05000341/LER-2016-014, Regarding Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

Regarding Secondary Containment Pressure Exceeded Technical Specification Due to Adverse Weather

ML17010A299
Person / Time
Site:	Fermi
Issue date:	01/10/2017
From:	Polson K DTE Electric Company, DTE Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC- 17-0002 LER 16-014-00
Download: ML17010A299 (6)

LER-2016-014, 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)(vii)(B), Common Cause Inoperability 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)
LER closed by
IR 05000341/2017001 (1 May 2017)
3412016014R00 - NRC Website

text

Keith 4. Poison Site Vice President DTIE Energy Comnpany 6400 'N. Dixie Highway, Nwport, MlI 4866 Tel: 734.586,4849 Fax: 734.5864 72 Ema il: keith.polson dteienergy com DTE Energy-10 CFR 50.73 January 10, 2017 NRC-17-0002 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0002

Reference:

Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43

Subject:

Licensee Event Report (LER) No. 2016-014 Pursuant to 10 CFR 50.73(a)(2)(v)(C), DTE Electric Company (DTE) is submitting LER No. 2016-014, 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. 2016-0 14 cc: NRC Project Manager NRC Resident Office Reactor Projects Chief, Branch 5, Region III Regional Administrator, Region III Michigan Public Service Commission R egulated Energy Division (kindschl~michigan.gov)

Enclosure to NRC-17-0002 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Licensee Event Report (LER) No. 2016-014

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3160-0104 EXPIRES: 10131/2018 (06-2016)

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.

LICENSEE EVENT REPORT 'LER Send comments regarding burden estimate to the FOIA, Privacy and Information Collections LEOBranch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail (See Page 2 for required number of digits/characters for each block) 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 (See NUREG-1022, R.3 for instruction and guidance for completing this form 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.

3. PAGE Fermi 2 05000 341 1 OF 4

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

6. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED SEUENTAL REV FAcILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SUE A

Rv MONTH DAY YEAR N/A 05000 1 2FAcILITY NAME DOCKET NUMBER 2016 014 00 2017 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) 20.2203(a)(3)(i)

Q 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2201(d) 20.2203(a)(3)(ii)

Q 50.73(a)(2)(ii)(B)

Q 50.73(a)(2)(vii)(B) 1 20.2203(a)(1) 20.2203(a)(4) j 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)

10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4) 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)

Ej50.73(a)(2)(i)(B) 50.73(a)(2)(vii)

[j73.77(a)(2)(ii) 50.73(a)(2)(i)(C)

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 on multiple occasions for approximately one second each. In Chapter 15 of the Updated Final Safety Analysis Report (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 SC vacuum was restored to greater than 0.125 inches vacuum water gauge in one second without Operator action when the wind subsided.

If the DBA LOCA for SC concurrent with a Loss of Offsite Power had occurred during the times 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 0.125 inches vacuum water gauge at the onset of the LOCA.

For these particular events, 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 +0.160 inches water gauge vice -0.125 inches water gauge for one second, would be minimal and negated by several very conservative assumptions in the existing analysis (e.g., 100 percent 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 effect of the high winds outside of the RB caused the momentary losses of SC.

The high winds outside the RB are known to cause large and rapid changes in RB differential pressure (i.e. between inside and outside the RB). There are two divisions to monitor SC pressure. Each division has four pressure transmitters

((PT)) located on the RB fifth floor, one on each of the four RB walls, with a pressure probe that penetrates the wall to the outside, and a recorder. The recorder indicates the highest pressure of the four inputs from the transmitters. Using the equation provided in Section 6.2 of the Fermi 2 UFSAR, wind speeds of 30 to 60 miles per hour (mph) on the RB result in an external pressure change of -0.27 to -1.07 inches water gauge on the leeward side of the building. The negative change on the leeward side of the building results in a higher indicated RB pressure. As a result, high wind gusts are sufficient to cause momentary indicated loss of SC even with no other contributing causes.

CORRECTIVE ACTIONS

No corrective actions were required to restore compliance with TS SR 3.6.4.1.1 as pressure was restored at the time of the event without Operator action when the wind subsided.

Corrective actions for similar events were identified in LERs 2016-003, 2016-004, 2016-007, 2016-008, 2016-010, and 2016-013 including adopting 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 exceeding the TS limit, such as those caused by wind gusts as described in this LER. Additional corrective actions taken in response to these past occurrences included benchmarking how other sites monitor and evaluate environmental effects on SC pressure, evaluating potential changes to how SC pressure is monitored at Fermi 2, and evaluating potential revisions to the Fermi 2 licensing basis.

Based on these actions, a modification was completed on December 23, 2016, to prevent momentary SC pressure indications from being received.

PREVIOUS OCCURRENCES

Similar events involving loss of SC due solely to high winds have been reported in the following LERs:

1) LER 2016-003 involved the loss of SC due to high winds on July 8, 2016.

2) LER 2016-004 involved the loss of SC due to high winds on July 13, 2016.

3) LER 2016-007 involved the loss of SC due to high winds on August 27, 2016.

4) LER 2016-008 involved a past reportability review of the loss of SC due to high winds for the period from September 1, 2013, to September 30, 2016.

5) LER 2016-010 involved the loss of SC due to high winds on October 26, 2016, and also a past reportability review of the loss of SC due to high winds for the period from October 1, 2016, to November 18, 2016.

6) LER 2016-013 involved the loss of SC due to high winds on November 19-20, 2016, and also a past reportability review of the loss of SC due to high winds for the period from November 19, 2016, to December 15, 2016.

The corrective actions for the above events were still in progress at the time of this event and, therefore, could not have prevented the instances included in this LER.Page 4

of 4