ML20238F677

Proposed Tech Spec Table 3.6-1, Containment Isolation Valves, Increasing Max Isolation Time for Containment mini- Purge Isolation Valves from 3 to 5

ML20238F677
Person / Time
Site:	Callaway
Issue date:	09/11/1987
From:	UNION ELECTRIC CO.
To:
Shared Package
ML20238F676	List: ML20238F674 ML20238F677
References
ULNRC-1606, NUDOCS 8709160281
Download: ML20238F677 (8)

Text

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ULNRC-1606

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I o-PROPOSED TECHNICAL' SPECIFICATION' CHANGES

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1 TABLE 3.6-1 (Continued)

CONT'AINMENT ISOLATION VALVES _

MAXIMUM LISOLATION TIME l

TYPE' LEAK PENETRATIONS VALVE NUMBER FUNCTION TEST REQUIRED (Seconds)

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.4.

Containment Purge Isolation (active)

V-161--

GT HI-4"**

CTMT Mint-Purge C 6 i

j Supply Outside CTMT Iso

-9 I j

V-161' GT HI-5***

CTMT Mini-Purge C

j Supply Inside 4

CTMT Iso 1

V-160 GT HZ-11***

CTMT Mini-Purge C

4-6 Exh Inside j

CTMT Iso l

V-160 GT HZ-12***

CTMT Mini-Purge C

+5-l Exh Outside CTMT Iso l

f.

5.

Containment Purge Isolation (passive)

I V-161 GT HZ-6***

CTMT S/0 Purge C

10 Supply Outside CTMT Iso V-161 GT HZ-7***

CTMT S/0 Purge C

10 Supply Inside

'i CTNT Iso V-16D GT HZ-8***

CTMT S/0 Purge C

10 Exh Inside CTMT Iso i

4 V-160 GT,HZ-9***

CTMT S/D Purge C

10 i

Exh Outside CTMT iso l

6.

Remote Manual f

P-41 BB HV-8351A RCP A Seal Water C

N.A.

Supply

• • • The provisions of Specification 3.0.4 are not appt4 cable provided the penetration is isolated by two passive devices.

J 3/4 6-23 CALLAWAY - UNIT 1 l-l i

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4 SAFETY EVALUATION This amendment request. Increases the maximum isolation time l

in Technical Specification Table 3.6-1 for the containment' mini-j purge isolation valves, GT-HZ-04, 05, 11, and -12, from 3 seconds i

to-5. seconds.

This ' change is acceptable from both a system operability as well as a licensing basis, as discussed

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hereinafter.

1.

Dose Contribution (exclusion area boundary and low population (LPZ) doses)

The radiological consequences of a LOCA were determined under the assumptions of unfiltered containment leakage passing directly to the environment of 0.2-volume per cent per day for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and 0.1 volume per j

cent per day between 1 and 30 days as well as filtered releases from ECCS recirculation and containment spray lines (see FSAR Table 15. 6-6).

This analysis did not consider the purge lines, nor any other containment penetrations, as individual leakage paths.

However, in order to demonstrate the negligible effects of increasing-the closure time of the mini-purge valves from 3 seconds to 5 seconds, a new calculation was performed in which the mini-purge supply and exhaust lines were treated as a.new leakage path in addition to the two leakage paths discussed above.

This calculation assumes that the blowdown is released unfiltered directly to the environment.

At the exclusion area boundary (0-2 hr.), this conservative analysis resulted in additional thyroid and whole body doses of 1.98 rem l

and 0.0048 rem, respectively.

When compared to the i

doses in FSAR Table 15.6-8 (i.e., 114 rem thyroid, 2.981 rem whole body), these additional doses result in less than a 2% increase.

At the LPZ boundary (0-30 day), the mini-purge dose analysis resulted in additional thyroid and whole body doses of 0.26 rem and 0.00062 rem, respectively.

These additional doses result in less than a 0.25% increase over the doses given in FSAR Table 15.6-8 (i.e.,114 rem thyroid,1.059 rem whole body).

The new mini-purge analysis verified that the additional I

releases through the purge lines will not affect the control room doses repor ted in FSAR Table 15.6-8.

The new total doses are well within 10CFR100 limits.

2.

Pressure / Temperature Ef fects a pressure / temperature calculation has been performed which assumes that the blowdown is released directly to the auxiliary building rooms where the outboard mini-purge isolation valves are located (GT-HZ-04 and -12 in rooms 1506 and 1507).

This calculation verified that the conditions in these rooms remain below the mild L

ULNRC-1606 environment criteria given in FSAR Section 3.ll(B).5.7

< 16.1 psia, < 90% R.H.).

This

- (i.e.,- < 110 degrees F, 6unt of blowd6wn and the is due Eo the limited am existence'of adequate' vent paths.

3.

Radiation Effects in Rooms 1506 and 1507 The calculation discussed at*ve in Item 2 (release to the auxiliary building) also determined 1that the additional dose contribution to equipment in rooms 1506 and 1507 is insignificant (less than 1000 rads) when compared to the 180-day total integrated doses for which-equipment in these rooms has previously been evaluated (0.722 megarads for room 1506, 1.01 megarads for room 1507 per FSAR Table 3.ll(B)-2).

4.

Pressure Effects on Structures For the release to auxiliary building scenario, there and will be a minimal effect on room pressuresIngs) structural components- (walls, floors, cei1 will be unaf fec ted.

5.

Containment Minimum Pressure Analysis This analysis is unaffected by changes to the mini-purge system, as discussed in FSAR Section 6.2.1.5.8.

6.

Ability of-Valves to Close Against Rising Containment Pressure As detailed in SLNRC 84-0004 dated 1/16/84, the mini-purge valves have been analytically proven to be able to close against the maximum LOCA containment pressure (47.3 psig), accounting for asymmetric flow effects due to the purge line piping configuration.

The analysis documented in this letter verifies that the valves stroke closed within their specified time (3 seconds for signal generation and lag time + 3 seconds for valve closure) with a large margin of available-to-required i

torque for closing.

The increase in valve stroke time requested in this application (3 seconds for signal 4

generation and lag time + 5 seconds for valve closure) does not change the conclusions reached in SLNRC 84-0004 since the valves' ability to close has been demonstrated for peak LOCA containment pressures which are reached after 100 seconds.

In reality, the mini-purge valves will be fully closed long before peak pressures are reached inside containment af ter a LOCA.

Pursuant to the above information, this amendment request does not adversely af fect or endanger the health of the general public.

ULNRC-1606 SIGNIFICANT HAZ ARDS CONSIDERATIONS This amendment request increases the maximum isolation time in Technical Specification Table 3.6-l'for the containment mini-purge isolation valves, GT-HZ-04, 05, 11, and -12, from 3 seconds to 5 seconds.

The following discussions address significant -

hazards evaluations associated with this change.

This change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed change is a relaxation of the closure time specified in Table 3.6-1 of Callaway. Technical Specification 3/4.6. 3 for the containment mini-purge system isolation valves (GT-HZ-04, 05, 11 and -12) f rom 3 seconds to 5 seconds following receipt of a

-signal to close.

The valves close to' isolate containment upon receipt of a containment purge isolation signal (CPIS), as discussed in FSAR Sections 6.2.4 and 7.3, which can be generated by a number of different mechanisms, including low steamline pressure (lead-lag compensated), low pressurizer pressure, high containment pressure (Hi-1), high containment purge exhaust I

radioactivity, as well as manual actuation.

The subject valves are fully qualified to NUREG-0588 guidelines for post-accident operation inside the containment.

fae system operates during normal plant operation; therefore, the subfoct valves could be open at any time during normal operation.

i Thero.is no change to any hardware as a result of this Technical Specification change.

There is no ef fect on the probability of any accident previously evaluated since the containment mini-purge system has no interf ace with high energy and/or potentially radioactive systems and is not involved in any postulated accidents other than for its isolation function.

Regarding the ef f ects on the consequences of any accident previously evaluated due to the subject Technical Specification change, an evaluation has verified that the blowdown from containment to the auxiliary building following a LOCA, prior to full closure of the subject valves in the mini-purge supply and exhaust lines, does not generate a harsh environment in the auxiliary building.

The mini-purge supply and exhaust lines consist of a short run of non-0, non-seismic duct inside containment coupled to ASME Class 2 pipe which leads to the containment penetration.

Outside containment ASME Class 2 pipe leads away f rom the containment penetration and is then coupled to non-0, non-seismic duct.

The subject containment isolation l

valves are located on the ASME Class 2 pipe.

For conservatism, j

l it was assumed that the duct is not present and that the containment blows down through the purge lines to the auxiliary I

building and dumps into the rooms where the ASME Class 2 pipe changes to duct.

This occurs in rooms 1506 and 1507 which are the only rooms through which the purge lines pass before exiting the auxiliary building.

Due to the short duration of the blowdown coupled with the existence of adequate vent paths from l

rooms 1506 and 1507, the pressure, temperature and humidity l

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ULWRC-1606 ef fects are minimal.

It was verified that -the pressure, temperature and humidity values generated in rooms 1506 and 1507 were below the values in FSAR Section 3.11(B).5.7 for a mild environment - (i.e.110 degrees F, 16.1 psia, and 90% R.H.).

Similarly, the mi'nimal pressurization effects would have no l

adverse effect on any auxiliary building structures (e.g., walls, 4

floors, and ceilings).

j Regarding the effects on exclusion area boundary and low' population zone doses due to the additional blowdown discussed 1

above, a calculation has been performed verifying that the dose 1

contribution due to the' blowdown prior to mini-purge valve closure is not significant (less than 2%) compared to the doses calculated for the current LOCA analysis as discussed in FSAR Section 15.6.5.

The new total doses are well within 10CFR10D limits.

For this calcule. tion, the activity is assumed to bq released directly to tho, environment with no filtering.

f Likewise, if the blowdown were released into the auxiliary building, the dose contribution is minimal when compared with the l'

180-day total integrated doses previously used to evaluate i

equipment in rooms 1506'and 1507.

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Relaxed closure time has no effect on the containment minimum pressure analysis for ECCS operation.

FSAR Section 6.2.1. 5 ' addresses' the containment minimum pressure analysis and discusses those parameters that impact this aualysis.

This section of the FSAR concludes that the containment mini-purge system does not have a substantial effect ou this analysis.

This. change does not create the possibility of a new or different kind of accident from any accident previously evalua ted.

This change in stroke time is still within the i

guidelines set forth in Branch Technical Position CSB 6-4 which j

states under Item A, paragraph 7 that the maximum time for valve 1

closure should not exceed five (5) seconds to assure that purge 1

valves are closed before the onset of fuel failures following a LOCA.

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The capability of the subject valves to close against the rising containment pressure following a large LOCA has been verified by the valve vendor, Fisher, as detailed in SLNRC 84-0004 dated January 16, 1984.

This letter contains the results of analyses verifying that the mini-purge valves will close in their l

specified time against the maximum LOCA containment pressure (47.3 psig) including the effects of asymmetric flow into the valves due to the piping configuration.

In reality, the valven will be. closed prior to the time that the containment reaches its maximum pressure after a LOCA of 62 psi 3 (i.e. closure in 8 seconds, including 3 seconds for signal' generation and lag time, vs. greater than 100 seconds to reach peak containment pressure).

I This change does not involve a significant reduction in a l

margin of safety.

As indicated above, this change will have no i

significant effect on the post-accident pressure, temperature and l

humidity environments in the auxiliary building.

Likewise, the 1

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ULNRC-1606 l

dose contribution for exclusion area boundary and LPZ doses f rom L

the containment purge lines is negligible.in comparison to the N,,

doses calculated for the current LOCA analysis.

Additionally, j

the qinimum containment pressure analysis remains unaffected by the proposed chance.

The Commission has provided guidance concerning the application of the standards in 10CFR50.92 by providing certain i

examples (4 8FR14679).

This change request is similar to the example of a change involving no significant hazards which relates to a change that may result in some increase in the consequences of a previously analyzed accident, but where the results of the change are clearly within all acceptance criteria as specified in the Standard Review Plan.

Pursuant to the above information, the requested amendment does not present a significar.t hazard, i.

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ULNRC-1606 APPLICATION FEE i

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