ML20138C313

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Application for Amend to License NPF-3,requesting Rev to TS 3/4.7.6 to Include New Required Actions in Event That One or Both Channels of Radiation Monitoring Instrumentation Becomes Inoperable
ML20138C313
Person / Time
Site: Davis Besse Cleveland Electric icon.png
Issue date: 04/18/1997
From: Jeffery Wood
CENTERIOR ENERGY
To:
Shared Package
ML20138C306 List:
References
2447, NUDOCS 9704300089
Download: ML20138C313 (10)
v • d • e


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Docket Numb @r 50-346

.. . Licenze Numbar NPF-3

, Scrial-Numb 3r 2447 ,

Enclosure Page 1 APPLICATION FOR AMENDMENT TO FACILITY OPERATING LICENSE NUMBER NPF-3 DAVIS-BESSE NUCLEAR POWER STATION UNIT NUMBER 1 f i

i Attached are the requested changes to the Davis-Besse Nuclear Power

' Station, Unit Number 1, Facility Operating License Number NPF-3. Also included is the Safety Assessment and Significant Hazards Consideration.

The proposed changes (submitted under cover letter Serial Number 2447) concern:

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Appendix A, Technical Specification Sections 3/4.7.6, Plant Systems -

Control Room Emergency Ventilation System, and the associated Bases.

By:

- Nuclear John p Wood, Vice ' President 4

Sworn to and subscribed before me this 18th day of April,1997.

% *Oh Nota V Publi ' tate of Ohio I J. STMAUSS MotoryPublic.Stateof Ohio My Commissen Egiros 3/22/98 9704300099 970418 7 PDR ADOCK 05000346i P PDR Q;

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Docket Number 50-346

. . License Numbar NPF-3

,, Serial Number 2447 Enclosure Page 2 The following information is provided to support issuance of the requested changes to the Davis-Besse Nuclear Power Station (DBNPS), Unit Number 1, Facility operating License Number NPF-3, Appendix A, Technical Specifications. The changes involve Technical Specifications (TS) 3/4.7.6, Plant Systems - Control Room Emergency Ventilation System, and the associated Bases 3/4.7.6, control Room Emergency Ventilation System.

A. Time Required to Implement: This change is to be implemented within 90 days after the NRC issuance of the License Amendment.

B. Reason for Change (License Amendment Request Number 97-0005):

This application proposes to revise the TS Limiting Condition for operation (LCO) to include new required Actions in the event that one or both channels of Station Vent Normal Range Radiation Monitoring instrumentation become inoperable. These radiation monitoring instrumentation channels serve to isolate the control room normal ventilation system in the event of high radiation levels in the station vent stack. The associated TS Bases are also proposed to be revised consistent with this proposed changes.

The proposed changes will eliminate the potential for an unnecessary plant shutdown in the event both channels of radiation monitoring instrumentation become inoperable during plant operation. The proposed changes will also bring the DBNPS Technical Specifications into closer agreement with NUREG-1430,

" Improved Standard Technical Specifications for Babcock and Wilcox Pressurized Water Reactors," Revision 1.

C. Safety Assessment and Significant Hazards Consideration: See

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4 a

. . Docket Number 50-346

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. License

  • Number NPF-3 Serial Number 2447 Attachment SAFETY ASSESSMENT AND SIGNIFICANT HAZA.RDS CONSIDERATION FOR LICENSE AMENDMENT REQUEST NO. 97-0005 (12 pages follow)

LAR 97-0005 Page 1 1

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SAFETY ASSESSMENT AND SIGNIFICANT IIAZARDS CONSIDERATION FOR LICENSE AMENDMENT REQUEST NO. 97-0005 TITLE 1 Proposed Modification to the Davis-Besse Nuclear Power Station, Unit Number 1, Facility Operating License NPF-3, Appendix A, Technical Specifications to Revise the Control Room Emergency Ventilation System (CREVS) Limiting Condition for Operation.

DESCRIPTION:

The purpose of the proposed changes is to modify the Davis-Besse Nuclear Power Station (DENPS) Operating License NPF-3, Appendix A, Technical Specifications (TS) and the associated Bases. The proposed changes would revise the TS Limiting Condition for Operation (LCO) to include new required Actions in the event that one or both channels of Station Vent Normal Range Radiation Monitoring instrumentation become inoperable. These radiation monitoring instrumentation channels serve to isolate the control room normal ventilation system in the event of high radiation levels in the station vent stack. The associated TS Bases are also proposed to be revised consistent with the proposed changes.

The proposed changes are described in further detail as follows:

TS 3/4.7.6.1 Plant Systems - Control Room Emeroency Ventilation System The present Action 3./.6.1 would be renumbered as Action 3.7.6.1.a, and Actions 3.7.6.1.b and 3.7.6.1.c would be added, to read as follows:

b. With one channel of Station Vent Normal Range Radiation Monitoring instrumantation inoperable, restore the inoperable channel to OPERABLE status within 7 days, or within the following i hour, isolate the control room normal ventilation system and place at least one control room emergency ventilation system train in operation.
c. With both channels of Station Vent Normal Range Radiation Monitoring instrumentation inoperable, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, isolate the control room normal ventilation system and place at least one control room emergency ventilation system train in operation.

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LAR 97-0005 Page 2

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These proposed changes will eliminate the potential for an unnecessary plant shutdown in the event both channels of radiation monitoring instrumentation become inoperable during plant operation, by requiring that at least one CREVS train be placed in operation. Currently, should both channels of station vent radiation monitoring instrumentation become inoperable, the plant must enter TS 3.0.3 and commence a shutdown within ]

one hour.

These proposed changes would also bring the DBNPS TS into closer agreement with NUREG-1430, " Improved Standard Technical Specifications for Babcock j and Wilcox Pressurized Water Reactors," Revision 1. Improved Standard Technical Specification (ISTS) LCO 3.3.16, " Control Room Isolation - High Radiation," requires only one radiation monitoring channel, and requires that the CREVS be placed in the emergency recirculation mode within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in the event the channel becomes inoperable in Modes 1 through 4. It is noted that for the ISTS, the control room isolation signal is provided by a single channel, while the DBNPS design has two channels.

Consistent with the terminology utilized in the new Action statements, surveillance Requirement (SR) 4.7.6.1.e.2 would be revised to change

" Station Vent Radiation High" to " Station Vent Normal Range Radiation Monitoring."

Baseo 3/4.7.6 Control Room Emeroency Ventilation System i Consistent with the proposed changes to TS 3/4.7.6.1, Bases 3/4.7.6 would be modified by adding two additional paragraphs, to read as follows:

The Station Vent Normal Range Radiation Monitoring isolation function provides that under the required conditions, an isolation signal will be given. The Station Vent Normal Range Radiation Monitors provide isolation and shutdown of the control room normal ventilation system.

With one channel of Station vent Normal Range Radiation Monitoring instrumentation inoperable for greater than 7 days, or with both channels of Station Vent Normal Range Radiation Monitoring instrumentation inoperable, the control room ventilation systems must be placed in a state equivalent to that which occurs after the high radiation isolation has occurred: the control room normal ventilation system is isolated and the control room emergency ventilation system is placed in operation. Plant operation can continue indefinitely in this state, provided that control room temperature can be maintained in an acceptable range, with the control room emergency ventilation system obtaining fresh-air makeup as described in the Updated Safety Analysis Report Section 9.4.1, " Control Room."

Each of the proposed changes is shown on the attached marked-up Operating License pages.

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LAR 97-0005 Page 3

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SYSTEMS, COMPONENTS, AND ACTIVITIES AFFECTED:

The affected systems, components, and activities are the Control Room Emergency Ventilation System (CREVS), the Control Room Normal Ventilation System, the Station Vent Normal Range Radiation Monitoring instrumentation channels, and the required TS actions to be taken in the event these instrumentation channels are inoperable.

FUNCTIONS OF THE AFFECTED SYSTKMS, COMPONENTS, AND ACTIVITIES:

I The CREVS is described in Section 9.4.1, " Control Room," of the USAR. The l CREVS is designed to provide filtered and conditioned air to the control room. This ensuits that control room equipment and habitability for I control room personnel remain unaffected during and following all credible I accident conditions. Operability of the CREVS, in conjunction with other f control room design provisions, is based on limiting control room personnel I exposure consistent with the requirements of General Design Criteria 19,

" Control Room," of Appendix A of 10 CFR 50.

Each section of the normal control room ventilation system that penetrates the control room pressure boundary is equipped with two (redundant) safety-related, pneumatically-operated isolation dampers which function to isolate the ductwork from the control room upon receipt of a safety Features Actuation System (SFAS) Incident Level 1 signal. An SFAS Incident Level 1 signal is currently initiated as a result of high radiation level within the containment building, low reactor coolant pressure, or high

[ pressure within the containment building. SFAS Actuation Channel 1 l isolates one of the redundant trains of dampers, and SFAS Actuation l Channel 2 isolates the other train. Each train of damper supply air is equipped with a pressure switch which senses low control air pressure to the dampers and initiates a station computer alarm and stops the corresponding train of control room air handling unit's (supply) fan and the control room return air fan. The CREVS is put into operation manually.

In addition to the SFAS Incident Level 1 signal, a Station Vent Normal l

Range Radiation Monitoring isolation signal from iadiation monitors

! RE4598AA or RE4598BA will also automatically isolate the control room and shutdown the corresponding train of normal control room ventilation. These independent radiation monitors measure station vent discharge, and upon detection of high radiation, isolate the control room in a manner similar to the SFAS Incident Level 1 signal described above (RE4598AA similar to SFAS Actuation Channel 1 and RE4598BA similar to SFAS Actuation Channel 2).

These radiation monitors continuously monitor the station vent during plant operational Modes 1 through 4 for particulate, iodine, and noble gas radioactivity. These monitors are discussed in Section 11.4.2.2.4, " Unit Vent Monitoring System," and Table 11.4-1, " Liquid, Gas, and Airborne Radiation Monitors," of the USAR. The station vent is the final discharge point for the gaseous radioactive effluents.

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LAR 97-0005 Page 4 Area radiation monitors are provided for the control room which continuously give the background radiation level. In case of any abnormal increase in the background level, the control room operator can manually isolate the normal ventilation system and start the CREVS.

RFFECTS ON SAFETY:

l The proposed change to LCO 3.7.6.1 would provide new required Actions in j the event that one or both channels of Station Vent Normal Range Radiation l Monitoring instrumentation become inoperable. In the event that one

! channel is inoperable for greater than 7 days, or in the event that both channels are inoperable, the proposed Action statement would require that l the control room normal ventilation system be isolated and at least one l CREVS train be placed in operation The proposed allowable outage time of 7 days for one inoperable channel allows a reasonable time period for corrective actions to repair the equipment. In addition, this time is consistent with the present allowable outage time for one inoperable CREVS i train. The proposed Action to place at least one CREVS train in operation within one hour, in the event both channels of radiation monitoring become inoperable, is more conservative than the present Action which requires that a plant shutdown commence within one hour, but does not require the CREVS be placed in operation. Since completion of these required actions places the ventilation systems in a state equivalent to that which occurs were a high radiation isolation to occur, this proposed change will have no adverse effect on plant safety.

With the control room isolated and CREVS in operation, continued plant operation is contingent upon maintaining control room temperature (as measured in the Cabinet Room) in an acceptable range. In accordance with Plant Procedure DB-OP-02533, " Control Room Emergency Ventilation System Load Shedding," if the temperature in the Cabinet Room reaches 105*F, a rapid plant shutdown is performed, and if the temperature in the Cabinet Room reaches 110*F, the reactor is manually tripped.

l l The proposed change to the terminology utilized in SR 4.7.6.1.e is an l administrative change made to make the terminology consistent with the proposed new Action statements. This change will have no adverse effect on plant safety.

The proposed changes to Bases 3/4.7.6 are administrative changes consistent with the proposed changes to LCO 3.7.6.1, and will have no adverse effect on plant safety.

FIGNIFICANT HAZARDS CONSIDERATION:

The Nuclear Regulatory Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazard exists due to a proposed amendment to an Operating License for a facility. A proposed amendment involves no significant hazards consideration if operation of the facility in accordance with the proposed changes would: (1) Not involve a significant increase in the probability or consequences of an accident

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i LAR 97-0005 )

Page 5 previously evaluated; (2) Not create the possibility of a new or different ,

kind of accident from any accident previously evaluated; or (3) Not involve a significant reduction in a margin of safety.. The Davis-Besse Nuclear j Power- Station has reviewed the proposed changes and determined that a j significant hazards consideration does not exist because operation of the Davis-Besse Nuclear Power Ste tion (DBNPS), Unit'No. 1, in accordance with this change would:  ;

- la. Not involve a significant increase in the probability of an accident

- previously evaluated because no accident initiators, conditions, or  ;

assumptions are affected by the proposed changes. i i The proposed change to Limiting condition for Operation (LCO) 3.7.6.1 j would include new required Action statements in the event that one or  ;

both channels of Station Vent Normal Range Radiation Monitoring

) instrumentation become inoperable. In the event that one channel is  ;

inoperable for greater than 7 days, or in the event that both channels are inoperable, the proposed Action statement would require ,

1 that the control room normal ventilation system be isolated and at  ;

least one Control Room Emergency Ventilation System (CREVS) train be {

placed in operation.

t 5 Under the proposed actions, the ventilation systems would be placed  ;

4 in a state equivalent to that which occurs were a high radiation  !

isolation to occur. These proposed changes have no bearing on the j i probability of an accident. l The proposed change to the terminology utilized in Surveillance l 4 Requiretat t (SR) 4.7.6.1.e is an adm nistrative change made to make  ;

the terminology consistent with the proposed new Action statements.  ;

The proposed changes to Bases 3/4.7.6 are administrative changes i consistent with the proposed changes to LCO 3.7.6.1. These changes  ;

, have no bearing on the prcbability of an accident.

Ab. Not involve a significant increase in the co:.t quences of an accident l

previously evaluated because the proposed caarges do not change the '

! source term, containment isolation, or allowable releases.

As described above, under the proposed new LCO 3.7.6.1 Actions, in i the event that one Station Vent Normal Range Radiation Monitoring instrumentation channel is inoperable for greater than seven days, or ,

in the event that both channels are inoperable, the ventilation systems would be placed in a state equivalent to that which occurs were a high radiation isolation to occur. Therefore, in the unlikely event of an accident requiring control room isolation while in this

, condition, the doce consequences to control room operators would be i unchanged.

The proposed change to the terminology utilized in Surveillance Requirement (SR) 4.7.6.1.e is an administrative change made to make  ;

the terminology consistent with the proposed new Action statements.  ;

The proposed changes to Bases 3/4.7.6 are administrative changes  ;

consistent with the proposed changes.to LCO 3.7.6.1. These changes [

have no bearing on the consequences of an accident, ,

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2. Not cr' ate the possibility of a new or different kind of accident fr 1 sny accident previously evaluated because no new accident initiators or assumptions are introduced by the proposed changes.

Ae described above, under the proposed new LCO 3.7.6.1 Actions, in the event that one Station Vent Normal Range Radiation Monitoring instrumentation channel is inoperable for greater than seven days, or in the event that both channels are inoperable, the ventilatio;,

systems would be placed in a state equivalent to that which occurs were a high radiation isolation to occur. Operation of the equipment and components in this manner would not introduce the possibility of any new or different kinds of accidents.

The proposed change to the terminology utilized in Surveillance Requirement (SR) 4.7.6.1.e is an administrative change made to make.

the terminology consistent with the proposed new Action statements.

The proposed changes to Bases 3/4.7.6 are 13ministrative changes consistent with the proposed changes to LCO 3.7.6.1. These changes would not introduce the possibility of any new or different kinds of accidents.

3. Not involve a significant reduction in a margin of safety because the proposed changes to the Action under LCO 3.7.6.1 ensure that control room isolation capability is maintained in the event a station vent radiation monitor is inoperable. The proposed allowable outage time of seven days for one inoperable channel is consistent with the [

paesently allowable outage time for one inoperable CREVS. The proposed Action to place at least one CREVS train in operation within one hour, in the event both channels of radiation monitoring become inoperable, is more conservative than the present Action which requires that a plant shutdown commence within one hour, but does not require the CREVS be placed in operation.

The proposed change to the terminology utilized in Surveillance Requirement (SR) 4.7.6.1.e is an administrative change made to make the terminology consistent with the prop ael new Action statements.

The proposed changes to Bases 3/4.7.6 aru wiministrative changes consistent with the proposed changes to LCO 3.7.6.1. These changes would not affect the margin of safety. l i

CONCLUSIOH1 on the basis of the above, the Davis-Besse Nuclear Power Station has determined that the License Amendment Reg- does not involve a significant hazards consideration.

ATTACHMENT:

Attached are the proposed marked-up changes to the Operating License.

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~LAR 97-0005 t Page 't i t

., ' REFERENCEst. t

i. l,J DBNPS Operating License NPF-3, Appendix A, " Technical -

i Specifications," through Amendment 214.  !

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2. DBNPS Updated Safety, Analysis Report (USAR).Section 9.4.1, " Control {

! Room," through Revision 20. .

'3. .DBNPS USAR Section 11.4.2.2.4, " Unit Vent Monitoring System,"

-through Revision 20. .l

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4, DBNPS USAR Table.11'.4-1, " Liquid, Gas, and Airborne Radiation j i

Monitors," through Revision 20.

i x -5. NUREG-1430, Revision 1, " Improved Standard Technical Specifications'  ;

for Babcock and Wilcox Pressurized Water Reactors."

Power Plants," " Criterion 19 - Control Room."

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