ML20154D194

Proposed Tech Specs,Providing Changes Resulting from Calculations Performed to Support Design Basis Reconstitution Effort

ML20154D194
Person / Time
Site:	Fort Calhoun
Issue date:	09/09/1988
From:	OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20154D164	List: ML20154D162 ML20154D185 ML20154D194
References
NUDOCS 8809150179
Download: ML20154D194 (3)

Text

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2.0 LIMITING CONDITIONS FOR OPERATION A 2.1 Electrical Systems (Continued) from either one of two dicac1 generators and off-site standby power via j the unit cuxiliary transformers.(1) i The two emergency diesel generators on site do not require outside power for start up or operation.

Upon loss of norm.21 and standby power sources, the 4.16 kV buses lA3 and j LA4 are energized from the diesel generators. Bus load shedding, trans-1 for to the diesel i automatically.(2) generator and pickup of critical loads are carried out When the turbine generator is out of service for an extended period, the l generator can be isolated by opening motor operated disconnect switch

DS-T1 in the bus between the generator and the main transformer, allow-1 ing the main transformer and the unit auxiliary power transformers to la returned to service.(3)

Equipment served by 4.16 kV and 480 V auxiliary buses and MCC's is arranged so that loss of an entire 4.16 kV bus does not compromise safety l of the plant during DBA conditions. For example, if 4.16 kV bus lA3 is lost, two raw water pu sps, one low pressure safety injection pump, one j #

high pressure safety injection pump, one auxiliary feedwater pump, two l

component cooling water pumps, two containment spray pumps and two con-i A tainment air fans are lost. This leaves two raw water pumps, one low pressure safety injection pump, two high pressure safety injection pumps,

one component cooling water pump, one containment spray pump and two con-i tainment air fans which is more than su.ficient to control containment pressure below the design value during the DBA.

The total fuel oil engine base tank capacity of 550 gallons o [eacn l l diesel is considered'more than adequate since approximately sours l running time (vorst case loading) is available before transfer of feel j oil from the 18,000 gallon underground storage tanks is mandatory. Two 13 spm diesel oil transfer pumps per diesel, with each being fed from

) the diesel it is associated with, are available for transferring fuel l oil from the storage tank to the day tanks. The 16,000 gallons in the storace tank in addit. ion to the day tanks wi'.1 provide diesel o "X under the required loading conditions for a minimum period of,r ays

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should only one diesel be in operation. It is considered incredible no to be able to secure fusi oil from one of a,uveral sources in the vicinity of Omaha in less than three days under the worst ot weather conditions.

One battery charger on each battery shall be operating so that the batteries will always be at full charge; this ensures that adequate 1-c.

power will be avilable for all emergency uses. Each battery has one battery charger permanently connected with a third charger espable of f

1 l being connected to either battery bus. The enargers are each rated i

Amendment No. 76 2-35 8009150179 8 9 i

PDA ADOCK O 295

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NO SIGNIFICANT HAZARDS CONSIDERATION  !

During the recently completed calculations performed to verify the adequacy of the onsite fuel oil storage capacity of 16,000 gallons as required in

Technical Specification 2.7, it was determined that the fuel requirements

appeared to exceed this amount. These calculations were performed as a part of the Omaha Public Power District Design Basis Reconstitution Effort.

The calculations indicate that the Technical Specification onsite fuel available gives a capacity of approximately 6 days of operation for one l diesel generator. This was contrary to the basis statement that the capacity was sufficient for 7 days. The station staff was informed of this l conclusion, and a reportability determination was made. Based on the

. conflicting information, a 10 CFR 50.72 telephone notification was made to the NRC on September 2, 1988. Additionally, the approach to resolve the

, situation was discussed, and Region IV was amenable to revising the basis to Technical Specification 2.7 to reflect the results of the calculations.  ;

1. WILL THE CHANGE INVOLVE A SIGNIFICANT INCREASE IN THE PROBABILITY OR CONSEQUENCES OF AN ACCIDENT PREVIOUS'Y EVALUATED 7 i i

No, the changes to the basis of Technical Specification 2.7 corrects <

errors in calculations and takes into account additional electrical loadings, which affect the amount of time the emergancy diesel generator can run on only its full base 'ank fuel oil supply. The change is from 5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> to L5 hours before the fuel oil transfer pumps l are required. Also, the amount of time one emergency diesel generator i

can run on its full base tank fuel oil supply and 16,000 gallons in the

! underground storage tank, after a DBA and the required loading conditions, changes from 7 days to 6 days.

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! This change will not involve a significant increase in the probability or conrequence of an accidant previously evaluated because the SCO ,

t gallon emergency diesel generator base tank has an additional 300 '

gallon wall mounted auxiliary day tank which gravity feeds the base  ;

j tank. l The level in the Auxiliary Fuel Oil Tank is maintained by automatic

, ones ation of the fuel oil transfer pumps in response to low and high ,

, level signals wHch are alarmed in the Control Room. This t itional '

l tank extends the available time before the fuel oil trans1. pumps

) would be required to keep the emergency diesel generator's base tank

full.

l The change from 7 days to 6 days of technical specified underground storage tank fuel oil capacity for one emergency diesel running does i not involve a significant increase in the probabilitu or consequence of I an accident previously evaluated because it is considered incredible l not to be able to sccure additional fuel oil for the underground j storage tank within J days. Additional fuel oil is available fa om our fuel oil distributer within 3 days of request for delivery, ewn for l the most severe weather conditions.

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2. WILL 13E CHANGE CREATE THE POSSIBILITY OF A NEW OR DIFFERENT KIND OF ACCIDENT FROM ANY ACCIDENT PREVIOUSLY EVAL' LATED?

No, the 550 gallon emergency diesel generator base tank, has an additional 300 gallon wall mounted auxiliary day tank which gravity feeds the base tank. The level in the auxiliary fuel oil tank is maintained automatically by the operation of the fuel oil transfer pumps. Power is supplied to the two fuel oil transfer pumps via a 480 volt, 3-phase transfer switch. In the event that both the normal and emergency power supplies are not available to the transfer switch when the engine is running, a manually interlocked breaker will supply power to the pumps from a transformer connected to the diesel generator output. The loss of power is annunciated in the Control Room. This ensures fuel oil will be transferred to the base tank from the underground storage tank.

The Technical Specification for undergrcund storage capacity of 16,000 gallons is sufficient to supply post-accident requirements for 6 days.

! It is considered incredible to not be able to receive additional fuel oil within 3 days. Fuel oil is available from our fuel oil distributor within 3 days of request for delivery, even for the most severe weather

conditions.

3. WILL THE CHANGE INVOLVE A SIGNIFICANT REDUCTION IN A MARGIN OF SAFETY?

, No, the run time change based on the emergency diesel generator base tank does not significantly reduce the margin of safety for the plant because the 550 gallon base tank has an additional 300 gallon wall mounted auxiliary day tank that gravity feeds the base tank. The

) auxiliary day tank's level is maintained automatically by two fuel oil j transfer pumps with normal and emergency sources of power, also the

! diesel generator's electrical output can be used as a source of power.

! The Technical Specification for underground storage capacity of 16,000 i gallons is sofficient to supply post-accident, one diesel generator, j requirements for 6 days. It is considered incredible not to be able to

receive additional fuel oil within 3 days. Fuel oil is available from j our fuel oil distributor within 3 days of request for delivery, even for the most severe weather conditions.

1 A change to the USAR describing the capacities of the Emergency Diesel Generator base tank and underground fuel oil storage will be submitted

upon approval of this request.

For the above reasons, the Omaha Public Power District does not believe the 1 proposed change constitutes a significant hazards considerations.

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