ML20066B578

Proposed Tech Specs,Adding Hydrogen Purge Sys

ML20066B578
Person / Time
Site:	Fort Calhoun
Issue date:	12/20/1990
From:	OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20066B567	List: LIC-90-1009, Forwards Application for Amend to License DPR-40,adding Hydrogen Purge Sys to Tech Specs ML20066B572 ML20066B578
References
NUDOCS 9101080137
Download: ML20066B578 (6)

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9is)1080137 901220 PfiR ADOCK 05000283 P PDR

2.0 LIMITING CONDITIONS FOR OPERATION 2.6 Containment System (Continued)

b. Modification of Minimum Reauirements After the reactor has been made critical, the minimum requirements may be modified to allow either or both of the following statements (i.ii) to be applicable at any one time, if the operability of the component (s) is not restored to meet the minimum requirements within the time specified below, the reactor shall be placed in a hot shutdown condition within six hours.

(i) One of the hydrogen purge fans, VA-80A or VA-8%, with associated valves and piaing may, be inoperable provided the fan is restored to opera)le status within 30 days.

(ii)Thehydrogenpurgefiltersystem,VA-82,maybeinoperable

)rovided the system is restored to operable status within 72 lours.

Basis The reactor coolant system conditions of cold shutdown assure that no steam will be formed and, hence, there would be no pressure buildup in the containment.if the reactor coolant system ruptures. The shutdown margins are selected based on the type of activities that are being carried out.

The refueling boron concentration provides a shutdown margin which precludes criticality under any circumstances. Each CEDM must be tested and some have two CEA's attached.

Regarding internal pressure limitations, the containment design pressure of 60 psi would not be exceeded if the intern of-coo $antaccidentwereasmuchas3psig.f})pressurebeforeamajorloss-The containment integrity will be protected if the visua' check of all " locked closed" manual isolation valves to verify them closed is made-prior to plant start-up after an extended outage where one or more valves could inadvertently be left open. .0peration of the purge isolation valves is prevented during normaloperationsduetothesizeofthevalves(42 inches)andaconcern about-their ability to close against the differential pressure that could result from a-LOCA or MSLB.

The Hydrogen Purge System is required to be operable in order to control thequantit)ofcombustiblegasesincontainmentinapost-LOCA condition. The containment integrity will be 3rotected by ensuring

.the penetration valves VA-280 and VA-289 are "locced closed" while HCV-881 and HCV-882 are normally closed during )ower operation. The applicable surveillance testing requirements of Taale 3-5 will ensure that the system is capable of performing ;its design function. The blowers (VA-80A and VA-808), associated valves, and piping are single failure proof, have been l -designed as a Seismic Class I System, and are redundant to the VA-82 filter header. VA-80A or VA-80B is capable of providing sufficient hydrogen removal capabilities as required by the USAR to prevent-the hydrogen concen ggtion inside of containment from exceeding the 4% flammability limit. / Electrical Equipment qualification was not required as the radiation doses in the area of belowtheminimumrequirements.gHydrogenPurgeSystemequipmentwere Amendment No. 68 2-31 I

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-JUSTIFICATION, DISCUSSION, AND i

NO SIGNIFICANT HAZARDS CONSIDERATIONS i

Justification and Discussion The proposed amendment-to the Technical Specifications.would add a Limiting

-Condition:of-Operation to Section 2.6 Containment System, revise the basis accordingly,_ add surveillance test requirements per Table 3-5 Item 17 for the hydrogenpurgesystem(HPS)andrevisethebasisaccordingly.

.The-Limiting Conditions of 0)eration (LCO) listed in Section 2.6 of the Technical Specification esta)lish the hydrogen purge system configuration in 3 order to meet.the.10CFR50.44 requirements for combustible gas control.

The LC0 lists the minimum requirements for criticality and the modifications of minimum requirements that will be allowed for maintenance and testing activities. The

- containment integrity is protected by ensuring the outside containment L penetration. valves are normally " locked closed" during power operation. The Surveillance Testing, as described below, ensures the system is capable of performing;its post-LOCA hydrogen control function in accordance with the

guidelines-of Regulatory Guide 1.7. The hydrogen purge vstem is designed as a  :'

Seismic' Class:1 system, meeting-the single failure critei j with redundant L blower units with associated valves:and piping to the common header for VA-82 filter.

Should the HEPA or charcoal filters in the VA-82. filter unit become obstructed,

-theiHPS would not maintain purge capability. The filter media is tested under-more! adverse conditions then-have been calculated during the accident to where no_ credible failure mode could be identified. A modification request has been.  !

issued to place a:bypassLline around the filters to ensure full compliance with ,

the-redundancy requirements.

The LC0 conditions will ensure that the 10CFR100 radiological consequences for ,

!the-event are not1 exceeded in a_ post-LOCA situationby maintaining and i verifying the hydrogen purge system as operable.

The amendment is conservative since it adds surveillance test requirements 'or thelhydrogen purge system-to,the Technical Specifications; The'h

. system (HPS)isclassifiedasanEngineeredSafety_ Features-(ESF)ydrogenpurge System in Section 6.1.2.1 of the Fort Calhoun Updated Safety Analysis Report (USAR)'.- As an ESF' system, periodic surveillance tests are requiredcto assure operability of!the system in accordance with the design basis. The HPS is utilized!to Emaintain the hydrogen gas concentration in containment below the 4%

h4 .f.lammability.limitoin accordance'with the design. basis specified in Section

-14.17 Eof 1the USAR. =The surveillance intervals were chosen-based on standard E -technical specif_ication intervals. The HPS was designed and installed prior to the requirements'of-10CFR50.44-and was not required to meet automatic '

e ntainment isolation criteria.

The requirements--toLcycle;all manual valves ensures that when the vaives are required to be repositioned they will operate as required. The manual valves

'have remote operators due to the-potentially high radiation fields in the area Lof the HPS inia post-LOCA: environment. The valves are required to make one complete cycle during each refueling outage.

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,The remotely; operated valves.in'the system are located on the containment penetrations'and are locally-leak rate tested to ensure the. containment

-isolatica function?is maintained. The proposed test also requires the valves

. demonstrate.the; ability to com>lete one cycle of operation from a remote (Al-43)1operatinglocation.- T1is ensures the ability to open and close the  ;

valvesias required to perform a purge of the containment.

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LThe flow through VA-80A or VA-808 is measured to be greater than 80 scfm and less_than 230 scfm. A flow rate greater than 80 scfm will ensure more hydrogen is removed from containment than is being generated during the event. The flow values include instrument: uncertainties. The maximum flow will limit flow to below the flow rate used'in the. design-basis radiological calculations. The

abilities of'the blowers-to provide the minimum flow and maintain the flow for

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a-test period of_10 hours-during refueling serves to demonstrate the  ;

operab.ility.in order to fulfill the se)arate_and redundant requirement. The

' blowers units will take suction from tie containment during the refueling flow test. sDuring power operation the blower units will take suction _from Room 59 i of the Auxiliary Building.in order to reduce the potential for inadvertent

-radiation release and th_e 30 minute test period will verify key operating parametersp The: basis for Sections'2.6 and 3.2 were revised to be consistent with the changes in the Sections due to the addition of the hydrogen purge system. This will verify.that.the offsite doses are less than those calculated in the safety 1 analysis report..

.No Sionificant-Hazards Considerations The proposed amendment'to the Technical-Specifications does.not involve a

=significant hazards consideration because operation of Fort Calhoun Station JUnit'l in accordance with this amendment would not

(1)-  ; Involve a,significant-increaseLin the probability of occurrence or. '

Lconsequences of.an accident or: malfunction of equipment important-to-

safety previously evaluated in the safety. analysis report. The-proposed surveillance. tests wilL be; conducted during refueling

. operations,-in accordanceiwith' approved: procedures, to verify input-assumptions and equipment operation assumed in the safety analysis.

report: remain v'alidgand the hydrogen purge, system is-considered '

o)erable. The' limiting conditions of operation-ensure the abilityLof L .tle hydrogen purge _ system.to meet the requirements of.10CFR50.44 and-L :10CFR100.- Therefore, the proposed change does not increase the-

! probability or._. consequences-of an accident or malfunction of equipment; important to-safety.

L '(2); LCrea'te the: possibility for an accident or malfunction of a' new or-differentJtyperthan previously evaluated in the safety analysis L

1 report. -The proposed change does not physically alter the configuration of-the plant and no new or different mode of operation has-been > implemented. Therefore, the possibility of an accident of a- '

new or different type than previously evaluated in the safety analysis report is not created.

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(3) Involve a significant reduction in the margin of safety as defined in the basis for any Technical Specification. The proposad change maintains the basis of the safety analysis. In addition, the surveillance tests will serve to verify that the margin of safety for the hydrogen purge system is maintained. Therefore, the margin of safety as defined in the basis for the Technical Specifications is not reduced.

Based on the above considerations, OPPD does not believe that this amendment involves a significant hazards consideration as defined by 10CFR50.92 and the proposed changes will not result in a condition which significantly alters the impact of the :tation on the environment. Thus, the proposed changes meet the eligibilitycriteriaforcategoricalexclusionsetforthin10CFR51.22(c)(9) and pursuant to 10CFR51.22(b) no environmental impact or environmental assessment need be prepared.

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