ML20086K442

Revised Proposed Tech Specs Re DG Enhancements Reflecting More Conservative Approach to Enhancing DGs

ML20086K442
Person / Time
Site:	Cooper
Issue date:	07/14/1995
From:	NEBRASKA PUBLIC POWER DISTRICT
To:
Shared Package
ML20086K433	List: ML20086K430 ML20086K442
References
NUDOCS 9507200146
Download: ML20086K442 (7)

Text

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IIMITING CONDITIONS FOR OPEPATION SURVEITlANCE PEOUTREMENTS 3.5.F (cont' d. ) 4.5 F (cont'd.) ,,

2. During any period when both diesel generators are inoperable, continued reactor operation is permissible

{f g' y , ey S/0h only during the succeeding h ours g f unless one diesel generator is h

.E sooner made operable, provided that both LPCI subsystems , both Core

.S Spray subsystems, and both PJiR  ;

C i Service Water subsystems are '

operablefand the reactor power level 9 1- fic reduced to 25% of rated nowe and 1 I thegrequirements of 3.9. A.1 are met. '

If this requirement cannot be met,

.[h N f 4M 00Mdf/h an orderly shutdown shall be --

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initiated and the reactor placedFin WlYb.lA [A hMIS, OO l

the cold shutdown condition within e 36 hours. ,

3. Any combination of inoperable _ _.

components in the LPCI, RHR Service Water, and Core Spray systems shall not defeat the capability of the remaining operable components to fulfill the cooling functions.

4 When irradiated fuel is in the reactor vessel and the reactor is in the Cold Shutdown Condition, both Core < Spray subsystems, both LPCI subsystems, and both RER Service Water subsystems may be inoperable, provided no work is being done which has the potential for draining the reactor vessel. Refueling requirements are as specified in Specification 3.10.F.

5. With irradiated fuel in the reactor vessel, one control rod drive housing may be open while the suppression chamber is completely drained provided that:

a. The reactor vessel head is removed,

b. The spent fuel pool gates are open and the fuel pool water level is maintained at a level 2 33 feet,

c. The condensate transfer system is operable and a minimum of 230,000 gallons of water is in the condensate storage tank.

9507200146 950714 -121- 3/11/92 PDR ADOCK 05000298 P PDR

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1.5 l' ASES (cont' d) is available at all times. It is during refueling outages that major maintenance is performed and during such time that all low pressure core cooling systems may be out of service. Specification 3.5.F.4 provides that should this occur,'no work will be performed on the primary system which could lead to draining the vessel. This work l would include work on certain control rod drive components and recirculation system. l Thus, the specification precludes the events which could require core cooling. ,

Specification 3.5.F.5 recognizes that, concurrent with control rod drive maintenance during the refueling outage, it may be necessary to drain the suppression chamber for maintenance or for the inspection required by Specification 4. 7. A.2.h. In this case, if excessive control rod housing leakage occurred, three levels of protection against loss of core cooling would exist. First, a special flange would be used to stop the leak. Second, sufficient inventory of water is maintained to provide, under worst case leak conditions, approximately 60 minutes of core coolins; while attempts to 4 secure the leak are made. This inventory Ifincludes a leak water in the :ceactor well, spent should occur. manually operated fuel pool, and condensate storage tank.

valves in the condensate transfer system can be opened to supply either the Core Spray System or the spent fuel pool. Third, sufficient inventory of- water is l maintained to permit the water which has drained from the vessel to fill the torus to a level above the Core Spray and LPCI suction strainers. These systems could then recycle the water to the vessel. Since the system cannot be pressurized during refueling, the potential need for core flooding only exists and the specifieh combination of the Core Spray or the LPCI subsystems can provide this.fA This specification also provides for the highly unlikely case that both diesel generators !

are found to be inocerable.JThe reouction of rated power to 25% will orovide a very)

M table operating condition.fThe allowable repair time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> will provide an]

fopportunity to repair tne diesel and thereby prevent theIf necessity of taking the necessary the repairs plant down through the less stable shutdown condition.

g cannot be made in the allowed 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. the plant will be shutdown in an orderly l

ofmehienJThis will be accomplished while the two off-site sources of power required ,

by Specification 3.9.A.1 are available.

C. Maintenance of Filled Discharra Pine If the discharge pipin5 of the Core Spray, LPCI, HPCI. and RCIC systems are not filled, a water hammer can develop in this piping when the pump and/or pumps are started. If a water hammer were to occur at the time at which the sys tem ' vere ,

k required, the system would still perform its design functions. However, to minimize damage to the discharge piping and to ensure added =argin in the operation of these systems, this Technical Specification requires the discharge lines to be filled '

whenever the system is in an operable condition.

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SF The remaining requirements of 3.9. A.1 ensures that highly reliable) g gfLT and diverse power sources remain with one diesel generator M inoperable. It is necessary to verify that the required off-site -

sources are available and capable of supplying power to the emergency buses, and that loss of voltage and undervoltage relay circuits associated with the emergency buses are operable. l For a detailed explanation of the 4.5.F.1 requirements see the )

gSES section 4.5 on page 131 of these Technical Specifications. j __

l IWith two Diesel generators (DGs) inoperable, there are no]  ;

remaining standby AC sources. Thus, with an assumed loss of b offsite electrical power, there are no standby AC sources available

' It0gT to power the minimum required ESF functions. Since offsite l

.. electrical power is the only source of AC power for the majority of ESF equipment at this level of degradation, the risk associated j  ;

i with continued operation for a very short time could be less than /

that associated with an immediate controlled shutdown. Immediate 3 shutdown could cause grid instability, which could result in a total ,

loss of AC power. Since any inadvertent unit generator trip could l result in a total loss of offsite AC power, however, the time  ;

allowed for continued operation is severely restricted. The intent here is to avoid the risk associated with an immediate controlled

shutdown and to minimize the risk associated with this level of degradation.

According to Regulatory 1.93, with both DGs inoperable,  !'

operation may continue for a period that should not exceed 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

If the Diesel Generators cannot be restored to OPERABLE status /

within the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> completion time, the unit must be brought to a /

MODE in which the LCO does not apply. To achieve this status, (

the unit must be in the HOT STANDBY CONDITION within 12 )  ;

hours, and in the COLD CONDITION within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed completion times are reasonable, based on operating experience, to reach the required plant conditions from full power g

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i conditions in an orderly manner and without challenging plant -

( systems. _ _

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LIMITING CONDITIOFS FOR OPEP>sTIO j .

3.9.B (cont' d. ) 4.9.A (cont'd)

2. Diesel Generators 2. Diesel Generators

a. From and after the/date that one of the diesel generators or an l b

( Each diesel-generator started manually and loaded to not p associated critical bus is made or I less than 50% of rated load for no s

$. $ found to be' inoperable for any k less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> once each month to demonstrate operational readiness.

\1 y reason, continued reactor operation Q is permis 1ble in accordance with  !

[b [During the monthly generator test ef,g.i S ' ' ation 3.5.F.1 ifk g g(g p ic 'on 9. A.1 is satisfied. ( p !l compressor -

the diesel generator starting air shall be checked for y are .S ,' and to

b. ro nd a er e date that both operation its ability U recharge air receivers. The f

9g g) iese to be co inue gener ors are made or found inoper 'e for any reason, reagtor operation is

{' I g operation of the diesel fuel oil transfer pumps and fuel oil day tank y level switches shall be pe issible o nly during the s g n, g 4 demonstrated, and the diesel

- b sue eding 1 ours in accordance if ( starting time to reach rated voltage qq {l with Specifica o S ci are etion

.9.A.1 s3.5.F.2 satisfied g and frequency shall be logged, zv I From and after t e date that one of b. Once every 18 months the condition D

d Q. the diesel generators or associated under which the diesel generator is y

critical buses and either the required will be simulated and a y

emergency or startup transformer test conducted to demonstrate that q $

power source are made or found to be it will start and accept the

-g> q emergency loan wicnan the specified i inoperable for any reason, continued time sequence. The results shall be

% reactor operation is permissible Oin pecorcance witn Snecification/ logged.

( 3.5.F.lfprovided the other off-site Once a month the quantity of diesel 8/ source, startup transformer or c.

fuel available shall be logged.

emergency transformer is available and capable of automatically

• he 4160 d. At least once per month the supplying power to buses.fand the NRC is particulate concentration . level of critical the Diesel Fuel Oil Storage Tanks G tified vitatrt'24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the shall be determined in accordance occurrence and the plans for with ASTM D2276-1989, Method A. The b restoration of the inoperablej

-> cotal particulate concentration in hmoonents. the diesel fuel oil storage tanks,

d. From and after the date that the shall have a limit ofchecked less than in diesel fuel oil particulate 10 mg/ liter when accordance with ASTM-D2276-1989.

concentration level defined in Method A.

Surveillance Requirement 4.9.A.2.d cannot be met, restore the diesel total particulate e. New fuel oil sampling vill be fuel oil accordance with concentration to within the performed in ASTM D4057-1988 within 30 days upon acceptable limits within 7 days, or Fuel oil testing will be declare the associated Diesel delivery.

Generator inoperable. performed in accordance with the following:

e. From and after the date that the new 1. By "arifying in accordance with diesel fuel oil properties defined specified in Requirement the tests in Surveillance prior to 4.9.A.2.e.2 cannot be met, restore ASTM-D975-1989a addition to the storage tanks the stored diesel fuel oil that the sample has:

properties to within acceptable limits within 30 days, or declare a) An API Gravity of within the associated Diesel Generator 0.3 degrees at 60*F, or a I inoperable. specific gravity of within 0.0016 at 60/60* F, when

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l LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REOUIREMENTS ,

.i n 3.5.F (cont'd.) 4.5.F (cont'd.) l

2. During any period when both diesel  ;

generators are inoperable, continued l reactor operation is permissible l only during the succeeding 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> i' unless one diesel.. generator is sooner made operable, provided that  !

both LPCI subsystems, both Core Spray subsystems, and- both RHR_  !

Service Water subsystems are operable 'and the remaining requirements of 3.9. A.1 are met. If this requirement cannot be met, an ,

orderly shutdown shall be initiated and the reactor placed in the hot standby condition within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, l and in the cold shutdown condition within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.  ;

3. Any combination of inoperable  !

components in the LPCI, RHR Service f Water, and Core Spray systems shall  ;

not defeat the capability of the i remaining . operable components to  ;

fulfill the cooling functions.  ;

4. When irradiated fuel is in the  !

reactor vessel and the reactor is in the Cold Ehutdown Condition, both Core Spray subsystems, both LPCI '

subsystems, and both RHR Service Water subsystems may be inoperable, provided no work is being done which has the potential for draining the reactor vessel. Refueling requirements are as specified ' in Specification 3.10.F. ,

5. With irradiated fuel in the reactor .

vessel, one control rod drive housing may be open while the suppression chamber is completely ,

drained provided that: '

a. The reactor vessel head is removed. j

b. The spent fuel pool gates are  !

open and the fuel pool water level is maintained at a level 2 33 feet, i

c. The condensate transfer )

system is operable and a j minimum of 230,000 gallons of  ;

water is in the condensate ,

storage tank. ]

I i

l

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3.5 BASES (cont'd) is available at all times. It is during refueling outages that major maintenance is performed and during such time that all low pressure core cooling systems may be out of service. Specification 3.5.F.4 provides that should this occur, no work will be performed on the primary system which could lead to draining the vessel. This work would include work on certain control rod drive components and recirculation system.

Thus, the specification precludes the events which could require _ core cooling.

Specification 3.5.F.5 recognizes that, concurrent with control rod drive maintenance during the refueling outage, it may be necessary to drain the suppression chamber for maintenance or for the inspection required by Specification 4.7. A.2.h. In this case, if excessive control rod housing leakage occurred, three levels of protection against loss of core cooling would exist. First, a special flange would be used to stop the leak. Second, sufficient inventory of water is maintained to provide, under worst case leak conditions, approximately 60 minutes of core cooling while attempts to secure the leak are made. This inventor fuel pool, and condensate storage tank.y includes water in the reactor well, spentIf a leak should valves in the condensate transfer system can be opened to supply either the Core Spray System or the spent fuel pool. Third, sufficient inventory of water is maintained to permit the wate. which has drained from the vessel to fill the torus to a level above the Core Spray and LPCI suction strainers. These systems could then recycle the water to the vessel. Since the system cannot be pressurized during refueling, the potential need for core flooding only exists and the specified combination of the Core Spray or the LPCI subsystems can provide this.

The remaining requirements of 3.9.A.1 ensures that highly reliable and diverse power sources remain with one diesel generator inoperable. It is necessary to verify that the required off-site sources are available and capable of supplying power to the emergency buses, and that loss of voltage and undervoltage relay circuits associated with the emergency buses are operable.

For a detailed explanation of the 4.5.F.1 requirements see the BASES Section 4.5 on page 131 of these Technical Specifications.

This specification also provides for the highly unlikely case that both diesel generators are found to be inoperable. With two Diesel Generators (DGs) inoperable, there are no remaining standby AC sources. Thus, with an assumed loss of offsite electrical power, there are no standby AC sources available to power the minimum required ESF functions. Since offsite electrical power is the only source of AC power for the majority of ESF equipment at this level of degradation, the risk associated with continued operation for a very short time could be less than that associated with an immediate controlled shutdown. Immediate shutdown could cause grid instability, which could result in a total loss of AC power. Since any inadvertent unit generator trip could also result in a total loss of offsite AC power, however, i the time allowed for continued operation is severely restricted. The intent here is to avoid the risk associated with an immediate controlled shutdown and to minimize the risk associated with this level of degradation. i i

According to Regulatory 1.93, with both DGs inoperable, operation may continue for l a period that should not exceed 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. I If the Diesel Generators cannot be restored to OPERABLE status within the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> completion time, the unit must be brought to a MODE in which the LCO does not apply.

To achieve this status, the unit must be in the HOT STANDBY CONDITION within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, r.nd in the COLD CONDITION within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed completion times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems. This will be accomplished while the two off-site sources of power required by Specification 3.9.A.1 are available.

G Maintenance of Filled Discharre Pine If the discharge piping of the Core Spra LPCI, HPCI, and RCIC systems are not filled, a water hammer can develop in thy,s piping when the pump and/or pumps are started. If a water hammer were to occur at the time at which the system were I required, the system would still perform its design functions. However, to minimize damage to the discharge piping and to ensure added margin in the operation of these systems this Technical Specification requires the discharge lines to be filled whenever, the system is in an operable condition.

1

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LIMITING' CONDITIONS FOR OPERATION SURVEILLANCE REOUIREMENTS

'3.9.fi '(cont'd.) 4.9.A (cont'd)

2. Diesel Generators 2. Diesel Generators

a. . From and after the date that one of a. 1. Each diesel generator shall be the diesel generators or an started manually and loaded to associated critical bus is made or not less than 50% of rated load found to be inoperable- for any for no less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> once reason, continued reactor operation each month to demonstrate  ;

is permissible in accordance with operational readiness. A Specification 3.5.F.1 if the mcdified DG start involving remaining requirements of idling and gradual acceleration Specification 3.9.A.1 are satisfied, to synchronous speed may be.

used as recommended by the .

b. From and af ter the date that both manufacturer. This Surveillance  :

diesel generators are made or found Requirement may be preceded to be inoperable for any reason, with an engine prelube period continued reactor operation is prior to starting and followed permissible only during the by a warmup period prior to i succeeding 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> in accordance loading. '

with Specification 3.5.F.2 if the remaining requirements of When modified start procedures Specification 3.9.A.1 are satisfied, are not used,- .the time, voltage, and frequency

c. From and af ter the date that one of requirements of 4.9.A.2.a.2 the diesel generators or associated must be met. The performance of critical buses and either the Surveillance Requirement  !

emergency or startup transformer 4.9.A.2.a.2 satisfies this power source are made or found to be Surveillance Requirement.

inoperable for any reason, continued reactor operation is permissible During this monthly generator only during the succeeding 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test the diesel generator unless such diesel generator or starting air compressor shall i power source is sooner made be checked for operation and operable, provided the other its ability to recharge air off-site source, startup transformer receivers. The operation of or emergency transformer is the fuel oil transfer pumps and available and capable of fuel oil day tank level automatically supplying power to the switches shall be demonstrated.  ;

l 4160V critical buses. 2. Each diesel generator shall be started mamally and loaded to

d. From and after the date that the n t less than 50% of rated load diesel fuel oil ' particulate frn less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> every concentration level defined in six months to demonstrate Surveillance Requirement 4.9.A.2.d Perational readiness.

cannot be met, restore the diesel fuel oil total particulate During this generator test the concentration to within the diesel generator starting air acceptable limits within 7 days, or compressor shall be checked for declare the associated Diesel operation and its ability to Generator inoperable, recharge air receivers. The Peration of the fuel oil

e. From and after the date that the new transfer pumps and fuel oil day diesel fuel oil properties defined tank level switches shall be in Surveillance Requirement dem nstrated and the diesel

4. 9. A. 2. e . 2 cannot be met, restore starting time to reach rated the stored diesel fuel oil v ltage and frequency shall be properties to within acceptable 1 gged. s Sune ance limits within 30 days , or declare Requirement may be preceded by the associated Diesel Generator an engine prelube period prior inoperable, to starting. The performance of this Surveillance Requirement satisfies the requirements of

. 4.9.A.2.a.l.

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