NRC-90-0096, Application for Amend to License NPF-43,providing Revised ECCS Response Time Requirements for LPCI Mode of RHR Sys.New Response Time Requirements Reflect Results of Recalculation of Applicable Accident Analysis by GE

Application for Amend to License NPF-43,providing Revised ECCS Response Time Requirements for LPCI Mode of RHR Sys.New Response Time Requirements Reflect Results of Recalculation of Applicable Accident Analysis by GE

ML20058M816
Person / Time
Site:	Fermi
Issue date:	08/01/1990
From:	Orser W DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20058M820	List: ML20058M824 NRC-90-0096, Application for Amend to License NPF-43,providing Revised ECCS Response Time Requirements for LPCI Mode of RHR Sys.New Response Time Requirements Reflect Results of Recalculation of Applicable Accident Analysis by GE
References
CON-NRC-90-0096, CON-NRC-90-96 NUDOCS 9008130077
Download: ML20058M816 (7)

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August 1,1990 NIC-90-0096 U. S. Ibclear Regulatory Ccanmission Attn Docunent Control Desk Washington, D. C. 20555 Peference: Fermi 2 NIC Docket tb. 50-341 NIC License No. If2F-43 Subject Proposed Technical Fpecification Change (License Anendnent) - Frergency Core Cooling Systern Actuation Instrumntation (3/4.3.3)

Pursuant to 10CFR50.90, Detroit Edison Conpany hereby proposes to anend Operating License iPF-43 for the Fermi 2 plant by incorporating the enclosed changes into the Plant Technical Specifications. The proposed change provides revised Energency Core Cooling System (IOCS)

Response Tine requirenents for the Low Pressure Coolant Injection (IPCI) node of the Residual Ihat Penoval (IGIR) system. The new Response Tine'requirenents reflect the results of recalculation of the zpplicable accident analysis by General Electric.

Detroit Edison has evaluated the propoced 'Ibchnical Specifications against the criteria of 10CFR50.92 and determined that no significant hazards consideration is involved. The Fermi 2 Onsite Review Organization han rpproved and the Ibclear Safety Review Group has reviewed the poposcd Tcchnical Specifications ard concurs with the enclos(d determinations. In eccordance with 10CFR50.91, Detroit Fdison has provided a copy of this letter to the State of Michigan.

If you have any questions, please contact Mr. Gordon Nader at (313) 586-4513.

Sincerely, Ihclosure cc A. B. Davis  !

i R. W. DeFayette W. G. Rogers J. F. Stang

- Supervisor, Electric Operators, Michigan '

Public Service Ccuniission - J. Padgett a 9008130077 900801 T hk

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. August _1, 1990 NIC-90-0096 Page 2 I, WILLIAM S. ORSER, do hereby af firm that the foregoing statments are based on facts and circunstances which are true and accurate to the best of my knowledge ard belief.

o WIILIAM S. OTGER Senior Vice President On this /. W f) day of M/#/l> ,1990, before ne personally @peared William S. Olsq/, being first duly sworn and says that he execut(d the foregoing as his free act and detd.

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- . Ub f4C Notary Public ROSt41E A AnUETTA Notory Public, Momoo County, MI WCornrntssion ExphesJan.11,1992 i

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I; hcl'osure to.

NIC-90-0096 Page 1 M G M ETImi Fermi 2 Technical Ebecification 3/4.3.3, Energency Core Cooling System (IOCS) Actuation Instrumentation, requires that IOCS Actuation Instrumentation channels have IOCS Response Tines as shown in Table 3.3.3-3, IOCS Response Tines. Included in Table 3.3.3-3 are response tina requirenents for the low Pressure Coolant Injection (LPCI) node of the Desidual Heat Penoval (PJIR) System.

Specification 1.11 defines IES Pccponse Tine as the tine interval from when the nonitored paraneter reaches the channel setpoint at the sensor until the IOCS equipnent is capable of performing its safety function. Specifically included are the tines involved for any required valve repositioning and energency diesel generator (IDG) starting and loading.

IPCI operation provides protection to the core for the case of a large break Ioss-of Coolant Accident (IOCA) . The protection provided by IPCI also exterds to a anall break LOCA in which systems with high-pressure nd up capability are unable to paintain reactor vessel water level, and i Autonatic Depressurization System has operated to lower the retctot :ssel pressure. The Core Spray System operates independently to achieve the sane objectives. l Plant IOCS response uust be evaluated under a broad spectrum of break  !

sizes and locations. In addition, coincident Loss of Off-site Power '!

(IOSP) and the occurrence of a worst single failure nuot be considercd . The worst case event for tiene events where the IPCI node of RIIR is relied upon is the maxinum large break IOCA (double ended i recirculation line bre,$.) with IOSP and failure of the Division II DC power supply. This event is nost limiting toth in terns of consequences and in terne of time availability for LPCI response.

Tlus, it is clear that the plant analyses need to recurately reflect this event. - The LPCI analysis has been rccently recalculated for the following two reasons ,

l (1) While performing a nodification to enhance LPCI Swing Bus to address a degraded voltage concern (this nodification was the subject of Fermi 2 Licensee Event Pcport 87-045-01, dated Novenber 6,1989), ,

it was determined that a five second tine delay in the reenergization of the LPCI Swing Bus, which is require 3 in sme cccident situations, had not teen specifically accounted for in the tecident analyses.

Please note that an existing analysis at the tine of this rccognition contained enough conservatism to bound the 5 sccond Swing Bus time delay even though it did not specifically consider it. The accident situation which is tpplicable to reenergization of the IPCI Swing Bus is outlined below:

In the event of a break (IOCA) in one of the two retctor '

recirculation system loops, logic is provided to sense the broken l i

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Enclosure to L~ RIC-90-0096 Page 2 loop and to inject full IPCI flow into the unbroken loop from both Divisions of IPCI. Ttus, the flow from the two IPCI divisions are interconnected by valving and dependent on individual valves wlose failure could conpletely inhibit IPCI flow. Since electrical power to each IPCI Division is divisionally separated (Divisions I and II), Fermi 2 has a IPCI Swing Bus arresigenent which permits essential IPCI/ Recirculation system valves that could be disabled.by a failure of a divisional elmtrical supply to be energized by either electrical division. Under IOSP conditions, the Swing Bus is normally reenergized from the Division II IDGs without further tine delay when this power source becones available. However, if this power source is not available because of a single failure, the logic to allow reenergization from the Division I IDGs has an inherent 5 secord tine delay.

Because this 5 secord tine delay was not specifically covercd in the

@plicable analysis of record, Detroit Edison had General Electric j recalculate the ICCS response tine to allow for this additional time 1 delay and to provide for cdditional nargin, as described below.

(2) . The secord reason was to verify that delaying IPCI would not exceed the accident consequences of the nost limiting analysis of record. This provides the technical justification for increasing the proposed IPCI Technical Specification (TS) response tine contained in this proposal. This time response increase is requestcd to prevent unnecessary restrictions on plant operation. Currently Detroit Edison 1 is in fuU vnliance with its IPCI system response TS. However, sme l valve stro;w es, which collectively input into the IPCI System response tine, a very close to their individual limits.

Specifically, tuo current TS IPCI System response Line of 43 seconds is achieved by restricting the naxinum allowable stroke tine of the recirculation punp discharge valves to 32 seconds. UFSAR Section 6.3.2.2.4.1 indicates the stroke tine for these valves is between 27 and 33 sccords. However to neet IPCI response tine we have reduced the upper limit from 33 to 32 secords. Any future increase in response tines could unnecessarily restrict plant operation.

l A recalculation of the applicable analysis for the IPCI node of RHR was perforned delayint IPCI for an a3ditional 12 seconds to specifically account for the lozding tine for reenergization of the IICI Swing Bus, as discussed above, and to justify an increase in the response tine. This revised analysis determined that the consequences of this accident scenario do not exceed the nost limiting analysis of record. The nost limiting analyses of record is asscciated with a IPCI injection valve failure which coupletely disables IPCI flow and thus relies on the Core Spray and High Pressure Coolant Injection Systens for core flooding. 'Iherefore, the purpose of this prcposal is to incorporate the excess nargin afforded by this new analysis to prevent unnecesssary restrictions on plant operation. It six>uld not

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Ehefosure to L 10C-90-0096 i Page 3 be construed that this alditional tir.e would be used for operational justification of excessive equipment degradation. For exanple, the Inservice Testing Program (perforned in accordance with Section XI of .

the A!ME Boiler and Pressure Vessel Code) trends valve stroke tines and has TERABILI'N provisions based on a valve's previous and current ,

stroke times which nust be satisfied. Please note that the added i nergin afforded by the proposed TS could also be utilized if a design change affected the IPCI System response tine (e.g., increasing a '

valve's closing / opening stroke tine) . However, any design change which would' affect tine responses testing criteria would require a safety evaluation in accordance with 10CFR50.59.

EVAIARTI(M i

Detroit Edison htd General Electric recalculate the appropriate ICCS decident response calculations accounting for a longer (by 12 seconds)

IPCI injection tine which conservatively bounds the additional 5 seconds required for the Swing Bus to be reenergized as previously described. This calculation uses an ECCS Evaluation Model in accordance with Ippendix K to 10CFR50 to determine the Peak Cladding Tenperature (PCI) of the repctor fuel. This PCr is conpared to the receptance criteria of 22007 PCT specified in 10CFR50.46(b)(1) .

The previous worst case PCT for events involving the respense of the IPCI node of RHR has increased from less than 18007 to less than 1900 F when evaluated with a new response tine of 55 socords from the ICCA/IOSP event.

However, the nost limiting PCT for the large break IOCA/L0fP still occurs for an event where the IPCI node of RHR does not respond. This "

is the case where a postulated IPCI injection valve failure causes the ,

IPCI node of RHR to conpletely fall. This case is unaffected by the new considerations discusged above and thus the nest limiting PCT renains unchanged at 20847. Further, the new response tine had no >

effect upon the calculational results in regards to the renaining acceptance criteria of 1CCFR50.46(b) because the nost limiting PCT was l

not exceeded.

,. This proposal requests a IPCI Response Tine change from 43 seconds to l 55 seconds.- Detroit Edison does not believe that a single failure has to be assunod when detennining response tine testing acceptance criteria. However, we believe that this situation nust be fully L analyzed to determine its effects, as described above, ard the Technical Specifications should reflect available excess nargin l afforded by the reanalysis to prevent unnecessary restrictions on i plant operations.

ICCS Fesponse Tine Testing requirenents in accordance with Tt.chnical Ebecification Definition 1.11 specify that tines for diesel generator ,

starting ard locding, and velve repositioning nust be considered but L

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• Page 4 does not state that a single failure necds to be considered. Pesponse Tine Testing.is intended to verify the tineliness of ICCS system response under nornal IPCI operation not abnornal operation. Tlus, the proposed tine does not include the 5 seconds required to reenergize the Swing Bus to its alternate post accident power supply l because the single failure which ctuses the Swing Dus to switch is not assuned in the response time testing teceptcoce criteria.

While Detroit Edison does not believe that a single failure is required when determining response tine testing acceptance criteria, we believe that a single failure slould be assuned for the bounding IPCI analysis. LPCI is initiatcd by a high drywell pressure signal or a reactor water level 1 signal. General Electric analyses conservatively assune that the later initiation signal (level 1) initiates IPCI; tius; the reanalysis is based on a conplete failure of of the high drywell pressure signal. This failure delays the initiation of IPCI note than the delay from a single failure which causes the Swing Re transfer and is therefore the bounding failure.

In summary, anple nargir 'I over 300 F remains between the new PCT valug for the IPCI node of RHR and the 10CFR50.46(bl(l) criteria of i 2200 F. Additionally, the nost limiting PCT (20847) for the event of concern remaina unchanged. For these retsons, Detroit Edison believes the proposed change to be recepttble.

SIGEFICM@ HMN06 CGEIDEEM10N In accordance with 10CFR50.52, Detroit Edison has made a deteunination that the proposed anondnent involves no significant hazards considerations. To make this determination, Detroit D31 son nust establish that operation in tccordance with the proposed anendnent would not: 1) involve a significant increase in the probability or consequences of an tecident previously evaluated, or 2) create the possibility of a new or different kind of accident from any cccident previously evaluated, or 3) involve a significant reduction in a nargin of safety.

The proposal change to the Pesponse Tine criteria of Technical Specification Table 3.3.3-3 for the Iow Pressure Coolant Injection (IPCI) of the Ecsidual Heat Renova! (RHR) System does not:

1) Involve a significant increase in the probability or consequences of an accident previously evaluated. The naxinum Pet.k Cla3 ding Tenperature (PCT) for cases where the IPCI node of RHR respords when calculated using an ECCS Evaluation Model in (qcordance with Appendix )* of 10CFR50 increases from less than 18007 to less than 19007. The nost limiting PCT of 20847 renains unchanged since the nost limiting case remains one where the IPCI node is assunw.d to conpletely fail. Since adequgte nargin to the 10CFR50.46(b)(1) PCT tcceptance criteria of 2200 F exists and

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Ehclosure to hlC-90-0096 Page 5 the results regarding the reaaining criteria of 10CFR50.46(b) are unchanged, the consequences of previously evaluated accidents are not significantly increased. The change does not affect the nanner of plant operation or involve a plant nodification and

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• therefore does not affect the prcbability of any previously b evaluated accident.

2) Create the possibility of a new or different kind of recident from any tecident previously evaluattJ. The proposed change does not alter the nenner of plant operation or involve a plant nodification. Rather, the change reflects a reevaluation of the plant ICCS perfornance using a revised response tine for the LPCI node of RHR. Therefore, the change ; involves no new tecident ncdes.

3) Involve a significant reduction in a nargin of safety. Since tim nost limiting PCT rennins unchanged, the proposal does not involve a rMuction in the nargin of safety. Additionally,.the proposed change does not alter the nanner of plant operation or involve a physical nodification to the plant.

hed on the above, Detroit Fdison has determined that the proposed amendnent does not involve a significant hazards consideration.

1 ENVIIGREMRL II@ACT

' Detroit Edison has reviewed the proposed Technical Specification changes against the criteria of 10CFR51.22 for environnental considerations. The proposed change does not involve a significant hazards consideration, nor significantly change the types or significantly increase the anounts of effluents that nay be released offsite, nor significantly increase individual or cunulative occupational rcdiation exposures. Dased on the foregoing, Detroit R11 son concludes that the proposed Technical Specifications do neet the criteria given in UR51.22(c) (9) for a categorical exclusion j from the requirenents , I an Dwironnental Inpact Statenent.  ;

mg i Based on the evaluation above: 1) there is reasonable assurance that i the health and safety of the public will not be endangered by  ;

operation in the proposd manner, ard 2) such activities will be conducted in conpliance with the Cmmission's regulations and proposed anendnents will not be inimical to the conmon defense and security or to the health and safety of the public.

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