ML20138E822

Requests Addl Info Re External Event Analyses in IPEEE, within 60 Days in Conformance W/Review Schedule

ML20138E822
Person / Time
Site:	Saint Lucie
Issue date:	08/31/1995
From:	Cunningham M NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Matthews D NRC (Affiliation Not Assigned)
Shared Package
ML20137B842	List: ML20137B837 ML20138E148 ML20138E822 ML20138E974
References
FOIA-96-485 NUDOCS 9509200184
Download: ML20138E822 (6)

Text

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MEMORANDUM FOR:

David Mathews, Project Director l

Project Directorate II-I i

Division of Reactor Projects I/II Office of Nuclear Reactor Regulation i

FROM:

Mark Cunningham, Chief Probabilistic Risk Analysis Branch i

Division of Systems Technology Office of Nuclear Regulatory Research

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON ST. LUCIE IPEEE SUBMITTAL Based on our ongoing review of the St. Lucie Individual Plant Examination of External Events (IPEEE) submittal and its associated documentation, we have developed the attached request for additional information (RAI). The RAI is related to the external event analyses in the IPEEE, including the seismic analysis, the fire analysis, and the analyses on effects of high winds, i

floods, and others. The RAI was developed by our contractor, Energy Research, 4

Inc., and reviewed by the " Senior Review Board" (SRB). The SRB is comprised of RES and NRR staff and RES consultants (Sandia National Laboratory) with i

probabilistic risk assessment expertise for external events.

We request that the licensee provide its response within 60 days in conformance with our review schedule.

If you have any questions concerning our review, please contact John T. Chen l

at 415-6549.

1

Attachment:

As stated cc:

W. Hodges J. Murphy S. Varga R. Hernan J. Norris Distribution:

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1 MEMORANDUM FOR:

David Mathews, Project Director Project Directorate 11-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation FRDM:

Mark Cunningham, Chief Probabilistic Risk Analysis Branch Division of Systems Technology Office of Nuclear Regulatory Research

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON ST. LUCIE IPEEE SUBMITTAL Based on our ongoing review of the St. Lucie-Individual Plant Examination of External Events (IPEEE) submittal and its associated documentation, we have developed the attached request for additional information (RAI). The RAI is related to the external event analyses in the IPEEE, including the seismic analysis, the fire analysis, and the analyses on effects of high winds, floods, and others.

We request that the licensee provide its response within 60 days in conformance with our review schedule.

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If you have any questions concerning our review, please contact John T. Chen at 415-6549.

i

Attachment:

As stated cc:

W. Hodges T. King S. Varga R. Hernan J. Norris Distribution:

CMcCracken SWest Econnell GBagchi RRothman AMurphy NChokshi TChang PChen RWoods ABuslik PRAB Sub/ File M8ohn, SANDIA SNowlen, SANDIA DOCUMENT NAME:G:\\ST LUCIE.01 CF Y

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NAME JChen:bg;f' MDrouin MCunningham DATE 9 / /6/9 51/

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/ /95 0FFICIAL RECORD COPY (RES File Code) RES 2C-5

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ATTACHMENT 1

REQUEST FOR ADDITIONAL INFORMATION-ON ST. LUCIE IPEEE SUBMITTAL i

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Seismic 4

l.

Two success paths (preferred and alternate paths) should be developed for-seismic IPEEE evaluation following EPRI seismic margin assessment I

methodology. Apparently, only one success path was developed in the i

. Turkey Point seismic adequacy study. Please identify the additional success path that insures that hot shutdown is maintained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

i Please provide the list and the walkdown findings of components associated with this alternate path. Please also. provide success path logic diagrams that illustrate the basis for their selection.

l 2.

Please provide a list of components that were (would be) consirdered in j

the containment performance walkdown for Turkey Point Nuclear Plant, i

describe the basis for developing this list, and provide the walkdown results.

3.

Please provide a discussion of the process for addressing seismic-fire interaction concerns at Turkey Point Nuclear Plant.

List all walkdown-i related findings pertaining to potential seismic-fire interactions i

involving IPEEE components.

l 4.

Please provide a discussion of your resolution pertaining to GI-131, i

with respect to potential seismic vulnerabilities (or interaction concerns) associated with the in-core flux mapping system.

Please j

describe the configuration of the flux mapping systems at Turkey Point, i

a demonstration of adequacy of lateral restraint of the systems, and j

evaluation findings pertaining to potential seismic interactions.

I 5.

For all instances of seismic interaction concerns related to block walls =

1 i

that were noted by the SRT, please provide calculations which demonstrate adequate seismic capability of these walls.

6.

The peer review report by Dr. Paul Smith, pertaining to the St. Lucie Unit 2 seismic adequacy evaluation, noted that additional seismic interaction concerns were identified during the peer review walkdown.

[

Please list these other seismic interaction concerns, and explain their disposition status.

II.

Fire 1.

-Did the analysis team conduct a walkdown of the plant prior to the completion of the fire analysis pcrtion of the IPE?

If a walkdown was J

conducted, provide information regarding team composition, areas j

surveyed, scope of the walkdown, and a summary of the walkdown findings.

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d 2.

The IPEEE submittal indicates that only selected areas were visited and reviewed.

Please provide the list of areas that were visited. What was 1

the basis for not visiting other areas of the plant?

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3.

The IPEEE does not address the initiatirg events (e.g., LOCAs, loss of offsite power, etc.) as a separate sd, ject. No list is provided as to which initiating events were analyz d and no description is provided concerning final conclusions as to which initiating events are ponnole.

Provide the list of initiating events that were addressed, as well as j

the conclusion and basis as to which initiating events could occur from 1

which compartment.

4.

A plant-specific fire events data base has not been used.

This can be an optimistic practice if St. Lucie Plant has experienced fire events in safety related areas.

If such events have taken place in any safety related area since initial commercial operation, provide an assessment of the effect of these events on the fire frequencies.

4 5.

Please provide an analysis of the effect on fire-induced CDF if the potential for the failure of active barrier components such as doors and l

dampers for all fire areas, and the potential for cross-zone fire propagation is considered for high hazard areas such as the turbine building, diesel generator room, cable spreading room, switchgear rooms, and lube oil storage areas.

6.

On page 17 of the IPEEE submittal, it is claimed that credit was taken for the installed preaction suppression system in screening out two Unit 2 compartments. Does this mean that it was assumed that the preaction suppression system will work perfectly, and therefore no fire propagation will take place? If it is assumed that it is not perfect, provide further information as to how the system was modelled in the fire analysis.

If it is assumed as a perfect system, what would the core damage frequency be if the suppression system is assumed to be non-existent?

7.

A single value is used to model the possibility of detection and suppression failure; for the majority of cases, a probability of 0.1 is used.

It is not apparent that this method addresses all the factors that affect the likelihood of failure to suppress the fire before critical damage has occurred using area specific information.

For example, if cables and equipment are in close proximity, fire may cause critical damage before successful suppression.

Provide justification for using the specific probability values.

8.

There is no discussion in the IPEEE of fire-suppression-induced damage in any of the phases of the analysis (i.e., damage to equipment as a result of the activation of the fire suppression system in extinguishing a small fire in a given area). Are there any compartments where equipment (e.g., motors and electrical cabinets) are susceptible to water damage, and yet the fire impact analysis has considered these equipment as available after the successful operation of the fire i 3 i

suppression system? Provide a summary discussion on how this issue has been addressed.

9.

Human recovery actions are identified as one of the most critical event in the fire scenario importance ranking list provided in the IPEEE i

submittal report. However, no details are provided concerning how probabilities of recovery failure were assessed. Provide a detailed description of how fire event recovery actions were assessed, including how factors such as sequence timing, elevated environmental stressors (e.g., reduced visibility, impaired communications, and impaired i

accessibility) were accounted for.

If IPE values were assumed, were they adjusted to reflect reduced reliability during a fire event and, if so, how were they adjusted?

If IPE values were used directly, provide a i

justification for not having adjusted the values.

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10.

Credit has been'taken for the activation of a cross-tie breaker connecting the electric power of one unit to the other unit. As stated in the preceding RAI, has the evaluation of recovery action failure 1

probability addressed the possibility of interference by the fire and smoke? Provide a description of the analysis, if smoke egress j

phenomenon has been considered. Otherwise, provide the basis for not including it in the analysis.

11.

The licensee has not demonstrated and summarized how the core damage frequency is estimated for each fire scenario.

Provide a set of typical calculations supporting the estimated P, values.

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12.

Fire modeling is used as the basis for concluding that the B Switchgear room does not pose a fire vulnerability.

Provide a sample set of the calculations used to reach this conclusion.

In the sample package, include a drawing of the area, location of the postulated pilot fires, j

and locations of. target cables and equipment. Also, include criteria used for equipment and cable failures.

l 13.

Provide accident sequence related information per Appendix 3 of GL 88-l 20, Supplement 4.

As a minimum, such information should be made available for all compartments for which core damage frequency is greater than 10/yr.

I 14.

Does Intake Cooling Water System failure lead to CCW failure?

If yes, provide a list of areas where a fire can cause loss of ICW and an assessment of their impact on core damage frequency.

If not, what systems can cause the failure of CCW, and how have those systems been accounted for in the fire analysis.

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.15.

The results of the screen-out computations for fire compartments listed in Table 4-2 have not been provided in the IPEEE submittal.

Please d

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provide a sumary of the computed results for each of those fire zones j

with screening criteria "C", "D" and "E" (per Table 4-2 definition).

III. Hiah Winds. Floods. and Others None.

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