ML20199E582
| ML20199E582 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/12/1997 |
| From: | Padovan L NRC (Affiliation Not Assigned) |
| To: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| TAC-M83657, TAC-M83658, NUDOCS 9711210254 | |
| Download: ML20199E582 (7) | |
Text
_____- _
Mr. George A. Hunger, Jr.
November 12, 1997 F'
Director-Licensing, MC 62A-1 l
PECO Energy Company Nuclear Group Headquarters Correspondence Control Desk P.O. Bcx No. 195 Wayne, PA 19087-0195
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) ON INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE) SUBMITTAL, PEACH BOTTOM ATOKIC POWER STATION (PBAPS), UNITS 2 & 3 (TAC NOS. M83657 AND M83658)
Dear Mr. Hunger:
We developed the enclosed RAI based on our ongoing review cf the Peach Bottom, Units 2 and 3, IPEEE submittal. The RAI is related to your IPEEE Seismic, Interr.a1 Fires, and High Winds, Floods, and Others Analysis.
Please provide your response to us within 60 days of the date of this letter.
Please contact me at (301) 415-1423 if you have any questions.
Sincerely,
/s/
L. Mark Padovan, Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278
Enclosure:
RAI cc w/ enc 1:
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November 12, 1997 Mr. George A. Hunger, Jr.
Director-Licensing, MC 62A-1 PECD Energy Company Nuclear Group Headquarters Correspondence Control Desk y
.P.O. Box No. 195 Wayne, PA 19007-0155 SUBJECT-REQUEST FOR ADDITIONAL INFORMATION (RAI) ON INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE) SUBMITTAL, PEACH BOTTOM l
ATOMIC POWER STATION (P3APS), UNITS 2 & 3 (TAC NOS. M83657 AND M836S8)
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Dear Mr. Hunger:
We developed the enclosed RAI based on our ongoing review of the Peach Bottom, h
Units 2 and 3, IPEEE submittal. -Tha RAI is related to your IPEEE Seismic, Internal Fires, and High Winds, Fh ds, and Others Analysis.
Please provide your response to us within 60 days of the date of this letter.
Please contact me at (301) 415-1423 if you have any questions.
L Sincerely.
o^
G.
L. Mark Padovan, Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278
Enclosure:
RAI cc w/ enc 1: P 2 next page
s Mr. George A. Hunger, Jr.
Peach Botton Atomic Power Station,
.PECO Energy Company Units 2 and 3 cc:
J. W. Durham, Sr., Esquire Chief-Division of Nuclear Safety Sr. V.P. & General Counsel PA Dept. of PECO Energy Company Environmental Resources 2301 Market Street, S26-1 P.O. Box 8469 Philadelphia, PA 19101 Harrisburg, PA 17105-8469 PECO Energy Company ATTN: Mr. T. N. Mitchell, Vice President Board of Supervisors Peach Botton Atomic Power Station Peach Botton Township 1848 Lay Road R. D. #1 Delta, PA 17314 Delta, PA 17314 PECO Energy Company Public Service Comission of Maryland ATTN:
Regulatory Engineer, A4-55 Engineering Division Peach Bottom Atomic Power Station Chief Engineer 1848 Lay Road 6 St. Paul Centre Delta, PA 17314 Baltimore, MD 21202-6806 Resident Inspector Mr. Richard McLean U.S. Nuclear Regulatory Comission Power Plant and Environmental Peach Bottom Atomic Power Station Review Division P.O. Box 399 Department of Natural Resource.c Delta, PA 17314 B-3, Tawes State Office Built:
Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Comission Dr. Judith Johnsrud 475 Allendale Road National Energy Comittee King of Prussia, PA 19406 Sierra Club 433 Orlando Avenue Mr. Roland Fletcher-State College, PA 16803 Department of Environment 201 West Preston Street Manager-Business & Co-owner Affairs Baltimore, MD 21201 Public Service Electric and Gas Company A. F. Kirby, III P.O. Box 236 External Operations - Nuclear Hancocks Bridge, NJ 08038-0236 Delmarva Power & Light Company P.O. Box 231 Wilmington, DE 19899 Manager-Peach Bottom Licensing PECO Energy Company PECO Energy Company Nuclear Group Headquarters Plant Manager Correspondence Control Desk Peach Bottom Atomic Power Station P.O. Box No. 195 1848 Lay Road Wayne, PA 19087-0195 Delta, PA 17314
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Reauest for Additional-Information Peach Bottom Atomic Power Station; UnitA 2 1 3 Individual Plant Examination of External Events (IPEEE)
Please provide the following information:
A, Seismic' Analysis I~
- 1. A reduced-scope evaluation was performed instead of the recomended focused-scope (or modified focused-scope) avaluation. No high confidence in low probability of failure (HCLPF) capacities were reported for the plant or key components that may entrol the plant capacity. The most apparent consequencef, of this deficiency are: (a) plant capability in the face of beyond-design-basis earthquakes has not been demonstrated; and (b) 4. anpreciable understanding has not been obtained of the most important e g nnents that act to limit the seismic capability of-the plant. Please identify the key components that control the HCLPF capacity of each of the selected success paths, report the HCLPF captcities for these components, and submit HCLPF calculations for the controlling set of components having capacities less than the 0.3g review level earthquake (RLE) recommended in NUREG-1407.
- 2. The submittal has not presented a list of the masonry / block walls whose failure could interact with: success path component list (SPCL) components; components needed to maintain early containment integrity; components whose failure could induce a fire, flood, or release of harmful chernicals; or components needed for fire suppression. The submittal references calculations that demonstrate block wall seismic design adequacy, but does not describe the approa.:' and results of such calculations.
Furthermore, Supplement No. 5 of Geiieric Letter 88-20 requestr. that seismic margins assessment evaluations of block walls affecting safety-equipment be performed for focused-scope plants at the RLE value of 0.3g, rather than at the safe-shutdown earthquake (SSE).
Please provide e list of masonry block walls potentially affecting safety equipment, report their HCLPF capacities, and submit capacity calculations for a bounding (lowest capacity) case.
- 3. The submittal dces not provide a description of unit differences, a:id does not identify which SPCL components (a) belong 7.o Unit 2, (b) belong to Unit 3, and (c) are shared among Units 2 and 3 Please identify and descriM in detail any differences among the plara units.
Please
- confirm (and justify) whether or not the reported capacity and other
-seismic IPEEE results apply equally to Units 2 and 3.
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- 4. The submittal' does not present random failure rates, operator failure rates (ii,cluding seismic impacts on error rates), or screening criteria applied to random and human failure rates. NUREG-1407 requests that such screening criteria be considered.
Provide a list of all operator actions that are required to ensure integrity of the chosen success paths.
For each human action, indicate the time after the earthquase that the operator action is required, and its location.
Indicate also the human w ror probabilities, accounting for seismic affects on operator actions.
Provide a list of the random failures (and their failure rates)-having the most significant potential to compromise integrity of the success paths.
Indicate the screening criteria applied to rates of random failures and operator errors, and report the results of your_ screening.evaluaticn.
- 5. There is no discussion in the IPEEE report pertaining to an evaluation of seismically-induced floods that specifically addresses failures of non-safety tanks e.nd piping (other than fire-water piping). Please report.the findings of your walkdown and resulting evaluation rertaining
' to seismically induced floods that may be caused by non-safety tank failures and non-fire-water piping l'ailures.
- 6. Even for plants characterized as rock sites, there may still exist some soil-founded or buried components (e.g., piping and tanks) or soil structures (including onsite or offsite canals, dams, or embanlonents) that can affect plant response.
Please identify any such components, evaluate their importance to plant safety, evaluate the potential and effects of soil resp nse/ failure (including soil settlements /
deformations, soil stresses, etc.) on their capacities, and report your related analyses and findings.
- 7. From Table 3.1.4-2 of the IPEEE submittal, for each equipesnt class where not all components were screened out, identify the bounding (lowest capacity or severest) case.
For each identified bounding case, please provide completed screening evaluation work sheets, walkdown notes /clecklists, photographs, and capacity calculations (where performed). The applicable equipment classes include:
motor control centers switchgear (low and medium voltages) transformers vertical pumps-valves (fluid-operated, motor-operated, and solenoid-operated types) fans air handlers distribution panels batteries and racks battery chargers and inverters engine generators instruments on racks control and instrumentation panels and cabinets tanks and heat exchangers
-_~ - - - - -
'.i
. i electrical-cable tray; and conduit -
control rod drive units and hydraulic control units 1
heating, ventilation, and air conditioning ducting j
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- 8. Discuss the ability of the primary and alternate success paths to respond to medium and large loss-of-coolant accidents resulting from
)
stuck-open safety-relief valves.
i B. Internal Fire Analysis
- 1. In Sections 4.4.1.1 and 4.4.1.2 of the submittal (pages 4-39 to 4-41),
4 it is stated that, for fire compartments 25, 2X, 2Y-2, 4, 50R-6, 31 through 39, and 41, the time ta damage is greater than the sum of the detection and suppression times.
It is assumed that for 4 kV switchgear rooms and battery rooms, the fire brigade can respond, and the response time is 30 minutes. Thus, the time to damage can be concluded to be greater th&u 30 minutes. Sufficient information is not provided in the i
submittal te verify this conclusion. A severe fire (i.e., one that 4
propagates relatively rapidly and damages a number of equipment and t
cables), is possible to occur in a 4 kV switchgear room, because of the l-high ensrgy equipment in-the room.
Please provide further information regarding the fire scenarios considered, and the' time to cable and equipment damage determined, for the compartments listed above.
- 2. The submittal does not provide any information regarding failed system trains caused by a fire, and the associated alternate shutdown paths.
NUREG-1407 requests such information to be provided.
Please provide, for the seven unscreened fire scenarios, the failed system trains and i
associated alternate shutdown paths.
- 3. The submittal includes a discussion on core damage frequency and how it is not used in the IPEEE. However, since t1 Probabilistic Safety Assessment (PSA) model is.used to quantif, N fire induced safe-shutdown system unavailability, it is infeired that actually core damage i
frequency is used to screen compartments and obtain the final seven unscreened compartments. Use of the PSA model implies that the analysis constriered potential initiating events caused by a fire,-failure of equipment needed to mitigate the effects of the initiating event, and unavailability of equipment that remained unaffected by the fire.
Without such considerations (i.e., an initiating event occurrence and chain of failures leading to core damage), a measure based on " safe-shutdown system unavailability" is difficult to interpret consistently 4
for all fire compartments, and any comparison with a stancard screeaing 1
criteria may be inappropriate. P1 case provide an interpretation of the measure that you used 3cr screening the fire compartments.
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' 4. The discussions provided in the submittal on scismic fire interaction do not address the possibility of the following scenario. A near-SSE j
seismic event may cause the non-safety electrical cabinets in the cable spreading room to either tip over cr slide and initiate a fire. These cabinets are located underneath a group of safety-related cables. Thus, there is a potential for safe-shutdown cable damage from such a fire.
The cable spreading room is protected by a CO, system. However, the system has two potential weaknesses that may arevent CO, from reaching the cable spreading roors.
Lack of proper anc1 ors for the CO storage tank may cause the tank to move and shear the supply pipe th,at is anchored to the ceiling, or a relay chatter may prevent the su) ply valve from opening. As a result of the cable spreading room fire, tie o)erators have to abandon the control room and shut both units down from t1eir respective remote shutdown panels. The human error probabilities for using the remote shutdown panel used in other parts of the fire analysis may not apply to this case, due to the special conditions created by the aarthquake.
Please provide a discussion on how this scenario was considered, the associated conditional core damage probability, and if appropriate, what mitigative measures are in place to minimize the consequences of this scenaric.
C. High Winds, Floods, and O'.hers Analysis
- 1. Please provide an evaluation demonstrating whether or not loss of the contents of the Conowingo Pond, due to dar. failure, can be screened out as a possible plant-unique hazard.
I