05000341/LER-2016-004, Regarding Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

Regarding Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

ML16256A751
Person / Time
Site:	Fermi
Issue date:	09/12/2016
From:	Polson K DTE Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC-16-0060 LER 16-004-00
Download: ML16256A751 (6)

LER-2016-004, Regarding Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
3412016004R00 - NRC Website

text

Keith J. Poison Site Vice President DTE Energy Company 6400 N. Dixie Highway, Newport, MI 48166 Tel: 734.586.4849 Fax: 734.586.4172 Email: poisonk@dteenergy.com DTE Energy-10 CFR 50.73 September 12, 2016 NRC-16-0060 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. 2016-004 Pursuant to 10 CFR 50.73(a)(2)(v)(C), DTE Electric Company (DTE) is submitting LER No. 2016-004, Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather.

No new commitments are being made in this LER.

Should you have any questions or require additional information, please contact Mr. Scott A. Maglio, Manager - Nuclear Licensing, at (734) 586-5076.

Sincerely, Keith J. Polson Site Vice President

Enclosure:

Licensee Event Report No. 2016-004, Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather cc: NRC Project Manager NRC Resident Office Reactor Projects Chief, Branch 5, Region III Regional Administrator, Region III Michigan Public Service Commission Regulated Energy Division (kindschlamichigan.gov)

Enclosure to NRC-16-0060 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Licensee Event Report (LER) No. 2016-004, Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

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a

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3. PAGE Fermi 2 05000 341 1 OF 4

4. TITLE Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.

N/A 05000 FACILITY NAME DOCKET NUMBER 07 13 2016 2016 -

004 00 09 12 2016 N/A 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b)

[l 20.2203(a)(3)(i)

[] 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A)

El 20.2201(d)

El 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 1 El 20.2203(a)(1) 20.2203(a)(4)

Q 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(i)

El 50.36(c)(1)(i)(A)

E 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)

10. POWER LEVEL El 20.2203(a)(2)(ii)

El 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A)

[]73.71(a)(4)

El 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(iv) 50.46(a)(3)(ii)

/

50.73(a)(2)(v)(C) 73.77(a)(1) 100 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(i) 20.2203(a)(2)(vi)

El 50.73(a)(2)(i)(B)

El 50.73(a)(2)(vii) 73.77(a)(2)(ii) 50.73(a)(2)(i)(C)

E OTHER Specify in Abstract below or in The specified safety function of the SC is to contain, dilute, and hold up fission products that may leak from primary containment following a Design Basis Accident (DBA). In conjunction with operation of the Standby Gas Treatment System (SGTS) ((BH)) and closure of certain valves ((V)) whose lines penetrate the SC, the SC is designed to reduce the activity level of the fission products prior to release to the environment and to isolate and contain fission products that are released during certain operations that take place inside primary containment, when primary containment is not required to be OPERABLE, or that take place outside primary containment. It is possible for the pressure in the control volume to rise relative to the environmental pressure (e.g., due to pump ((P)) and motor ((MO)) heat load additions). To prevent ground level exfiltration while allowing the SC to be designed as a conventional structure, the SC requires support systems to maintain the control volume pressure at less than the external pressure. For the SC to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum can be established and maintained.

During this particular event, a higher indicated SC pressure was recorded 26 times for a total of 44 seconds. In Chapter 15 of the UFSAR, RBHVAC is assumed lost at the onset of a loss of coolant accident (LOCA) concurrent with a Loss of Offsite Power. As a result, calculations show that the SC would be pressurized until the SGTS restores vacuum. For this event, the structural integrity (i.e., leak tightness) of the SC was re-confirmed when RBHVAC restored pressure to less than -0.125 inches water column.

If the DBA LOCA for SC concurrent with a Loss of Offsite Power had occurred during the time when the SC pressure TS limit was exceeded, the SC was sufficiently leak tight such that the SGTS would still have established and maintained vacuum greater than the TS required value.

The radiological consequences of the DBA LOCA for SC contained in Chapter 15 of the Fermi 2 UFSAR result in doses that are below 10 CFR 50.67. The SC is assumed to be at a pressure of -0.125 inches water column at the onset of the LOCA. For this particular event, had the DBA LOCA for SC actually occurred, the increase in magnitude of radiological dose as a result of increased draw-down time from the highest recorded pressure of 0.26 vice -0.125 inches water column for between 1 and 6 seconds, would be minimal and negated by several very conservative assumptions in the existing analysis (e.g., 100% exfiltration from SC during the first 15 minutes of drawdown with SGTS in operation, 10% exfiltration from SC with SGTS in operation throughout the remaining 30 day duration of the accident, no holdup time in SC throughout the 30 day duration of the accident, and all exfiltration and filtered releases are at ground level).

Cause of the Event

The cause of this event was environmental conditions due to high winds during a severe thunderstorm.

Corrective Action

Fermi 2 will adopt Technical Specification Task Force Traveler (TSTF) 551, "Revise Secondary Containment Surveillance Requirements," when it is approved by the U.S. Nuclear Regulatory Commission. This TSTF would eliminate the need to declare SC inoperable due to momentary pressure indications above the TS SR requirement due to wind gusts, as described in this LER. Additional corrective actions will be evaluated and tracked in the Corrective Action Program (CAP).

Previous Occurrences

On July 8, 2016, SC pressure was exceeded due to high winds as documented in LER 2016-003. Corrective actions for the July 8, 2016, event were not complete prior to the event on July 13, 2016, being reported in this LER due to the short timeframe between the two events. Furthermore, on August 27, 2016, SC pressure was exceeded again due to high winds. This will be documented in a future LER and has been entered into the CAP.

During the review of these events, it was identified that wind effects have resulted in momentary pressure indications above the TS SR requirement for SC on multiple occasions. This has been entered into the CAP.Page 4

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