RIS 2002-04, Results of the Pilot Test of the Proposed Changes to The Unplanned Scrams Performance Indicatolr and Thescrams with Loss of Normal Heat Removal Performance Indicator
| ML013340158 | |
| Person / Time | |
|---|---|
| Issue date: | 03/01/2002 |
| Revision: | 0 |
| From: | Beckner W D NRC/NRR/DRIP/RORP |
| To: | |
| Sanders S | |
| References | |
| TAC MB3806 RIS-02-004 | |
| Download: ML013340158 (7) | |
March 1, 2002
NRC REGULATORY ISSUE SUMMARY 2002-04RESULTS OF THE PILOT TEST OF THE PROPOSED CHANGES TOTHE UNPLANNED SCRAMS PERFORMANCE INDICATOR ANDTHE SCRAMS WITH LOSS OF NORMAL HEAT REMOVALPERFORMANCE INDICATOR
ADDRESSEES
All holders of operating licenses for nuclear power reactors, except those who havepermanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.
INTENT
The U.S. Nuclear Regulatory Commission (NRC) is issuing this Regulatory Issue Summary(RIS) to inform power reactor licensees of the results of a 6-month pilot test of proposed changes to the "unplanned scrams per 7,000 critical hours" and the "scrams with loss of normal heat removal" performance indicators (PIs) in the Reactor Oversight Process (ROP). The NRC/Industry Working Group evaluated the pilot results using the guidelines inRIS 2000-21, "Changes to the Unplanned Scram and Unplanned Scram With Loss of Normal Heat Removal Performance Indicators." Based on the results of the pilot test, the NRC has concluded that the replacement indicators would not be as effective or reduce the potential for unintended consequence Therefore, the current unplanned scrams per 7,000 critical hours PI will not be change The definition of the unplanned scrams with loss of normal heat removal PI will be slightly revised.
BACKGROUND INFORMATION
On March 28, 2000, senior NRC and industry managers met to discuss industry's concernregarding potential adverse impact of the current scram indicator Some industry representatives indicated that including manual scrams in the current scram PIs could potentially result in nonconservative decision-making by operators during a plant event for which a manual scram is warrante To address these concerns, the industry proposed two replacement PIs, "unplanned reactor shutdowns per 7,000 critical hours" and "unplanned reactor shutdowns with loss of normal heat removal." The NRC/Industry Working Group, which consists of NRC management and staff, NuclearEnergy Institute (NEI) management, and senior industry representatives, met in monthly meetings to refine the proposed replacement scram indicators, plan a pilot test, and develop the criteria to be used to evaluate the pilot result In developing and evaluating the proposed replacement PIs, the NRC/Industry Working Group followed the formal process that is documented in Inspection Manual Chapter 0608, "Performance Indicator Program."The 6-month pilot test began in October 200 The plants that participated in the pilot wereJames A. FitzPatrick; Salem Units 1 and 2; Hope Creek; Shearon Harris; Joseph M. Farley Units 1 and 2; Vogtle Units 1 and 2; Edwin I. Hatch Units 1 and 2; Dresden Units 2 and 3; Prairie Island Units 1 and 2; Palo Verde Units 1, 2, and 3; Diablo Canyon Units 1 and 2; and Fort Calhou Upon completion of the pilot, the data was evaluated to determine if the proposed replacement PIs were as effective as the current PIs at indicating performance in the initiating events cornerstone and more effective at minimizing the potential for unintended consequence ISSUE SUMMARY Some industry representatives expressed the concern that including manual scrams in thecurrent PIs could potentially result in nonconservative decision-making during a plant event for which a manual scram may be warrante As a result of these concerns, the NRC and Industry pilot-tested proposed replacement PIs to evaluate their effectiveness and accuracy to determine if they should be adopted.The NRC/Industry Working Group used the five criteria delineated in RIS 2000-21 to evaluatethe data from the 6-month pilot tes The criteria and results of the evaluation are as follows: 1.Criteria: Differences between data collected for the "unplanned reactor shutdowns per7,000 critical hours" and "unplanned scrams per 7,000 critical hours" PIs.Results: There were no differences between the data collected in the pilot test of theproposed unplanned reactor shutdowns per 7,000 critical hours PI and the currentunplanned scrams per 7,000 critical hours P The same 8 scrams were reported by the 13 pilot plants under each indicato The NRC staff also reviewed the licensee event report (LER) database for all scrams reported by the industry in 2000 (before the pilot test) to identify any events that would likely not have been reported under the replacement PIs if they had occurred during the tria The staff found 13 such scrams (about 14 percent of the 92 scrams that year). As a result, the NRC determined that implementation of the proposed replacement PI as proposed would likely not have captured all reactor scram Needed changes to the proposed PI to address this concern would not be simple or necessarily effective.2.Criteria: Comparability of the data reported for the "unplanned reactor shutdowns withloss of normal heat removal" and the "scrams with a loss of normal heat removal" PI Additionally, the NRC would compare the rate of occurrence of "unplanned reactor shutdowns with loss of normal heat removal" and the scrams with loss of normal heat removal results presented in NUREG/CR-5750, "Rates of Initiating Events at U.S.Nuclear Power Plants 1987 - 1995," (Sections: Loss of Feedwater and Loss of Heat Sink Events), to identify differences.Results: According to NUREG/CR-5750, the expected number of scrams with loss ofnormal heat removal for the pilot plants is 2.42 events per 6 month Two of theseevents were reported during the pilot (a good correlation), but none were reported under the existing ROP guidanc The two events captured in the pilot should have been captured in the existing PI dat Early in the initial implementation of the ROP and before the pilot, the NRC/Industry Working Group became aware of problems in the definition of "loss of normal heat removal" in the existing guidanc Consequently, the NRC/Industry Working Group developed a revised definition and tested it during the pilot, along with a revised definition of "scrams." The pilot results demonstrated that the revised definition of "loss of normal heat removal" should be included in the ROP guidance regardless of which PI is employed.3.Criteria: Ability of licensees to report the requested data accurately and with minimalneed for clarification.Results: The pilot test results did not favorably indicate the licensee's ability to reportthe replacement PI data accurately and with minimal need for clarificatio A significantnumber of reactor scrams would likely be missed by the proposed replacement indicator A simple clarification in the guidance would have captured 6 of the 13 scrams in the year 2000 that might have been misse The NRC/Industry Working Group attempted but was not able to develop a simple and effective clarification for the other seven scram Therefore, the staff concluded that the proposed replacement indicators would likely not provide the same data as provided by the current PI .Criteria: Ability of each alternate PI to reduce the potential for unintendedconsequences without introducing other unintended consequences.Results: The proposed alternative PIs did not demonstrate the ability to reduce thepotential for creating unintended consequences below those which might be postulatedusing the existing scram PI For example, it has been suggested that continued use of the current scram PIs may result in operators not initiating a manual scram when needed to avoid a PI "hit," which would be counter to safety-conscious operatio However, the proposed replacement PIs do not resolve this concer .Criteria: Whether there are minimal changes in reporting burden for licensees.Results: Based on the review of the pilot experience, the proposed replacementindicators would not increase the regulatory burden of reporting dat However, twoclarifications would be needed to ensure that accurate data is reporte One clarification would be straightforward, the other would no The more complex clarification could increase licensee reporting burden by requiring more interaction with the staff to ensure data accuracy. In summary, the replacement PIs would likely miss some of the scrams that would be capturedby the existing PI Changes to address this concern would further complicate the PIs and would require increased effort on the part of the NRC and the Industry to ensure that they are reported accuratel Finally, the replacement PIs would not decrease and would likely increase any potential for unintended consequences.Based on the results of the pilot test, as evaluated by the NRC/Industry Working Group inaccordance with the formal change process, the NRC has decided to retain the existing scram PIs and not to adopt the proposed replacement PI However, the definition and the clarifying notes in the current "loss of normal heat removal" PI were revised in NEI 99-02, "Regulatory Assessment Performance Indicator Guideline," Rev. This document was made available to the public on January 1, 2002.
BACKFIT DISCUSSION
This RIS requires no action or written respons Any action on the part of addresses to collectand transmit PI data is strictly voluntary and, therefore, is not a backfit under 10 CFR 50.10 Therefore, the staff did not perform a backfit analysis.
FEDERAL REGISTER NOTIFICATION
A notice of opportunity for public comment on this RIS was not published in the FederalRegister because the NRC has worked closely with NEI, industry representatives, members ofthe public, and other stakeholders since early 1998 on the development of NRC's ROP, including the collection of PI dat A January 10, 2001, Federal Register notice solicitedwritten comments by April 13, 2001, on all aspects of the new RO A 3-day public workshop for external stakeholders was held in late March, 200 Monthly public meetings on the PI process and other ROP issues were held during Spring 2001, at which time, the pilot PI effort was discussed and interested stakeholders were given the opportunity to commen
PAPERWORK REDUCTION ACT STATEMENT
This RIS does not request any information collection; therefore, this RIS is not subject to thePaperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)If you have any questions about this matter, please telephone or email the technical contactlisted below./RA/William D. Beckner, Program DirectorOperating Reactor Improvements Program Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation
Technical Contact:
Serita Sanders, NRR301-415-2956 E-mail: SXS5@nrc.gov
Attachment:
List of Recently Issued NRC Regulatory Issue Summaries RIS 2002-04
______________________________________________________________________________________OL = Operating License CP = Construction PermitAttachment LIST OF RECENTLY ISSUEDNRC REGULATORY ISSUE SUMMARIES_____________________________________________________________________________________Regulatory Issue Date of Summary N Subject IssuanceIssued to_____________________________________________________________________________________2002-03Guidance on the ContentMeasurement Uncertainty Recapture Power Uprate Applications01/31/2002All holders of operating licensesfor nuclear power reactors, except those that have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.2002-02Lessons Learned Related toRecently Submitted Decommissioning Plans and License Termination Plan01/16/2002All NRC licensees.2002-01Changes to NRC Participation inthe International Nuclear Event Scale01/14/2002All NRC licensees and certificateholders.2001-25NEI-099-02, Revision 2, VoluntarySubmission of Performance Indicator Data12/12/2001All holders of operating licensesfor nuclear power reactors, except those who have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.2001-24Status of Receipt of NRC MailFollowing the Closing of the Brentwood Postal Facility12/06/2001All NRC licensees2001-23Resetting Fault Exposure Hoursfor Safety System Unavailability Performance Indicators12/03/2001All holders of operating licensesfor nuclear power reactors, except those who have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel