ML19332B337
| ML19332B337 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 09/09/1980 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Mcgoughy J MISSISSIPPI POWER & LIGHT CO. |
| References | |
| NUDOCS 8009260531 | |
| Download: ML19332B337 (9) | |
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g UNITED STATES g
NUCLEAR REGULATORY COMMISSION g
E WASHINGTON, D. C. 20655
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SEP 9 1980 Docket Nos.: 50-416/41?
Mr. J. P. McGaughy Assistant Vice President - Nuclear Production Mississippi Power and Light Company P. O. Box 1640 Jackson,tiississippi 39205
Dear Mr. McGaughy:
SUBJECT:
RE0 VEST FOR ADDITIONAL INFORMATION - GRAND GULF NUCLEAR STATION, UNITS 1 AND 2 As a result of our review of the information contained in the Final Safety Analysis Report for the Grand Gulf Nuclear Station, Units 1 and 2, we have developed the enclosed request for additional information.
Included are questions from the Auxiliary Systems Branch and the Accident Evaluation Branch.
We request that you amend your Final Safety Analysis Report to reflect you'r responses to the enclosed requests as soon as possible and to inform the Project Manager, Joseph A. Martore, of the date by which you intend to respond.
Sincerely, MD%
Robert L. Tedesco Assistant Director for Licensing Division of Licensing
Enclosure:
As stated cc: See next page 8009260531
cc:
Robert B. McGehee, Esq.
Wise, Carter, Child, Steen & Caraway P. O. Box 651 Jackson, Mississippi 39205 Troy B. Conner, Jr., Esq.
Conner, Moore & Corber 1747 Pennsylvania Avenue, N. W.
Washington, D. C.
20006 Mr. Adrian Zaccaria, Project Engineer Grand Gulf Nuclear Station Bechtel Power Corporation Gaithersburg, Maryland 20760 Mr. Alan G. Wagner, Resident Inspector P. O. Box 469 Port Gibson, Mississippi 39150 I. Charak Argonne National Laboratory 9700 South Cass Avenue Argonne, Illinois 60439 C. Scheibelhut Argonne National Laboratory 9700 South Cass Avenue i
Argonne, Illinois 60439 R. Jaross Argonne National Laboratory 9700 South Cass Avenue Argonne, Illinois 60439 Y
Enclosure Accident Evaluation Branch Grand Gulf Units 1 & 2 - Q-2's.
312.19 Section 11.3.2.1.6.3 discusses the bypass mode for the charcoal 7
(11.3,15.7.1) adsorbers in the waste gas treatment system and indicates that it may be " desirable to use the bypass for short periods of time during startup or normal operations." The section notes that there is a high high-high alarm on the process monitor to isolate the system from the vent if established re!,ase limits are exceeded. Analyze the bypass isolation for single f ailures.
312.20 The secondary containment volume claimed includes the enclosure (6.5.3,15.6) building, steam line tunnel, and auxiliary building volumes, all areas of which, in the event of an accident, are to be reduced to sub-atmospheric pressure by exhcust through the Standby Gas Treatment System. Approximately uniform pressure reduction is to be achieved by the control of dampers directing air flow into the recirculation fans in the enclosure building ventilation system.
Analyze in detail the response of this ventilation system to unequal leakage, and to air flows differing from those estimated in Figure 6.5-4.
In particular, include in the analysis the following effects:
(1) The release of high temperature fluids into the secondary containment volume.
(2) The possibility of moisture collection in long pressure sensing lines.
(3) The failure of a damper, the possibility of rapid cycling of motor-operated two-position dampers in the event of changing air flows, and the puncture or deformation of ductwork.
(4) The effect upon the rate of release to the environment by the leakage model described in Figure 15.6-3 of different air flows.
(Note that Figure 15.6-3 is inconsistent with Figure 6.5-4, in that the mean residence time in the enclosure building of effluent from the MSIV leakage collection system is calculated to be 130 minutes from information in Figure 15.6-3, and 110 minutes from that in Figure 6.5-4.)
312.21 Section 6.4.2.1 of t~ e FSAR states that the safety-related panels of n
(6.4) the upper cable spreading room are included within the control room ventilation envelope.
Please provide additional information describing in detail why this arrangement poses no safety problems with respect to control room habitability. The potential involvement of control room operators, directly or indirectly, in activities related to the cable spaces, such as fire fighting, should be included. The submittal should address the effects of smoke and noxious fumes which could originate within the cable spaces. Potential habitability impacts upon alternate /
reactor shutdown procedures should be decribed.
The applicant is encour-aged to identify and evaluate habitability improvements which could minimize the potential problems associated with the inclusion of these cable spaces within the envelope, including removal of these cable spaces from within the control room habitability envelope.
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Auxiliary Systems Branch Second Round Request for Additional Infomation Grand Gulf Nuclear Station, Units 1 and 2 Docket Nos:
50-416 and 50-417 010.19 Your response to Question 010.08 is not acceptable.
In keeping with past (RSP)
(6.7) practice, it is our position that the plant Technical Specifications impose a limit of 11.5 scfh for the main steam isolation valve (MSIV) leak rate and a leak rate verification test frequency consistent with plant Technical Specifications for other operating BWRs.
Modify your response accordingly.
010.20 a) Your response to question 010.10 is not acceptable. Verify that you (9.1.1) have detemined that your new fuel storage rack arrangement will main-tain a k,ff of less than or equal to 0.98 with fuel of the highest anticipated reactivity in place in the new fuel storage racks assuming optimum moderation (foam, small droplets, spray, and fogging).
b) You state in subsection 9.1.1.2 a fuel spacing of 7 inches minimum center-to-center within a new fuel storage rack and 12 inches minimum between adjacent racks results in a K of not more than 0.95.
In eff subsection 9.1.1.3.2e you state that the minimum center-to-center spacing within a rack is 6.535 inches and 11.875 inches between adja-cent rows. Confim that K,ff is not more than 0.95 when the lesser dimensions given above are used in the calculations of K eff*
' 010.21 a) Your response to question 010.11 is not acceptable.
Indicate whether (9.1.2) or not the spent fuel pool liner plate is designed to seismic Category I requirements.
If it is not, describe the means provided by your design to assure that failure of the liner plate as a result of an SSE i
l will not result in 1) significant release of radioactivity due to either mechanical damage to the spent fuel, or due to water loss from the pool and subsequent overheating of the spent fuel, and 2) loss of ability to cool the fuel due to flow blockage caused by any portion of the liner plate falling on top of the fuel racks.
b) You state in subsection 9.1.2.2 a fuel spacing of 7 inches minimum center-to-center within a spent fuel storage rack and 12 inches minimum between adjacent racks results in.a K,7f of not more than 0.95.
In subsection 9.1.2.3.2e you state that the minimum center-to-center spacing within a rack is 6.535 inches and 11.875 inches between adjacent rows.
Confirm that K is not mom than 0.95 when the lesser dimensions given eff above are used in the calculation of Keff*
010.22 You state that the fuel pool cooling system will maintain the temperature (9.1.3) of the fuel pool below 125'F during normal operating conditions and the temperature may be allowed to rise to 150*F when the maximum possible heat load is present. Provide the heat loads under these two conditions, and the fuel pool heat exchanger capability as a function of the pool tempera-tu re. Verify that the above calculated heat loads were determined in accordance with Branch Technical Position ASB 9-2.
010.23 Your response to question 010.16 is not acceptable. Provide responses to (9.2.1)
(9.2.5) the following concerns in order that we may assess your ultimate heat eM (URS) design against the positions of Regulatory Guide 1.27, Rev. 2.
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- _ _ - a) In subsection 9.2.1. 3 Safety Evaluation, certain assumptions are made as a basis to show adequacy of the system. One assumption made is loss of a standby diesel generator (Unit 1. Division 1). You claim this results in the loss of standby service water (SSW) loop A.
This is not true.
The redundant SSW pump is connected to the 1E division 1 bus of Unit 2 and would therefore be available. What would be lost would be the loads on the Unit 1 division 1 bus which would include among other loads, two of the cooling tower fans and the RHR-A system for U' i'; 1.
Tables 9.2-14 n
thmugh 9.2-20 and Figs. 9.2-28 through 9.2-42 do not reflect this.
Revise the necessary information and reevaluate your UHS design accordingly.
b) Table 9.2-21 provides a listing of SSW loads following a DBA. Under loop A are shown loads that would not exist using your assumptions; i.e.,
standby diesel generator cooler and RHR-A Unit 1 loads.
However, the table does not list the loop C load (HPCS system) which would exist following a DBA and loss of a standby diesel. The existing table would presumably be valid for Unit 2.
Prepare a separata table for Unit 1, and reevaluate the UHS perfonnance for the revised heat loads.
c) The text states that Figs. 9.2-5 and 9.2-6 show the heat rate into each of the two cooling towers. However, the figums do not show any heat contribution from loop C.
Table 9.2-3 purports to show SSW system loads.
Again, loads are shown that would not exist under your assumptions. Also,
" Design Duty" loads are shown without stating whether the loads are for one reactor or two. Revise the necessary information and reevaluate your UHS design accordingly.
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d) Tables 9.2-14 and 9.2-15 an.' Figs. 9.2-28 and 9.2-31 give the total integrated heat rejection for the 30 days following a DBA; Basin A 10 10 10 at 4.74x10 BTU and Basin B at 13.51x10 BTU for a total of 18.25x10 BTU. Assuming the towers reject 86% of the heat by evaporation and 14% to sensible heat in the air and using an h of 1043 BTU /lb., a fg 6
total of 18.04x10 gals of water would have to evaporate to reject this 6
much heat. On Page 9.2-5, you state that 12.8x10 gals would evaporate 6
and the combined basin capacity is 13.93x10 gals.
Resolve this apparent discrepancy and indicate how your URS design meets the requirements of Regulatory Guide 1.27, Rev. 2, Position 1.C for providing 30 days of cooling to both units without an assured makeup capability.
e) Other items that require clarification or further infomation:
(1) Section 9.2.13 states that there are two service water pumps and one HPCS pump per basin. However, Fig. 9.2-1 shows a HPCS pump in basin A and none in basin B.
Also it shows only one service water pump per basin. The figure is for one unit and a duplicate would show the other unit. Therefore, the relationship between these six pumps and the three cooling loops is not clear. A simplified schematic of the system arrangement should be provided to clarify this point.
(2) Provide further details concerning cooling tower basin minimum level, placement of the service water pumps, and their NPSH require-ments to allow us to independently verify that adequate NPSH is avail-able for these pumps during long term (30-day) plant cool down without additional makeup to the UHS.
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_. (3) The FSAR does not separate pump work and sensible heat from the in ficated loads.
Indicate whether or not they were overlooked, neglected, or combined in other heat loads.
f) Provide the necessary disscussion and tables sim'lAr to those currently i
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in the FSAR for the case of LOCA in one unit and cold shutdown of t' ^ other to show that the UHS can adequately reject the necessary heat to bring the plant to a safe shutdown assuming a loss of offsite power in both units with no additional failures.-
Indicate the maximum length of time the UHS can operate in this mode before exceeding the design service water temperature assuming the worst design site meteorology.
010.24 Describe the means provided to assure that the temperature in the control (9.4.1)
)
room HVAC equipment room which houses essential equipment can be maintained l
at acceptable levels under accident conditions and loss of the normal control building HVAC system.
Include a failure mode and effects analysis which shows that no single failure could cause an unacceptably high ter perature in the essential HVAC equipment room. Also, verify that the HVAC equipment necessary #or maintaining control room habitability under emergency condi-tions is powered from the ESF busses.
' 010.25 Describe the means provided to assure that the temperatere in the room (9.4.2) housing the spent fuel pool cooling pumps can be maintained at acceptable levels for pump operation under accident and emergency conditions when the nomal fuel handling building HVAC system is not operating.
010.26 Identify the seismic, safety class and quality group classification for (10.3) the main steam shutoff (block) valves and include this infomation in Table 3.2-1.
Also, describe the functional design and operation of these
_ _. valves during accident and transient conditions including their power sources.
010.27 We note that the ESF switchgears are located at al.110 ft. in the control (10.4.5)
(3.4.1) building. Discuss the means provided to assure that this equipment and any other safety related equipment is protected against possible flooding resulting from a postulated rupture of the circulating water lines in the turbine building as a result of a seismic event and the draining of the cooling tower basin volumes into the plant.
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