05000412/LER-2014-001, Regarding Unacceptable Indication Identified During Reactor Vessel Head Inspection

Regarding Unacceptable Indication Identified During Reactor Vessel Head Inspection

ML14181B080
Person / Time
Site:	Beaver Valley
Issue date:	06/27/2014
From:	Emily Larson FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-14-201 LER 14-001-00
Download: ML14181B080 (4)

LER-2014-001, Regarding Unacceptable Indication Identified During Reactor Vessel Head Inspection

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
4122014001R00 - NRC Website

text

Beaver Valley Power Station P.O. Box 4 FirstEnergy Nuclear Operating Company Eric A. Larson 724-682-5234 Site Vice President Fax: 724-643-8069 June 27, 2014 L-14-201 10 CFR 50.73 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 LER 2014-001-00 Enclosed is Licensee Event Report (LER) 2014-001-00, "Unacceptable Indication Identified During Reactor Vessel Head Inspection." This event is being reported in accordance with 10 CFR 50.73(a)(2)(ii)(A).

There are no regulatory commitments contained in this submittal. Any actions discussed in this document that represent intended or planned actions are described for the NRC's information, and are not regulatory commitments.

If there are any questions or if additional information is required, please contact Mr. William C. Cothen, Manager, Regulatory Compliance at 724-682-4284.

Sincerely, Eric A. Larson Enclosure - BVPS Unit 2 LER 2014-001-00 cc:

Mr. W. M. Dean, NRC Region I Administrator Mr. J. A. Krafty, NRC Senior Resident Inspector Mr. J. A. Whited, NRR Project Manager INPO Records Center (via INPO Consolidated Event System)

Mr. L. E. Ryan (BRP/DEP)

. & I NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 01/31/2017 (02-2014) the NRC may not conduct or sponsor, and a person is not required to respond to, the Sinformation collection.

AGE Beaver Valley Power Station Unit Number 2 050004127 1 OF 3

4. TITLE Unacceptable Indication Identified During Reactor Vessel Head Inspection

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE 1

8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MOT A

ER FACILITY NAME DOKE NUMBER NUMBER No MONTH DAY YEAR None I L L IFACILITY NAME DOCKETNUMBER 05 01 2014 2014 - 001

- 00 06 27 14 1None

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

[j 20.2201(b)

El 20.2203(a)(3)(i)

EI 50.73(a)(2)(i)(C)

LI 50.73(a)(2)(vii)

Undefined [1 20.2201(d)

El 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A)

[: 50.73(a)(2)(viii)(A)

El 20.2203(a)(1)

El 20.2203(a)(4)

El 50.73(a)(2)(ii)(B)

[: 50.73(a)(2)(viii)(B)

El 20.2203(a)(2)(i)

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

El 50.73(a)(2)(iii)

El 50.73(a)(2)(ix)(A)

10. POWER LEVEL [L 20.2203(a)(2)(ii)

E] 50.36(c)(1)(ii)(A)

LI 50.73(a)(2)(iv)(A)

[: 50.73(a)(2)(x) 0I 20.2203(a)(2)(iii)

El 50.36(c)(2)

El 50.73(a)(2)(v)(A)

[: 73.71(a)(4) 000 El 20.2203(a)(2)(iv)

RI 50.46(a)(3)(ii)

LI 50.73(a)(2)(v)(B)

El 73.71(a)(5)

LI 20.2203(a)(2)(v)

El 50.73(a)(2)(i)(A)

LI 50.73(a)(2)(v)(C)

ED OTHER Specify in Abstract below or in NRC

__ 20.2203(a)(2)(vi)

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

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

CAUSE OF EVENT

Primary Water Stress Corrosion Cracking (PWSCC) of the Alloy 600 penetration tube material was determined to be the apparent cause of the identified flaw. The failure mechanism is a known issue that is addressed by the requirements of 10 CFR 50.55a(g)(6)(ii)(D). The repair to Penetration No. 41 utilized an embedded flaw weld overlay to encapsulate the surface attached flaw with an Alloy 690 material. A weld overlay of PWSCC resistant material to isolate the indication from the borated water environment arrests any further PWSCC on the penetration. The embedded flaw weld overlay methodology was previously approved by the NRC for use at BVPS-2.

ANALYSIS OF EVENT

The safety significance associated with the BVPS Unit 2 reactor vessel upper head penetration indication found on Penetration 41 during the 2R17 refueling outage inspection is considered to be very low. This is based on the fact that the indication was not through wall, there was no indicated RCS leakage, and the estimated conditional core damage probability and conditional large early release probability for the event are very small, assuming that there is a 0.1 percent probability that the axial weld flaw could have propagated circumferentially to become a through-weld failure and ejected the penetration tube, resulting in a reactor vessel head penetration Loss of Coolant Accident (LOCA).

CORRECTIVE ACTIONS

1. Reactor head Penetration No. 41 was repaired in accordance with the applicable embedded flaw repair methodology approved by the NRC for use at BVPS-2.

Planning is ongoing for a reactor vessel head replacement which is expected to occur during a future outage at BVPS-2.

PREVIOUS SIMILAR EVENTS

Similar reactor vessel head indications were found and repaired during the previous BVPS-2 refueling outages in 2012, 2009, 2008, and 2006. The BVPS-2 reactor vessel head is an original component.

BVPS Unit 1 replaced its reactor vessel head in 2006 with a new head containing PWSCC resistant material.

CR 2014-08078