Text

Application for Amend to License DPR-65,modifying Expected Time EDGs Will Operate Utilizing Onsite Fuel Oil Sources Required by TS
	ML20216E389
Person / Time
Site:	Millstone
Issue date:	09/03/1997
From:	Bowling M; NORTHEAST NUCLEAR ENERGY CO.
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20216E392	List: B16594, Application for Amend to License DPR-65,modifying Expected Time EDGs Will Operate Utilizing Onsite Fuel Oil Sources Required by TS; ML20216E410;
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	B16594, NUDOCS 9709100178
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'Ibe Nortimt Utilities System September 3,1997 Docket No. 50-336 B16594 Re: 10CFR50.90 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Final Safety Analysis Report Emeroency Diesel Generator Fuel Oil l

l f Northeast Nuclear Energy Company (NNECO) has recalculated the length of time the '

emergency diesel generators (EDGs) will operate following a Loss of Coolant Accident and a Loss of Normal Power, utilizing only the onsite diesel fuel oil sources required by Technical Specifications. The new EDG run times do not agree with the current EDG ,

run times contained in the Millstone Unit No; 2 Final Safety Analysis Report (FSAR),- l Section 8.3

Emergency Generators." NNECO has determined this deviation constitutes an unreviewed safety question, as defined in 10CFR50,59. Therefore, per 10CFR50.59(c), NNECO requests the NRC review and approve this change to the FSAR through an amendment to Operating License DPR-65, pursuant to 10CFR50.90.

Attachment 1 provides a discussion of the proposed changes and the Safety Assessment. Attachment 2 provides the Significant Hazards Consideration. 1 Attachment 3 provides the marked-up version of the appropriate FSAR pages.

Environmental Considerations 4

NNECO has reviewed the proposed License Amendment Request against the criteria of 10CFR51.22 for environmental considerations. The proposed change modifies the expected time the emergency diesel generators will operate utilizing the onsite fuel oil- \

sources required by Technical Specifications.- This change does not increase the type and amounts of effluents that may be released offsite. In addition, this amendment request will not significantly increase individual or cumulative occupational radiation

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8 U.S. Nuclear Regul: tory Commission B16594/Page 2 exposures. Therefore, NNECO has determined the proposed changes will not have a signific'ant effect on the quality of the human environment.

Conclusions The proposed changes were evaluated utilizing the criteria of 10CFR50.59 and were determined to be an unreviewed safety question. The new calculated run time for the EDGs following a Loss of Coolant Accident and a Loss of Normal Power, utilizing only the onsite safety related diesel fuel oil sources required by Technical Specifications, is less than specified in the FSAR. Since this volume of diesel fuel oil is a Technical Specification requirement, this License Amendment Request does involve a reduction in the margin of safety as defined in the Bases for Technical Specifications 3.8.1,1 and 3.8.1.2. However, since the change a) does not result in any increase in initiating event frequency, b) does not adversely affect the probability of failure of operator mitigation, c) does not adversely affect the probability of failure of mitigating equipment, and d) does not adversely impact the consequences of the design basis analysis, it has been cr>ncluded to be safe.

The proposed changes do not involve a significant impact on public health and safety (see the Safety Assessment provided in Attachment 1) and do not involve a Significant Hazards Consideration pursuant to the provisions of 10CFR50.92 (see the Significant Hazards Consideration provided in Attachment 2).

Plant Operations Review Committee and Nuclear Safety Assessment Board The Plant Operations Review Committeo and Nuclear Safety Assessment Board have reviewed and concurred with the determinations. {

Schedule We request issuance at your earliest convenience, with the amendment to be implemented within 30 days of issuance.

State Notification in accordance with 10CFR50.91(b), a copy of this License Amendment Request is being provided to the State of Connecticut.

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U.S. Nuclear Regul: tory Commission B16594/Page 3 If you should have any questions on the above, please contact Mr. Ravi Joshi at (860) 440-2080.

Very truly yours NORTHEAST NUCLEAR ENERGY COMPANY

- M. L. Bowling, Jr. L/-

Millstone Unit No. 2 Recovery Officer Subscribed and sworn to before me

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this d day of 3dwtrz 1997 be Iwu (d00th e Data Commission Expires: fN 30 acol

, Attachments (3) l cc: H. J. Miller , Region l Administrator D. G. Mcdonald, Jr., NRC Senior Project Manager, Millstone Unit No. 2 D. P. Beaulieu, Senior Resident inspector, Millstone Unit No. 2 I W. D. Travers, Ph.d, Director, Special Projects W. D. Lanning, Director, Millstone Assessment Team Director Bureau of Air Management Monitoring and Radiation Division Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127

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Docket No. 50-336 B36194 Attachment 1 Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Final Safety Analysis Report Emergency Diesel Generator Fuel Oil Discussion of Proposed Changes September 1997

U. S. Nuclear Regul: tory Commission B16594/ Attachment 1/Page 1 Proposed Revision to Final Safety Analysis Report Emergency Diesel Generator Fuel Oil Discussion of Proposed Changes

. introduction Northeast Nuclear Energy Company (NNECO) has recalculated the length of time the emergency diesel generators (EDGs) will operate following a Loss of Coolant Accident and a loss of Normal Power, utilizing only the onsite diesel fuel oil sources required by Technical Specifications. The new EDG run times do not agree with the current EDG run times contained in the Millstone Unit No. 2 Final Safety Analysis Report (FSAR),

Section 8.3

Emergency Generators." NNECO has determined this deviation constitutes an unreviewed safety question, as defined in 10CFR50.59. Therefore, per 10CFR50.59(c), NNECO requests the NRC review and approve this change to the FSAR through an amendment to Operating License DPR 65, pursuant to 10CFR50.90.

D.ackoround Millstone Unit No. 2 submitted a Licensee Event Report' (LER) on August 19,1994 to report that the emergency diesel generator (EDG) onsite safety related fuel oil supply required by Technical Specifications did not meet the requirements of IEEE Standard 308-1971. Section 5.2.4 (6) of IEEE Standard 308-1971 states:

" Stored energy at the site shall have capacity to operate the standby power supply while supplying post - accident power requirements to a unit for the longer of the following:

(a) seven days (b) time required to rep;enish the energy from sources away from the generating unit's site following the limiting design basis accident."

A revised engineering calculation had determined that the inventory of EDG diesel fuel oil required by Technical Specifications (12,000 gallons for each EDG) was not sufficient to support EDG operation for 7 days.

In this LER, NNECO committed to resolve the EDG fuel oil storage issue by proposing a change to the Millstone Unit No. 2 Technical Specifications. A License Amendment D. B. Miller, Jr, letter to the U.S. Nuclear Regulatory Commission, " Facility Operating License No. DPR-65, docket No. 50 336, Licensee Event Report 94-020-00," dated August 19,1994.

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U.S. Nuclxr R:gul: tory Commission B16594/ Attachment 1/Page 2

. Reqwst was submitted by letter dated November 30, 1994'. In a letter dated Match 20, 1995*, the Nuclear Regulatory Commission (NRC) requested additional information to complete the review of the License Amendment Request. The requested information was provided in a Pages Also Encl|letter dated May 8,1995]]*. In a letter dated June 12, 1995', the NRC requested additional information to complete the review of the License Amendment Request. The requested information was provided in a letter dated August 1,1995',

in a letter dated February 24, 1997 ,7 NNECO retracted the License Amendment '

Request dated November 30,1994, as supplemented on May 8,1995 and August 1, 1995. NNECO had determined that the information concerning the EDG diesel fuel oil supply license basis should be located in the Bases section of the Technical Specifications, rather than as a footnote to the Technical Specification Limiting Conditions for Operation. However, further evaluation has determined that this information should only be located in the FSAR. The revised FSAR pages are contained in this submittal.

l J. F. Opeka letter to the U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications Emergency Diesel Generator Fuel Oil Supply," dated November 30,1994.

O. S. Vissing letter to J. F. Opeka, ' Millstone Nuclear Power Station, Unit No. 2 -

Amendment Request Relating Emergency Diesel Generator Fuel Oi! Supply (TAC No.

M91019)," dated March 20,1995.

J. F. Opeka letter to the U. S. Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No. 2, Request for Additional Information Proposed Revision to Technical Specifications Emergency Diesel Generator Fuel Oil Supply (TAC No.

M91019)," dated May 8,1995.

G. S. Vissing letter to J. F. Opeka, " Millstone Nuclear Power Station, Unit No. 2 -

Amendment Request Relating Emergency Diesel Generator Fuel Oil Supply (TAC No.

M91019)," dated June 12,1995.

J. F. Opeka letter to the U. S. Nuclear Regulatory Commission,

Millstone Nuclear Power Station, Unit No. 2, Request for Additional Information Proposed Revision to Technical Specifications Emergency Diesel Generato, Fuel Oil Supply (TAC No.

M91019)," dated August 1,1995.

M. L. Bowling, Jr. letter to the U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No. 2 Retraction of Proposed Revision to Technical Specifications Regarding Emergency Diesel Generator Fuel Oil Supply (TAC No. M91019)," dated February 24,1997.

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U.S. Nucirr Regul: tory Commission B16594/ Attachment 1/Page 3 Desian Basis and Licensino Basis Millstone Unit No. 2 is required to have a reliable onsite source of auxiliary power if the preferred source is lost. This onsite source consists of two EDGs. The EDGs are redundant, independent, and used as a backup source of power to the emergency 4160 VAC busses.

Each EDG has a separate and independent fuel oil system consisting of a diesel oil supply tank (T - 48A and T - 488) and the associated piping to supply fuel oil to the respective EDG. Fuel oil is supplied to the EDG by gravity from the associated diesel oil supply tank. The volume of fuel oil in each diesel oil supply tank is maintained at a level above the required Technical Specification volume of 12,000 gallons by operation of the respective diesel oil transfer pump. Both diesel oil transfer pumps take a suction on the underground diesel oil storage tank (T - 47A).

The following description of the Millstone Unit No. 2 diesel fuel oil system is contained in the Millstone Unit No. 2 FSAR.

' Diesel fuel oil for the diesel generator engine is stored in a 25,000-gallon underground diesel oil storage tank. The fuel oil is transferred from the storage tank by two 25-gpm diesel fuel oil transfer pumps to the two 13,500-gallon s (approximate capacity), Class I, diesel fuel oil supply tanks which are located in the structure that houses the associated diesel generator. A minimum of 12,000 gallons of fuel oil is stored in each aboveground supply tank. The piping is arranged such that normally one diesel fuel oil transfer pump supplies diesel fuel i

oil to one diesel oil supply tank. However, there is an interconnection in the (

supply piping with a " locked closed" valve so that each transfer pump can supply diesel fuel oil to either supply tank. Diesel fuel oil is transferred by gravity from the supply tank to the engine-driven diesel fuel oil pump which supplies fuel oil to the diesel engine. The piping is arranged such that normally one supply tank provides diesel fuel oil to one diesel generator. However, there is an interconnection in the piping with a " locked closed" valve so that one diesel generator can be provided with diesel fuel oil from either or both supply tanks.

The combined capacity of the diesel oil sucolv tanks is sufficient for one diesel aenerator to operate for aooroximately seven days plus the other diesel aenerator for one hour followino a t.OCA. Postulating the loss of the diesel fuel oil storage tank, the transfer pump and/or the piping between the storage tank and the supply tanks, the diesel fuel oil supply tanks have adequate capacity for post-accident operation until replenished by a tank truck."

New EDG run time calculations have been performed. These calculations assume both diesel oil supply tanks are at the Technical Specification limit of 12,000 gallons and that both EDGs will operate initially for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The change to two EDGs for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months results in a significant reduction in overall EDG operating time using just the Technical Specification required volume of fuel oil. However, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months will provide sufficient time

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U.S. Nuclear R:gul: tory Commission B16594/ Attachment 1/Page 4 so that the Technical Support Center can be manned to order fuel oil, provide load she'dding recommendations, and ascertain the status of fuel oil delivery to the site. In addition, the reduction in EDG run time using only the Technical Specification required volume of fuel oil will be offset by the required volume in the underground storage tank.

The total volume of fuel oil maintained at Millstone Unit No. 2 in the diesel oil supply tanks will allow two EDGs to operate for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and then one EDG to continue operation for a total of approximately 3.5 days. The total EDG run time is based on the EDGs operating at a continuous rated load of 2750 KW. This exceeds the electrical loading expected during a Loss of Coolant Accident (LOCA) coincident with a Loss of Normal Power (LNP), and does not account for the electrical load decreasing as loads are secured during plant recovery efforts. If load shedding is assumed, the total volume of fuel oil rnaintained in the diesel oil supply tanks will allow two EDGs to operate for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and then one EDG to continue operation for longer than a total of approximately 3.5 days.

The required Technical Specification volume in the diesel oil supply tanks (T - 48A and T - 488) will provide sufficient fuel oil for two EDGs to operate at 2750 KW for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and then one EDG to continue operation at 2750 KW for a total of l approximately 3.5 days from the event initiation, assuming the two tanku are cross-

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connected after securing one EDG. An EDG run time of approximately 3.5 days provides a significant margin of time for replenishment of EDG fuel oil. Replenishment can be accomplished from the nonsafety-related underground diesel oil storage tank or offsite sources. The non-seismic underground diesel oil storage tank provides the normal make-up path for fuel oil to the fuel oil supply tanks. It contains fuel oil which is fully qualified and tested regularly.

f At least one diesel oil transfer pump will be available to supply fuel oil from the underground tank to the diesel oil supply tanks, since the pumps are supplied from vital power sources. If the volume of fuel oil in the underground diesel oil storage tank is taken into consideration, the one remaining EDG will be able to continue operation at 2750 KW for an additional 3.5 days. This will increase the total time one EDG will be able to operate to approximately 7 days.

If a seismic event occurs, the fuel oil in the underground diesel oil storage tank can not be relied upon, because the underground diesel oil storage tank is not seismically qualified. However, replenishment of fuel oil could be accomplished via an offsite source.

The required Technical Specification volume of 12,000 gallons in each diesel oil supply tank (T - 48A and T - 488) is verified by Surveillance Requirement 4.8.1.1.2.a.1. The required volume of fuel oil in the underground diesel oil storage tank, approximately 17,700 gallons, is not required by Technical Specifications. It will be added to the Technical Requirements Manual and will be verified by a similar surveillance requirement. Also, the underground diesel oil storage tank low level alarm wi!I be set

U.S. Nucl:ar Regul: tory Commission j 816594/ Attachment 1/Page 5 above this required volume. The associated alarm response procedure will provide the

' ec'essary guidance to restore the required underground tank volume.

n It is only necessary to maintain the required volume in the underground diesel oil storage tank when the plant is operating in Modes 1 through 4. When the plant is in ,

Mode 5 or below, the expected EDG loading will be significantly below rated load.

Therefore, the Technical Specification requirement for diesel fuel oil will provide reasonable assurance that sufficient time will be available to obtain diesel fuel oil from an offsite source, if the underground tank is not available.

In addition to the total volume of fuel oil maintained onsite, Millstone Unit No. 2 has a fuel oil supply contract for delivery of fuel oil to the unit. Emergency Plan procedures require an evaluation of the need to order additional fuel from offsite sources within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months following a LOCA and LNP. The Emergency Plan procedures also require the Technical Support Center staff to provide load shedding recommendations within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of a LOCA and LNP. These load shedding recommendations may include securing one EDG, cross connecting the two diesel oil supply tanks, and securing any electrical loads not needed to support plant recovery. The specific recommendations will vary depending on the situation, and will be developed within the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months time period. This time is sufficient to allow the Technical Support Center staff to develop the specific load shedding recommendations, and will allow an evaluation of the likelihood of fuel oil delivery to Millstone Unit No. 2. If fuel oil delivery is imminent, load shedding will not be necessary.

Calculations Several calculations have been performed to analyze the EDG fuel oil storage issue.

l The calculations performed by NNECO to support this License Amendment Request l are summarized below.

1. 91-BOP-813-ES - Revision 04, August 7,1997 MP2 EDG Operating Time With 24,000 Gallons of Diesel Fuel Oil Available at a Continuous Rated Loaded of 2750 KW This calculation determined that the total volume of fuel oil maintained at Millstone Unit No. 2 in the diesel oil supply tanks will allow two EDGs to operate for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and then one EDG to continue operation for a total of approximately 3.5 days (3.61 days). The total EDG run time is based on the EDGs operating at a continuous rated load of 2750 KW. EDG fuel oil consumption is assumed to be constant at approximately 217 gallons / hour.

'I.S. Nuclear Regulatory Commission 816594/ Attachment 1/Page 6

2. 97 DES-01787 M2 - Revision 02, August 5,1997 Minimum Level Required in MP2 Diesel Oil Storage Tank T-47A to Support Seven Day EDG Run This calculation determined that the total volume of fuel oil required at Millstone Unit No. 2 to allow two EDGs to operate for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and then one EDG to continue operation for a total of 7 days is approximately 41,700 gallons (41,515 gallons). The two diesM oil supply tanks will contain 24,000 gallons of this required volume. The remaining diesel fuel oil (approximately 17,700 gallons) will be stored in the underground diesel l oil storage tank. To ensure a useable volume of approximately 17,700 l gallons, a level of approximately 92 inches is required.

3. 97 ENG-1804E2 - Revision 00, August 8,1907 Diesel Oil Storage Tank (T-47A) Level Lcep Uncertainty and Alarm Sotpoint, L-7004 This calculation determined the minimum low level alarm setpoint for the underground diesel oil storage tank to allow two EDGs to cperate for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and then one EDG to continue operation for a total of 7 days. This will ensure a useable volume of approximately 17,700 gallons of diesel fuel oil is maintained in the underground diesel oil storage tank.

These calculations are available for review.

Description of Proposed Chanae FSAR Section 8.3,

Emergency Generators," will be expanded to discuss the length of time the EDGs will operate following a LOCA and LNP, utilizing only onsite diesel fuel oil sources. The onsite sources include the Technical Specification required volume of 12,000 gallons in each diesel oil supply tank, and an additional approximate 17,700 gallons that will be maintained in the underground diesel oil storage tank. This combined volume of diesel fuel oil, that will be maintained onsite, is sufficient to allow two EDGs to operate at rated load for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months following a design basis large break LOCA and LNP. The remaining diesel fuel oil will be sufficient for one EDG to continue operation at rated load for a total of 7 days from event initiation.

If approved by the NRC, this will become the new licensing basis for the Millstone Unit No. 2 EDG diesel fuel oil system. This will also meet the intent of Section 5.2.4 (6) of IEEE Standard 3081971.

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U.S. Nuclear R:gul: tory Commission B16594/ Attachment 1/Page 7 Safety Assessment The proposed change expands FSAR Section 8.3

Emergency Gonorators,' to discuss the length of timo the EDGs will operate following a LOCA and LNP, utilizing only onsite diesel fuel oil sources. The onsite sources include the Technical Specification required volume of 12,000 gallons in each diesel oil supply tank and an additional approximate 17,700 gallons that will be maintained in the underground diesel oil storage tank. This onsite volume of diesel fuel oil is sufficient to allow two EDGs to operate at rated load (2750 KW) fu 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months following a design basis LOCA and ; NP, The remaining diesel fuel oil will be sufficient for one EDG to continue opera ion at rated load for a total of 7 days from event initiation.

IEEE Standard 3081971, Section 5.2.4 (6), requires a 7 day supply of diesel fuel oil to be mairitained onsite. Millstone Unit No. 2 has revised the original EDG loao calculations and determined that the quantity of diesel fuel oil maintained in the two safety-related diesel fuel oil supply tanks (Technical Specification required volume of 12,000 gallons in each tank) is not sufficient to provide EDG operation for 7 days, Therefore, NNECO is proposing to use the additional diesel fuel oil that is stored onsite in the non sofoty related underground diesel oil storage tank to supplement the volume contained in the two safety related diesel fuel oil supply tanks. This additional fuel oil l will enable one EDG to oporate for a minimum of 7 days following a LOCA and LNP. ('

An approximato 3.5 day EDG run time provides a significant margin of time for replenishment of EDG fuel oil. Replenishment can be accomplished from the nonsafety-related underground diesel oil storage tank or offsite sources. The non-selsmic underground diesel oil storage tank provides the normal make-up path for fuel oil to the fuel oil supply tanks. It contains fuel oil which is fully qualified and tested regularly.

At least one diesel oil transfer pump will be available to supply fuel oil from the underground tank to the diesel oil supply tanks, since the pumps are supplied from vital power sources. If the volume of fuel oil in the underground diosol oil storage tank is taken into consideration, the one remaining EDG will be able to continue operation at 2750 KW for an additional 3.5 days. This will increase the total time one EDG will be able to operate to approximately 7 days, if a seismic event occurs, the fuel oil in the underground diesel oil storage tank can not be rolled upon, because the underground diesel oil storage tank is not soismically qualified. However, replenishment of fuel oil could be accomplished via an offsite source, in addition to the total volume of fuel oil maintained onsite, Millstone Unit No. 2 has a fuel oil supply contract for delivery of fuel oil to the unit. Emergency Plan procedures require an evaluation of the need to order additional fuel from offsite sources witbin 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months following a LOCA and LNP. The Emergency Plan procedures also require the

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U.S. Nuclear Regul: tory Commission B16594/ Attachment 1/Page 8 Technical Support Center staff to provide load shedding recommendations within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 'of a LOCA and LNP. These load shedding recommendations may include securing one EDG, cross cornecting the two diesel oil supply tanks, and securing any electrical loads not needed to support plant recovery. The specific recommendations will vary depending on the situation and will be developed within the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months time period. This time is sufficient to allow the Technical Support Center staff to develop the specific load shedding recommendations, and will allow an evaluation of the likelihood of fuel oil delivery to Millstone Unit No. 2. If fuel oil delivery is imminent, load shedding will not be necwsary.

The high reliability of the electrical grid and the high probability that offsite power can be restored within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months reduces the need to rely on extended EDG operation.

However, extreme environmental conditions such as hurricanes and earthquakes could cause an extended loss of offsite power.

The progress of hurricanes is monitored. Also, Abnormal Operating Procedure 2560,

' Storms, High Winds and High Tides," requires a plant shutdown if wind speed is forecasted to excoed 90 mph, within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months , at the Millstone site. Therefore, if a loss of offsite power occurred due to a hurricane, the plant would be in a shutdown condition. Thus, the expected EDG loading would be significantly below rated load.

Offsite power is susceptible to damage from a larger rango of seismic events than are local roads and bridges. The probability of seismic events which would affect local roads and bridges is low. Therefore, after a seismic event, diesel fuel oil is expected to be available from offsite sources. In the event of a high magnitude earthquake damaging local roads and bridges, efforts would be made to fly in diesel fuel oil or deliver it by barge.

Based on the above, the proposed change to FSAR Section 8.3, ' Emergency Generators,' has no effect on any of the design basis accidents previously evaluated.

Thus, there is no significant impact on public health and safety, i

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Docket No. 50-336 4

B16594

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Attachment 2 Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Final Safety Analysis Report !

Emergency Diesel Generator Fuel Oil Significant Hazards Consideration '

September 1997

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U. S. Nuclear Regulatory Commission B16594/ Attachment 2/Page 1 Proposed Revision to Final Safety Analysis Report Emergency D!esel Generator Fuel Oil Significant Hazards Consideration Sionificant Hazards Consideration in accordance with 10CFR50.92, NNECO has reviewed the proposed change and has concluded that it does not involve a significant hazards consideration (SHC). The basis for this conclusion is that the three criteria of 10CFR50.92(c) are not compromised. The proposed change does not involve an SHC because the changes would not:

1 1. Involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed change expands FSAR Section 8.3, ' Emergency Generators," to discuss the length of time the emergency diesel generators (EDGs) will operate following a loss of coolant accident (LOCA) and a loss of normal power (LNP),

utilizing only onsite diesel fuel oil sources. The onsite sources include the Technical Specification required volume of 12,000 gallons in each diesel oil supply tank and an additional approximate 17,700 gallons that will be maintained in the underground diesel oil storage tank. This onsite volume of diesel fuel oil is sufficient to allow two EDGs to operate at rated load (2750 KW) for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months following a design basis LOCA and LNP. The remaining diesel fuel oil will be sufficient for one EDG to continue operation at rated load for a total of 7 days from event initiation.

The proposed change to the FSAR has no ofiect on EDG operation and reliability. The EDGs will continue to operate as designed to supply the electrical loads assumed to mitigate the design basis accidents. Therefore, there is no significant increase in the probability or consequences of an accident previously evaluated.

2. Create the possibility of a new or different kind of accident from any accident previously evaluated.

The proposed change will not alter the plant configuration (no new or different type of equipment will be installed) or require any new or unusual operator actions. Plant operating procedures will be changed. However, the changes will not require the performance of any task not currently performed by the plant operators. Emergency Plan procedures already specify the action to provide load shedding recommendations within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of a LOCA and LNP, and to evaluate the need to order additional fuel from offsite sources within four hours after the accident.

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U. S. Nuclear Regul: tory Commission l

816594/ Attachment 2/Page 2

' The proposed change does not alter the way any structure, system, or component functions and does not alter the manner in which the plant is operated it does not introduce any new failure modes and does not alter assumptions made in the safety analysis.

Therefore, the change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Involve a significant reduction in a margin of safety.

The length of time the emergency diesel generators (EDGs) will operate following a loss of Coolant Accident and a Loss of Normal Power, utilizing only the onsite diesel fuel oil sources required by Technical Specifications has been recalculated. The new EDG run times do not agree with the current EDG run times contained in the Millstone Unit No. 2 Final Safety Analysis Report (FSAR),

and therefore do not agree with the current Technical Specification Bases for 3.8.1.1, "A.C. Sources - Opersting," and 3.8.1.2, 'A.C. Sources - Shutdown."

This deviation does result in a reduction in the margin of safety as defined in the Technical Specification Bases for 3.8.1.1, 'A.C. Sources - Operating," and 3.8.1.2, 'A.C, Sources - Shutdown.' However, this proposed change will require additional diesel fuel oil to be maintained onsite in the non seismic underground diesel oil storage tank. This will ensure sufficient diesel fuel oil will be maintained onsite to provide a 7 day supply, assuming a seismic event does not occur. Therefore, this is not a significant reduction in the margin of safety as defined in the Technical Specification Bases for 3.8.1.1, 'A.C. Sources -

Operating," and 3.8.1.2, "A.C. Sources - Shutdown.'

The NRC has provided guidance concerning the application of standards in 10CFR50.92 by providing certain examples (March 6, 1986, 51 FR 7751) of amendments that are considered not likely to involve an SHC. The changes proposed herein are not enveloped by a specific example. However, the proposed changes do not alter the design, function, or operation of the equipment involved. Therefore, NNECO has concluded that the proposed changes do not involve an SHC.

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B16594, Application for Amend to License DPR-65,modifying Expected Time EDGs Will Operate Utilizing Onsite Fuel Oil Sources Required by TS

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