ML20088A858
| ML20088A858 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 04/05/1984 |
| From: | Musolf D NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC-53558, TAC-53559, NUDOCS 8404130227 | |
| Download: ML20088A858 (6) | |
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Northem States Power Company 414 Nicollet Ma:t Minneapoks. Minnesota 55401 Te!ephone 16?2) 330-5500 April 5, 1984 Director Office of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Information in Support of Exemption Requests Submitted January 23, 1984 and Request for Exemption from the Requirements of Section III.0 of Appendix R to 10 CFR Part.50 Reference (a) Letter from D M Musolf to Director of NRR dated January 23, 1984 " Exemption Requests to the Requirements of Appendix R to 10 CFR 50" Attached for Com:rission review and approval is a request for exemption from Section III.0 of Appendix R to 10 CFR Part 50 and supplemental information in support of exemption requests submitted on January 23, 2984 which the Staff requested. contains a Technical Exemption Request from the requirements of III.0 of Appendix R to 10 CFR 50 to have a closed vented container inside containment which can hold the entire contents of the Reactor Coolant Pump lube oil collection system. contains supplemental information in support of Reference (a) as requested by the Staff.
Please contact us if you have any questions or if additional information is required.
NNw D M Musolf Manager - Nuclear Support Services I00 DMM/ TAP / dab I
ii c: See of the Commission (Original and 2 copies)
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Resident Inspector, NRC Project Manager, NRR, NRC Regional Administrator-III, NRC G Charnoff 8404130227 840405 PDR ADOCK 05000282 F
UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket No. 50-282 50-306 I
LETTER DATED APRIL 5, 1984 REQUEST MR RELIEF FROM THE REQUIREMENTS OF 10 CFR PART 50, APPENDIX R, III.0, FIRE PROTECTION Northern States Power Company, a Minnesota corporation, by this letter dated April 5,1984 hereby submits a request for exemption from the requirements of 10 CFR Part 50, Appendix R, Section III.O.
This letter contains no restricted or other defense information.
NORTHERN STATES POWER COMPANY By
/s/ David Musolf David Musolf Manager - Nuclear Support Services
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i On this 5th day of April 1984 before me a notary public in and for said County, personally appeared David Musolf, Manager - Nuclear Support Services,
- and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof and that to the best of his knowledge,:information and. belief, the statements made in it are true and that it is not interposed for delay.
/s/-Dody A Brose Dody A Brose Notary Public Minnesota
-Hennepin County My commission expires Dec 26, 1989
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April 5, 1984 Director of NRR Prairie Island Nuclear Generating Plant Exemption Request to the Specific Requirements of Section III.0 of Appendix R to 10 CFR 50 Reactor Coolant Pump Lube Oil Collection System Per the provisions of 10 CFR Part 50, Section 50.12, Northern States Power requests exemption from the specific requirement of Section III.0 of Appendix R to 10 CFR Part 50 to have a closed vented container inside containment capable of holding the entire inventory of the Reactor Coolant Pump Lube Oil Collection System.
Following is a description of the lube oil collection system that is currently installed at the plant:
Description Prairie Island Units 1 and 2 have two Reactor Coolant Pumps each.
For purposes of this description the units are identical.
Each Reactor Coolant Pump contains 265 gallons of lube oil for a total of 530 gallons per unit.
The lube oil is Mobile Synthetic lube oil which has a flash point of 480*F and an ignition point of 520*Fc A series of drip pans and deflectors are located around the pump such that leakage from,all potential pressurized ~and unpressurized leakage sites in the Reactor Coolant Pump lube oil systems are collected and piped to the adjacent floor drain which empties into Sump A in the basement of the contain-ment. Sump A is a concrete open pit, covered with grating, built into the floor which has a capacity of 990 gallons.
There is no Safe Shutdown Equipment in the area surrounding the Reactor Coolant Pumps or Sump A.
Sump A is designed to automatically pump down when the level of the tank reaches the 695'-9" elevation.
(The bottom of the sump is at 693'-6".)
This is at approximately the 555 gallon point.
If level continued to rise due to failure of the automatic pump function, an alarm would sound in the Control room at the 696'-9" level of the sump, approximately 800 gallons. An operator can then initiate manual control of the sump pump for pumping down. The top of the sump pit is at floor level, che 697'-6" elevation which represents the 990 gallon maximum capacity point of the sump.
In addition to the automatic function, operators may at any level manually control the pump to pump down the sump.
The sump is normally lined up to pump to the aersted sump tank in the Auxiliary Building which has a capacity of 600 gallons. The aerated sump tank is a vented closed tank. The aerated sump tank then pumps to the aerated drain tanks in the Auxiliary Building.
Each aerated drain tank has,,a capacity of 1000 gallons for a total capacity of 2000 gallons.
The aerated sump tank and drain tanks serve both units. The aerated drain tanks are vented closed tanks.
The capability also exists to pump from the aerated sump tank to the 25,000 gallon waste hold-up tank which is also a vented closed tank.
a 2-In support of the system as is currently installed it should be noted:
- 1) The Lube Oil Collection System is seismically designed.
- 2) High flash point Mobile Synthetic lube oil is being utilized.
- 3) There is no safety related equipment in the vicinity of the Reactor Coolant Pump or Sump A inside containment.
- 4) Safe shutdown equipment and cabling is separated from the Reactor Coolant Pumps and Sump A by the shield wall and 18" thick concrete floors.
5)
During the design and installation (1978) of the collection system a decision was made to not install a vented closed collection tank inside containment because, in addition to its function as a lube oil collection system, the drip pans serve to collect seal leakage to prevent the spread of contaminated water.
If a tank was utilized, its capacity to accept lube oil could be limited because of water from seal leakage being present in the tank.
If a large quantity of oil was introduced quickly into the tank with water present, it would overflow through the vent onto the floor into the floor drains to the sump.
It was therefore determined it would be better to deliver the leakage directly to the sump via the floor drain system since the sump i
automatically pumped down to a vented closed tank, this option was chosen.
The floor drain is adequately sized to handle the flow l
from the leakage collection system.
In summary, Northern States Power has made an extensive effort to comply _with the requirements of Appendix R.
In comparing the lube' oil collection system
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to the requirements of Section III.0, concerns were voiced over the use of a closed vented container inside containment because of the need for it to also act as a collection point for seal leakage.
Northern States Power believes that the existing configuration meets the. intent of Appendix R in that all
_ lube oil is collected to a common point which will prevent its contact with not piping in the area and is isolated from electrical power cable which might.cause ignition.
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e April 5, 1984 Director of NRR Prairie Island Nuclear Generating Plant Supplemental Information in Support of Exemption Requests Submitted January 23, 1984 Question: How much of the fire loading inside containment is comprised of lube oil from the reactor Coolant Pump? Of the remaining fire loading (i.e., combustible cables) what is the fire severity on an elevation by elevation basis.
Reply:
Of the 22,520 Btu /ft fire loading on Unit 1 and 23,915 Btu /f t fire loading on Unit 2 approximately 11,450 Btu /ft is comprixed of lube oil from the Reactor Coolant Pumps.
The Reactor Coolant Pumps are separated from the areas of cable concentration by the shield wall and 18" thick floors which will act as radiant energy shields intheunlikelyeventofalubeoil{ ire.
The remaining 11,070 2
Btu /ft for Unit I and 11,465 Btu /f t for Unit 2 is compri, sed primarily of cabling.
Following is a break down of the cabling on an elevation by elevation basis.
UNIT 1 Elevation App. Max % Cable Btu /ft Fire Severity (minutes) 698' - 712' 40 4430 3.3 712' - 735' 35 3875 2.9 735' - 755' 15 1660 1.3 755' - 770'*-
10 1110 0.8 11,075 i-UNIT 2 Elevation App. Max-% Cable Btu /ft Fire Severity (minutes) 698' - 712' 40 4585 3.4 712' - 735' 35 4015 3.0 735' - 755' 15 1720 1.3 755' - 770'*
10 1150 0.9 11,470
- No safe -shutdown components or cabling are IncAted on - this elevation.
Even if one were to conservatively consider all-of the cabling to be massed togethat withinLthe twenty foot separation area dictated by Appendix R the resulting fire severity is limiting.
As.has been discussed with the staff the actual situation is that only a limited amount of. the cable inside -
- containment is located within the twenty ' foot zone which is required to be free of combustibles. One copy of pictures and drawings has been forwarded tolthe Prairie Island Project Manager, in the Division of Licensing, under
- separate cover.
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. For the one set of redundant components which is not separated 20 feet (the pressurizer level transmitters) Northern States Power will commit to wrapping the associated cable of one division in an approved one hour barrier for both Units 1 and 2.
Question: What instrumentation is being considered inside containment in NSP's review of equipment necessary to achieve and maintain hot / cold shutdown?
Reply:
1)
Pressurizer Level
- 2) Steam Generator Level
- 3) Reactor Coolant System Temperature Hot and Cold Legs
- 4) Reactor Coolant System Pressure Question: What is the status of Appendix R modifications other than the cable wrapping modifications for fire areas 58, 59, 73 and 74?
Reply:
All are complete.
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