05000387/LER-2016-020, Regarding Reactor Coolant Pressure Boundary Leakage at LPRM Housing as a Result of IGSCC

Regarding Reactor Coolant Pressure Boundary Leakage at LPRM Housing as a Result of IGSCC

ML16216A378
Person / Time
Site:	Susquehanna
Issue date:	08/03/2016
From:	Franke J Susquehanna, Talen Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7508 LER 16-020-00
Download: ML16216A378 (4)

LER-2016-020, Regarding Reactor Coolant Pressure Boundary Leakage at LPRM Housing as a Result of IGSCC

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2) 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
LER closed by
IR 05000387/2016004 (10 February 2017)
3872016020R00 - NRC Website

text

AUG 0 3 2016 Jon A. Franke Susquehanna Nuclear, LLC Site Vice President 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.2904 Fax 570.542.1504 Jon.Franke@TalenEnergy.com U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2016-020-00 UNIT 1 LICENSE NO. NPF-14 PLA-7508 TALEN~

ENERGY 10 CFR 50.73 Docket No. 50-387 Attached is Licensee Event Report (LER) 50-387/2016-020-00. This LER reports a degraded condition conceming a leak in the Reactor Coolant Pressure Boundary. This LER is being submitted pursuant to the requirements of 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(ii)(A) as a condition prohibited by Technical Specifications and as degradation of a principal safety barrier.

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

This letter contains no new regulatory commitments.

~~

~.J.-4.~/,

J. A. Franke Attachment: LER 50-387/2016-020-00 Copy:

NRC Region I Mr. J. E. Greives, NRC Sr. Resident Inspector Ms. T. E. Hood, NRC Project Manager Mr. M. Shields, PA DEP/BRP

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (11-2015)

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

r* PAGE Susquehanna Steam Electric Station Unit 1 05000387 1 of 3

4. TITLE Reactor Coolant Pressure Boundary Leakage at LPRM Housing as a result of IGSCC

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR MONTH DAY YEAR 05000 NUMBER NO.

()3 FACILITY NAME DOCKET NUMBER 06 08 2016 2016

- 020

- 00 06 2016 05000

9. OPERATING MODE

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

D 2D.2201(b)

D 20.2203{a)(3)(i)

~ 50.73(a)(2){ii)(A)

D 50.73(a)(2){viii)(A) 4 D 20.22D1{d)

D 20.2203(a)(3)(ii)

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

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

D 20.2203(a)(1)

D 20.2203(a)(4)

D 50.73(a)(2)(iii)

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

D 20.2203(a)(2)(i)

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

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

D 50.73(a)(2)(x)

D 20.2203(a)(2)(ii)

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

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

D 73.71(a)(4)

10. POWER LEVEL D 20.2203(a)(2)(iii)

D 50.36(c)(2)

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

D 73.71(a){5)

D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

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

D 73.77(a)(1) 000 D 20.2203(a)(2)(v)

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

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

D 73.77(a)(2)(i)

D 20.2203(a)(2)(vi)

~ 50.73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D 73.77(a)(2)(ii)

D 50.73(a)(2)(i)(C) 0 OTHER Specify in Abstract below or in

ANALYSIS/SAFETY SIGNIFICANCE

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

2. DOCKET NUMBER

3. LER NUMBER YEAR I SEQUENTIAL I REV NUMBER NO.

05000387 2016

- 020

- 00 Technical Specification Limiting Condition for Operation (LCO) 3.4.4, RCS Operational Leakage, requires no pressure boundary leakage and less than or equal to 5 gallons per minute (GPM) unidentified leakage when operating in Modes 1, 2 and 3. At the time of discovery, Unit 1 was in Mode 4.

The 5 GPM Technical Specification limit for unidentified leakage is a small fraction of the calculated flow from a critical crack in the primary system piping. Crack behavior from experimental programs show that leakage rates of hundreds of gallon per minute will precede crack instability. As such, the Technical Specification limit allows time for corrective action to be taken before the RCPB could be significantly compromised. The RCPB leak identified during this event was about 2 drops per minute (DPM) with the reactor in depressurized conditions. It is estimated that during rated plant operations, the leakage would have been about 68 DPM or about 0.0009 GPM. Using the crack length identified by Ultrasonic Testing, the point at which the crack became through-wall is estimated to have occurred about 10 months prior to discovery. Based on the information above, including the size of the crack, and the estimated maximum leakage rate, this leak was a small contributor to the actual drywell unidentified leakage of about 0.53 GPM prior to plant shutdown and resulted in no actual consequence to public health or safety.

CORRECTIVE ACTIONS

The corrective action to address this event was to repair the through wall leak on the LPRM 24-09 housing using an ASME Section XI weld repair. In addition, a visual inspection was performed on all the Unit 1 LPRM, IRM, and SRM In-core monitor housings and no further issues were identified. Lastly, an extent of condition review will be performed through visual inspections of the Unit 2 LPRM, IRM and SRM in-core housings during the next refueling outage.

No other corrective actions are required for this event.

COMPONENT FAILURE INFORMATION

Vendor Component: General Electric In-core Housing Material: SA 182-304

PREVIOUS SIMILAR EVENTS

LER 50-388/ 2015-004-00, PLA-7337, "Degraded Condition Due to Reactor Coolant Pressure Boundary Leakage Caused by Vibration and Stiff Pipe Connection." June 10, 2015.

LER 50-387/2015-009-00, PLA-7419, "Pressure Boundary Leakage from an Inadequate Weld Repair in Small Bore Pump Seal Vent Piping." January 11, 2016.

LER 50-387/2014-011 -00, PLA-7286, "Degraded Condition Due to Reactor Coolant Pressure Boundary Leakage Caused by an Inadequate Weld." February 11, 2015.

NRC FORM 366 (11-2015)