NRC 2004-0002, Reply to a Notice of Violation EA-03-057 NRC Inspection Report
| ML040210675 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 01/12/2004 |
| From: | Cayia A Nuclear Management Co |
| To: | Document Control Desk, NRC/RGN-III |
| References | |
| EA-03-057, NRC 2004-0002 | |
| Download: ML040210675 (6) | |
Text
-
Committed to Nuclear Excellen Point Beach Nuclear Plant Operated by Nuclear Management Company, LLC January 12, 2004 NRC 2004-0002 10 CFR 2.201 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 License Nos. DPR-24 and DPR-27 Reply to a Notice of Violation EA-03-057 NRC Inspection Report No. 50-266/02-15 (DRP): 50-301/02-15 (DRP)
References:
1.
Letter from J. L. Caldwell (NRC) to A. J. Cayia (NMC), "Point Beach Nuclear Plant, Units I and 2, Final Significance Determination for a Red Finding and Notice of Violation (NRC Inspection Report No. 50-266/02-15(DRP); 50-301/02-15(DRP)),"
dated December 11, 2003
- 2.
Licensee Event Report 266/2002-003-01, "Possible Common Mode Failure of AFW Due to Partial Clogging of Recirculation Orifices," dated October 10, 2003 The Nuclear Regulatory Commission (NRC) forwarded the final results of its significance determination and Notice of Violation (NOV) for a Red Finding via Reference 1. The NRC letter cited a violation of 10 CFR 50 Appendix B, Criterion ll, "Design Controls."
Pursuant to the provisions of 10 CFR 2.201, Nuclear Management Company, LLC (NMC) has prepared a written response to the violation as an enclosure to this letter. NMC concurs that the failure to adequately consider the AFW system design bases prior to installing the revised AFW recirculation line orifice design is a violation of 10 CFR 50, Appendix B, Criterion Ill, "Design Control" as stated in the inspection report.
6590 Nuclear Road
- Two Rivers, Wisconsin 54241 Telephone: 920.755.2321
Document Control Desk Page 2 Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.
AJ. Caya K>
Site p
- rside, Point Beach Nuclear Plant Nuc anagement Company, LLC Enclosure cc:
Administrator, Region 111, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector - Point Beach Nuclear Plant, USNRC Director, Office of Enforcement PSCW
ENCLOSURE REPLY TO A NOTICE OF VIOLATION EA-03-057 NRC INSPECTION REPORT NO. 50-266/02-15(DRP); 50-301/02-15(DRP)
Pursuant to the provisions of 10 CFR 2.201, the following is the NMC response to Notice of Violation (EA-03-057) as cited in Reference 1:
NRC VIOLATION Criterion 1II, "Design Control," of 10 CFR Part 50, Appendix B, requires, in part, that design control measures be established to assure that applicable regulatory requirements and the design basis for structures, systems, and components were correctly translated into specifications, drawings, procedures, and instructions.
Contrary to the above, as of March 24, 2003:
- 1.
The licensee failed to establish adequate measures to assure that the auxiliary feedwater (AFW) system design bases were correctly translated into specifications, drawings, procedures, and instructions (modification packages) for the installation of the pressure reduction orifice in the recirculation line of the Unit 1 turbine-driven AFW pump (1 P-29). Specifically, the licensee developed Modification Packages 99-029*A, B, C, and D in 1999 to install a revised design orifice in the four recirculation lines of the four pumps of the AFW system. By May 2002, the revised design orifices were installed per Modifications Packages 99-029* A, B, and D in three of the four recirculation lines. Subsequently, the licensee developed Modification Package 02-029, "Safety Upgrade of the AFW System Recirculation Line Air-Operated Flow Control Valve," to change the safety-related design basis of the AFW system to require that the recirculation line, including the pressure reduction orifice, be able to pass flow during all required operating conditions. This modification package was implemented on September 12, 2002. On October 14, 2002, the licensee installed the revised design orifice into the 1 P-29 turbine-driven AFW pump recirculation line per Modification Package 99-029*C. However, the licensee failed to establish adequate measures to assure that the design basis change requiring the safety-related passing of flow during all required operating conditions, approved as part of Modification Package 02-029, was translated into Modification Package 99-029*C prior to the installation of the revised design orifice.
- 2.
The licensee failed to correctly translate the AFW system design basis recirculation line flow requirements into modification packages. Specifically, service water (SW) strainer mesh size was not considered when the pressure reduction orifice design using 0.125-inch diameter holes and smaller-sized, inscribed flow channels was incorporated into Modification Packages 99-029*A, B, C, and D. The SW strainer mesh size of 0.125-inch was larger than the smallest limiting flow dimensions of the Page 1 of 4
revised orifice design. Consequently, a common mode failure of all AFW trains could have occurred because debris passing through the SW strainers could plug the holes and flow channels of the AFW recirculation line pressure reduction orifices.
- 3.
The licensee failed to correctly translate the AFW system design basis power supply requirements into Modification Package 02-029 for the safety classification upgrade of the recirculation line air-operated flow control valve (AOV) in each of the four recirculation lines. Specifically, the licensee did not assure that the upgraded safety design relied only upon a safety-related power source for a relay associated with the AOVs. Instead, the AFW system relied on a single train of nonsafety-related power supply for all trains of the AOV relays. Consequently, a common mode failure could have occurred during a loss of the nonsafety-related power supply.
This violation is associated with a Yellow SDP finding for Unit 1 and a Red SDP finding for Unit 2.
NMC RESPONSE NMC concurs this is a violation of 10 CFR 50, Appendix B, Criterion ll, "Design Control," and that the finding has been properly characterized through the significance determination process (SDP) as Yellow for Unit 1 and Red for Unit 2.
Reason for Violation:
As stated in LER 50-266/2002-003-01 (Reference 2), there was a direct root cause and an organizational root cause that resulted in this violation. The direct root cause was the failure by design engineering to properly evaluate the potential for orifice plugging within the design process. Instead of evaluating the potential for plugging of the proposed orifices within the rigor of the design process, the 10 CFR 50.59 evaluation was used to evaluate the proposed design for the potential to plug.
The organizational root cause was less than adequate management oversight of the design modification process. Specifically, management did not:
Assure that a formal technical evaluation was performed for the potential plugging issue rather than allowing it to be resolved via the safety evaluation.
Assure that independent reviewers are provided with clear and concise expectations for the performance of reviews, are truly independent of the person performing the original work and are held accountable for an effective review.
Assure that management oversight of critical activities includes second level and higher management personnel from engineering and from other departments.
Page 2 of 4
Significant contributing causes included:
The vendor information concerning its design to preclude orifice plugging was misapplied and not verified.
Information on the design functions of the Appendix R flow path and throttling of AFW flow during emergency operations was omitted from the safety evaluation.
There was inadequate knowledge of AFW recirculation line design functions.
Inadequate independent verification resulted from inadequate program management.
Corrective Steps Taken and Results Achieved:
Immediate compensatory actions and interim corrective actions are as described in Reference 2.
The following long-term corrective actions affecting the physical configuration of the auxiliary feedwater system were taken:
Design and installation of new recirculation line orifices with an aperture size greater than 1/8 inch were installed and accepted for operation. The orifices were tested prior to installation and are not susceptible to clogging by service water (SW) debris.
Modifications to correct electrical vulnerabilities in the control circuits for the recirculation air-operated valves (AOVs) and associated differential pressure indicating switch (DPIS) devices were installed and accepted for operation.
The AFW system was restored to operable status following approval of a 10 CFR 50.59 evaluation that addressed removal of compensatory actions.
Operations procedure changes that reflected removal of compensatory actions were issued.
An assessment was performed of flow restricting devices in use in other safety-related applications. No other safety-related flow-restricting device was found to be susceptible to small particle clogging.
An evaluation of the AFW system was completed to identify the sources of potential corrosion products.
An engineering evaluation was performed to assess the potential for plugging the originally installed restricting orifice with debris from the service water system.
Laboratory testing of the susceptibility of the orifices to plugging was subsequently completed that included full-scale testing of an orifice assembly using the types and quantities of debris found to reside in the SW system. The testing demonstrated a Page 3 of 4
high likelihood that the recirculation flow control orifices installed in the AFW system recirculation lines would have plugged if the system were operated with suction from the SW system.
The following reviews, process and procedure changes were made to address organizational causes of the three design control issues identified in the NOV:
A design and licensing basis review of the AFW system was completed by an independent consultant in March 2003.
A self-assessment of the design and licensing basis was performed during July-August 2003 in preparation for the September engineering, operations and maintenance inspection portion of the 95003 supplemental inspections conducted by NRC during September 2003.
A Design Review Board process was implemented to improve the quality of modification packages. This process requires stakeholders to take an active role in modification preparation and to improve the quality of site reviews. The Design Review Board provides a comprehensive review of modifications such that all facets of design, scheduling, planning, construction, maintenance testing, and operations are considered throughout the development of the modification package. The Design Review Board process has been formalized in an administrative procedure.
A number of process improvements in the modification process were implemented to prevent recurrence of these design control-related issues. Changes included assignment of an independent verifier and requiring pre-installation reviews of modification packages.
The improvements were formalized by issuance of a new administrative procedure and revisions to existing administrative procedures.
Corrective Steps To Be Taken There are no additional corrective actions to be taken.
Date Full Compliance Will Be Achieved Full compliance was achieved on October 1, 2003.
Page 4 of 4