ML20127J097

Forwards Description of Reactor Coolant Pump Lube Oil Collection Sys for Approval.Withdrawal of 820701 Exemption Re Proposed Design for Sys,Per 10CFR50,App R Requested.Oil Collection Sys Will Be Installed During Next Outage

ML20127J097
Person / Time
Site:	Maine Yankee
Issue date:	05/15/1985
From:	Whittier G Maine Yankee
To:	John Miller Office of Nuclear Reactor Regulation
References
5548L-FWS, 5557L-FWS, GDW-85-141, MN-85-90, NUDOCS 8505210373
Download: ML20127J097 (8)

Text

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r EDISON DRIVE MAIRE HARHEE AT0ml0POWERComPARSe avauSra. uaine oas3s (207) 623-3521 9

May 15, 1985 MN-85-90 GDW-85-141 Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, D. C.

20555 Attention:

Mr. James R. Miller, Chief Operating Reactors Branch No. 3 Division of Licensing

References:

(a) License No. OPR-36 (Docket No. 50-309)

(b) USNRC Letter to MYAPCo dated January 7, 1985 - Draft Safety Evaluation (SE) on Appendix R Exemption Request

/

(c) MYAPCo Letter to USNRC dated July 1, 1982 (MN-82-127)

Fire Protection - RCP Oil Collection System Exemption Request

Subject:

Reactor Coolant Pump Lube Oil Collection System Gentlemen:

In Reference (b) above you transmitted to Maine Yankee your draft Safety Evaluation on our request for exemption to certain provisions of 10 CFR 50 Appendix R.

Specifically, the safety evaluation did not supnort our request for an exemption from Section III.0 concerning collection c: reactor coolant pump lobe oil.

In the cover letter you noted that our options included proposal of an additional alternative which required an exemption from the provisions of Appendix R, or full implementation of the Appendix R requirements.

In the latter case, no additional submittal to the staff would be necessary.

Subsequently, Maine Yankee representatives have met with your staff and discussed the collection of reactor coolant pump lubricating fluids. At that meeting we presented a conceptual design for a collection system for the bearing lube oil which was acceptable to your staff.

This letter provides additional descriptive information concerning the planned collection system for your review and approval.

Section III.0 of Appendix R stipulates that:

" Leakage points to be protected shall include lift pump and piping, overflow lines lube oil cooler, oil fill and drain lines and plugs, flangeconnectionsonoillines,andthelubeoilreservoirswhere

(

such features exist on the reactor coolant pumps."

I l 8505210373 850515 PDR ADOCK 05000309 5548L-FWS

' MAINE YANKEE ATOMIC POWER COMPANY

-United States Nuclear Regulatdry Commission Page Two Attention: Mr. James R. Miller, Chief ~

fH-85-90 iThe modifications described in the attachment to this letter meet ~the intent of those-requirements. As discussed with your staff, we do not plan to.

address shaft leakage. We consider this source of oil to be minor since the lower bearing housing-is'unpressurized and of small volume. To design a

. system to wipe and collect shaft leakage would be extremely _ difficult on a retrofit basis. - Additionally, such a system would interfere with vibration monitoring of the reactor coolant pump and seal-cartridge replacement..It would also greatly increase the risk of equipment failure and substantially increase personnel radiation exposure.

Therefore, with this letter we wish to withdraw our earlier exemption

" request, Reference (c), subject to NRC approval of our proposed design for a RCP lube oil collection system as meeting the intent of 10 CFR 50 Appendix R.

We would appreciate any comments that you may have on our proposed design as soon as possible as we plan to install the RCP lube oil collection system during the next refueling outage.

We believe that this information is complete. However, if you have any further questions, please feel free to contact us.

Very truly yours, MAINE YANKEE ATOMIC POWER COWANY khN G. D. Whittier, Manager -

Nuclear Engineering & Licensing GDW/bjp

Enclosure:

(6 pages)

-cc: Dr. Thomas E. Murley Mr. Cornelius F. Holden i

,5548L-FWS s

7 MAINE YANKEE ATOMIC POWER COMPANY MINE YA?KEE REACTOR COOLANT PUf4)

LUBE OIL COLLECTION SYSTEM DESCRIPTION A separate lubricaat oil collection cystem will be installed on each of the three reactor coolant pump (RCP) motors.

'The upper lubrication oil system supplies oil to the thrust and radial bearings in the upper-bearing housing of the motor. Each system consists of:.

(1) an oil' reservoir, (2) two high pressure. oil lift pumps, (3) two backstop oil pumps,- (4) two oil / water coolers and (5) associated piping and fittings.

The oil reservoir encloses the upper bearings and contains approximately 122 gallons of oil. The lift pumps provide oil to the thrust bearing during start-up. The backstop oil pumps provide oil for the backstop device during Estart-up. The oil / water coolers are connected to the lift and backstop pumps and to the oil reservoir. Each reactor coolant pump has this system mounted on the upper bearing housing.

,The lower radial' bearing sits in an oil bath which supplies the necessary lubrication. The bearing and oil are contained in the lower bearing housing.

There are no external pumps or coolers associated with the lower bearing.

'There is only one oil lina that is used for filling,. draining and level indication.

The' upper bearing housing will be fitted with a steel curb to contain any oil that leaks out of the system. The oil-pumps, oil coolers, and all associated oil pipe, fittings, flow sensors and level indicators will be within the curb

-so that any leaks will be containeJ.

In addition to the steel curb, spray shields will be installed to assure that any oil from pressurized lines is contained within the curb. The oil collected within the curb will flow out two drains to a vented collected tank-located inside.the loop area.

The lower bearing exterior oil line will have a tray mounted directly below

'it. All of the oil that drops into the tray will flow out a drain line and into the collection ta'k along with oil from the upper bearing oil collection system.

The entire oil collection system will be designed to prevent damage to safety class equipment and to be operational after an SSE event.

DESIGN CONSIDERATIONS The upper bearing housing will be fitted with a curb around its periphery.and spray shields over the oil lines. These will channel any oil spills into a drain line to a collection tank located on the minus 2 foot elevation.

The verticle radial members of the housing.have limber holes near the base which will permit oil leakage in any. segment to flow to the drains.

5557L-FWS

. MAINN NK'EE ATO IC PO VER OMPANY x

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i The curb will be carbon steel approximately'1/8 inch thick and.5 inches high.

ThefcapacityLof the_ top curbing will be such that the entire' upper bearing oil-linventcry could be' contained within the curbing..It will be attached by

welding to the1 bearing housing._ Where-necessary,7a sealant will be applied,to 1 ensure leak tightness. Welding will be_done according to the manufacturers.

recommendations to avoid any possibility of damage due to circulating currents. All of the lube oil pipes will be located within the curb.

c The ' spray ' shields will.be stainless steel approximately 1/16 inch thick. They will'be removable to facilitate maintenance and repair work.

The shields will' be designed to divert spraying oil.to the curbed area and to also allow air ~

circulation around the small motors and electrical equipment.

~

Two. schedule 40 carbon steel drain: lines will collect the oil from the top of the.fCP motor from opposite sides of the motor and direct it to a common drain

-line. 'The comon drain line > ill be 11/2 inches. The common line will run lto:aJcollection tank located at the minus 2 foot level. A section of the-

' drain liner will be nonconductive to electrically isolate the upper bearing

housing fron, ground. -

-The collection tank will be ar. proximately 150 gallon capacity.

It will-hold-

.all-of the oil that may drain out of the upper and lower bearings. It will be

-mounted above the maximum flood level in containment and will be designed to Lwithstand tne air presure changes associated with a Loss of Coolant Accident.

LThe;1ower bearing oil line (3/4 inw) that is used for filling, draining and 1

checking the oil level will be equipped with a full length tray to channel the 1o11 into a lower drain line. The tray will be fabricated from steel and will-

-be secured to the motor's mounting frame. A collection tray will also be positioned under the lower bearing level transmitters, which are connected to Lthe end of the existing oil ~ lines. The lower bearing oil collection system components will drain the oil to the collection system's tank through a piping drain system separate from the top bearing. The drain line will be made of 1 1/2: inch schedule 40 carbon steel pipe.

All carbon steel will-be painted according to approved procedures.

~ Maine Yankee has' ordered a new Reactor Ccolant Pump Motor which is to be installed during the 1985 refueling outags as part. of an ongoing program of plant betterment. ~We will install the lu3e oil collection system on the new

-motor prior to installation. Minor-desiga changes which may be found necessary may be'made away from critical path time and our workers will gr.in experience in installation. The other two collection systems may tnen be

--installed more rapidly, in keeping with our ALARA Program, a

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9.i 5557L-FWS

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