IR 05000369/2008009
| ML083370336 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, McGuire  |
| Issue date: | 11/25/2008 |
| From: | Hamilton B H Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| EA-08-220 IR-08-009 | |
| Download: ML083370336 (8) | |
Text
BRUCE H HAMILTON Vice President PdrEnergye McGuire Nuclear Station Duke Energy Corporation MGO1 VP / 12700 Hagers Ferry Road Huntersville, NC 28078 704-875-5333 704-875-4809 fax bhhamilton@duke-energy.com November 25, 2008 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
Document Control Desk Duke Energy Carolinas, LLC (Duke)McGuire Nuclear Station Units 1 and 2 Docket Nos. 50-369 and 50-370
SUBJECT: Reply to Notice of Violation EA-08-220 (NRC Inspection Report Nos. 05000369/2008009 and 05000370/2008009)
Duke Energy Carolinas, LLC (Duke) is in receipt of the referenced NRC Inspection Report. The subject Inspection Report identified a White Finding and communicated a Notice of Violation identified as VIO 05000369, 370/2008009-01, Failure to Take Adequate Corrective Action for Implementation of Safety Related RN Strainer Backwash.Pursuant to the provisions of 10 CFR 2.201, Duke is submitting this written response to the Notice of Violatio Even though Duke continues to believe this event was of very low safety significance, Duke does not contest the violation.
Enclosure 1 describes the violation, immediate corrective actions, corrective actions to prevent recurrence, and the date when full compliance will be achieve The commitments contained in Enclosure 1 of this letter are captured in Enclosure 2 and supersede the corrective actions identified in the License Event Report submitted October 5, 2007.Questions or requests for additional information may be directed to Ken Ashe, at (704) 875-4535.Bruce H. Hamilton, Vice President McGuire Nuclear Site www. duke-energ corn U.S. Nuclear Regulatory Commission November 25, 2008 Page 2 xc w/
Attachments:
L. A. Reyes Administrator, Region II U.S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth St., Suite 23T85 Atlanta, GA 30303 J. F. Stang, Jr. (addressee only)NRC Senior Project Manager (MNS)U.S. Nuclear Regulatory Commission Mail Stop 0-8 G9A Washington, DC 20555-0001 J. B. Brady NRC Senior Resident Inspector McGuire Nuclear Station B. 0. Hall, Section Chief Division of Radiation Protection Section 1645 Mail Service Center Raleigh, NC 27699-1645 Enclosure 1 McGuire Nuclear Station -Units 1 and 2 Docket Nos. 50-369, 500-370 Reply to a Notice of Violation; EA-08-220 NRC Inspection Report No. 05000369/2008009 and 05000370/2008009 Enclosure 1 Restatement of Violation EA-08-220 10 CFR 50 Appendix B Criterion XVI, Corrective Action, states that measures shall be established to assure that conditions adverse to quality, such as deficiencies, deviations, and non-conformances are promptly identified and correcte In the case of significant conditions adverse to quality, the measures shall assure that the cause of the condition is determined and corrective action taken to preclude repetitio This requirement is implemented through the Duke Quality Assurance Program Topical Report and procedure NSD 208, Problem Identification Process.Contrary to the above, between 2003 and August 7, 2007, the licensee failed to correct a significant condition adverse to quality related to macro-fouling of the nuclear service water (RN) strainers, in that the corrective action that was implemented failed to ensure that the design and licensing basis required capability for manual strainer backwash be maintained during accident condition Specifically, the 2003 plant modification that was implemented to address macro-fouling (i.e., upgrade and reclassification of the strainer backwash function to safety-related):
(1)utilized non-safety-related instrument air (VI) to maintain each RN pumps strainer backwash discharge valve open, but did not provide a means to manually open (or bypass) the discharge valve to support backwash operations upon a loss of VI; and (2) did not account for the impact on timely operator response from higher strainer macro-fouling rates and expected (nuisance)
strainer differential pressure alarms (without fouling)at the onset of high RN flow events (i.e., safety injection (SI) and loss of VI). As such, there was a lack of reasonable assurance that the RN system would be able to perform its safety-related function upon a SI or loss of VI event during periods of macro-fouling.
This violation is associated with a White finding for Units I and 2.Reasons for the Violation Duke Energy performed a root cause analysis of the issues described in the above violatio The root cause is documented in the McGuire Corrective Action Program, and determined that process and organizational breakdowns created the potential for plant configurations that did not support manual backwash of the RN Strainer on a loss of instrument air events.The Root Cause of this event is that the plant configuration was changed without a total understanding of the Design and Licensing Bases of the RN System Strainer during accident conditions regarding safety vs. non-safety interaction The configuration changes took place during the design of minor modifications in 2000 & 2001. A 10CFR50.59 was performed as 1 Enclosure 1 part of the modifications but did not take into consideration that the UFSAR states that the RN Strainer would be able to manually perform backwashes during accident condition Prior to the modifications, valves could be manually positioned to allow backwashin However, after the modifications were implemented, the valves required instrument air to be available for manual or automatic positionin Instrument air is non-safety and cannot be counted on during accident conditions.
Three missed opportunities were identified for this event.Missed Opportunity 1: In 1993 -1994, a design change was completed without using the 10CFR50.59 process to downgrade the RN Strainers to non-safety.
Missed Opportunity 2: An internal assessment was conducted in 1993 to assess the operational readiness and functionality of McGuire's RN system. The report identified a design deficiency with RN strainer backwash valves utilizing non-safety instrumentatio The organization did not take effective measures to address the internal assessment.
Missed Opportunity 3: A design change was initiated in 2002 to classify the RN strainer as safety related based on the change in fouling sources (detection of Alewife fouling).
The 2002 design change failed to identify the changes in RN strainer backwash valve configuration (2000/2001 modification)
which created the dependence on non-safety related instrument air.Corrective Actions Taken and the Results Achieved The significant corrective actions taken to date include the following:
1. Installed a stainless steel macrofouling barrier at the Low Level Intake.The barrier acts as a fence to prevent alewife intrusion into the Nuclear Service Water System, and inhibits fouling mechanisms which could challenge the Nuclear Service Water strainer Without a fouling mechanism there is no time critical action required by operations staff for RN Strainer backwash.2. Installed Nuclear Safety Related (QA condition
-1) instrumentation for the Nuclear Service Water Strainers and removed the safety injection signal from each supply valve (1RN-21A, 1RN-25B, 2RN-21A, and 2RN-25B).This instrumentation upgrade controls automatic strainer backwash and provides control room indication of strainer differential pressur This design change provides adequate information to the operators to properly 2 Enclosure 1 diagnosis abnormal strainer condition The safety injection signal to close the backwash supply isolation valve is not necessary to protect standby nuclear service water system inventor This design change allows automatic backwash supply actuation during accident conditions 3. The following Procedural changes were made to optimize RN System operation:
- To direct operations to monitor RN Strainer differential pressure via the new safety related instrumentation upon loss of Instrument Air,* To open the supply valves for RN Strainer backwash as needed" Upon loss of Instrument Air, align the "B" Train to the Standby Nuclear Service Water Pond (SNSWP)" Upon a Operating Basis Earthquake or greater align both "A" and "B" Trains to the SNSWP 4. Periodically monitor Lake and SNSWP environments to ensure no new macro fouling mechanism develops.5. Backwash discharge valves 1 RN-22A, 1 RN-26B, 2RN-22A, and 2RN-26B were modified to allow manual operatio This action eliminates the dependence on non-safety related Instrument Air.6. Trained personnel qualified to perform 1OCFR50.59 screens or evaluations in the details of this event and provided them with tools to enhance their ability for researching the licensing basis. This minimizes the likelihood of not considering pertinent licensing basis information during the plant change process.Corrective Actions that will be taken to Avoid Further Violations 1. Address Nuclear Service Water System strainer discharge flow design deficiencie The Nuclear Service Water System has an identified design non conformance with the current licensing basis for the ability to backwash the RN Strainer As a result, a License Amendment Request will be generated to resolve the non conforming condition.
Status: The proposed resolution of this will be made by updating the licensing basis by submitting a License Amendment Request prior to the conclusion of the fall 2009 refueling outage, 2EOC19.2. Update the UFSAR, per 10 CFR 50.71(e), to incorporate the physical and procedural changes that have been made to the facility as a result of this even Enclosure 1 Status: The UFSAR change package will be completed by April 30, 2009 Date when full compliance will be Achieved.Actions identified above and captured in Enclosure 2 to this letter to address the non conforming issue associated with the Nuclear Service Water System will be completed prior to the conclusion of the fall 2009 refueling outage. (This includes submitting a clarifying License Amendment Request but does not presume approval by the NRC or implementation by Duke).4 Enclosure 2 Regulatory Commitments in response to Violation EA-08-220 contained in NRC Inspection Report No. 05000369/2008009 and 05000370/2008009 Commitment Completion Date Update the UFSAR, per 10 CFR * April 30, 2009 50.71(e), to incorporate the physical and procedural changes that have been made to the facility as a result of this event.Address Nuclear Service Water ° Prior to the conclusion of the System strainer discharge flow design Fall 2009 Refueling Outage deficiencie The Nuclear Service (This includes submitting a Water System has an identified design clarifying License Amendment non conformance with the current Request but does not presume licensing basis for the ability to approval by the NRC or backwash the RN Strainer As a implementation by Duke).result, a License Amendment Request will be generated and submitted to the NRC to resolve the non conforming condition 1