Text

Response to Disputed Non-Cited Violation - IR 05000455-09-003
	ML093220952
Person / Time
Site:	Byron
Issue date:	11/18/2009
From:	Pederson C; NRC/RGN-III
To:	Pardee C; Exelon Generation Co, Exelon Nuclear
References
	EA-09-247, IR-09-003
	Download: ML093220952 (5)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

REGION III

2443 WARRENVILLE ROAD, SUITE 210

LISLE, IL 60532-4352

November 18, 2009

EA-09-247

Mr. Charles G. Pardee

Senior Vice President, Exelon Generation Company, LLC

President and Chief Nuclear Officer (CNO), Exelon Nuclear

4300 Winfield Road

Warrenville IL 60555

SUBJECT: RESPONSE TO DISPUTED NON-CITED VIOLATION BYRON STATION,

UNIT 2, INSPECTION REPORT 05000455/2009003

Dear Mr. Pardee:

On September 8, 2009, Mr. Daniel J. Enright, Exelon Generation Company, LLC

(Exelon), Byron Station, Unit 2 provided a response to an NRC Inspection Report issued

on August 7, 2009, concerning activities conducted at your facility. Specifically, the Exelon

letter contested one non-cited violation (NCV) contained in the inspection report, namely

NCV 05000455/2009003-01, associated with the Failure to comply with Technical Specification (TS) 3.4.13.B reactor coolant system (RCS) pressure boundary leakage." By our letter dated

October 8, 2009, the NRC acknowledged your letter and advised you that we were evaluating

your reply and would inform you of the results of our evaluations. We have completed our

review of your response.

In the September 8, 2009 letter, your staff stated that on June 24, 2009, Byron Station Unit 2

correctly complied with TS 3.4.13.B. Specifically, the leakage from the process sampling line

was an isolable reactor coolant system pressure boundary leak and therefore excluded from

TS 3.4.13 pressure boundary limit. Your staff provided information to support this position,

including:

an interpretation of the definition of a "nonisolable fault and inferred definition of isolable

fault;

the potential for uncontrolled RCS leakage growth and further deterioration did not exist in

this process line fault condition because an isolation valve upstream of the fault was closed;

the leakage was bounded by 0.5 gpm, the design seat leakage past this valve's seat. At the

time of the event, the leakage past the valve seat was very small;

the very small leakage past the isolation valve's seat was acceptable because leak tightness

(zero leakage) is not a requirement as evidenced by allowed leakages for other TS valves;

and

C. Pardee -2-

the NCV is not consistent with how the NRC approached similar situations at other utilities.

NRC Staff's Review:

The NRC staff reviewed the information you provided to determine whether the leakage from

the process sampling line should be classified as a pressure boundary leak as stated in the

Inspection Report or as identified leakage as presented in your September 8, 2009, letter.

These staff members were independent of the initial inspection effort. The staff members

reviewed several documents including Regulatory Guide 1.45, Guidance on Monitoring and

Responding to Reactor Coolant System Leakage, and NUREG 1431, Standard Technical

Specifications Westinghouse Plants, recordings of discussions associated with a request for

a Notice of Enforcement Discretion, Action Report 000934800, numerous emergency

notifications, and licensee events reports. After careful consideration of the information you

provided, we have concluded that the violation occurred as stated in the inspection report.

Pressure boundary leakage as defined by TS 1.1 is LEAKAGE (except SG [steam generator]

LEAKAGE) through a nonisolable fault in an RCS component body, pipe wall, or vessel wall.

On June 26, 2009, your staff identified a pinhole in a weld on a reactor coolant system piping

connection between a closed sample isolation valve (2PS9350B) and the closed inboard

containment isolation valve (2PS9355B). The source of the leakage was pressure boundary

piping. Your staff provided information with respect to the definition of nonisolable. The staff

agrees that an isolation device in a piping system could be used to isolate a leak such that the

leak would not be considered pressure boundary leakage as defined above. The staff agrees

the leakage would be bounded by the design seat leakage of about 0.5 gpm during the periods

of time the sample isolation valve (2PS9350B) remained closed. However, prior to the repairs

on June 26, the as-found position of the sample isolation valve (2PS9350B) did not isolate the

pressure boundary flaw, that is, leakage continued through the weld.

Your letter presented a position that valve seat for 2PS9350B did not need to be leaktight as

evidenced by the allowance of leakage past pressure isolation valve seats. The staff agrees

that NUREG 1431, Standard Technical Specifications Westinghouse Plants, specifically states

that the leakage past the pressure isolation valve seats is not pressure boundary leakage;

however, no such distinction is made with other valves. The leakage limit for the pressure

isolation valves is an indication that the pressure isolation valves themselves are degraded or

degrading and is not indicative of material degradation of a pressure retaining component,

piping wall or vessel wall.

Although the leakage through the weld was very small, the staff concluded the leak through the

pinhole in the weld was a breach in the pressure boundary and indicative of degradation of the

material of pressure retaining components. Therefore, the leak through the pinhole in the weld

constituted pressure boundary leakage and the violation as stated is valid. With respect to an

apparent inconsistency with how the NRC approached similar situations at other utilities, each

situation was evaluated independently. The staff does believe that the Standard Technical

Specifications should be clarified to avoid future confusion on this issue. Accordingly, the staff

will engage the Technical Specifications Task Force, and work with them to provide a solution,

which can be made available for adoption by licensees through the NRC's Consolidated Line

Item Improvement process.

C. Pardee -3-

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and your

September 8, 2009, response will be available electronically for public inspection in the NRC

Public Document Room or from the NRC's document system (ADAMS), accessible from the

NRC Web site at http://www.nrc.gov/reading-rm/adams.html.

Sincerely,

/RA/

Cynthia D. Pederson

Deputy Regional Administrator

Docket No. 50-455

License No. NPF-66

cc w/encl: Distribution via ListServ

C. Pardee -3-

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and your

September 8, 2009, response will be available electronically for public inspection in the NRC

Public Document Room or from the NRC's document system (ADAMS), accessible from the

NRC Web site at http://www.nrc.gov/reading-rm/adams.html.

Sincerely,

/RA/

Cynthia D. Pederson

Deputy Regional Administrator

Docket No. 50-455

License No. NPF-66

cc: Distribution via ListServ

DOCUMENT NAME: G:\Byron\disputed violation letter.doc

Publicly Available Non-Publicly Available Sensitive Non-Sensitive

To receive a copy of this document, indicate in the concurrence box "C" = Copy without attach/encl "E" = Copy with

attach/encl "N" = No copy

OFFICE RIII RIII RIII RIII RIII

NAME RSkokowski:dtp AMStone SOrth *PL SWest CPederson

for*(see below)

DATE 11/10/09 11/10/09 11/10/09 11/16/09 11/18/09

OFFICIAL RECORD COPY

also indicates that NRR and OE have reviewed this position and concur

Letter to C. Pardee from C. Pederson dated November 18, 2009.

SUBJECT: RESPONSE TO DISPUTED NON-CITED VIOLATION BYRON STATION,

UNIT 2, INSPECTION REPORT 05000455/2009003

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