United States Nuclear Regulatory Commission - Protecting People and the Environment

NOED-00-6-003 - LaSalle (Commonwealth Edison Company)

February 23, 2000

Mr. Oliver D. Kingsley, President
Nuclear Generation Group
Commonwealth Edison Company
Executive Towers West III
1400 Opus Place, Suite 500
Downers Grove, IL 60515

SUBJECT: LASALLE - NOTICE OF ENFORCEMENT DISCRETION, NOED NO. 00-6-003 (TAC NO. MA8241)

Dear Mr. Kingsley:

By letter dated February 18, 2000, Commonwealth Edison Company (ComEd, the licensee) requested that the NRC exercise discretion not to enforce compliance with the actions required in Technical Specification (TS) 3.4.8, "Structural Integrity." ComEd's letter documented information previously discussed with the NRC in a telephone conference on February 18, 2000, at 10:45 a.m. EST. The principal NRC staff members who participated in that telephone conference included S. Singh Bajwa, Director, Project Directorate III, NRR; Marc Dapas, Deputy Director, Division of Reactor Projects, Region III; William Bateman, Chief, Materials and Chemical Engineering Branch, NRR; John Jacobson, Chief, Mechanical Engineering Branch, Region III; Anthony Mendiola, Section Chief, Project Directorate III, NRR; Keith Wichman, Section Chief, Materials and Chemical Engineering Branch, NRR; Darrel Roberts, Acting Chief, Branch 2, Division of Reactor Projects, Region III; Eric Duncan, LaSalle Senior Resident Inspector; Paul Krohn, LaSalle Resident Inspector; Michael Parker, Senior Reactor Analyst, Region III; Ken Riemer, Project Engineer, Division of Reactor Projects, Region III; William Koo, Materials and Chemical Engineering Branch, NRR; Jack Foster, Technical Specifications Branch, NRR; and Donna Skay, LaSalle Project Manager, Project Directorate III, NRR.

During our phone call, ComEd stated that on February 18, 2000, at 3:27 p.m. CST, LaSalle Unit 2 would not be in compliance with TS 4.0.5.f. TS 4.0.5.f requires that the inservice inspection program for piping identified in NRC Generic Letter (GL) 88-01, "NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping," be performed in accordance with the NRC staff positions on schedule, methods, personnel, and sample expansion included in GL 88-01 or in accordance with alternate measures approved by the NRC staff. Because your staff determined that a weld examination was not conducted in accordance with the augmented inspection program required by GL 88-01, Unit 2 entered TS 3.4.8 Action A, which requires restoration of the affected component before increasing the reactor coolant system temperature more than 50 degrees Fahrenheit above the minimum temperature required by nil ductility temperature (NDT) considerations. Since the unit was at a temperature in excess of this requirement when the condition was discovered, the action statement could not be complied with and entry into TS 3.0.3 was required. Because entry into TS 3.0.3 was due to a missed surveillance, Surveillance Requirement (SR) 4.0.3 was applied, allowing 24 hours until the action statement requirements must be applied. ComEd requested that a Notice of Enforcement Discretion (NOED) be issued pursuant to the NRC's policy regarding exercise of Section VII.c of the "General Statement of Policy and Procedures for NRC Enforcement Actions" (Enforcement Policy) in NUREG-1600, and be effective from February 18, 2000, until ComEd's request for an exigent amendment is approved to allow continued operation of Unit 2 by deferring the required augmented inspection of a weld until the next refueling outage. This letter documents our telephone conversation on February 18, 2000, starting at 10:45 a.m. EST when we verbally issued this NOED.

ComEd stated that during a review of historical intergranular stress corrosion cracking (IGSCC) weld examination data, a clerical error was discovered involving two IGSCC-susceptible welds in the Unit 2 "A" residual heat removal shutdown cooling return piping. The stress relief that was believed to have been applied to welds RH-2005-28 and RH-2005-29 was actually applied to other welds. Consequently, these two welds have never been subjected to any stress improvement process and should have been categorized as IGSCC Category D welds in accordance with GL 88-01. The examination for Category D welds would have required that the two welds be examined every two refueling cycles, beginning with refueling cycle L2R02 in 1987. Examinations of weld RH-2005-28 were not completed during the third or fifth refueling outages, but the weld was examined during the seventh refueling outage (which ended in April 1999) with no indication of cracking noted. Therefore, weld RH-2005-28 is not required to be examined again until the ninth refueling outage (L2R09) beginning fall 2002. Weld RH-2005-29 was examined in the third refueling outage (March 1990) with no indication of cracking noted, but was not reexamined during the fifth or seventh refueling outages. Examination of the welds requires the plant to be in a shutdown condition. ComEd stated that it is requesting an NOED to allow continued operation of Unit 2 by deferring the required augmented examination of the weld until the next refueling outage in order to avoid cycling the unit through a thermal transient.

ComEd stated that industry experience with Category D welds has been excellent with only one reported crack in a Category D weld in the past eight years, as noted in a report by the Boiling Water Reactor Vessel and Internals Project, BWRVIP-75 (EPRI TR-113932), "BWR Vessel and Internals Project, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules." In addition, ComEd stated that industry experience has revealed that small-bore, thin-wall pipe will develop IGSCC flaws early in life and, therefore, if this weld were to crack, cracking would have occurred prior to the examinations in 1990. ComEd also stated that, based on a review of the LaSalle Unit 2 reactor water chemistry program, chemistry parameters have been maintained within Electric Power Research Institute (EPRI) guidelines 93.7 percent of the time since the last inspection of weld RH-2005-29 in 1990 and, when a non-standard condition developed, the EPRI guidelines were followed to restore chemistry to normal operating parameters. ComEd stated that no major chemistry excursions have occurred since the last weld examination in 1990. ComEd also stated that, if the weld is actually flawed due to weld-unique conditions, safety is not jeopardized because austenitic stainless steel is ductile and IGSCC has an irregular crack form and, therefore, the piping will leak before it breaks. ComEd stated that a plant-specific flaw evaluation was performed to assess the weld using the loads from the LaSalle stress reports and the results are bounded by the EPRI report NP-4991, "Application of the Leak-before-Break Approach to BWR Piping." Therefore, ComEd concluded that if weld RH-2005-29 is flawed, it will create a leak that would be readily detected by reactor coolant system leakage detection instrumentation well in advance of the pipe break. ComEd stated that, as a compensatory action, the leak detection system is operating properly and will provide reasonable assurance that small leaks across the reactor coolant system boundary can be detected.

The NRC staff reviewed ComEd's safety rationale for the requested NOED and verified that the request not to enforce compliance with TS 3.4.8 for weld number RH-2005-29 until the exigent amendment is reviewed and approved does not involve a significant increase in risk to the safe operation of LaSalle Unit 2. The proposed TS change will involve adding a footnote to TS 4.0.5.f that defers examination of weld RH-2005-29 until the next scheduled refueling outage, L2R08, or December 31, 2000, whichever is earlier. The staff notes that there have been very few Category D weld cracks reported and is aware of industry initiatives to extend the examination frequency for these welds from every other refuel cycle to once every 6 years. In addition, the staff finds that the reactor water chemistry for Unit 2 since the last examination of weld RH-2005-29 in 1990 has been good, as evidenced by the fact that only one significant chemistry excursion occurred in the last 10 years and it resulted in conductivity, sulfate, and chloride concentrations much below regulatory limits. The staff reviewed ComEd's risk assessment and agreed that the core damage frequency and large early release frequency associated with deferring this examination are well below the risk increase thresholds considered acceptable for permanent plant changes as delineated in Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant Specific Changes to the Licensing Basis," and are much lower than the risks associated with shutting down the reactor for a forced outage.

LaSalle County Station Unit 2 is currently operating at full power. In order to avoid the transient associated with plant shutdown, the staff concludes that the requested NOED should be authorized. Based on the considerations discussed in the previous paragraphs, the staff concludes that Criterion 1 of Section B.2 and the applicable criteria in Section C.4 of NRC Manual Chapter 9900, "Technical Guidance, Operation - Notice of Enforcement Discretion," are satisfied. Criterion 1 of Section B.2 states that for an operating plant, the NOED is intended to avoid an undesirable transient as a result of forcing compliance with the license and, thus, minimizes the potential safety consequences and operational risks.

ComEd stated that the request had been reviewed and approved by the LaSalle County Station Plant Operations Review Committee (PORC) to meet the requirements of station administrative procedures.

On the basis of the staff's evaluation of ComEd's request, we have concluded that an NOED is warranted because we are satisfied that this action involves minimal safety impact, is consistent with the enforcement policy and staff guidance, and has no adverse impact on public health and safety. Therefore, it is our intention to exercise discretion not to enforce compliance with TS 4.0.5.f for the period from 3:27 p.m. CST, February 18, 2000, until issuance of a license amendment. The licensee agreed to submit the amendment request no later than February 22, 2000. The staff plans to complete its review and issue the license amendment within 4 weeks of the date of this letter.

As stated in the Enforcement Policy, action will be taken, to the extent that violations were involved, for the root cause that led to the noncompliance for which this NOED was necessary.

Sincerely,

/RA/

S. Singh Bajwa, Project Director
Project Directorate III
Division of Licensing Project Management
Office of Nuclear Reactor Regulation

Docket No. 50-374

cc:  

Phillip P. Steptoe, Esquire
Sidley and Austin
One First National Plaza
Chicago, Illinois 60603

Assistant Attorney General
100 W. Randolph St. Suite 12
Chicago, Illinois 60601

U.S. NRC-LaSalle Resident Inspectors Office
2605 N. 21st Road
Marseilles, Illinois 61341-9756

Chairman
LaSalle County Board
707 Etna Road Ottawa, Illinois 61350

Attorney General
500 S. Second Street
Springfield, Illinois 62701

Chairman
Illinois Commerce Commission
527 E. Capitol Avenue, Leland Building
Springfield, Illinois 62706

Illinois Department of Nuclear Safety
Office of Nuclear Facility Safety
1035 Outer Park Drive
Springfield, Illinois 62704

Regional Administrator
U.S. NRC, Region III
801 Warrenville Road
Lisle, Illinois 60532-4351

Commonwealth Edison Company
LaSalle Station Manager
2601 N. 21st Road
Marseilles, Illinois 61341-9757

Mr. R. M. Krich
Vice President - Regulatory Services
Commonwealth Edison Company
1400 Opus Place, Suite 500
Downers Grove, Illinois 60515

Robert Cushing, Chief, Public Utilities Division
Illinois Attorney General's Office
100 W. Randolph Street
Chicago, Illinois 60601

Document Control Desk-Licensing
Commonwealth Edison Company
1400 Opus Place, Suite 400
Downers Grove, Illinois 60515

Commonwealth Edison Company
Site Vice President - LaSalle
2601 N. 21st Road
Marseilles, Illinois 61341-9757

Mr. David Helwig
Senior Vice President
Commonwealth Edison Company
Executive Towers West III
1400 Opus Place, Suite 900
Downers Grove, Illinois 60515

Mr. Gene H. Stanley
Vice President - Nuclear Operations
Commonwealth Edison Company
Executive Towers West III
1400 Opus Place, Suite 900
Downers Grove, Illinois 60515

Mr. Christopher Crane
Senior VP - Nuclear Operations
Commonwealth Edison Company
Executive Towers West III
1400 Opus Place, Suite 900
Downers Grove, Illinois 60515

Commonwealth Edison Company
Reg. Assurance Supervisor - LaSalle
2601 N. 21st Road
Marseilles, Illinois 61341-9757

Ms. Pamela B. Stroebel
Senior Vice President and General Counsel
Commonwealth Edison Company
P.O. Box 767
Chicago, Illinois 60690-0767

 

Page Last Reviewed/Updated Thursday, March 29, 2012