ML20072S008

Proposed Tech Specs Re Primary Containment,Oxygen Concentration & Vacuum Relief

ML20072S008
Person / Time
Site:	Pilgrim
Issue date:	09/06/1994
From:	BOSTON EDISON CO.
To:
Shared Package
ML20072R992	List: ML20072R989 ML20072S008
References
94-100, NUDOCS 9409130388
Download: ML20072S008 (6)

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ATTACHMENT B PROPOSED TECHNICAL SPECIFICATION PAGES 9409130388 940906 PDR ADOCK 05000293 p

PDR

LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENTS 3.7 Primary Containment 4.7 Primary Containment

3) Neither of the two position alarm systems, which annunciate in the Control Room when any vacuum breaker opening exceeds 3/32",

are in alarm.

b.

Any drywell-suppression chamber b.

During each refueling interval:

vacuum breaker may be non-fully closed as determined by the (1)

Each vacuum breaker shall be position switches provided that tested to determine that the the drywell to suppression disc opens freely to the touch h

chamber differential decay rate and returns to the closed is demonstrated to be not position by gravity with no greater than 25% of the indication of binding.

differential pressure decay rate for the maximum llowable (2) Vacuum breaker position bypass area of 0.2ft switches and installed alarm systems shall be calibrated and c.

Reactor operation may continue functionally tested.

provided that no more than 2 of the drywell-pressure (3) At least 25% of the vacuum suppression chamber vacuum breakers shall be visually breakers are determined to be inspected such that all vacuum inoperable provided that they breakers shall have been are secured or known to be in inspected following every the closed position.

fourth refueling interval. If deficiencies are found, all d.

If a failure of one of the two vacuum breakers shall be installed position alarm visually inspected and systems occurs for one er more deficiencies corrected.

vacuum breakers, reactor operation may continue provided (4) A drywell to suppression that a differential pressure chamber leak rate test shall decay rate test is initiated demonstrate that the immediately and performed every differential pressure decay 15 days thereafter until the rate does not exceed the rate failure is corrected. The test which would occur through a 1 shall meet the requirements of inch orifice without the l

Specification 3.7.A.4.b.

addition of air or nitrogen.

5.

Oxvaen Concentration 5.

Oxvaen Concentration a.

The primary containment The primary containment oxygen i

atmosphere shall be reduced to concentration shall be measured less than 4% oxygen by volume and recorded at least twice with nitrogen gas during weekly.

reactor power operation with reactor coolant pressure above i

100 psig, except as specified l

in 3.7.A.5.b.

Revision Amendment No. 68 149 157 1

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l BASES:

3.7.A & 4.7.A Primary Containment Vacuum Relief The purpose of the vacuum relief valves is to equalize the pressure between the drywell and suppression chamber and reactor building so that the structural integrity of the containment is maintained. The vacuum relief system from the pressure suppression chamber to reactor building consists of two 100% vacuum relief breakers (2 parallel sets of 2 valves in series).

Operation of either system will maintain the pressure differential less than 2 4

psig; the external design pressure.

One valve may be out of service for repairs for a period of seven days.

If repairs cannot be completed within seven days, the reactor coolant system is brought to a condition where vacuum relief is no longer required.

The capacity of the 10 drywell vacuum relief valves is sized to limit the pressure differential between the suppression chamber and drywell during post-accident drywell cooling to the design limit of 2 psig. They are sized on the basis of the Bodega Bay pressure suppression system tests.

The ASME Boiler and Pressure Vessel Code,Section III, Subsection B, for this vessel allows a 5 psig vacuum; therefore, with two vacuum relief valves secured in the closed position and eight operable valves, containment integrity is not impaired.

l Reactor operation is permissible if the bypass area between the primary l

containment drywell and suppression chamber does not exceed an allowable area.

l The allowable bypass area is based upon analysis considering primary system l

break area, suppression chamber effectiveness, and containment design i

pressure. Analyses show that the maximum allowable bypass area is 0.2 fta, i

l which is equivalent to all vacuum breakers open 3/32".

(See letters from Boston Edison to the Directorate of Licensing, dated May 15, 1973 and October 22, 1974)

Reactor operation is not permitted if differential pressure decay rate is demonstrated to exceed 25% of allowable, thus providing a margin of safety for the primary containment in the event of a small break in the primary system.

Each drywell suppression chamber vacuum breaker is equipped with three switches. One switch provides full open indication only.

Another switch provides closed indication and an alarm should any vacuum breaker come off l

its closed seat by greater than 3/32". The third switch provides a separate i

and redundant alarm should any vacuum breaker come off its closed seat by l

greater than 3/32". The two alarms above are those referred to in Section i

3.7.A.4.a(3) and 3.7.A.4.d.

The water in the suppression chamber is used only for cooling in the event of an accident; i.e.,

it is not used for normal operation; therefore, a daily check of the temperature and volume is adequate to assure that adequate heat removal capability is present.

Revision Amendment No. 113, 170 i

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ATTACHMENT C CURRENT TECHNICAL SPECIFICATION PAGES ANNOTATED WITH PROPOSED CHANGES i

b k

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LIMITING CONDITION FOR OPERATION SURVEILLANCE RE0VIREMENTS 3.7 Primary Containment 4.7 Primary Containment

3) Neither of the two position alarm C ' rd,which annunciate - " 1 m N M,d/ b systems Pasi 005 when any vacuum e

breaker opening exceeds 3/32") are in alarm.

b.

Any drywell-suppression chamber b.

During each refueling vacuum breaker may be non-fully interval:

closed as determined by.the position switches provided that (1) Each vacuum breaker shall be-the drywell to suppression tested to determine that the chamber differential decay rate disc opens freely to the touch is demonstrated to be not and returns to the closed greater than 25% of the position by gravity with no differential pressure decay indication of binding, rate for the maximum llowable bypass area of 0.2ft (2)

Vacuum breaker position switches and installed alarm c.

Reactor operation may continue systems shall be calibrated and provided that no more than 2 of functionally tested, the drywell-pressure suppression chamber vacuum (3) At least 25% of the vacuum breakers are determined to be breakers shall be visually a

inoperable provided that they inspected such that all vacuum are secured or known to be in breakers shall have been the closed position.

inspected following every fourth refueling interval. If l d.

If a failure of one of the two deficiencies are found, all installed position alarm vacuum breakers shall be systems occurs for one or more visually inspected and vacuum breakers, reactor deficiencies corrected.

operation may continue provided that a differential pressure (4) A drywell to suppression decay rate test is initiated chamber leak rate test shall immediately and performed every demonstrate that the 15 days thereafter until the differential pressure decay failure is corrected.

The test rate does not exceed the rate shall meet the requirements of which would occur through a 1 Specification 3.7.A.4.b.

inch orifice without the addition of air or nitrogen.

5.

Oxvaen Concentration 5.

Oxvoen Concentration a.

The primary containment atmosphere shall be reduced to The primary containment oxygen less than 4% oxygen by volume concentration shall be measured with nitrogen gas during and recorsled at least twice reacter power operation with weekly.

reactor coolant pressure above 100 psig, except as specified in 3.7.A.5.b.

Revision 168 Amendment No. 68,-87, 149 157

BASES:'

3 7.A & 4.7.A Primary Containment

'ecuum Relief ihe purpose of the vacuum relief valves is to equalize the pressure between the drywell and suppression chamber and reactor building so that the structural integrity of the containment is maintained.

The vacuum relief system from the pressure suppression chamber to reactor building consists of 4

teo 100% vacuum relief breakers (2 parallel sets of 2 valves in series).

Operation of either. system will maintain the pressure differential less than 2 psig; the external design pressure. One valve may be out of service for repairs for a period of seven days.

If repairs cannot be completed within seven days, the reactor coolant system is brought to a condition where vacuum relief is no longer required.

The capacity of the 10 drywell vacuum relief valves is sized to limit the pressure differential between the suppression chamber and drywell during post-accident drywell cooling to the design limit of 2 psig.

They are sized on the basis of the Bodega Bay pressure suppression system tests.

The ASME Boiler and Pressure Vessel Code,Section III, Subsection B, for this vessel allows a 5 psig vai.uum; therefore, with two vacuum relief valves secured in the closed position and eight operable valves, containment integrity is not impaired.

Reactor operation is permissible if the bypass area between the primary containment drywell and suppression chamber does not exceed an allowable The allowable bypass area is based upon analysis considering primary area.

system break area, suppression chamber effectiveness, and containment design 2

ressure. Analyses show that the maximum allowable bypass area is 0.2 ft,

hich is equivalent to all vacuum breakers open 3/32".

(See letters from Boston Edison to the Directorate of Licensing, dated May 15, 1973 and October 22, 1974)

Reactor operation is not permitted if differential pressure decay rate is demonstrated to exceed 25% of allowable, thus providing a margin of safety for the primary containment in the event of a small break in the primary system.

Each drywell suppression chamber vacuum breaker is equipped with three 1

suitches. One switch provides full open indication only. Another switch provides closed indication and an alarm ee N el C ' should any vacuum breaker come off its closed seat by greater than 3/32".

The third switch provides a separate and redundant alarm e ;- M 905 should any vacuum breaker come off its closed seat by greater than 3/32".

The two alarms above are those referred to in Section 3.7.A.4.a(3) and 3.7.A.4.d.

The water in the suppression chamber is used only for cooling in the event of an accident; i.e., it is not used for normal operation; therefore, a daily check of the temperature and volume is adequate to assure that adequate heat removal capability is present.

Revision 116 Amendment No. 113 170