ML18065B170
| ML18065B170 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/04/1998 |
| From: | Robert Schaaf NRC (Affiliation Not Assigned) |
| To: | Bordine T CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| GL-88-20, TAC-M83653, NUDOCS 9803120415 | |
| Download: ML18065B170 (6) | |
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Mr. Thomas C. Berdine Manager, Licensing Palisades Plant 27780 Blue Star Memorial Highway Covert, MI 49043 March 4, 1998 e
SUBJECT:
PALISADES PLANT - REQUEST FOR ADDITIONAL INFORMATION RELATED TO CONSUMERS ENERGY COMPANY'S RESPONSE TO GENERIC LETTER (GL) 88-20, SUPPLEMENT 4, "INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS" (TAC NO. M83653)
Dear Mr. Berdine:
The staff requires additional information in order to complete our review of your response to GL 88-20, Supplement 4, submitted June 30, 1995, and supplemented on May 31, 1996, based on Consumers Energy's reanalysis of internal fires, and on September 30, 1996, in response to the staff's request for additional information dated June 14, 1996. Please provide a response to the enclosed questions within 90 days of the date of this letter. If you have any questions regarding this request, please contact me at 415-1312.
Docket No. 50-255 Sincerely, ORIGINAL SIGNED BY KEVIN A. CONNAUGHTON FOR Robert G. Schaaf, Project Manager Project Directorate 111-1 Division of Reactor Projects - 111/IV Office of Nuclear Reactor Regulation
Enclosure:
Request for Additional Information cc w/encl: See next page DISTRIBUTION: See attached list DOCUMENT NAME: G:\\WPDOCS\\PALISADE\\PAL83653.RAI To receive a copy of this document, indicate in the box C=Copy w/o attachment/enclosure E=Copy with attachment/enclosure N = No copy OFFICE LA:PD31 NAME CJamerson DATE b I 3_, /98 J. I ~ (? /98 9803120415 980304 PDR ADOCK 05000255 F
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Distribution for Letter to Consumers Energy Co.. Palisades Plant. dated: March 4, 1998
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PUBLIC PD3-1 Rdg E. Adensam (EGA 1)
R. Schaaf C. Jamerson A. Rubin J. Chen A. J. Lee C. Tan OGC ACRS B. Burgess, Rill
Mr. Thomas C. Berdine Consumers Energy Company cc:
Mr. Thomas J. Palmisano Site Vice President Palisades Plant 27780 Blue Star Memorial Highway Covert, Michigan 49043 Mr. Robert A. Fenech, Sr Vice Pres Nuclear, Fossil, and Hydro Operations Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan 49201 M. I. Miller, Esquire Sidley & Austin 54th Floor One First National Plaza Chicago, Illinois 60603 Mr. Thomas A. McNish Vice President & Secretary Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Energy Company 212 West Michigan Avenue Jackson, Michigan 49201 Regional Administrator, Region Ill U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Jerry Sarno Township Supervisor Covert Township 36197 M-140 Highway Covert, Michigan 49043 Office of the Governor Room 1 - Capitol Building Lansing, Michigan 48913 Palisades Plant U.S. Nuclear Regulatory Commission Resident Inspector's Office Palisades Plant 27782 Blue Star Memorial Highway Covert, Michigan 49043 Drinking Water and Radiological Protection Division Michigan Department of Environmental Quality 3423 N. Martin Luther King Jr Blvd P. 0. Box 30630 CPH Mailroom Lansing, Michigan 48909-8130 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, N. W.
Washington DC 20037 Michigan Department of Attorney General Special Litigation Division 630 Law Building P.O. Box 30212 Lansing, Michigan 48909 July 1997
REQUEST FOR ADDITIONAL INFORMATION RELATED TO CONSUMERSENERGYCOMPAN~S RESPONSE TO GL 88-20, SUPPLEMENT 4 INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS Based on the Consumers Energy submittals and the September 30, 1996, response to the staff's request for additional information (RAI), the staff is unable to conclude at this time that you have met the intent of Supplement 4 to GL 88-20 with respect to seismic events. Please provide responses to the following questions in order to facilitate completion of staff review of Consumers' IPEEE submittal.
- 1.
Based on the response to RAI question A.11 in the September 30, 1996, letter, the
- reported high confidence of low probability of failure (HCLPF) capacity for the plant does not exceed even the safe shutdown earthquake (SSE) spectrum for vibration frequencies less than about 5 Hz. The reported HCLPF spectrum is also much lower, over frequencies of interest, than the review level earthquake (RLE) spectrum defined by a NUREG/CR-0098 median spectral shape anchored to a peak ground acceleration (PGA) value of 0.3g. Please provide a discussion on why the plant is considered to have adequate margins against potential seismically induced severe accidents.
- 2.
Although the submittal reports numerous anomalous conditions, outliers, and low capacity components (e.g., poor anchorage, unanalyzed [and unqualified] block walls, and interaction concerns), no potential plant improvements have been identified. For each such case where an anomaly, outlier, or evaluated low capacity has been identified, please
. discuss the disposition and basis for such disposition.
- 3.
Based on the responses to seismic RAls questions A.1 and A.3 in the September 30, 1996, letter, the staff believes that the practice of simply assigning a 0.1 g PGA HCLPF to identified anomalies/outliers is inappropriate. The response to RAI question A.1 indicated that some of the components in this category were not walked down. Hence, the statement in the response to RAI question A.3, that "All equipment assigned a HCLPF of 0.19 is expected to have a much higher value if detailed fragility analysis were to be performed" does not appear to have a sound basis. Furthermore, it is not clear that the risk achievement worth and Fussell-Vesely thresholds cited in the response to RAI question A.3 would ensure a sufficiently low contribution to seismic core damage frequency (CDF), such that the components in question could be collectively screened out from the seismic PRA model. Therefore, please provide plant specific analyses of the seismic fragilities for these components, requantify the seismic CDF, and reassess the important risk contributors for those components.
- 4.
In the IPEEE submittal, the most important seismic failures contributing to the seismic CDF were identified as:
Fire Protection System (FPS) (needed to provide make-up to condensate storage tank
[CST] following seismic-induced lost of offsite power [LOOP])
Diesel day tanks (T-24 and T40) for diesel-driven fire pumps Control panel for diesel-driven fire pumps (EC-137)
Station transform~r 13 (EX-13)
Enclosure
2 MSIVs (interaction hazard may prevent them from closing)
Diesel fuel oil storage tank (needed to supply diesel fuel to both diesel generators following seismic LOOP)
Bus 1 D undervoltage relays (needed to power auxiliary feedwater [AFW] pump P-BC, the only AFW pump available following the loss of the FPS)
In contrast, your response to RAI question A.3 in the September 30, 1996, letter indicated that the most important seismic equipment failures were:
Service water pumps P-7A,B,C Auxiliary feedwater pump P-BC Diesel generator 1-1 undervoltage relay 1270-1 High pressure air receiver tanks T-9A,B Please explain why these two lists differ and provide the sequences associated with the equipment failures. Please identify the ranking and contribution of seismic-induced equipment failures that are most important to the seismic CDF.
- 5.
The submittal uses sensitivity analysis to conclude that nonseismic failures are an important part of the seismic core damage frequency. This conclusion hinges on the fact that (for the likely core damage sequences) nonseismic failures must occur in combi_nation with seismic failures, in order for core damage to be realized. The study's conclusion that random failures are important, and yet its implication that seismic failures are not, suggests that the importance of seismic failures may have been missed. The study shows that the largest contribution to seismic core damage frequency comes from motions in the range of 0.359 to 0.459 PGA. Since seismic failure rates are more significant at this level than are random failures, it is difficult to see why seismic failures are not deemed to be important. Similarly, the implication that operator errors are more important to seismic CDF than are seismic failures ignores the highly uncertain nature of operator fragility estimates and the potential that such estimates could mask the effects of seismic failures.
Please identify and discuss the relative importance of seismic failures as compared to nonseismic failures a*nd operator errors. Also, please discuss what, if any, procedural improvements are planned to reduce the risk associated with human errors.
- 6.
The response to RAI question A.1 O did not provide adequate information on seismically induced loss of fire suppression system capability. The evaluation apparently focused on potential interactions Vt.!ith safety equipment, rather than on loss of fire suppression capability itself. Also, no walkdown findings are mentioned, and the discussion was limited to FPS piping. Some examples of relevant items found in past studies include (but are not limited to):
Unanchored C02 tanks or bottles Sprinkler standoffs penetrating suspended ceilings Fire pumps (unanchored or on vibration isolation mounts)
3 Unrestrained batteries/rack for diesel-driven fire pumps Block wall interactions with fire pumps or batteries Use of cast iron fire mains to provide fire water to fire pumps NUREG-1407 suggests a walkdown as a means of identifying any such items. Please identify equipment in fire suppression systems that may be damaged due to the review level earthquake and discuss resolution of these items, if any. Provide guidelines given to walkdown personnel for evaluating these issues (if they exist).