IR 05000483/2009007
| ML091530546 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 06/01/2009 |
| From: | Vincent Gaddy NRC/RGN-IV/DRP/RPB-B |
| To: | Heflin A AmerenUE |
| References | |
| IR-09-007 | |
| Download: ML091530546 (19) | |
Text
UNITED STATES NUC LE AR RE G UL AT O RY C O M M I S S I O N R E GI ON I V 612 EAST LAMAR BLVD , SU I TE 400 AR LI N GTON , TEXAS 76011-4125 June 1, 2009 Mr. Adam C. Heflin, Senior Vice President and Chief Nuclear Officer AmerenUE P.O. Box 620 Fulton, MO 65251 Subject: CALLAWAY PLANT - NRC INTEGRATED INSPECTION REPORT 05000483/2009007 Dear Mr. Heflin On April 30, 2009, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Callaway Plant. The enclosed inspection report documents the inspection findings, which were discussed on April 30, 2009, with Mr. Scott Sandbothe, Manager, Regulatory Affairs, and other members of your staff. This report documents baseline inspection activities related to a failure of emergency diesel generator Train B due to a jacket water leak which occurred on December 24, 2008. Region IV management decided to document this inspection in a separate report because the underlying performance deficiencies were complex and the preliminary significance of associated findings appeared to be of greater than very low safety significance.
The inspections examined activities conducted under your license as they relate to safety and compliance with the Commissions rules and regulations and with the conditions of your license.
The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel.
This report documents an NRC-identified finding of very low safety significance (Green). This finding was determined to involve violations of NRC requirements. However, because of the very low safety significance and because it is entered into your corrective action program, the NRC is treating this finding as a noncited violation, consistent with Section VI.A.1 of the NRC Enforcement Policy. If you contest the violation or the significance of the noncited violation, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555-0001, with copies to the Regional Administrator, U.S. Nuclear Regulatory Commission, Region IV, 612 E. Lamar Blvd, Suite 400, Arlington, Texas, 76011-4125; the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555-0001; and the NRC Resident Inspector at the Callaway Plant. In addition, if you disagree with the characterization of any finding in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the Regional Administrator, Region IV, and the NRC Resident Inspector at the Callaway Plant. The information you provide will be considered in accordance with Inspection Manual Chapter 0305.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, and its enclosure, will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of NRCs document system (ADAMS).
ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
/RA/
Vincent G. Gaddy, Chief Project Branch B Division of Reactor Projects Docket: 50-483 License: NPF-30
Enclosure:
NRC Inspection Report 05000483/2009007 w/Attachments: Supplemental Information Final Significance Determination Evaluation
REGION IV==
Docket: 05000483 License: NPF-30 Report: 05000483/2009007 Licensee: AmerenUE Facility: Callaway Plant Location: Junction Highway CC and Highway O Fulton, MO Dates: January 29 through April 30, 2009 Inspectors: D. Dumbacher, Senior Resident Inspector J. Groom, Resident Inspector Reactor Analyst: D. Loveless, Senior Reactor Analyst Approved By: V. Gaddy, Chief, Project Branch B Division of Reactor Projects-1- Enclosure
SUMMARY OF FINDINGS
IR 05000483; 01/29/2009 - 04/30/2009; Callaway Plant, Operability Evaluations.
The report covered a three month long period of announced focused baseline inspection by a senior resident inspector and a resident inspector. One Green noncited violation of significance was identified. The significance of most findings is indicated by their color (Green, White,
Yellow, or Red) using Inspection Manual Chapter 0609, Significance Determination Process.
Findings for which the significance determination process does not apply may be Green or be assigned a severity level after NRC management review. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 4, dated December 200
NRC-Identified Findings and Self-Revealing Findings
Cornerstone: Mitigating Systems
- Green.
The inspectors identified a noncited violation of 10 CFR Part 50, Appendix B,
Criterion III, "Design Control," after the licensee failed to adequately select suitable replacement parts essential to the operation of emergency diesel generator Train B. On December 24, 2008, during performance of Procedure OSP-NE-0001B, Standby Diesel Generator B Periodic Tests, Callaway operations personnel identified that the emergency diesel generator Train B had an approximately 0.82 gallon per minute jacket water leak resulting in operators declaring the equipment inoperable. Upon removal, the gasket was found to be soft and extruding from the flange edge. The licensee originally concluded the gasket failed due to vibrations associated with engine shutdown but altered that conclusion after discussions with the resident inspectors and additional investigation. The licensee ultimately determined that the cause of the failure was due to incorrect gasket material being used during Job W200773 performed on October 16, 1999. The gasket was 1/8 thick versus 1/16 thick which resulted in a lack of compression. Since the gaskets are composed of an aramid fiberous material, the lack of compression allowed the gasket to absorb water and soften. The leak identified on December 24, 2008, developed once the gasket softened sufficiently to extrude from the flange edge. This issue has been entered into the licensees corrective action program as Callaway Action Request 200812985.
This finding was greater than minor because it was associated with the mitigating systems cornerstone attribute of design control and affects the associated cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Using Manual Chapter 0609.04,
Phase 1 - Initial Screening and Characterization of Findings, this finding was determined to represent an actual loss of safety function of a single train for greater than its Technical Specification allowed outage time. When evaluated per Manual Chapter 0609 Appendix A, "Determining the Significance of Reactor Inspection Findings for At-Power Situations," and the Callaway Plant Phase 2 pre-solved table item Diesel Generator Fails to Run after Start, the inspectors determined this finding to be potentially risk significant. This finding was forwarded to a senior reactor analyst for review. The results of the senior reactor analysts Phase 3 analysis determined the finding to be of very low safety significance. This finding did not have a crosscutting aspect since it was not a performance deficiency indicative of current licensee performance (Section 1R15).
REPORT DETAILS
REACTOR SAFETY
Cornerstones: Mitigating Systems
1R15 Operability Evaluations
a. Inspection Scope
The inspectors reviewed the following issue:
- January 29, 2009, jacket water gasket leak on emergency diesel generator Train B (CAR 200812985)
The inspectors selected this potential operability issue based on the risk-significance of the associated components and systems. The inspectors evaluated the technical adequacy of the evaluations to ensure that Technical Specification operability was properly justified and the subject component or system remained available such that no unrecognized increase in risk occurred. The inspectors compared the operability and design criteria in the appropriate sections of the Technical Specifications and Final Safety Analysis Report to the licensees evaluations, to determine whether the components or systems were operable. Where compensatory measures were required to maintain operability, the inspectors determined whether the measures in place would function as intended and were properly controlled. The inspectors determined, where appropriate, compliance with bounding limitations associated with the evaluations. The inspectors also reviewed a sampling of corrective action documents to verify that the licensee was identifying and correcting any deficiencies associated with operability evaluations. Specific documents reviewed during this inspection are listed in the attachment.
These activities constitute completion of one operability evaluations inspection sample as defined in Inspection Procedure 71111.15-04.
b. Findings
Introduction.
The inspectors identified a Green noncited violation of 10 CFR Part 50, Appendix B, Criterion III, "Design Control," after the licensee failed to adequately select suitable replacement parts essential to the operation of emergency diesel generator Train B.
Description.
On December 24, 2008, during performance of Procedure OSP-NE-0001B, Standby Diesel Generator B Periodic Tests, Callaway operations personnel identified that the emergency diesel generator Train B had an approximately 0.82 gallon per minute jacket water leak. Since the leak exceeded the licensees acceptance criteria for jacket water leakage, operations personnel immediately declared the diesel engine inoperable. The source of the leakage was from a two-bolt flanged connection on the jacket water return line from the right turbocharger bank. Upon removal, the gasket was found to be soft and extruding from the flange edge. The failed gasket was replaced and emergency diesel generator Train B was successfully tested on December 25, 2008.
The licensees initial past operability determination concluded that vibrations associated with engine shutdown contributed to the gasket failure observed on December 24, 2008.
The inspectors reviewed the licensees analysis and questioned if vibrations associated with engine shutdown are different than those associated with normal engine operation.
Additionally, the inspectors questioned if other diesel generator gaskets were susceptible to vibration induced failure since they are subjected to similar operating conditions.
The licensee performed additional investigation and determined that vibrations did not contribute to the gasket failure. Their investigation concluded that gasket material used in the failure location was not original equipment material as specified by the diesel vendor. The failed gasket was 1/8 thick as opposed to 1/16 thick and had been installed during Job W200773 performed on October 16, 1999. The thicker gasket was generically approved for use by the licensee in Request for Resolution 4327A which inappropriately concluded the increased thickness was insignificant and would allow the system to seal under the same pressure as the thinner material. Consultation with the gasket vendors technical support revealed that the increased thickness resulted in a lack of compression. Specifically, the gasket requires a minimum of 2500 psi of compression to seal. An estimate provided by the vendor determined that in the two-bolt configuration using the increased thickness gasket, the gasket was compressed only to approximately 2100 psi. Since the gaskets are composed of an aramid fiberous material, the lack of compression allowed the gasket to absorb water and soften. The leak identified on December 24, 2008, developed once the gasket softened sufficiently to extrude from the flange edge.
Since the emergency diesel generators rely on jacket water to remove heat from the engine during operation, the licensee performed a past operability determination to establish the impact of the failed gasket. Analysis by the licensee determined that once the level in the jacket water system was reduced to below the outlet of the cylinder heads, heat would begin to accumulate within the diesel engine and jacket water system. If water temperature exceeded 195°F the diesel engine would trip. Automatic makeup to the jacket water system would not be available during a design basis accident since the source of makeup is via the non-safety demineralized water system.
Assuming no makeup, the licensee determined that the 0.82 gallon per minute leak would adversely affect engine performance after approximately 130 minutes of operation. In this scenario, the seven day mission time requirement of emergency diesel generator Train B would not be met.
Analysis.
The performance deficiency associated with this finding involved the licensees failure to adequately select suitable replacement parts essential to the operation of emergency diesel generator Train B. This finding was greater than minor because it was associated with the mitigating systems cornerstone attribute of design control and affects the associated cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Using Manual Chapter 0609.04, Phase 1 - Initial Screening and Characterization of Findings, this finding was determined to represent an actual loss of safety function of a single train for greater than its Technical Specification allowed outage time. The finding required a Phase 2 analysis. When evaluated per Manual Chapter 0609 Appendix A, "Determining the Significance of Reactor Inspection Findings for At-Power Situations," and the Callaway Plant Phase 2 pre-solved table item Diesel Generator Fails to Run after Start, the inspectors determined this finding to be
potentially risk significant. The finding was forwarded to a senior reactor analyst for review. The senior reactor analyst performed the Phase 3 analysis, which is contained in Attachment 2 of this report, which determined that the finding was of very low safety significance.
This finding did not have a crosscutting aspect since it was not a performance deficiency indicative of current licensee performance.
Enforcement.
Title 10 of the Code of Federal Regulations Part 50, Appendix B, Criterion III, Design Control, requires, in part, that measures be established for the selection and review for suitability of application of materials and parts that are essential to the safety related functions of structures, systems, and components. Contrary to the above, from October 16, 1999, through December 24, 2008, the licensee failed to ensure the suitability of repair parts essential to the safety-related function of emergency diesel generator Train B. Because this violation is of very low safety significance and has been entered into the licensee's corrective action program as CAR 200812985, this violation is being treated as a noncited violation, consistent with Section VI.A.1 of the NRC Enforcement Policy: NCV 05000483/2009007-01, Failure to Ensure Suitable Replacement Parts Essential for Emergency Diesel Generator Train B.
OTHER ACTIVITIES
4OA2 Identification and Resolution of Problems
Cornerstones: Mitigating Systems
.1 Selected Issue Follow-up Inspection
a. Inspection Scope
During a review of items entered in the licensees corrective action program, the inspectors recognized a corrective action item documenting a potential non-compliance with ASME Section III, Class 3 code requirements. Specifically, CAR 200902095 documents that jacket water supply and return lines are two-bolt flanged connections versus four-bolt flanged connections as required by code. The licensees Final Safety Analysis Report details the classification of structures, systems and components and lists piping and valves associated with diesel generator support systems and ASME Section III, Class 3, thereby requiring four-bolt flanged connections. Following discussions with the licensee and the NRC Office of Nuclear Reactor Regulation, the inspectors learned that the particular two-bolt flanged connections associated with jacket water cooling to the turbocharger are considered integral and internal to the diesel engine and are therefore exempt from the ASME Section III, Class 3 requirement to be a four-bolt configuration.
These activities constitute completion of one in-depth problem identification and resolution sample as defined in Inspection Procedure 71152-05.
b. Findings
No findings of significance were identified.
4OA6 Meetings
Exit Meeting Summary
On April 30, 2009, the inspectors presented the inspection results to Mr. Scott Sandbothe, Manager, Regulatory Affairs, and other members of the licensee staff. The licensee acknowledged the issues presented. The inspectors asked the licensee whether any materials examined during the inspection should be considered proprietary. No proprietary information was identified.
ATTACHMENT: Supplemental Information
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
- D. Bonvillian, Shift Manager, Operations
- G. Bradley, Manager, Operations
- T. Elwood, Supervising Engineer, Regulatory Affairs/Licensing
- S. Maglio, Assistant Manager, Regulatory Affairs
- K. Mills, Manager, Plant Engineering
- S. Petzel, Engineer, Regulatory Affairs
- S. Sandbothe, Manager, Regulatory Affairs
- R. Wissel, System Engineer
LIST OF ITEMS
OPENED AND CLOSED
Opened and Closed
Failure to Ensure Suitable Replacement Parts Essential for
- 050002009007-01 NCV Emergency Diesel Generator Train B (Section 1R15)