ML20052G868
| ML20052G868 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/03/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20052G859 | List: |
| References | |
| NUDOCS 8205190097 | |
| Download: ML20052G868 (6) | |
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'f UNITCD STATES f' g NUCLEAR REGULATORY COMMISSION b;
WASHINGTON, D. C. 20555
%*****/SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
RELATED TO AMENDMENT NO. 22 TO FACILITY OPERATING LICENSE NO. NPF-7 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION, UNIT NO. 2 DOCKET NO. 50-339 I
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Introduction:==
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By letters dated February 17, 1982 and March 18, 1982, the Virginia Electric and Power Compa_ny (the licensee) requested that License Condition 2.C.(15)(h) to Facility Operating License NFP-7 be revised for the North l
Anna Power Station, Unit 2 (NA-2).
License Condition 2.C.(15)(h) and subparts thereto, numbered (1), (2), (3),
(4), (5), and (6), stipulate certain design and procedural modifications for diesel generator reliability which must be completed prior to restart after the first refueling outage.
The stipulations of License Condition 2.C.(15)(h), and all subparts thereto are in conformance with the recommendations of NUREG/CR-0660 regarding the enhancement of diesel generator reliability.
In our SER, Supplement No.11 (August 1980) related to the operation of NA-2, we stated that the modifications as specified in License Condition 2.C.(15)(h) would provide reasonable assurance of diesel generator reliability through the design life' of the plant.
The licensee's request for revising License Condition 2.C.(15)(h) specifically applies to only subparagraphs 2.C.(15)(h)(2) and 2.C.(15)(h)(4). The require-ments specified in subparagraphs 2.C.(15)(h)(1), (3), (5) and (6) have either been or will be completed prior to restart after the first refueling outage.
Restart for NA-2 is presently scheduled to commence May 14, 1982.
License Condition 2.C.(15)(h)(2) addresses certain modifications required for the diesel generator prelube system. License Condition 2.C.(15)(h)(4) addresses modifications required to reroute the diesel day tank overflow line back to the seven day underground diesel storage tank.
The licensee has requested that 2.C.(15)(h)(2) be revised to incorporate alternate modifications for the diesel prelube system and that the time required for completing the modifications be extended to the NA-21982 Fall maintenance outage.
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1 For 2.C.(15)(h)(4). the licensee proposed modifications regarding the rerouting of the diesel day tank overflow line which we found unacceptable.
The licensee has further revised the original proposed modifications and has requested that the time for completing the revised modifications be extended to the 1982 Fall maintenance outage.
l The licensee's request for an extension in time. for both subparagraphs (h)(2) and (h)(4) is based on equipment delivery dates which come after
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the scheduled May 14, 1982 restart date for NA-2.
Our discussion of the above matters including our evaluation and con-clusions regarding the licensee's request is provided below.
i License Condition 2.C.(15)(h)(4); Emergency Diesel Engine l
Lubricating Oil System Discussion:
The emergency diesel generator system for NA-2 consists of two Fairbank Morse Model 3800 TD 8-1/8, opposed piston diesels. According to the licensee and the manufacturer, the design of the Fairbanks Morse (FM) diesels was such that continuous lubrication of the wearing parts when the engine is on standby service is not feasible. The FM diesel is provided with a keep warm lubrication system which operatas continuously when the engine is on standby service. This system does not lubricate the engine wearing parts. Therefore, when the engine is on standby service for a prolonged period of time, lubricating oil drains from the wearing parts and the engine is subject to a dry start.
Dry starting of these diesel generators under emergency conditions results in momentary lack of lubrication at the various moving parts which could eventually lead to failures with resultant equipment unavailability.
Therefore, at the time NA-2 received a fuli power operating license (August 21,1980), License Condition 2.C.(15)(h)(2) was formulated to require a modification to the diesel lube oil system to alleviate dry starting and the modifications were to be completed during the first refueling outage.
By letter dated February 17, 1982 the licensee proposed to install the manufacturer's modification to the lube oil system instead of the modification imposed by the staff as a licensing condition to the i
operating license. The modification as proposed by the licensee will result in the continuous lubrication of the lower portions of the en-gine. The upper portions of the engine will not be prelubricated in the standby condition.
Lubricating the upper portions of the engine in the standby condition would result in excessive amounts of oil collecting i
in the cylinders, which is an unacceptable condition to the manufacturer.
However, the modification will provide for partial filling of the upper lube oil supply header and a lube oil booster / accumulator system which will force lube oil into the upper lube oil header during starting.
Therefore, the wearing parts in the upper portion of the engine will get lubricated immediately upon engine starting. We find this modification to be acceptable and hence our concern on dry starting is alleviated.
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By letter dated February 17, 1982, the licensee requested a postpone-ment of the licensing condition until the second refueling outage due to equipment unavailability. We found this unacceptable and informed the licensee.
In a letter dated March 18, 1982, the licensee stated l
that the manufacturer, Fairbanks Morse, had scheduled final delivery of the equipment needed for the lube oil system modification for May 1982, which would come after the scheduled restart for NA-2.
The I
licensee further stated that the modification to the lube oil system would be installed during the fall maintenance outage scheduled for l
October 1982. We find this date acceptable and will modify License j
Condition 2.C.(15)(h)(2) to reflect this revised implementation i
date.
Evaluation:
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Based on our review of the licensee's proposed modifications, we con-1 clude that the emergency diesel engine lubricating oil system as modi-fied above meets the requirements of General Design Criteria 2, 4, 5 and 17, meets the guidance of the cited Regulatory Guides and Stand-ard Review Plan 9.5.7, can perform its design safety function, meets the recommendations of NUREG/CR-0660 and industry codes and standards, l
and is therefore acceptable.
Further, we conclude that, based on the above, the licensee has com-plied with the requirements of 2.C(15)(h)(2) to the extent practicable j
at this time, and we find that an additional six (6) months extension in time for completing the approved modifications does not adversely affect the intent of License Condition 2.C.(15)(h) for providing reasonable assurance of diesel generator reliability through the design life of the plant.
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Therefore, Licence Condition 2.C.(15)(h)(2) is hereby revised to stip-i late:
"The lube oil system shall be modified to the j
manufacturer's recommendations for providing t
continuous lubrication of the lower portions I
of the engine. The modifications shall further l
provide for partial filling of the upper lub' oil j
supply header and a lube oil booster / accumulator system which will force oil into the upper lube oil header during engine startup. The modifications shall be completed no later than the October 1982 Fall me.intenance outage."
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1 l l 2.C.(15)(h)(4); Emergency Diesel Engine Fuel Oil Storage and Transfer System Discussion l
Tra overflow line from the diesel generator day tank, as presently designed l
and installed, permits fuel oil to be spilled to the ground whenever the tank is overfilled. or in the event of level controller malfunction. We l'l found this design to be unacceptable because the capacity of the 7 day j
fuel oil storage tank could be compromised and because a ground oil spill is a fire hazard that could endanger the availability of the diesel generators.
License Condition 2.C.(15)(h)(4) required that the day tank overflow line be rerouted to return excess fuel to the 7 day fuel oil storage tank, and that the modification be installed prior to start-up following the first re-fueling.
In its letter dated February 1982, the licensee stated that routing an over-flow line from the day tank to the seven day storage tank would be impossible due to above and below ground interferences such as the refueling water storage tank, condensate storage, auxiliary feedwater pumphouse, buried service water piping, and tank an.d building foundations. The licensee proposed to install a separate day tank high level alarm for each tank with separate annunciation in the control room. We found this to be unacceptable, since the proposed modification did not alleviate the original concern. The licensee was informed of the unacceptability of his modification.
In its letter dated March 18, 1982, the licensee revised his proposal to include, in addition to the separate high level alarms, independent and redundant shut-off switches to the lead transfer pump and backup transfer pump. Presently the i
diesel generator fuel oil transfer pumps (lead and backup) stop on high level from two independent level switches (one level switch stops the lead pump and one level switch stops the backup pump) mounted on the day tank. The modifica-tion would add a pressure switch per pump which will be set to stop the pump t
on high level making them redundant to the existing high level shut off switches.
l We find this design modification and addition of a high level alarm to be an j
acceptable alternative to an overflow line from the day tank to the seven day storage tank, provided the following condition is met: We will require that the licensee submit technical specifications prior to implementation of the modifi-cations which will verify proper operation of the transfer pump high level r
shutoff control switches, day tank high level alarms, and transfer pump pressure shutoff switches. The frequency of the inservice inspection will be monthly.
License Condition 2.C.(15)(h)(4) required the installation of the overflow line prior to startup followir.g the first refueling.
In the March 18, 1982 j
letter, the licensee proposed to install the modifications described above during the fall maintenance outage scheduled for October 1982. The licensee stated that delivery of qualified pressure switches is such that they could not be installed by the end of the first refueling outage scheduled to end in May 1982. We find the installation of the above items, during the fall maintenance outage scheduled for October 1982, to be acceptable.
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Evaluation:
l Based on our review, we conclude that the emergency diesel engine
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fuel oil system as modified meets the requirements of General Design Criteria 2, 4, 5, and 17, meets the guidance of the cited Regulatory I
Guides and Standard Review Plan 9.5.7, except as stated above, can perform its design safety function, meets the recommendations of NUREG/CR-0560 and industry codes and standards, and is therefore acceptable.
l We also conclude, based on the above, that the licensee has complied I
with the requirements of 2.C.(15)(h)(4) to the extent practicable l
at this time, and we find that an additional six (6) months exten-i sion in time for completing the approved modifications does not j
adversely affect the intent of License Condition 2.C.(15)(h) for providing reasonable assurance of diesel generator reliability I
through the design life of the plant.
i Therefore, License Condition 2.C.(15)(h)(4) is hereby revised to stipulate:
"The fuel oil storage and transfer system shall be nodified to include the installation of a sepa-rate high level alarm for each day tank, the in-4 stallation of independent pressure switches for each pump which will be set to stop the pumps on high day tank level, and the submittal of Technical Specifications verifying proper operation of all j
transfer pump control switches and day tank high level alarms. The modifications shall be completed i
no later than the October 1982 Fall maintenance l
outage."
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l Environmental Consideration I
We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not resul t in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of l
environmental impact and, pursuant to 10 CFR $51.5(d)(4), that an environmental impact statement or negative declaration and environ-mental impact appraisal need not be prepared.in connection with the issuance of this amendment.
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. Conclusion We have concluded, based on the considerations discussed above, that:
l (1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered i
and does not involve a significant decrease in a safety margin, the l
amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) l such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical j
to the common defense and security or to the health and safety of the public.
Date:
May 3, 1982 Principal Contributors; j
R. Giardina L. Engle I
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