05000410/LER-1917-002, Regarding Secondary Containment Inoperable Due to Wind Conditions
| ML17346A745 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 11/28/2017 |
| From: | Kreider R Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP2L2659 LER 17-002-00 | |
| Download: ML17346A745 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 4101917002R00 - NRC Website | |
text
Exelon Generation NMP2L2659 November 28, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69 Docket No. 50-41 O 10 CFR 50.73
Subject:
NMP2 Licensee Event Report 2017-002, Secondary Containment Inoperable Due to Wind Conditions In accordance with the reporting requirements contained in 1 O CFR 50.73(a)(2)(v)(C), please find enclosed NMP2 Licensee Event Report (LER) 2017-002, Secondary Containment Inoperable Due to Wind Conditions.
There are no regulatory commitments contained in this letter.
Should you have any questions regarding the information in this submittal, please contact Dennis M. Moore, Site Regulatory Assurance Manager, at (315) 349-5219.
Respectfully,
~
- Robert E. Kreider Jr.
Plant Manager, Nine Mile Point Nuclear Station Exelon Generation Company, LLC REK/RSP
Enclosure:
NMP2 Licensee Event Report 2017-002, Secondary Containme~t Inoperable Due to Wind Conditions cc:
NRG Regional Administrator, Region I NRG Resident Inspector NRG Project Manager
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)
, the http://www.nrc.qov/readinq-rm/doc-collections/nureqs/staff/sr1022/r3/)
NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Nine Mile Point Unit 2 05000410 1 OF 5
- 4. TITLE Secondary Containment Inoperable Due to Wind Conditions
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR
- YEAR NUMBER NO.
MONTH DAY YEAR N/A N/A FACILITY NAME DOCKET NUMBER 09 30 2017 2017 - 002
- - 00 11 29 2017 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201 (bl D 20.2203(a)(3)(i)
D 50.73(a)(2){ii)(A)
D 50.73{a){2){viii)(A) 1 D 20.2201 (dl D 20.2203(a)(3)(iiJ D 50.73(a){2)(ii)(B)
D 50.73{a){2){viii)(B)
D 20.2203(aJ(1 l D 20.2203(aJ(4l D so.13(aJ(2)(rnJ D 50.73(a)(2)(ix)(A)
D 20.2203(aJ(2Hil 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(aJ(2J(iiJ D 50.36(c)(1 )(ii)(A)
D 50.73(a){2){v)(A)
D 13.11 (aJ(4l D 20.2203{aJ(2)(iiiJ D so.36{cJ(2J D 50.73(a)(2)(v)(B)
D 13.11 (a)(sJ D 20.2203{a){2){iv)
D so.46{aJ(3J(iiJ
~ 50.73(a)(2)(v)(C)
D 13.77{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)
D 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 13.11(a)(2)(ii)
D 50.73(a){2)(i)(C)
D OTHER Specify in Abstract below or in 0135 Control Room Operator starts Standby Gas Treatment Fan per procedure, Reactor Building 0/P improves to -0.45 inches water gauge.
0135 Secondary Containment was declared operable and Technical Specification 3.6.4.1 was exited
E. METHOD OF DISCOVERY
The condition was recognized by Operations as they monitored Secondary Containment vacuum during the period of changing wind conditions.
F. SAFETY SYSTEM RESPONSES:
This event was caused by changing wind conditions. The GTS equipment performed as expected.
II. CAUSE OF EVENT
Secondary Containment was declared inoperable because of changing wind conditions.
Though the effect of high winds on normal Reactor Building ventilation was recognized in 2015, attempts to mitigate building D/P changes due to high winds did not prevent the wind conditions during this event (East to Northeast) from affecting Reactor Building D/P enough to enter Technical Specifications.
III. ANALYSIS OF THE EVENT
The event described in this LER is reportable under 1 O CFR 50.72 (b)(3)(v)(C) and 1 O CFR 50.73(a)(2)(v)(C) as any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
Analysis concluded that Secondary Containment was declared inoperable because of changing wind conditions. The effect of high wind on Reactor Building ventilation was recognized in 2015 and actions were taken attempting to mitigate building D/P changes during sustained high wind c;:onditions. However, these actions did not prevent the wind conditions during this event from affecting Reactor Building 0/P enough to enter Technical Specification required action.
TS 3.6.4.1 Condition A was entered and subsequently exited once Secondary Containment vacuum was restored to above the required TS value (required action) within the associated completion time. The Secondary Containment structural integrity, the ability to automatically isolate the non-safety related Reactor Building Ventilation System, and GTS availability were not impacted. Secondary Containment would have continued to perform its intended safety function throughout the duration of the event.
Based on the above discussion, it is concluded that the safety significance of this event is low and the event did not pose a threat to the health and safety of the public or plant personnel.
This event does not affect the NRC Regulatory Oversight Process Indicators.
IV. CORRECTIVE ACTIONS
A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:
Operators declared Secondary Containment inoperable and entered TS LCO 3.6.4.1 Condition A with a required action to restore Secondary Containment to operable within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Operators placed GTS in operation and returned the Secondary Containment to pre-event status (operable).
B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:
One action has been completed to aid in preventing recurrence; this action changes "Building Rounds" Attachment 1 to align Reactor Building D/P bands with Reactor Building Ventilation procedure. This revision changed the range for Reactor Building D/P from -0.25 to -0.80 inches WG to -0.47 to -0.90 inches WG, providing more margin to inoperability.
Additionally, the site has submitted a license amendment request to allow for containment vacuum to be momentarily less than the required vacuum due to changes in wind conditions in accordance with TSTF-551, Revision 3 "Revise Secondary Containment Surveillance Requirements".
V. ADDITIONAL INFORMATION
A. FAILED COMPONENTS:
There were no failed components that contributed to this event.
REV NO.
00 B. PREVIOUS LERs ON SIMILAR EVENTS:
NMP2 LER-2014-005, dated 05/09/2014, was submitted for Secondary Containment Inoperable due to Sustained high winds. The corrective actions following this event included revising a plant procedure to provide direction to initiate the Standby Gas Treatment System and isolate the Reactor Building during sustained high wind conditions prior to exceeding the Technical Specification (TS) D/P limit for Secondary Containment. These actions do not mitigate the change in wind conditions associated with this LER (2017-002)
NMP2 LER-2015-001, dated 03/12/2015, was submitted for Secondary Containment Inoperable due to Sustained high winds. The wind conditions of the event described within this LER differ from those captured in LER-2015-001. Actions resulting from the 2015 event have successfully mitigated the challenge posed from sustained high winds from West to East but did not prevent D/P challenges presented from the wind conditions during the event described in this LER (2017-002)
C. THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT FUNCTION IDENTIFIER AND SYSTEM NAME OF EACH COMPONENT OR SYSTEM REFERRED TO IN THIS LER:
COMPONENT Reactor Building (BWR)
Standby Gas Treatment System D. SPECIAL COMMENTS:
None IEEE 803 FUNCTION IDENTIFIER N/A N/A IEEE 805 SYSTEM IDENTIFICATION NG BH REV NO.
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