ML20196C274

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Proposed Tech Specs Re Limiting Conditions & Surveillance Requirements for RCS Relief Valves & Block Valves
ML20196C274
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 12/06/1988
From:
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20196C263 List:
References
NUDOCS 8812070240
Download: ML20196C274 (9)
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,,1 ENCLOSURE 1 I l

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PROPOSED TECHNICAL SPECIFICATION CHANGE I SEQUOYAH NUCLEAR PIANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 j

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-] RfACTO  %'7 SYSlEM R3 IEF VALVES - OPERATING LIMITING CONDITION FOR OPERATION 3.4.3.2 Two power relief valves (PORVs) and their associated block valves

, shall be OPERABLE.

APPLICABILITY: M00ES'1, 2, and 3.

ACTION:

a. With one or more PORV(s) inoperatle, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> either restore ,

the PORV(s) to OPERABLE status or close the associated block valve (s) and remove power from the block valve (s); otherwise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTOOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />,

b. With one or more block valve (s) inoperable, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> either ,

restore the block valve (s) to OPERABLE status or close the block valve (s) and remove power from the block valve (s); otherwise, he in R16 at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUT 00WN within the follo**ing 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. .

c. The provisions of Specification 3.0.4 are not applicable, ,

t SURVEILLANCE REOUIREMENTS

, 4.4.3.2.1 In addition to the requirements of Specification 4.0.5, each PORV sha'il be demonstrated OPERABLE at least once per 18 months by:

a. Performance of a CHANNEL CALIBRAT!0ri, and i

, sf cperating the valve through one complete cycle of full travel.

! 4.4.? ,; ch block valve shall be demonstrated OPERABLE at least once per 92 days ry operating the valve through one complete cycle of full travel.

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! MAR 251982 SEQUOYAH - UNIT 1. 3/4 4-4a Amendment No, 12 j l

REACTOR COOLANT SYSTEM ,

RELIEF VALVES - OPERATING LIMITING CONDITION FOR OPERATION 3.4.3.2 All pcwer operated relief valves (PORVs) and their associated block valves shall be OPERABLE.

APPLICABILITY: HODES 1, 2, and 3. .

AC1.dN:

a. With one or more PORV(s) inoperable, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> either restore the PORV(s) to OPERABLE status or close the associated block valve (s) I and remove power from the block valve (s); otherwise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUT 00WN within t!,e following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />,
b. With one or more b' lock valve (s) inoperable, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> either ,

restore the block valve (s) to OPERABLE stated or close the block val"e(s) and remove power from the block valve (s); otherwise, ce in '

at 'aast HOT STANOBY within the next 6 nours and in COLD SHUTDOWN

> within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

c. The provisions of Soecification 3.0.4 are not applicable. ,!

SURVEILLANCE RE0VIREMENTS 1,

4.4.3.2.1 In addition to the requirements of Specificction 4.0.5, each PORV shall b3 demonstrated OPERABLE at least once per 18 months by:

a. Performance of a CHANNEL CALIBRATION, and

! b. Operating the valve through one complete cycle of full travel. ,

4.4.3.2.2 Each block valve shall be demonstrated CPERABLE at least once per 92 days by operating the valle throug one completejc' ele of full travel.

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SEQUOYAH - UNIT 2 3/4 4-8

ENCLOSURE 2 d

PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2

DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-88-29) 1 DESCRIPTION AND JUSTIFICATION FOR DELETING SURVEILLANCE REQUIRLW.NT

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ENCLOSURE 2 Description of Change Tennessee Valley Authority proposes to modify the Sequoyah Nuclear Plant Units 1 and 2 Technical Specifications to delete surveillance requirement (SR) 4.4.3.2.3 for the pressurizer power-operated relief valves (PORVs) and associated block valves. This SR vas designed to demonstrate the operability of the emergency power supply for these valves.

Reason for Change The pressurizer PORVs have been changed from air-operated to solenoid operated valves in order to meet requirements of NUREG-0737. The PORVs are now permanently aligned to the 125-volt (V) direct current (de) vital battery boards, which are the emergency power supply. Therefore, no transfer is required to demonstrate operability of the emergency power supply.

The block valves are motor-operated valves (MOVs) powered from the 480-V reactor MOV boards, which are powered by the shutdown boards. The emergency power transfer is performed at the feed to the 6.9-kilovolt (kV) shutdown boards by transfer from offsite power to the diesel generators (DGs). Eaergency power supply operability to the shutdown boards is accomplished by SR 4.8.1.1.2. Thus, the requirement for block valve operation provides no additional assurance of emergency power supply operability.

Justification for Change The PORVs are powered by the 125-V de vital battery boards. The de power systeta is described in section 8.3.2 of the Final Safety Analysis Report (FSAR). The vital 125-V de control power system is a class 1E system whose safety function is to provide control power for engineered safety features equipment, emargency lighting, solenoid valve fuse panels, vital inverters, and other safety-related de power equipment for the entire plant. The system capacity is sufficient to supply these loads during normal operation to permit safe shutdown and isolation of the reactor during a loss of all alternating current (ac) powe. conditions.

Figure 8.1.2-2 of the FSAR shows the power supplies for the 125-V de battery beacd. Thu normal power supply to the battery boards is from the battery charger in each channel. The charger converts a three-phase, 480-V ac input to a 125-V de output. Power (ac) for each charger comes from the 480-V shutdown boards. Upon a loss of offsite power supply, the standby DGs automatically start to provide the emergency power supply to the shutdown boards.

Because the charger is permanently aligned to the shutdown boards, no transfer is required to ensure operability of the emergency power supply.

An existing SR for tl.e DGs (SR 4.8,1,1.2) ensures capability of the DCs to automatically start aad provide the emergency power supply to the shutdown boards. SR ' 4.3.2.1 adequately ensures cperability of the PORV itself.

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The block valves are powered from the 480-V reactor MOV boards.

Figure 8.1.2-1 of the FSAR shows the station power system. The reactor MOV boards receive a continuous power supply from the 480-V shutdown boards. The normal power supply for the shutdown boards comes from  !

offsite power. Upon a loss of the offsite power supply, the standb.y DGs automatically provide the emergency power supply to the shutdown be .rds.

The reactor MOV boards are powered from the shutdown boards regera. 9ss of whether power is from the normal cupply or the emergency supply.

Therefore, once the reactor MOV board is energized, specific test of

  • the block valve provides no additional assurances of emergency pow supply operability. Existing DG test requirements (SR 4.8.1.1.2) asure capability of the DGs to automatically start and energize the shutaown boards, and SR 4.4.3.2.2 adequately demonstrates operability of the block i valve itself.

The SR to test the emergency power supply for the PORVs and block valves is ttnnecessary as discussed above Also, the SR is confusing as written because the PORVs and block valves are permanently aligned to their electrical power boards. The present testing requirements for these valves are included in an already complex test required to demonstrate DG operability. The testing of these valves simply adds additional components that must be in service and operable (i.e., all hold orders cleared) in order to run the test. Deletion of the proposed SR removes ,

unnecessary burden to the operators and avoids any potential confusion ,

about the intent of the requirement.  !

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ENCLOSURE 3 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-88-29)

DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATIONS ,

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ENCL 0SURE 3 Significant Hazards Evaluation l

l TVA has evaluated the proposed technical specification change and has l determined that it does not represent a significant hazards consideration i based on criteria established in 10 CTR 50.92(c). Operation of SQN in accordance with the proposed amendment will nots (1) Involve a significant increase in the probability or consequences of an accident previously evaluated. The pressuriser PORVs are designed

  • to limit pressuriser pressure and prevent the undesirable opening of the safety valved. The PORVs are also used for automatic and manual pressure control. The TSAR analysis for overpressure protection a

assumes that the FORVs do not actuate. The steam generator safety valves and pressuriser safety valves provide the required pressure relief. However, the TSAR accident analysis for a steam generator j tube rupture does rely on the PORVs for pressure reductions.

The intent of the subject SR for the PORVs and associated block valves is to demonstrate operability of the emer'ency power supply.

Because power supply operability for these valve is included in other SRs with equal time interval requirements, no additional operability assurance is gained by this redundant testing. Existing SRs for the PORVs and block vsives, along with the existing SRs for 1 emergency power supplies, provide adequate assurance of valve l'

capability to functionally control pressure. Thus, the pronosed change does not affect the probability or consequences of at. accident .

previously analyzed.

(2) Create the possibility of a new or different kind of accident from any previously analyzed. The deletion of the subject SR does not -

require any hardware changes nor any change to the operating procedures. This change simply removes an unnecessary operator burden during perforrances of the DG test sequences and avoids any potential confusion about the intent of the requirement. Thus, the 4

possibility of a new or different kind of accident is not created.

(3) Involve a significant reduction in a margin of safety. The intended

! desirm and operation of the PORVs and block valves have not been changed. Appropriate testing of the valves and power supplits still exists. Thus, the margin of safety has not been changed.

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