ML17320A671
| ML17320A671 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 08/10/1983 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | Dolan J AMERICAN ELECTRIC POWER SERVICE CORP., INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| References | |
| NUDOCS 8309020521 | |
| Download: ML17320A671 (7) | |
Text
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50-315 and 50-316 Mr. John Dolan, Vice President Indiana and Michigan Electric Company c/o American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216
Dear Mr. Dolan:
DI RI BUT ION
~k NRC PDR Local PDR GRB 1 File D. Eisenhut OELD E. Jordan D. Higginton C. Parrish NSIC J. Taylor ACRS (10)
As par t of our continuing review of hydrogen control for ice condenser plants during postulated degraded core accidents, we have identified the need for additional information on several matters.
The items pertain to the CLASIX code which has been used to support the licensing activities associated with ice condenser plants; e.g., determining the environmenta'I conditions against which equipment survivabi'lity is to be evaluated.
It is requested that the Indiana and Michigan Electric Company estatjlishaa schedule to provide the information in response to the enclosed questions.
These questions are also being sent to the Duke Power Company and TVA and a
coordinated response will be acceptable.
In regards to the overall review program for hydrogen control and equipment survivability, it is also requested that you inform us of your plans and schedules.
particular ly of the remaining submittals.
We suggest that this can be done in a meeting between our staffs but no later than early September.
This request affects less than ten respondents.
therefore, OHB clearance is not required.
Sincerely,
@'iginal signed 5~
Po Ai Varga
Enclosure:
As stated cc w/enclosgre:
See next page 830902052i 8308i0 PDR ADOCK 050003i5 P
PDR Steven A. Varga. Chief Operating Reactors Branch IIo.
1 Division of Licensing OFFICE P SURNAMEQ DATE Q ORB 1
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!nc';a.-:a and Mi hican =iectric Comoany cc:
Mr.
M.
P. Alexich Assistant Vic
?resident.
'or Nuclear Encineering American Electr'.'c Power Service Corporation 2 Broadway New York, New York 10004 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.M.
Washington, D.
C.
20036
'k.
G. Smith Jr., Plant Manager Donald C.
Cook Nuclear Plant P. 0.
Box 458 Bridgman, Michigan 49106 U.
S.
Nuclear Peoulatory Commission Resident Inspectors Office 7700 Red Arrow Highway S. vensvi lie, Michigan 49127 The '."'.onorable Tom Corcoran United Sta-;es House of Representatives Mashington,'D.
C.
20515 James G. Veppler Regional Administrator - Region Ill U.
S.
Nuclear Regula-.ory Conmission 799 Roosevel:
Ro-d Glen Ellyn, illinois 60137
REQUEST FOR ADDITIONAL I NFORMATION With regard to the CLASIX code, the staff has previously requested clarification of the structural heat sink heat ~'ransfer models.
The following pertinent points have been derivdd from the responses:
i)
Heat transfer is based on a temperature difference determined by (Tbulk ii)
Heat transfer coefficients for degraded core accident analysis are determined from a natural convection (stagnant) correlation applicable to condensation heat transfer.
iii)
CLASIX does not explicitly model mass removal due to condensation heat trans er.
Based on the description of the CLASIX structural heat sink model, it appears that the CLASIX model differs dramatically from generally accepted approaches and is noi, as is claimed, consistent with standard methods such as those used in CONTEMPT.
The differences are related to the treat-ment of the three items cited above.
By comparison, previously accepted approaches are ch~racterized by the following:
i)
Heat transfer is based sn (Tsat Tall), when the surface temperature of the heat sink is less than Tsat'.e.
Twall <
Tsat ii)
Heat transfer coefficients are based on condensation only when wall ~
sat' iii)
Condensed mass removal is based on condensation heat transfer with pr ovisions for revaporizing a small fraction of the condensate,
A more detailed description of accepted practice is contained in NUREG-0588 and NUREG/CR-0255.
The effect of the CLASIX models would appear to be the de-superheating o,
the atmosphere too rapidly thus reducing gas temperatures and possibly altering the combustion characteristics.
Based on the above discussjon, provide justification for the models incorporated in CLASIX or provide the results of analyses with accep-table models as outlined above.
The analyses should encompass selected sensitivity studies to assure that the effects o
the changes are deter-mined for both containment integrity and equipment survivability considera-tions.
2.
Provide a complete evaluation of fan (both air return and hydrogen skimner as applicable) operability and survivability for degraded core accidents.
In this regard discuss the following items:
a.
The identification of conditions which will cause fan overspeed, in terms of differential pressure and duration, and hydrogen combustion events.
b.
The consequences of fan operation at overspeed conditions.
The response should include a discussion of thermal. and overcurrent breakers in the power supply to the fans, the setpoints and physical locations of these
- devices, and the fan loading conditions required to trip the breakers.
c.
Indication to the operator o
fan inoperability, corrective actions which may be possible, and the times required for operators to complete these actions.
d.
The capability of fan system componetns to withstand differential pressure transients (e.g;, ducts,
- blades, thrust bearings, housing),
in terms of limiting conditions and components.
3.
Provide an evaluation of the ultimate capability of ice condenser doors to withstand reverse differential pressures.
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