05000387/LER-2012-006, Regarding D Outboard Main Steam Isolation Valve Leakage

Regarding D Outboard Main Steam Isolation Valve Leakage

ML12195A019
Person / Time
Site:	Susquehanna
Issue date:	07/12/2012
From:	Helsel J Susquehanna
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-6879 LER 12-006-00
Download: ML12195A019 (4)

LER-2012-006, Regarding D Outboard Main Steam Isolation Valve Leakage

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 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)(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)(v), Loss of Safety Function
3872012006R00 - NRC Website

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U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OP1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2012-006-00 LICENSE NO. NPF-14 PLA-6879 Docket No 50-387 Attached is Licensee Event Report (LER) 50-387/2012-006-00. The event involved the Unit 1 "D" Outboard Main Steam Isolation Valve (MSIV) exceeding its Technical Specification (TS) leakage limit. This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications. The Unit 1 "D" Outboard MSIV also exceeded the TS leakage criteria during the previous refueling outage in 2010, and this LER also is intended to meet the reporting requirements for that event.

There were no actual consequences to the health and safety of the public as a result of this event.

No r_>.g a tory commitments are associated with this LER.

L!Ji~Jl'tj J.

- ~1 Attachment: LER 50-387/2012-006-00 Copy:

NRC Region I Mr. P. W. Finney, NRC Sr. Resident Inspector Mr. R. R. Janati, DEP/BRP Ms. C. J. Sanders, NRC Project Manager TM

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BYOMB: NO. 3150-0104 EXPIRES:1 0/31/2013 (10-2010)

, the NRC digits/characters for each block) may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Susquehanna Steam Electric Station Unit 1 05000387 1 OF3

4. TITLE "D" Outboard Main Steam Isolation Valve Leakage

5. EVENT DATE

6. LEA NUMBER

7. REPORT DATE

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

MONTI-DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 04 09 2012 2012

- 006

- 00 07 ld-2012 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 5 D 2o.2201(b)

D 20.2203(a)(3)(i)

D 50.73(a)(2)(i)(C)

D 50.73(a)(2)(vii)

D 20.2201 (d)

D 20.2203(a)(3)(ii)

D 50.73(a)(2)(ii)(A)

D 50.73(a)(2)(viii)(A)

10. POWER LEVEL D 20.2203(a)(1)

D 20.2203(a)(4)

D 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B)

D 20.2203(a)(2)(i)

D 50.36(c)(1 )(i)(A)

D 50.73(a)(2)(iii)

D 50.73(a)(2)(ix)(A) 0%

D 20.2203(a)(2)(ii)

D 50.36(c)(1 )(ii)(A)

D 50.73(a)(2)(iv)(A)

D 50.73(a)(2)(x)

D 20.2203(a)(2)(iii)

D 50.36(c)(2)

D 50.73(a)(2)(v)(A)

D 73.71 (a)(4)

D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

D 50.73(a)(2)(v)(B)

D 73.71 (a)(5)

D 20.2203(a)(2)(v)

D 50.73(a)(2)(i)(A)

D 50.73(a)(2)(v)(C) 00THER D 20.2203(a)(2)(vi)

[gl 50.73(a)(2)(i)(B)

D 50.73(a)(2)(v)(D)

Specify in Abstract below or in Event in 2010 The causes of the event was determined to be as follows:

2012

- 006 The valve body seat had poor contact area at the lower segment (6 o'clock location)

- 00

3. PAGE 30F3 The X-7D as-left penetration leakage having minimal margin to the TS limit, contributed to the as-found testing failure in the next refueling outage.

ANALYSIS/SAFETY SIGNIFICANCE

Actual Consequences:

The actual safety consequence of the "D" inboard MSIV LLRT failures is minimal. The MSIVs have a safety function to close to prevent a large release of radiation to the site boundary under accident conditions. As-Found and As-Left LLRTs of "D" Main Steam Line Penetration X-7D in both 2010 and 2012 demonstrated that "D" inboard MSIV penetration would have performed satisfactorily to prevent the release of radioactive materials through penetration X-7D.

Potential Consequences:

The potential consequence is that, in the event of a LOCA combined with a failure of the "D" Inboard MSIV to isolate, the "D" Outboard MSIV would not have isolated Penetration X-7D sufficiently to prevent fission products from being released. This potential consequence involves multiple safety system failures both to cause the LOCA and then to create the release path.

CORRECTIVE ACTIONS

Key corrective actions:

1.

Engineering will benchmark industry best practices for MSIV reworks.

2.

The MSIV rework procedure will be revised to address the identified issues.

3.

Replacing, instead of reworking, the poppet assembly for MSIVs that have failed their As-Found LLRT will be evaluated.

4.

A root cause evaluation will be performed for these events.

PREVIOUS SIMILAR EVENTS

The following LER was also the result of:

A cause of this LER was a less than adequate procedure. The following recent LERs identified similar causes:

LER 387/2011-002, "Unit 1 Manual Scram Due to Unisolable Extraction Steam System Leak" identified deficient work instructions as one of the causes.

LER 388/2011-003, "Unit 2 Scram due to Main Turbine Trip during ICS Surveillance Testing" identified conflicting and unclear procedure requirements and less than adequate reinforcement of management expectations for work package content as one of the causes.

LER 388/2011-002, "Condition Prohibited by Technical Specification Due to Unknown RCIC lnoperability" identified test procedures that did not test all aspects of the system that were relied upon for operability.