 50.73(a)(2)(ii)(B)
[
50.73(a)(2)(viii)(B) 5 20.2203(a)(2)(i)
E] 50.36(c)(1)(i)(A)
E] 50.73(a)(2)(iii) 5 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL Fl 20.2203(a)(2)(ii) j] 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A)
E] 50.73(a)(2)(x) 100 20.2203(a)(2)(iii)
[
50.36(c)(2) 5 50.73(a)(2)(v)(A) 5 73.71(a)(4) 100 20.2203(a)(2)(iv)
E] 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 5 73.71(a)(5) 20.2203(a)(2)(v) 5 50.73(a)(2)(i)(A)
E] 50.73(a)(2)(v)(C)
OTHER 5 20.2203(a)(2)(vi)
[
50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in Abstract below or in I1. CAUSE OF THE EVENT The root cause of this event is the original RHR system design and system operating guidance provided by Westinghouse were deficient and have allowed conditions to exist where steam flashing can occur in the RHR shutdown cooling piping and pump suction if the RHR system had to be transitioned to the ECCS mode for injection and recirculation from the shutdown cooling mode in Mode 4 or soon after transitioning to Mode 3.
A contributing cause to the event is that HNP did not perform an adequate review of Westinghouse Nuclear Safety and Advisory Letter NSAL-93-004 which addressed the operation of the RHR pumps in the ECCS modes in operational Modes 3 and 4 and provided guidance for preventing the formation of voids in the shutdown cooling piping. The conditions addressed by the NSAL were not fully investigated and therefore the recommendations were not incorporated into plant operating procedures. The inadequate review of NSAL-93-004 resulted in a missed opportunity to implement procedure changes which would have assured that flashing would not have occurred in the portion of RHR shutdown cooling piping that is not forced cooled if RHR had to be aligned to the ECCS mode during Mode 4 or transitioning Mode 3. The NSAL did not address the most limiting condition which is alignment to the ECCS sump. In Westinghouse NSAL-09-008, "Presence of Vapor in Emergency Core Cooling System/Residual Heat Removal System in Modes 3/4 Loss-of-Coolant Accident Conditions", Westinghouse recognized that the saturation pressure used to determine a permissible RHR system operating temperature must consider both the injection and recirculation modes of ECCS operation.
Ill.
SAFETY SIGNIFICANCE
This issue addressed the potential for the development of steam voiding in RHR pump suction shutdown cooling piping if the RHR system had to be transitioned from shutdown cooling to the ECCS mode due to a LOCA occurring in operational Modes 3 or 4.
No actual LOCA conditions have occurred so the conditions discussed in this report have never occurred. In Modes 3 or 4, at least one high head Safety Injection pump is available to supply flow to the RCS in a timely manner and the RHR pumps need not be relied on for short-term LOCA mitigation. As a result, a loss of the RHR injection capability during shutdown conditions would pose insignificant consequences. Since the potential exists for steam voids to occur under these conditions and during power ascension, a reportability determination was performed. This reportability determination identified eleven different occasions in the past three years where the LCO requirements for the ECCS subsystems were not satisfied. These violations of Technical Specification requirements are reportable to the NRC under 10 CFR 50.73(a)(2)(i)(B) as operation or condition prohibited by Technical Specifications, under 10 CFR 50.73(a)(2)(ii)(B) for being in an unanalyzed condition, and under 10 CFR 50.73(a)(2)(v)
(B) as a condition that could potentially have prevented the fulfillment of a safety function.
IV. CORRECTIVE ACTIONS
Immediate corrective actions to address this issue have been completed to revise Operations procedures to preclude conditions that would lead to void formation in the RHR suction piping.
Planned corrective actions are to utilize the results from a detailed analysis provided by an outside vendor to determine the RCS temperature and actions required to assure prevention of steam flashing in the RHR suction piping when aligning to the ECCS mode including taking suction from the RWST and ECCS containment sump during cool down of the plant, in Mode 4, during heat up of the plant, and finally transitioning to Mode 3. Operations procedures will then be updated to incorporate the results of the detailed analysis.
V.
PREVIOUS SIMILAR EVENTS
No previous similar events have been identified at the Harris Nuclear Plant.PRINTED ON RECYCLED PAPERPRINTED ON RECYCLED PAPER