ML17158A258
| ML17158A258 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 04/21/1994 |
| From: | Shea N Office of Nuclear Reactor Regulation |
| To: | Byram R PENNSYLVANIA POWER & LIGHT CO. |
| References | |
| NUDOCS 9405030197 | |
| Download: ML17158A258 (11) | |
Text
gP,R 4g0f/
+
~
O~
co s
O P
gO
+sb*dc+
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTONs D.C. 2055&0001 April 21, 1994 Docket Nos. 50-387 and 50-388 Mr. Robert G.
Byram Senior Vice President-Nuclear Pennsylvania Power and Light Company 2 North Ninth Street Allentown, Pennsylvania 18101
Dear Hr. Byram:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) CONCERNING LOSS OF SPENT FUEL POOL COOLING, SUSQUEHANNA STEAM ELECTRIC STATION (SSES),
UNITS 1
AND 2 (TAC NO. H85337)
The NRC staff is continuing its review of spent fuel pool cooling issues that were raised in a report filed pursuant to 10 CFR Part 21 on November 27, 1992.
The staff has reviewed numerous submittals from Pennsylvania Power and Light.-
Company (PP&L) and from the Part 21 report authors.
The staff has made several visits to the Susquehanna site as well as to PP&L headquarters.
The staff has reviewed the information from these various channels and has certain additional questions.
The staff's questions are included in the attached request for additional information.
'The staff issued a letter dated March 16, 1994, that included the conclusions from the staff's review of the Susquehanna licensing basis as it pertains to the issues raised in the Part 21 report.
One of those conclusions, regarding boiling of the spent fuel pools following a seismic event, was the subject of an RAI dated Harch 7, 1994.
In the Harch 16, 1994 letter, the staff also concluded that the link between loss of spent fuel pool (SFP) cooling events and design basis loss of coolant accidents
'(LOCA) and/or loss-of-offsite power (LOOP) events postulated by the authors of the Part 21 report could not be considered within the original licensing basis of SSES.
The staff received a letter from the authors of the Part 21 report dated March 21,
- 1994, which provided additional discussions of licensing basis related issues.
The staff is reviewing those discussions and will document its review of those issues in the future.
Apart from the discussions provided in that letter, the staff has determined that the addition of make-up water to the spent fuel pool from the emergency service water system during LOCA or LOCA/LOOP conditions is a commitment documented in the licensing basis of the Susquehanna facility.
The staff has not revised its conclusion that loss of spent fuel pool cooling events following from a LOCA or LOCA/LOOP is not within the licensing basis of the facility, but rather has identified the commitment, documented in the Final Safety Analysis Report (FSAR) and discussed in the operating license safety evaluation report (SER),
conc'erning make-up from the emergency service MI:AILEmmeI r
+4QGQSQ 1 Q5QQQe387 PDR ADOC PDR P
Hr. Robert G.
Byram April 21, 1994 water (ESW) system to the spent fuel pools under accident conditions.
The staff has identified a question regarding the ability to provide make-up to the spent fuel pool from the emergency service water system under accident conditions.
The staff's question is guestion 5'3 in the attached RAI.
Your response to the enclosed questions is requested by Hay 2, 1994.
This request affects fewer than 10 respondents and, therefore, is not subject to Office of Management and Budget review under P.L.96-511.
If you have any questions, please contact me at (301) 504-1428.
Sincerely,'nclosure:
Request for Additional Information cc w/enclosure:
See next page Original signed'by:
Joseph W. Shea, Project Manager Project Directorate I-2 Division 'of Reactor Projects'- I/II Office of Nuclear 'Reactor Regulation DISTRIBUTION Docket Fi~le NRC an Local PDRs PDI-2 Reading SVarga MVirgilio RPedersen, PRPB JCalvo CHiller MO'Brien JShea SJones J
EWenzinger, RGN-I CMcCracken
- JWhite, RGN-I LPrividy, RGN-I
- GKelly, SPSB
- GHubbard, SPLB LCunningham OFFICE NAME M
i PDI P
JS SPLB CMcCracke na am PDI-2 D
CHi DATE
/
94
/
/94
/
/94
/8/94
/L /94 OFFICIAL RECORD COPY DOCUMENT NAME:
SUESWRAI. GEN
l l
)'t r
Ll 1
f'I
'l l
Mr. Robert G.
Byram April 21, '.1994 water (ESW) system to the spent fuel pools under accident conditions.
The staff has identified a question regarding the ability to provide make-up to the spent fuel pool from the emergency service water system under accident conditions.
The staff's question is guestion ¹3 in the attached RAI.
Your response to the enclosed questions is requested by May 2, 1994.
This request affects fewer. than 10 respondents and, therefore, is not subject to Office of Management and Budget review under P.L.96-511.
If you have any questions, please contact me at (301) 504-1428.
Sincer ly,
Enclosure:
Request for Additional Information cc w/enclosure:
See next page J
eph W. Shea, Project Manager Project Directorate I-2 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
~C
'jP
Mr. Robert G.
Byram Pennsylvania Power and Light Company Susquehanna Steam Electric Station, Units 1 5 2 CC:
Jay Silberg, Esq.
- Shaw, Pittman, Potts 5 Trowbridge 2300 N Street N.W.
Washington, D.C.
20037 Bryan A. Snapp, Esq.
Assistant Corporate Counsel Pennsylvania Power. 5 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Mr. J.
M. Kenny Licensing Group Supervisor Pennsylvania Power 8 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Mr. Scott Barber Senior Resident Inspector U. S. Nuclear Regulatory Commission P.O.
Box 35 Berwick, Pennsylvania 18603-0035 Mr. Thomas M. Gerusky, Director Bureau of Radiation Protection Resources Commonwealth of Pennsylvania P. 0.
Box 2063 Harrisburg, Pennsylvania 17120 Mr. Jesse C. Tilton, III Allegheny Elec. Cooperative, Inc.
212 Locust Street P.O.
Box 1266 Harrisburg, Pennsylvania 17108-1266.
Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 Mr. Harold G. Stanley Superintendent of Plant Susquehanna Steam Electric Station Pennsylvania Power and Light Company Box 467 Berwick, Pennsylvania 18603 Mr. Herbert D. Woodeshick Special Office of the President Pennsylvania Power and Light Company Rural Route 1,
Box 1797 Berwick, Pennsylvania 18603 George T. Jones Manager-Engineering Pennsylvania Power and Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Mr. David A. Lochbaum 80 Tuttle Road Watchung,'New Jersey
- 07060, Mr. Donald C. Prevatte 7924'oodsbluff Run Fogelsville, Pennsylvania 18051
RE VEST FOR ADDITIONAL INFORMATION REGARDING LOSS OF SPENT FUEL POOL COOLING EVENTS ENCLOSURE l.
In a letter dated May 24,
- 1993, PP&L stated that "the normal SFP cooling system will automatically be shed from the plant electrical
- system, along with other non-safety-related equipment, to permit the start-up of the large emergency core cooling system (ECCS) pumps on the LOCA unit."
In a letter dated March 21,
- 1994, PP8L provided clarification that indicated that the service water pumps are lost due to the auxiliary load shed feature and that the cooling function of the fuel pool cooling system will no longer be provided for the accident unit only.
The staff requests that you provide a comprehensive description of the response and operation of the spent fuel pool cooling and cleanup system following a LOCA.
Please address the following issues as a minimum:
a.
The March 21, 1994 letter indicated that loads such as the service water system can be restored 10 minutes after initiation of the event and that complete restoration of the service water system would take approximately one 12-hour shift.
Please describe what activities, including relevant procedures, would be specifically required to restore service water to the fuel pool cooling system and the expected duration of these activities.
b.
Describe the expected response and operation of the fuel pool cooling system following the loss of service water.
Describe the expected system response, including system heat-up and any impact of system heat-up as well as expected or necessary operator manipulation of the fuel pool cooling system following the loss and restoration of service water.
2.
In previous discussions with the staff, including discussions on July 8,
- 1993, PPKL indicated that one possible action for mitigating or preventing the spread of vapor from one (or two) boiling spent fuel pools entails shutting down the reactor building recirculation fans.
Please describe your plans to provide procedures to perform these activities including guidance to the emergency response staff and/or system-specific procedures.
3.
The staff has reviewed additional portions of the licensing basis documentation.
Section 9.2.5 of the Final Safety Analysis Report (FSAR) describes the emergency service water system (ESW) and Section 3. 1.2.4. 15 describes compliance of the facility design with General Design Criteria 44.
Section 3.1.2.4. 15 states:
"The emergency safeguard service water system, which comprises both
" the Emergency Service Water System and the Residual Heat Removal Service Water System, provides cooling water for the removal of excess heat from all structures,'ystems and components which are necessary to maintain safety during all abnormal and accident conditions.
These include the standby diesel generators, the RHR
'\\
'i~i K
pump oil coolers and seal water coolers, the core spray pump room unit coolers,
[reactor core isolation cooling]
RCIC pump room unit
- coolers, the [high pressure coolant injection] HPCI pump room unit
- coolers, the [residual heat removal]
RHR heat exchangers, RHR pump room unit coolers, emergency switchgear and load center room coolers, the.,control structure chiller and the fuel pool make-up."
Section 9.2. 1 of the SER describes the above function of the ESW system and states:
"The emergency service water system is an engineered safety features system designed to supply cooling water to the emergency diesel generators, residual heat removal pumps and to those rooms identified below, that are required during normal and emergency conditions to safely shutdown the plant.
The emergency service water system takes water from the spray pond (ultimate heat sink),
pumps it to the heat exchangers which serves the above components or systems and returns
" 'it to the spray pond by way of a network of sprays.
The emergency service water system is required to supply cooling water to the residual heat 'removal pumps room coolers, residual heat removal pump bearing oil coolers,...
and to the spent fuel pools as emergency makeup...
...Therefore a failure of the nonsafety related piping coupled with any single active failure of the safety-related Emergency Service Water System will not preclude one of the loops from performing its function.
By providing this isolation capability and redundancy in components, we conclude that the requirements in General Design Criteria 44 "Cooling Water" are met, including the single active failure criterion."
The staff concludes that provision of make-up to the spent fuel pool during a design basis
- accident, including design basis loss-of-coolant
- accident, is within the design and licensing basis of the SSES facility.
The staff review did not conclude that boiling of the spent fuel pool was necessarily implied but recognizes that make-up to the pool will be necessary to compensate for, at the very least, evaporative losses.
The staff requests that you provide information to demonstrate that make-up can be supplied to the spent fuel pool from the ESW system under design basis accident conditions (specifically, design basis LOCA).
The staff has noted the dose estimates that you supplied in previous correspondence regarding activities necessary to manipulate the ESW-fuel pool make-up valves under various accident conditions.
The staff requests that you reanalyze the performance oF these activities using design basis assumptions.
Please specifically describe the correlation between the point in the accident sequence time line that make-up actions would be
- required, and times in the accident sequence when expected operator dose would exceed design basis limits.
4.
Earlier PP&L submittals have identified that a
SFP with no operable cooling system may be cooled by natural convection through the cask storage pit by cooling systems associated with the remaining SFP.
The staff requests that PP&L describe 'the basis (i.e., test results, calculational results, or operational experience) for concluding that this method of cooling is adequate.
The staff also requests that PP&L estimate the temperature difference between the pools assuming that the decay heat load in the SFP without an operable cooling system is 6.2xl0 BTU/hr.
5.
Bechtel specifications for the watertight doors between the "A" core spray/reactor building sump room and other ECCS pump rooms reviewed during an audit on February 7,
1994, indicated that an unseating pressure of zero was specified for certain water tight doors.
- However, PP&L Calculation EC-035-0510 stated that the relevant watertight doors provide protection to 15 psid based on a pre-delivery hydrostatic test.
Because the subject watertight doors were credited with preventing flooding of ECCS pump rooms in certain analyses, the staff requests that PP&L clarify the apparent inconsistency between the specification and the assumed performance of the watertight doors in Calculation EC-035-0510.
6.
The staff requests that PP8L evaluate the qualification of standby gas treatment system (SGTS) components within the control structure for operation in the environment created by ventilating the reactor building through the system for cases where one SFP is boiling and where two SFPs are boiling.
The assumptions used in the evaluation should be consistent with previous evaluations of SGTS duct conditions during SFP boiling scenarios.
7.
In the March 7, 1994 RAI, the staff noted that the licensing basis of the plant credits the use of the SGTS during a boiling pool event following a seismic event.
In the RAI, the staff asked a question to assess the potential to use the residual heat removal system to cool the spent'uel pools following a seismic event.
The diesel generator loading associated with a seismic event and coincident loss of offsite power (LOOP) was presented in PP&L's letter dated Harch 25, 1994.
The staff requests that PP&L perform an assessment of diesel generator loading considering the limiting single failure for a seismic event with a coincident LOOP.
Justification for the assumed single failure should be provided.
The staff also requests that PP&L assess the ability of the diesel generators to accommodate the additional loading associated with operating one loop of the RHR system in the SFP cooling assist mode and one loop of alternate decay heat removal, as described in procedure ON-l(2)49-001, "Loss of RHR Shutdown Cooling," on the non-accident unit.
The intent is to determine maximum diesel generator loading during a loss of coolant accident (LOCA) in the opposite unit coincident with a
- LOOP, assuming no single failure. If one of the diesel generator loading patterns presented in the FSAR is bounding, describe the basis for this conclusion.
g
~