05000366/LER-2012-001, 0 for Edwin I. Hatch Nuclear Plant, 2B Standby Gas Treatment Filter Train Found Operating at Higher Flow than Allowed by Technical Specification

0 for Edwin I. Hatch Nuclear Plant, 2B Standby Gas Treatment Filter Train Found Operating at Higher Flow than Allowed by Technical Specification

ML13039A328
Person / Time
Site:	Hatch
Issue date:	02/07/2013
From:	Madison D Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-13-0303 LER 12-001-0
Download: ML13039A328 (7)

LER-2012-001, 0 for Edwin I. Hatch Nuclear Plant, 2B Standby Gas Treatment Filter Train Found Operating at Higher Flow than Allowed by Technical Specification

Event date:
Report date:
Reporting criterion:	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)(ii)(B), Unanalyzed Condition 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
3662012001R00 - NRC Website

text

oBlOis fl. M,lIl isun SoullllJrII Nucicnr

(..1 f'e p'D ~* !rJ~'ri ~

rl lid

• Opr.rllting CompallV. Illc.

1" 1111 ~ 1-' '1" H;H

! If:~ " Il illr II P<!rf':. ~ : N.* 11 O;jX! ~ l

~ f~0r'~ j.

J SOUTHERN.......

COMPA February 7, 2013 Docket No.:

50-366 NL-13-0303 U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant Submittal of Corrected Licensee Event Report 2012-001-0 2B Standby Gas Treatment Filter Train Found Operating at Higher Flow than Allowed by Technical Specification Ladies and Gentlemen:

This letter supersedes letter NL-13-0150, dated January 31, 2013, which transmitted Licensee Event Report (LER) 2012-001-0. Specifically, subsequent to its submittal, SNC discovered that the report date cited in Block 7 of the LER form was noted to be the date when the letter NL-13-0150 was signed, when, in fact, the LER was not actually transmitted until February 5,2013.

Enclosed is the corrected LER form. If you have any questions regarding this transmittal, please contact Mr. B. D. McKinney at (205) 992-5982.

Respectfully submitted,

/~

y7/L.

~{1'£7:

Vice President - Hatch DRM/SBT/lc Enclosure: LER 2-2012-001-0

U. S. Nuclear Regulatory Commission NL-13-0303 Page 2 cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bost, Executive Vice President & Chief Nuclear Officer Mr. D. R. Madison, Vice President - Hatch Mr. B. L. Ivey, Vice President - Regulatory Affairs Mr. B. J. Adams, Vice President - Fleet Operations Mr. M. A. Dowd RTYPE: CHA02.004 U. S. Nuclear Regulatory Commission Mr. V. M. McCree, Regional Administrator Mr. R. E. Martin, NRR Senior Project Manager - Hatch Mr. E. D. Morris, Senior Resident Inspector - Hatch

Edwin I. Hatch Nuclear Plant Submittal of Corrected Licensee Event Report 2012-001-0 2B Standby Gas Treatment Filter Train Found Operating at Higher Flow than Allowed by Technical Specification Enclosure Licensee Event Report 2-2012-001-0

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 9-2007)

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 re~arding burden estimate to the Records and FOINPrivacy Service Branch

- 5 F53), U.S.

LICENSEE EVENT REPORT (LER)

Nuclear Re~ulatOry Commission, Washington, DC 20555-0001, or by internet e-mail to in ocollects.resources@nrc.gov. and to the Desk Officer, Office of Information and Re~Ulalory Affairs, NEOB-l0202, (3150-0104), Office of Mana~ement and Bu get, Washington, DC 20503. " a means used to impose an in ormation collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to resoond to. the information collection.

13. PAGE Edwin I. Hatch Nuclear Plant 05000366 1 OF 4

14. TITLE "28" Standby Gas Treatment Filter Train Found Operating at Higher Flow Than Allowed by Technical Specification

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 FACILITY NAME DOCKET NUMBER 11 15 2012 2012 001 0

02 07 2013 05000

~. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) o 20.2201 (b) o 20.2203(a)(3)(i) o 50.73(a)(2)(i)(C) o 50.73(a)(2)(vii) 1 o 20.2201(d) o 20.2203(a)(3)(ii) o 50.73(a)(2)(ii)(A) o 50.73(a)(2)(viii)(A) o 20.2203(a)( 1) o 20.2203(a)(4) o 50.73(a)(2)(ii)(B) o 50. 73(a)(2)(viii)(B) o 20.2203(a)(2)(i) o 50.36(c)(1 )(i)(A) o 50.73(a)(2)(iii) o 50.73(a)(2)(ix)(A)

10. POWER LEVEL o 20.2203(a)(2)(ii) o 50.36(c)(1 )(ii)(A) o 50.73(a)(2)(iv)(A) o 50.73(a)(2)(x) o 20.2203(a)(2)(iii) o 50.36(c)(2) o 50.73(a)(2)(v)(A) o 73.71 (a)(4) o 20.2203(a)(2)(iv) o 50.46(a)(3)(ii) o 50. 73(a)(2)(v)(B) o 73.71(a)(5) 98.3%

o 20.2203(a)(2)(v) o 50.73(a)(2)(i)(A) o 50.73(a)(2)(v)(C) o OTHER o 20.2203(a)(2)(vi)

I8l 50.73(a)(2)(i)(B) o 50.73(a)(2)(v)(O)

Specify in Abstract below or in NRC Form 366A

12. LICENSEE CONTACT FOR THIS LER FACILITY NAME I ~ELEPHONE NUMBER ('ndude Area Code)

Edwin I. Hatch / Steven Tipps - Principal Engineer - Licensing 912-537-5880 MANU-REPORTABLE MANU-REPORTABLE

CAUSE

SYSTEM COMPONENT

CAUSE

SYSTEM COMPONENT FACTURER TO EPtX FACTURER TO EPIX D

BH BLO F030 Yes

14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED SUBMISSION MONTH DAY YEAR o YES (If yes, complete 15. EXPECTED SUBMISSION DATE) 181 NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)

On December 10, 2012, at 14:31 EST, with Unit 2 operating near 100 percent rated thermal power (RTP), HNP Engineering reported that removal of the Unit 2 refueling floor hatch resulted in a flow increase of approximately 60 cfm for the Unit 2 'B' Standby Gas Treatment (SGT) filter train. The 2B SGT train had recently been operating near its upper limit of 4000 cfm due to slight incremental increases in flow rate induced by normal wear and tear of door seals and other mechanical seals in the reactor building. The combination of operating so close to its upper flow limit and the increase in flow due to the removal of the refueling floor hatch caused the 2B SGT train to exceed its upper flow limit by approximately 30-50 cfm during the performance of the secondary containment test on November 15, 2012.

Records were reviewed and it was determined that the refueling floor hatch had been removed November 6, 2012. Engineering determined that the 2B SGT train would have exceeded its technical specifications flow rate during any surveillance performed since that time. The 2B SGT train was thoroughly checked and adjusted back within its flow rate limits by adjusting a flow damper on November 17,2012.

NRC FORM 366 (9-2007)

PRINTED ON RECYCLED PAPER

4 u.s. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)

(10-2010)

CONTINUATION SHEET

1. FACILITY NAME

2. DOCKET

6. LER NUMBER

3. PAGE SEQUENTIAL IREVISION YEAR NUMBER LNUMBER Edwin I. Hatch Nuclear Plant 05000366 I

2 OF 2012 001 0

NARRATlVE On December 10, 2012, at approximately 1431 EST, with Unit 2 operating at approximately 100 percent rated thermal power (RTP), HNP Engineering reported that removal of the Unit 2 refueling floor hatch resulted in an approximate increase in flow of 60 cfm for the 'B' Unit 2 Standby Gas Treatment (SGT) filter train. The 2B SGT train had recently been operating near its upper limit of 4000 cfm. The combination of operating so close to its upper flow limit and the increase in flow due to the removal of the refueling floor hatch, the 2B SGT train exceeded its upper flow limit by approximately 30-50 cfm during the performance of the secondary containment test on November 15, 2012.

When the secondary containment surveillance was completed on November 15, 2012, a timeout was called while the operating crew and engineers reviewed the results of the test.

Since drawdown (dP greater than 0.20 in WG within 120 seconds) was achieved and maintained for one hour with considerable margin, secondary containment was determined to be operable throughout the test. While the flow rate of SGT is required to be between 3000 and 4000 cfm by the Ventilation Testing Program in Technical Specifications 5.5.7, the upper and lower limits were derived from calculations prepared for each of the dual safety functions of SGT. The minimum flow rate ensures drawdown of secondary containment while the upper flow limit ensures holdup and residence time in the treatment train are effective for removal of activated gaseous elemental iodine and methyl iodide in the carbon bed.

The SGT train exceeded its technical specifications upper limit at approximately 20 minutes into the surveillance and fluctuated between 4020 and 4030 cfm during the rest of the surveillance. No release had occurred, but the 2B train of SGT was determined to be inoperable for its residence time requirement and the crew entered a required action statement on November 15, 2012 in accordance with Technical Specification 3.6.4.3. A subsequent apparent cause determination found that HI\\JP currently has no trending or monitoring programs that are capable of determining the point at which normal wear and tear of mechanical seals in the reactor building is likely to cause the SGT train to operate at increased flow rates. In response, an administrative limit of 3900 cfm flow was set on SGT 2B while trending and monitoring were updated. This flow rate bounds secondary containment configurations and ensures the SGT flow remains below the upper Technical Specification flow limit, while ensuring that drawdown can be achieved.

The question of whether or not the "as found" condition of the 2B SGT filter train was a condition that existed prior to its discovery on 11/15/2012 was pursued in order to determine if the condition met NRC reporting requirements. This information was provided 12/10/2012, at which time the determination was made that there was firm evidence that the "as found" condition of the 2B SGT filter train would have automatically operated at greater than the 4,000 cfm Technical Specifications limit. This response established the starting time frame for the 60 day report to the NRC.

REPORTABILITY ANALYSIS AND SAFETY ASSESSMENT This event is reportable in accordance with Title 10 of the Code of Federal Regulations (CFR), Part 50.73(a)(2)(i)(B) because an event occurred which is prohibited by Technical Specification 3.6.4.3. u.s. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)

(10-2010)

CONTINUATION SHEET I

1. FACILITY NAME

2. DOCKET

6. LER NUMBER

3. PAGE SEQUENTIAL IREVISION YEAR NUMBER NUMBER Edwin I. Hatch Nuclear Plant 05000366 3

OF 4

2012 001 o

NUREG 1022 notes that "discrepancies found in technical specifications surveillance tests should be assumed to occur at the time of the test unless there is firm evidence, based on a review of relevant information (e.g., the equipment history and the cause of failure) to indicate that the discrepancy occurred earlier. Based on this guidance and the discovery that the refueling floor hatch had been removed for 11 days, the determination was made that this "as found" condition is reportable under the requirements of 1 OCFR50. 73(a)(2)(i)(B).

The function of the secondary containment is to contain, dilute, and detain fission products that may leak from primary containment following a Design Basis Accident (DBA). In conjunction with operation of the Standby Gas Treatment (SGT) System and closure of certain valves whose lines penetrate the secondary containment, the secondary containment is designed to reduce the activity level of the fission products prior to release to the environment.

This is necessary 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. It is also necessary for events that take place outside primary containment.

The secondary containment is a structure that completely encloses the primary containment and those components that may be postulated to contain primary system fluid. This structure forms a control volume that serves to detain and dilute the fission products. It is possible for the pressure in the control volume to rise relative to the environmental pressure (e.g., due to pump and motor heat load additions). The secondary containment encompasses three separate zones: the Unit 1 reactor building (Zone I), the Unit 2 reactor building (Zone II), and the common refueling floor (Zone III).

For the secondary containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum (0.20 inch of vacuum WG) can be established within 120 seconds and be maintained. The secondary containment boundary required to be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, SCIVs, and available flow paths to SGT Systems. The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the condition of each unit, and furthermore, must include zones not isolated from the SGT subsystems being credited for meeting LCO 3.6.4.3.

The Unit 1 and Unit 2 SGT Systems automatically start and operate in response to actuation signals indicative of conditions or an accident that could require operation of the system.

Following initiation, all required charcoal filter train fans start. Upon verification that the required subsystems are operating, the redundant required subsystem is normally shut down.

There are two principal accidents for which credit is taken for secondary containment operability. These are a loss of coolant accident (LOCA) and a fuel handling accident inside secondary containment. The secondary containment performs no active function in response to either of these limiting events; however, its leak tightness is required to ensure that the release of radioactive materials from the primary containment is restricted to those leakage paths and associated leakage rates assumed in the accident analysis and that fission products entrapped within the secondary containment structure will be treated by the Unit 1 and Unit 2 SGT Systems prior to discharge to the environment. Postulated LOCA leakage paths from the primary containment into secondary containment include those into both the reactor building LICENSEE EVENT REPORT (LER) u.s. NUCLEAR REGULATORY COMMISSION (10-2010)

CONTINUATION SHEET

1. FACILITY NAME

2. DOCKET

6. LER NUMBER

3. PAGE SEQUENTIAL

/REVISION YEAR NUMBER NUMBER

/

Edwin I. Hatch Nuclear Plant 05000366 4

OF 4

2012 001 0

and refueling floor zones (e.g., drywell head leakage).

For this event secondary containment was in the Type 'A' configuration and the SGT filter trains used established the required vacuum with a good margin well within the required time frame of 120 seconds. The flow of the 2B SGT filter train was approximately 3875 cfm at the onset of the test and within 20 minutes had reached approximately 4020 cfm. The increase in vacuum that accompanied the increase in SGT flow rate was expected and was a clear indication that the increase in flow of the 2B SGT filter train did not affect the presumption of operability of secondary containment. The test revealed the degraded condition of the 2B SGT filter train flow, which affected its operability. This "as found" condition had no effect on the ability to maintain the secondary containment structure as the required vacuum was maintained and the secondary containment safety function was preserved. Based on this information this event had no adverse impact on nuclear safety.

CORRECTIVE ACTIONS

The volume damper on the discharge of the 2B SGT filter train fan (2T 46-C001 B) was adjusted to achieve the administrative limit of 3900 cfm. Engineers were directed through the Corrective Action Program to utilize the results from the Operations surveillance procedure to determine the optimal flow rate at which actions are taken to repair seals and other conservation measures well before the 2B SGT technical specification upper flow rate limit is approached. These limits were incorporated into plant procedure(s).

ADDITIONAL INFORMATION

Other Systems Affected: None

Failed Components Information

Master Parts List Number:

2T46-D001B EllS System Code: BH Manufacturer: Farr Company Reportable to Epix: Yes Model Number: N-208-2 Root Cause Code: D Type: Filter Train EllS Component Code: BLO Manufacturer Code: F030 Commitment Information: This report does not create any new permanent licensing

PREVIOUS SIMILAR EVENTS

None were identified.