ML20091C008

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Application for Emergency Amend to License DPR-69,to Allow Operation of Unit 2 After Completion of Mods to Containment Spray Sys,Iodine Removal Sys & Containment Cooling Sys.Mods Will Change ESF Actuation Sys Signal That Starts Sys
ML20091C008
Person / Time
Site: Calvert Cliffs Constellation icon.png
Issue date: 03/25/1992
From: Creel G
BALTIMORE GAS & ELECTRIC CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20091C009 List:
References
NUDOCS 9204020234
Download: ML20091C008 (6)
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March 15,1992 U. S. Nuclear Regulatory Commission Washington, DC 2P55 ATTENTION: Document Control Desk SUWECT: Calver? Cliffs Nuclear Power Plant Unit No. 2: Docket No. 50-318 Btquest for EmcIgency License AmendmengEylveillance lleauhrJDals Gentlemen:

llattimore Gas and Electric Company (llG&E) hereby requests an 1;mergency Amendment to its Operating License No. DPR-69 for Calvert Cliffs Unit No. 2, to allow operation of Unit 2 after completion of modifications to the Containment Spray System. the lodine Removal System, and the Containment Cooling System. Dese modifications will change the type of Engineered Safety Features Actuation System (ESFAS) signal that starts these systems. Accordmgly, we request a change to the surveillance requirements which addresses the ESFAS signals to these systems, pursuant to 10 CFR 50.90.

I)ESCHIPTION During the ongoing Electrical Distribution System Functional Inspection (EDSFI), an unusual , and highly improbabic, accident scenario was identified which has the potentiel to adversely impact the operation of our onsite electrical distribution rystem during a loss of offsite power. Specihcally, it could have resulted in greater than expected voltage drops at the Emergency Diesel Generators (EDG), which could have imparted the proper operation of some engineered safety features in the interest of safety, all of the EDGs were declared inoperable and both Units were subsequently shet down. Unit I has cetered a scheduled refueling outage. Modifications are being performed to clitninnte the possibility of an execssive voltage drop at the EDGs. These modifications will result in changes to the ESFAS signals sup, lied to some equipment and will require changes to the .

surveillance requirements for this equ pment.

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i Document Control Deck March 25,1W2

.. Page 2 llACKGHOUNJ)

During accident conditions accompanied by a toss of offsite power, the EDO sequencers will automatically load the EDOs in a controlled manner. The sequencer initielly bk) cts the Safety injection Actuation Signal (SIAS) and Containment Spray Actuation Signal (CSAS) to the equipment to be sequenced and then unbh>cks thesc signals m controlled steps. Engineered Safety features equipment requires two different signals to start; an accident response signal (SIAS, CSAS.

etc.) and a permissive signal fmm the EDO sequencer. His unblocking is the permissive signal from the sequencer, which by itself will not stait the equipment. %c equipment must hase on additional signal (SIAS, CSAS, etc.) to start. Because the loss of coolant incid ent (LOCl) sequencer is ini,iated upon receipt of a SIAS, equipment w hich is also started on a Sl AS signal will receive both signals and i start as soon as the sequencer unblocks it. Ilowever, some equipment does not start upon receipt of l a SIAS and must have an a.iditional signal present to start. Bota the Containment Spray System and I the Containment Cooling System must also receive a CSAS in order to start after the sequencer unblocks it. He lodine Removal System requires a Containment isolation Signal (CIS) to start after l the sequencer unblocks it. These additions'algnals may not be present at the time the SIAS actuates l became of their differem initiation setpoints. %c additional signals add an clement of uncertainty to the acwal start time of this equipment. nis uncertainty couhl lead to a situation whcce equipment which is assumed to start at sequencer step 3 is not started until sequencer step 7, which could lead to the simultaneous starting of the equipment from two different steps. This could cause low voltage conditions in the electn .al distribution system and prevent safety equipment from operating properly.

To climinate the unecriainty associated with the equipment start t ime, a modification is being performed which will change the start signals of the containment spray pumps, the containment cooler fans and the iodine removal units. After the modiGeations are performed, these cornponents will receive their start signals from a SI AS only.

}{JMESTED CllANGE nc Technical Specifications for this equipment specifies which ESFAS signal must be used to test the equipment during refueling intervals. The proposed changes to the Technical Speci0 cations will change the specific signal name to a requirement that the equipment be tested utilizing "the appropriate ESFAS test signal". The affected Technical Specifications are: 4.6.2.1.b.1,4.6.2.1.b.2, 4.6.2.2.b, and 4.6.3.1.d.2.

The Technical Speci0 cation changes being requested are similar for the four affected Technical Specifications. Technical Speci0 cation 4.6.2.1.b.1 and 2 address some of the surveillance requirements for the Containment Spray System. %c Technical Specification requires that, *. . .

cach automatic valve in the now path actuates to its correct position on Safety injection Actuation test signal." We propose to change the Technical Specification to, ". . . each automatic valve la the Dow W ; duates <a fis correct position on the appropriate ESFAS test signal." The containment spc y hwp turycinance currently requires that the spray pump start automatically on a containment

& 'rk. on test signal. Similar wording has been proposed to require that the spray pump start

-auc #n oy on receipt of the appropriate ESFAS test $;gnal. Simi!arly, Technical SpechWon 4.6.2.2.b addresses the start signals required by the contamment cooling units. %c propowd change would replace the specific signal name with the generie wording described above.

Technical Specification 4.6.3.1.d.2 addresses the surveillance testing for the iodine removal units. It L

requires that the Glter trains start upon receipt of a containment isolation test signal. We are ll proposing to change the wording of the surveillance to climinate the reference to a particular ESFAS test signal and s**ute the generic wording proposed above.

Document Control Desk March 25, IW2

, Page 3 FAI tilY AN4lNSISl.lWIIIKMIDE 1he function of the Containment Spray System is to limit the rise in containment atmosphere pressure and temperature after an accident, and thus reduce the possibility of leakage of air mrne radioacthity to the outside environment. As currently designed, the containment spray pumps are started by a CSAS. in prevent an inadvertent actuation of containment spray in the case of an undesired CSAS, the containment spray valves are opened only by a SlAS. 'the modiGeation that will be performed will reverse this arrangement of signals and equipment; the containment spray pumps will start on a SIAS and the containment spray valves will open on a CSAS. The containment pressure setpoint for a CSAS is 4.25 psig, while the pressure setpoint for a SIAS is 2.8 psig. By changing the signals on the containment spray pumps, the containment spray pumps would be started

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at the lower set 1 mint pressure. 1he containment pressure / temperature resp (mse to a Loss of-Coolant Accident (LOCA), as calculated for Updated Final Safety Analysis Report (UFSAR)

Section 14.20 is unchanged by this modification because containment spray is assumed to commence 60 seconds after pressure in the contallment reaches 4.75 psig. 'the opening of the containrnent spray valves on a CSAS enn.res that initiation of containment spray is still tmunded by the UFSAR analyses. The function of the containment spray system is unchanged. Because the start signals for the containment spray pumps and valves have been changed, a change to the surveillance requirements which desenbe the test signals for these components is necessary.

1he function of the containment Air Cooling System is to limit the containment atmosphere pressure and temperature after an accident, and thus reduce the possibility ofleakage of airtorne radioactivity to the outside environment. As currently designed, the air cooler fans receive their low speed start signal from CSAS. Additionally, the semce water outlet valves for the air coolers open upon receipt of a CSAS. A modincation is being performed which will replace the CSAS start signals with a SlAS start signal. Because SIAS is actuated before CSAS on high containment pressure (2.8 psig versus 4.25 psig), the air coolers wuuld start sooner in a pressuritation transient than previously assumed.

1here is no detrimental ciTect to starting the air coolers earlier in a transient and it would have no impact on long term containment response. Because the start signal for the containment air coolers t has been modiGed, a change to the surveillance requirements which address the test signals for the air coolers is necessary.

1hc iodine removal units are designed to collect the iodine which could be released into the containment atmosphere following a postulated accident. 1he fans would start on a CIS in the current design. As in the systems described above, the fan start signalis being changed from a CIS to a SIAS. Although toth CIS and SIAS are actuated at a containment pressure of 2.8 psig, SIAS can also be actuated by a low pressurizer pressure condhion. Ily switching the signal from CIS to SlAS, the iodine removal units might be actuated during an event which did not result in containment pressurization. 1here is no detrimental effect to operating the lodine removal units during a transient in which they might not be needed. The effectiveness of the charcoal is tested after every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation to ensure that they still retain the capacity for iodine removal assumed in the accident analyses. Because the start signal for the iodine removal units has been changed, a change to the surveillance requirement which addresses the test signal for the iodine removal units is necessary.

Other systems are being similarly modified, however, tt.cre is no impact on the Technical Specifications from these additional modiGeations.

Document Control Desk March 25,1992  ;

, Page 4  ;

l DLTERMINK110N OF NQ SIGNIFICANT 1147d}1113 l

This propsed change has been evaluated agalmt the standards in 10 CFR 50.92 and has been '

determined to involve no sigt.ificant haards considerations, in that operation of the facility in accordance with the proposed amendrnent wuu!d not:

1. involve a significant increase in the probability or consequences of an accident previously evaluated;or The changes to the surveillance acquirements associated with the Containment Spray System, the Containment Cooling System and the lodine Reinoval System rencet the changes made to the Engineered Safety Features Actuation System (ESFAS) signals that this equipment receives. The proposed changes will ensure that the equipment continues to be tested in a manner consistent with its safety function by verifying that the equipment resgxmds as required to the a?propriate ESFAS signal. Therefore, there has been no increase in the probabiity or consequences of a previously evaluated accident.
2. crrate the possibility of a new or different type of accidentfrom any accidentpreviously evaluated; or The change in test signal requirements reDects the change made to the ESFAS signals received by the equipment. No new test requirernents have been added, nor have any been deleted.1he equipment will not be tested in a manner different than the existing test requirementt 1herefore, the possibility of a new os different type of accident from any previously evaluated has not been created.
3. involve a significant reduction in a margin ofsafety.

The proposed Technical Specification changes ensure that the affected equipment i will continue to be tested in a manner consistent with its safety function. No additional requirements are being proposed and no existing testing requirements are being rc:noved, Therefore, there is no seduction in the margin of safety assoela9 d with these testing requirements.

STATEMENT OF_131ERGEN_GY CIRC 11MSTANCljj The Technical Specifications, unless amended, would prevent Unit 2 from start!ng up on schedule, ncicfore, we request that this amendment be treated as an emergency change. This situation occurred as the result of our evaluation of the icsponse of the onsite electrical distribution mtem to a specific accident scenario. During that evaluation, we determined that the electricsl distribution system may not have functioned properly, ihus preventing safety equipment from functioning -

properly. In response, we are undertaking improvements to the onsite c!cctrical distribution system so that it would function properly during this specific accident scenario, These modifications will change the actuation signal for several engineered safety features resuhing in a coricsponding change in the Technical Specification surveillance requirements. This situation could not have been avoided because it is based on an unusual and highly improbabic scenario. Application for an amendment was made as soon as possible after the need was identified.

4 Document Control Desk March 25,1992

, . 'Page5 l

Unit 2 is currently in a forced outage to perform improvements to the electrical distribution system.

Following the modifications, the Containment Spray System, the Containment Cooling System and the lodine Removal System will be considered inoperable because of their inability to satisfy Surveillance Requirernents 4.6.2.1.b.1,4.6.2.1.b.2,4.6.2.2.b, and 4.6.3.1.d.2, respectively, railute te satisfy these requirements would prohibit a Mode change.

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sal IslY CON 1M11 TEE REVil3V These proposed changes to the Technical Specifications and our determination of significant hazards

- have been reviewed by our Plant Operations and Safety Review Committee and Off. Site Safety Review Committee, and :y have concluded that implementation of these changes will not result in '

an undue risk to the heak nd safety of the public.

Should you have any questions regarding tHs matter, we will be pleased to discuss them with you.

Very truly nuts, O

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STATE OF MARYLAND t TO WIT COUNTY OF CALVERT t 92, before me, the .ubscriber, a Notary Public of the I hereby State of Maiylandecrtify that on for in and the(42 25th 1ay hurf, L of March,1]4zMG t - appeared George C.

, personally Creel, being duly sworn, and states that he is Vice PresR!cnt of the Baltimore Gas and Electric Company, a corporation of the State of Maryland; that he provides the foregoing response for the 3urposes therein set forth; that the statements made are true and correct to the best of his

. cnowledge,information, and belief; and that he was authoriicd to provide the response on behalf of said Corporation.

W11NE90 my lland and Notarial Seah /. AMM c Notary Public d My Commission Expires: h 1 N Date '? b b

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GCC/ PSF / psf / dim Attachments

4 Document Control Desk March 25, lW2

. Pagc 6 cc: D. A. Isrune, Paquire J. E. Silberg, F2 quire R. A. Capta, NRC D. G. Mcdonald, Jr., NRC T.T. Martin, NRC L 11 Nicholson, NRC R.1. M"'.can. DNR J.11. Walter. PSC M'

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