ML20214N463
| ML20214N463 | |
| Person / Time | |
|---|---|
| Issue date: | 08/20/1986 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Harold Denton, Ross D, Taylor J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE), Office of Nuclear Reactor Regulation, NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| Shared Package | |
| ML20214N466 | List: |
| References | |
| NUDOCS 8609160314 | |
| Download: ML20214N463 (3) | |
Text
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+.***f August 20, 1986 AE0D/P603 MEMORANDUM FOR: Harold R. Denton, Director, NRR Denwood F. Ross, Jr., Acting Director, RES James M. Taylor, Director, IE Regional Administrators FROM:
C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
SUBJECT:
TRENDS AND PATTERNS ANALYSIS OF ENGINEERED SAFETY FEATURE ACTUATIONS AT COMMERCIAL U.S. NUCLEAR POWER PLANTS Enclosed is a report of a trends and patterns analysis of engineered safety feature (ESF) actuations which occurred during the last six months of 1984 at commercial U.S. nuclear power plants. The investigation documented in this report was limited to those ESF actuations which involved systems other than the reactor protection system (RPS).
RPS actuations were the subject of a companion study, AE00 P504.
Based on the analysis and evaluation of these actuations, it was apparent that the majority of the ESF actuations were unnecessary and that the rate of these actuations could be decreased by (a) reducing the number of equipment failures during normal operation, (b) reducing the number of personnel errors during maintenance and testing, and (c) reducing spurious actuations due to electrical noise spikes.
Nine units were identified as being of particular concern because they appear to be experiencing repeated unresolved actuations which could ultimately challenge continued equipment operability and proper personnel response. These units were: Byron 1, Callaway 1, LaSalle 1 and 2, San Onofre 2 and 3, Sequoyah 1 and 2, and WPPSS 2.
Finally, the wide variety of ESF systems and the differences in the types of ESF actuations (including variations in immediate safety significance) make comparisons among units very difficult. Limiting the actuations included in the statistics to more significant events such as safety injections (which are more or less comparable across plants) does not seem practical because such events are rare and 11ttle discrimination in performance would result either among plants or over time for a given plant.
8609160314 860820 PDR ORG NEXD
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j Multiple Addressees The distribution of ESF actuation rates among plants (i.e., the vast majority )
of plants have fairly low rates and, only 25% or so have relatively high rates and the variety of ESF actuations suggest a two-step strategy for using ESF actuations as a performance indicator:
first, to use a value of 10 ESF actu-ations in a 6 month period as an alert level (plants with a value below this frequency are deemed acceptable with no further analysis made); and secondly, to perform a detailed examination of the circumstances for the plants exceeding the threshold with unacceptable performance being frequent actu-ations as a result of ineffective corrective actions. Sustained operation (e.g., two consecutive 6 month periods) with a high rate of ESF actuations may be indicative of a willingness to accept ESFs that are not performing as in-tended.
Additionally, further study should focus on the specific units found to have high actuation rates and contfruing problems, in order to verify that effective corrective actions are being taken.
We are placing a copy of this final report in the Public Document Room.
If you have any questions regarding this matter, please feel free to contact Bob Dennig (24490) or Marc Harper (24480) of my staff.
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1 C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
Enclosure:
As Stated cc w/ enclosure:
See Attached Distribution:
PTB SF MHarper CHeltemes PTB CF RDennig AE0D SF MWillianis AE0D CF FHebdon PDR
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- CH emes lDATE :8///86
- 8/[/86
- 8/19/86
- 8/1>986 0FFICIAL RECORD COPY 1
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cc_w/ enclosure:
V. Stello, ED0' J. Roe, DEDO T. Rehm, A0/ED0 J. Sniezek, DEDR0GR K. Brach, DEDROGR '
H. Thompson, NRR R. Bernero, NRR T. Speis, NRR W. Russell, NRR G. Holahan, NRR M. Miraglia, NRR G. Arlotto, RES F. Gillespie, RES E. Jordan, IE S. Schwartz, IE J. Partlow, IE J. Shea, IP H. Faulkner, IP D. Humenansky, OCM K. Raglin, RTC K. Murphy, RI E. Schweibinz, RIII SRI, Byron 1, RIII SRI, Callaway 1, RIII SRI, LaSalle 1, RIII SRI, laSalle 2, RIII SRI, San Onofre 2, RV SRI, San Onofre 3, RV SRI, Sequoyah 1, RII SRI, Sequoyah 2, RII SRI, WPPSS 2, RV