ML20116M855

Application for Amend to License NPF-58,revising Tech Spec 3.6.3.4, Suppression Pool Makeup Sys, Providing Water from Upper Containment Pool to Suppression Pool by Gravity Flow Through Two 100% Capacity Dump Lines Following LOCA

ML20116M855
Person / Time
Site:	Perry
Issue date:	11/16/1992
From:	Lyster M CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20116M857	List: ML20116M886 PY-CEI-NRR-1537, Application for Amend to License NPF-58,revising Tech Spec 3.6.3.4, Suppression Pool Makeup Sys, Providing Water from Upper Containment Pool to Suppression Pool by Gravity Flow Through Two 100% Capacity Dump Lines Following LOCA
References
PY-CEI-NRR-1537, NUDOCS 9211230091
Download: ML20116M855 (9)

Text

- - . _ _ - _ _ _

l

. A CENTERDOR ENERGY PERRY NUCLEAR POWER PLANT Mad Adorni.

PO W W Echad D hsW 10 CE NT ER ROAD PERRt OHIO 44091 VICE PRESII'ENT NUCLEAR PERR% OHIO 44081 (216) 2 9 3737 November 16, 1992 PY-CEI/NRR-1537 L U. S. Nuclear Regulatory Commission I

Document Control Desk Vashington, D. C. 20555 Perry Nuclear Power Plant Docket No. 50-440 Technical Spec.ification Clyarge Request:

Revisions to the Suppression Pool Makeup Specification to Operate with a Reduced Upper containment Poc1 Vater Lcvel Provided the Suppression Pool Vater Level is Raiced to Compensate Gentlemen:

Elalosed is a request for amendment of Facility Operating License NPF-58 for the Perry Nuclear Power Plant (PNPP) Unit 1. .

This change involves Technical Specification 3.6.3.4, "Suppressica Pool Makeup

'SPMU) System," and allows continued operation with a reduced upper containment pool vater level when the minimum required suppression pool vater level is increased to compensate, thereby allowing for maintenance in portions of the upper containment pool. Changes to the Bases are lacluded f or your information, although not a Ice ml part of the Technical Specifications as desc"ibed in 10 CFR 50.36.

Attachmen: 1 provides the Suiumary, safety Analysis Bases for the SPMU System.

Description of the Cnanges, a listing of the Proposed thanges and the Significant Hazards and Environmental Conciderations. Attachment 2 provides a q copy of the marked-up Technical Specification and Bases peges.

If you have any questions, please feel free to call.

Sincercly, 200043 Y;).dA< ll Michael D. Lyster MDL RAl. ss Attachm9nts cc: NRC Project Manager NRC Resident Inspettor Office NRC Region III State of Ohio bg 9211230C91 921116 j owe 3 cc w s, PDR ADOCK 05000440 g\g c%ew em , er a y p PDR \ )

eemey

- PY-CEI/NRR-1537 L l Attachm2nt 1  !

. Page 1 of 8 l Summan ,

Technical Specificction 3.6.3.4, " Suppression Pool Makaup System," specifies '

the conditions on the upper containment pool (UCP) vater level in Operational Conditions 1, 2, and 3. The s 4yression pool makeup (SPHU) system provides water from the upper containment pool to the suppression pool (SP) by gravity flow throrgh two 100% capacity dump lines following a LOCA. . The suppression pool volume, between the normal lov vater level (LVL) and the minimum post accident vater level, plus the makeup volume added by the UCP following i the UCP dump, is sufficient to account for all conceivable post-accident t

entrapment volumes, ensuring the long-term energy 'nk capabilities of the suppression pool and maintaining the two foot minimum vater coverage over the uppet.nost hori ontal vents. This capability is currently enforced by maintaining the water level within the suppression pool above tM LVL'(through t Specification 3.6.3.1) and maintaining the upper containment pool above its minimum vator level (through Specification 3.6.3.4). Alternatively, the same volume of water could be maintained by reducing the upper containment pool vater level and raising the suppression pool level above the minimum vater level to compensate. This is the primary change proposed by this Amendment Request. Additionally, the requirements for t'.e upper containmsnt pool gate positions have been clarified.

Safety Analysis Bases for the Suppression Pool Hakeup System The suppression pool makeup system is described in Section 6.2.7 of the PNPP Updated Safety Analysis Report.(USAR) and in Technical Specification Bases 3.6.3.4. The purpose of the SPMU system is to maintain the operability of the suppression pool post-accident by providing additional water as needed. The SPHU system consists of two 100% subsystems, where each is capable of dumping the makeup volume from the upper containment pool to the suppression po)1. by aravity flow. TSe makeup volume is based-on the determination of all possible places where water can be trapped after a LOCA and prevented from returning to the suppression pool. Following a LOCA the SPHU system is relied upon to dump the upper containment pool vater to maintain horizontal vent coverage and an l adequate suppression pool heat sink to ensure the primary containment internal

! pressure and temperature stays within design limits. Each dump line includes two normally closed valves in series. The upper containment pool is dumped on a lov-low suppression pool level signal (with a LOCA permissive) to ensure the post-LOCA suppression pool requirements described belov are met. In.eddition, the upper containment pool is also dumped on the basis of a timer to ei are that the makeup volume is available as part of the long. term enorgy sink for small breaks which might not cause a dump on suppression pool lov-lov vater level. A dump initiation time of 30 minutes following a LOCA vas chosen since the initial suppression puol mass is adequate for any sequence of ves,sel blevdown energy and decay heat out to at least 30 minutes.

l For a LOCA, with ECCS injection fror the suppression' pool, a large amount of l vater can be held '.'p in various ont oment volumes, such as; the volume in the dryvell behind the dryvell veir va' the volume required to completely fill the reattor vessel from normal operm ang level to tne top of the steam dome, the volume required to fill the steam lines out to the inboard MSIV for three lines H c1t to the outboard MSIV for one line, and a volume allowance for containment spray hold-up on equipment and structural surfaces. This holdup. "

of water in these entrapment volumes can significantly lover the suppression L

.- 4 PY-CEI/NRR-1537 L Attachtint 1 Page 2 of 8 pool vater level. The vater transfer from the SPHU System ensures a post-LOCA-suppression pool vent coverage of at least 2 feet above the top'of the top row of horizontal vents to prevent direct steam bypass so that long-term steam condensation is maintained. The additional makeup vater is also used as part of the long-term suppression pool heat sink. The SPMU system provides a means for storing and transferring vater from the UCP through a post-LOCA. delayed dump, thereby allowing tha suppression pool vater Jevel to be maintained lover than vould otherwise be the case, providfng an initially-lov vent submergence which results in lower dryvell pressure loadings and lover pool dynamic loadings during the blevdown phase of a LOCA as compared to a higher vent submergence.

The E MU vater solume required to be dumped to the suppression pool is numally established and controlled by: maintaining a minimum water volume above the inlets to the dump lines in the steam separator portion of the upper containment pool, the height of the veir vall betweer. the reactor vell and.

steam separator storage portions of the upper containment pool, and the gate positions between the various areas in the upper containment pool.

Description of the Changej The upper containmant pool vater level is required to be inaintained during Operational Conditions 1, 2, and 3 at a level of 22'-10" above the reactor pressure vessel (RPV) ilange (which is also the elevation of the top of the fuel transfer tube pool vall), in accordance with the Suppression Pool Makeup System Specification (3/4.6.3.4). In order to provide for safe performance of maintenance within the fuel transfer tube pool portion of the upper containment pool ducing plant operation (e.g. for vork on the inclined fuel transfer system (IF'IS)), and for some other situations discussed belov, several modificationa are being proposed to the SPMU Specification. These modifications vould Lully maintain the existing safety function of the SPHU system, by compensating for a reduction in volume of water within the UCP with an equal increase in volume within the suppression pool.

In addition to the desireability of reducin; the UCP level to enhance

, personnel safety for work within the frel transfer tube pool, other situations

vere identified where the ability to operate with a reduced UCP 1 m 1 vould be L

beneficial. For example, in ths. event that the fuel pool conling and cleanup (FPCC) system could not maintain supply to the upper containment pool,-the UCP l

level vould eventually decrease to the level of the bottom of the skimmers 1

-(which is below the Technical Specification UCP limit'of 22'-10"). If the UCP level couli not be restored to at least the Technical Specification limit within four (4) hours (which is a very short duration to fix an inoperable pump or valve - if that was the problem), the plant vould begin the shutdown l

process and be required to be in at least HOT SHUTD0VN vithin the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOVN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Since the function of the upper containment pool as part of the suppression pool makeup system is to provide a source of makeup vater to the suppression pool, the minimum required suppression pool level (volume) could be increased-to compensate for a corresponding reduction in the upper containment pool level (volume).- An Action statement (and corresponding Surveillance Requirement) have been developed to control and implement this redistribution of UCP vater. This redistribution of water meets the overall suppression pool

I i

. PY-CEI/NRR-1537 L  !

- Attcch::nt 1 Page 3 of 8 makeup nystem and suppression pool design bases. .

Consequently, the addition of this new Action provides a significant improvement in plant safety as there is now an alternative to entering the shutdown process when the UCP is slightly below the normel Technical Specification limit. Avoiding a rapid forced shutdown reduces the chances of plant trips, inadvertent scrams or safety system actuations during this complex evolution and reduces the cycling of plant components.

A revised Action statement is proposed, which splits the existing Action 3.6.3.4.b into two sub-parts. Action 3.6.3.4.b.1 vould maintain the present requirement to restore the water level in the upper containment pool to above 22'-10", if the level were to fall below that limit. If the UCP vater level drops below this limit, and cannot be restored within the time required (and no compensatory action is taken as directed by new Action 3.6.3.4.b.2), it is still required that the plant be in the same shutdovn conditions as for the existin:. tetion (be in at least HOT SHUTD0VN vithin the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTOOVN vithin the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />). New Action 3.6.3.4.b.2 allows the upper containment pool vatar level to be reduced provided the requirements of Surveillance Requirement 4.6.3.4.a.1.b are met.

Surveillance Requirement 4.6.3.4.a.l.b specifies that the UCP level may be reduced below the limit of 22'-10", to a level of 22'-5", as long as the suppression pool vater level is raised 2.75 inenes above the minimum suppression pool vater level value determined in Limiting Condition for Operation (LCO) 3.6.3.1.0 to compensate (pages from Specification 3/4.6.3.1 are included for information as part of Attachment 2). If this reduced UCP vater level and increased suppression pool vater level requirement cannot be '

met, the same shutdown conditions as currently exist (described above) are imposed. This new Action maintains the same " effective upper containment-pool water volume" as the current design basis, the difference being that some of this " effective UCP vater volume" has been relocated to the suppression pool as additional volume needeo beyond that required to meet the minimum r suppression pool LVL requirement of LC0 3.6.3.1.a. Therefore, there is no change in the overall volume available for long-term cooling and there vould be no reduction in containment performance. Since the suppression pool high water level value is unchanged, there is no effect on the dryvell pressure loading or pool dynamic loads during a LOCA due to the relocated water.

In order tb assure that the required upper containmer.. pool vater level (volume) is available during times when the UCP level _is reduced to below the normal minimum level, the suppression pool level (volume) is increased and Surveillance Requirement 4.6.3.4.a.1 has been split into two separate

-surveillances to ensure the two separate sets of requirements (those for normal UCP level and those for reduced UCP level with SP compensation) are maintained. Surveillance Requirement 4.6.3.4.a.1.a maintains the present requirement of verifying the water level in the upper containment pool to be 22'-10" above the reactor pressure vessel (RPV) flange. A nev Surveillance Requirement 4.6.3.4.a.1.b has been added to allow the UCP vater level to be reduced to a level of 22'-5" above the RPV flange provided that the minimum suppression pool vater level is verified to be 2.75 inches higher than the level specified in LCO 3.6.3.1.a. These surveillance requirements ensure that.

the same " effective upper containment pool vater volume" is always maintained.

i 7 w- y-- - , - g

• m.i- --

• PY-CE1/NRR-1537 L

• Attechnent 1

. Page 4 of 8 Tne fuel transfer tube pool gate was formerly required to be installed in accordance with Surveillance Requirement 4.6.3.4.b.1, implying that it was needed to restrict the volume of water available to be dumped as part of a SPMU system actuation * , isolating the fue' transfer tube pool from the rest of the upper containment pool). However, the effect of this slight increase in UCP dump volume on the SP'tu system safety analysis had been previously evaluated and was found to be negligible, as described in the following paragraph. The Technical Specifications vere not revised since this engineering evaluation was made late in the initial licensing phase, the Technical Specifications had already been submitted for NRC review, maintaining the minimum required UCP dump volume was the essential parameter for determining SPPJ system operability,_and with the gate installed sufficient UCP volume was available, consequently no Technical Specification changes were required. The Surveillance-Requirement is now being revised since it is convenient to address this issue together vith the other proposed i changes to this Specification. This change clarifies that the fuel transfer tube pool gate is not required to be installed, but may be left in place, if desired, to allow for maintenance of equipmen* Within the fuel transfer-tube ,

pool. Vith the gate installed the same amount of UCP vater is available as 1 was assumed in the current analysis. Also, with the gate lef( installed, and with the upper containment pool level lowered as described above, tests can-be run to ensure that the inclined fuel transfer system is performing properly  ;

several months prior to entering a refueling outage. This provides time to '

effect repairs or order replacement parts priot to an outage. After completion of the IFTS checkout the fuel transfer tube pool gate could be removed in preparation for the upcoming refueling outage. Vith the tuel-transfer tube pool gate removed additional vater vould then be available 'or an upper pool dump which enhances the suppression pool cooling capability. .

The effect of an inadvertent UCP tump on overflow into the dryvell'is minimal, as described below.

The slight increase in UCP volume from removing the fuel transfer tube pool gate, combined with the rare instance of the suppression pool being at its maximum permissible level, could result in a small increase in the amount of water that vould overflow the dryvell veir vall in the event of.the unlikely occurrence of an upper containment pool dump during normal power operation.

However, the minimum freeboard distance above the suppression pool high water level to the top of the dryvdl voir vall is adequate to preclude flooding of the dryvell in most situations, and a LOCA permissive signal is used to prevent an erroneous suppression pool level signal f ro.n caust'g an upper pool dump. Also, as described within Settions 6.2.7.1.1 and 6.2.7.3.3 of the USAR, the occurrence of a bounding overflov (up to ten feet of water in the dryvell) has been previously analyzed, and this analysis has demonstrated that for the piping and components vetted in the event of a dryvell flooding transient under vorst case conditions, no safety concerns would result. This analysis was reviewed and agreed with by the NRC as documented in Section 10.1 of Appendix R to Supplement'8 of the Safety Evaluation Report for Perry (NURr.G-088 7 ) . Therefore, removing the fuel transfer tune pool gate during Operational Conditions 1. 2, and 3, while slightly increasing the available volume of UCP vater, does not present e safety concern regarding dryvell flooding, and provides a positive benefit by providing additional vater to  ;

increase the long-term energy absorption capabilities of the suppression pool following an upper containment pool dump.

a PY-CE1/NRR-1537 L Attech:2nt 1

. Page 5 of 8 Proposed Changes Action 3.6.3.4.b (page 3/4 6-27)

Split the existing Action 3.6.3.4.b into two separate Actions, 3.6.3.4.b.1 and 3.6.3.4.b.2, to provide courses of action to take when the UCP is belov the normal level, including either restoration of the normal level, or increase of the SP level to compensate for the reduced UCP level.

Surveillance Requirement 4.6.3.4.a.1 (page 3/4 6-27)

Split the existing Surveillante Requirement 4.6.3.4.a.1 into two separate Surveillance Requirements, 4.6.3.4.a.l.a and 4.6.3.4.a.l.b, to provide requirements to verify UCP level during normal operating conditions, and to verify both the UCP and SP levels when the UCP is below the normal level.

Surveillance Requirement 4.6.3.4.b.1 (page 3/4 6-23 Revise Surveillance Requirement 4.6.3.4.b.1 to indicate that "all upper containment pool gates are removed (except the fuel transfer pool gate may be installed)."

Bases Change to Section 3/4.6.3 - ['epressurization Systems (Page B 3/4_6-5)

Add a new paragraph as the last paragraph in this section describing how the SP level can be raised to compensate for a reduced UCP level.

Note: If this Techt.ical Specification amendment request is processed after the changes proposed in letter PY-CEI/NRR-1510L are approved and' issued, the value for the UCP vater level vill have been changed from 22'-10" to 22'-9".

Vithin this letter, all references to 22'-10" should then be revised to read 22'-9". The reference to 2.75 inches as the suppression pool _ compensatory-value within this letter, should also be' changed from 2.75 to 2.20 inches.

Vithin the Technical Specification page markups (see Attachment _2)

Surveillance Requirement 4.6.3.4 a.l.a vould_then be revised to read-22'-9",

and Surveillance Regelrecent 4s.6.3.4.o.l.b vould specify a' suppression pool compensatory value of 2.20 inches, 00c i # " ss vater would be assumed to be in the UCP in accordance with the containunt e'sponse analysis presented.in letter PY-CEI/NRR-1510L, but the " effective upper containment pool vater volume" argument used throughout this letter would remain unchanged.

Significant Hazards consideration The standards used to_ arrive at a determinntion that a request for amendment-involves no significant hazards considerations are included in the Commission's' Regulations, 10_CFR 50.92, which state that the operation of the facility'in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident:

previously evaluated, (2) create the possibility of a new or different kind of accident from any previously evaluated, or (3) involve a significant reduction n a margin of safety.

- = . - - . .. . - - - - . -- -

Pf-CEI/NRR-1537 L l

Attachm:nt 1

}

Page 6 of 8 The proposed amendment has been revieved with respect to these three factors and it has been determined that the proposed changes do not involve a significant hazard because:

1. The proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

The function of the upper containment pool (UCP) as part of the suppression pool makeup (SPHU) system is to provide a source of makeup water to the suppression pool (SP), subsequent to the occurrence of a LOCA, in order to maintain the required horizontal vent coverage and provide an adequate suppression pool heat sink to ensure the primary containment internal pressure and temperature stays within design limits.

The proposed Action statement and Surveillance Requirement to permit reductions in the upper containment pool level, maintains the same

" effective upper containment pool vater volume" as the current design basis, the difference being that some of this " effective UCP vater volume" has been relocated to the suppression pool as additional volume needed beyond that required to meet the minimum suporession pool lov vater level requirement of Limiting condition for Operation 3.6.3.1.a. The probability of a LOCA occurring has not increased as a result of the proposed changes since the probability of a LOCA is unaffected by a relocation of the UCP vater. The consequences of a LOCA are also not changed because under normal operating conditions the apper containment pool level is maintained within the required limits by the $1dministrative controls imposed through the SPMU system Technical Specification Action and Sutveillance Requirements. This change simply extends that approach by providing an additional Action and Surveillance Requirement to ensure that both the upper containment pool and suppression pool are maintained within their proposed respective limits (which ensure that the effective UCP vater volume is maintained) when the upper containment pool is below its normal level. The proposed surveillance regt.irement ensures that the same " effective upper containment pool water volume" is alsays maintained.

Therefore, there is no change in the overall water volume available as a heat sink for long-term con 11ng, no reduction in containment performance, and hence no change in consequences for any postulatet LOCA.

There is also no change in the probability of occurrence of an inadvertent SPHU system dump, since no change has been made to the system design or initiating circuitry. This change clarifier that the fuel transfer tube pool gate is not required to be installed, but that it may be left in place, if desired, to allov for maintenance of ,quipment within the fuel transfer tube pool. Vith the gate installed the same amount of UCP vatar is available as was assumed in the current incdvertent dump analysis, therefore there is no change in consequences. With the gate removed there vould be a slight increase in the volume of water contained in the UCP vhich would be dumped in the event of an inadvertent upper containment pool dump. However, there is a very small likelihood of an inadvertent UCP dump due to the necessity to have a LOCA permissive signal in conjunction with a low-lov suppression pool level signal or the completion of a 30-minute time delay. The total volume vould only actually be increased if the dump were to occur when the suppression pool is at its high vater level (vith maximum differential pressure). Even if a UCP dump

PY-CEI/NRR-1537 L Attech::nt 1 Page 7 of 8 vere to occur, a bounding analysis (for up to ten feet of water in the dryvell) for the dryvell piping and components vetted in this event under vorst case conditions has demonstrkted that there vould be no safety concerns. This analysis was reviewed and egreed with by the NRC as documented in Section 10.1 of Appendix R to Supplement 8 of the Safety Evaluation Report for Perry (NUREG-0887). Therefore, removing the fuel transfer tube pool gate during Operational Conditions 1, 2, and 3 does not impose a significant increase in consequences, regarding a dryvell flooding transient, while it does provide a positive benefit in t?at extra vater vould be made available to provide for the long-term energy absorption within the suppression pool.

2. The proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

The proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated because no design changes 7 or new or different modes of operation are proposed for the plant.

2 Operation under the proposed Action statement and Surveillance Requirement (determined to be acceptable on the basis discussed above) does not constitute a different mode of operation since adequate monitoring of both the suppression pool and upper containment pool levels is required by the Technical Specification Surveillance Requirements under both normal and reduced UCP vater level conditions. The required upper containment pool gate positions are also controlled by Surveillance Requirements. The proposed Action statement and Surveillance Requirements on pool levels and gate positions ensure that the same (or greater) " effective upper containmen* pool volume" is available following an UCP dump, which is equivalent to the current design basis, therefore, the proposed changes do not create the possibility of a new or different accident from any previously evaluated.

3. The proposed changes do not involve a significant reduction in a margin of safety.

The design basis of the suppression pool makeup system is to provide 2 makeup volume from the UcP following an UCP dump, that together with the suppression pool volume (between the normal lov vater level (LVL) and the minimum post-accident water level) is sufficient to account for all conceivable post-accident entrapment volumes, to ensure the long-term energy sink capabilities of the suppression pool and maintain the two toot minimum vater coverage over the uppermost horizontal vents. This capability is currently enforced by maintaining the vater level within the suppression pool above the LVL (through Specification 3.6.3.1) and maintaining the upper containment pool above its minimum vater level (through Specification 3.6.3.4). Adding Attion statements and Surveillance Requirements to provide an alternative way of maintaining the same volume of water between the upper containment pool and the suppression pool does not reduce, but rather maintains the same margins of safety, provided that both the suppression pool and the upper containmer pool levels are properly controlled. The water level values chosen, and enforced through :he new Action and Surveillance Requirement meet both sets of requirements and consequent'y do not reduce the margin of safety.

i

_.---_-_-~__.._____m __-

PY-CEI/NRR-1537 1,

• Attachment 1 Page 8 of 8 As described in the answer to question 1, a very unlikely set of circumstances has to occur to initiate an upper containment pool dump, and even if a dump were to occur, a bounding analysis for the dryvell piping and components vetted in this event under vorst case conditions has demonstrated that there vould be no safety concerns. Therefore, removing the fuel transfer tube pool gate during operationni Conditions 1, 2, and 3 does not impose a significant reduction in the margin of safety, regarding a dryvell flooding transient, while it does provide a positive benefit in that extra vater would be made available to provide for the long-term energy absorption within the surpression pool (which vould increara the margin of safety in this respect).

Environmental Consideration The proposed Technical Specification change request was evaluated against the criteria of 10 CFR 51.22 for environmental considerations. As shown above, the proposed change does not involve a significant hazards consideration, nor does it increase the types and amounts of effluents that may be released offsite, nor does it significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, it has been concluded that the proposed Technical Specification change meets the criteria given in 10 CFR 51.22(c)(9) for a categorical exclusion from the requirement for an Environmental Impact Statement.

-- _ _ . . .__ . _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ - . - _ - - _ _ _ _ _ - _ _ - _ _ _ _ ___ _____ _ _ _ _ _ _ _ _ _ _ _