W3P89-1544, Application for Amend to License NPF-38,revising Tech Spec 3.1.2.9 Re Boron Dilution

Application for Amend to License NPF-38,revising Tech Spec 3.1.2.9 Re Boron Dilution

ML20248H195
Person / Time
Site:	Waterford
Issue date:	10/05/1989
From:	Dewease J LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20248H198	List: ML20248H199 W3P89-1544, Application for Amend to License NPF-38,revising Tech Spec 3.1.2.9 Re Boron Dilution
References
W3P89-1544, NUDOCS 8910110209
Download: ML20248H195 (7)

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Louistna Power & Light Company '.

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J 317 Baronne Streat -

P O. Box 60340 New Orleans LA 70160-0340 Tel 504 595 2781 E,,

. J. G. Dewease Senior Vice President-Nuclear Opuatons M

- W3P89-1544 A4.05 0ctober 5, '1989 .QA U.S.; Nuclear-Regulatory Commis'sion ATTN: : Document Control Desk Washington, D.C. 20555~ .

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.Subj ect : Waterford 3 SES Docket No. 50-382 License ~No. NPF-38-101'

' Technical Specification 3.1.2.9: Boron Dilution Gentlemen:

This document justifies a revision ~ to Technical Specification 3.1.2.9:

' Boron Dilution. LP&L uncovered a conflict between this LCO and LCO 3.1.2.4: Charging Pumps -- Operating.

On September.22', 1989, . a power descent began at Waterford 3 to prepare for

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j a refueling' outage. On November 15, 1989, Waterford 3 is scheduled to enter Mode-2.. The conflict in the technical specifications will prohibit entering Mode 2 by diluting RCS boron concentration. Therefore, LP&L would greatly appreciate an expedited review of this submittal'.

'Should you have any questions or comments on this matter, please feel free to contact' Steven Farkas at (504) 464-3383.

Very.truly yours, t . l

-Jy/j} ewease OO enior Vice President -

.4qdelear Opr.ations JGD/SEF/pi Attachments: NPF-38-101 2

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Messrs. R.D. Martin F.J. Hebdon D.L. Wigginton E.L. Blake I

W.M. Stevenson NRC Resident Inspectors Office g$f

. Administrator Nuclear Energy Division (State of Louisiana)

American Nuclear Insurers l'

\ l 8910110209'891005 PDR ADOCK 05000382 P PDC

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the matter of )

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Louisiana Power & Light Company ) Docket No. 50-382 Waterford 3 Steam Electric Station )

AFFIDAVIT J,G. Dewease, being duly sworn, hereby deposes and says that he is Senior Vice President - Nuclear Operations of Louisiana Power & Light Company; that he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached Technical Specification Change Request NPF-38-101; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.

A _M[bLbs '

g,'d. Deweas.e Senior Vice President-Nuclear Operations 1

STATE OF LOUISIANA)

) ss PARISH OF ORLEANS )

Subscribed and sworn to before me, a Notary Public and or the Parish and State above named this $~M day of ,

1989.

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% 1W E otary Public My Commission expires ,.

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i u DESCRIPTION AND SAFETY ANALYSIS ,

! 0F PROPOSED CHANGE This ' document justifies a revision to Technical Specification '3.1.2.9:

Boron Dilution. LP&L uncovered a conflict between this LCO and LCO 3.1.2.4: Charging Pumps -- Operating. Under one reading of the current

-technical specifications, upon attempting to achieve criticality by:

deborating.the RCS, Waterford cannot change from MODE 3 into MODE 2.

f-Existing Specifications l-See Attachment A I '

Proposed Specifications See. Attachment B Description Specification 3/4.1.2.9 ensures sufficient time exists'to prevent a loss of.

shutdown margin should an inadvertent boron dilution event occur.

Amendment 48, on this same subject, accommodated a new boron dilution analysis that assumed more restrictive water volumes while in MODE 4 and MODE 5 because of the potential for reactor coolant system flow stagnation 3 in these MODES. The stagnation reduces the amount of mixing occurring during normal opcrations.

The LCO gives operators time to respond to a boron dilution event.

Standard Review Plan 15.4.6: Chemical and Volume Control System Malfunction that Results in a Decrease in Boron Concentration in the Reactor Coolant -- lists different operator response times for different MODES. Thirty minutes is allowed in MODE 6. While in MODES 5 through 3, the standard allows 15 minutes.

Under normal conditions, two measures precluding boron dilution events are acceptable. First, have two OPERABLE boron dilution alarms (with additional precautions while in MODES 4 through 6 because of the reactor coolant flow stagnation potential). Or second, isolate the primary (cican) water makeup to the reactor coolant system (with additional precautions from Tables 3.1-1 through 3.1-5 because of the reactor coolant flow stagnation potential).

The revised boron dilution analysis shows possible MODE 4 and MODE 5 situations when zero flow might exist in either one, or both steam generators. The condition may occur when, during a reactor coolant system cool down while on shutdown cooling, the steam generator secondary side temperature becomes higher than reactor coolant temperature. In this scenario, flow through a steam generator changes from forward flow to reverse flow and thus, for a short time no flow exists. Another scenario ,

I occurs near the end of a long outage. Then, core decay heat levels are low and may be unable to provide sufficient driving head to move water through the steam generators. In both cases, the effective reactor coolant >

available for mixing decreases by the amount in the steam generators. The above concerns do not apply if one or more reactor coolant pumps are I

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'W3P89'1544 l-A4.05 l

I' operating. Note, the reactor coolant pumps are not safety-related and cannot be relied on to fulfill any safety function, e.g., preventing boron dilution. Amendment 48 ensures compliance with the times given in the standard review plan -- times within which the operator must act to prevent loss of SHUTDOWN NARGIN.

When the boron dilution alarms do not work and primary water makeup cannot be isolated, ACTION statements and Tables 3.1-1 through 3.1-5 provide

' alternative measures. With one or more boron dilution alarms inoperable.

l measuring boron concentration requires taking a reactor coolant sample.

Instead of the immediacy of the boron dilution alarm, operators must wait up to 30 minutes (laboratory work time) before they know corrective action is necessary. The 30 minute sample time with one or more boron dilution alarms inoperable then needs to be added to the standard review plan times

-(re SRP 15.4.6). Tables 3.1-1 through 3.1-5 give the sampling frequency when operators rely on reactor coolant samples to determine if a boron dilution event started.

NPF-38-76, sent to the NRC on March 25, 1988, proposed specific boron dilution LCOs when the plant operated in MODES 4 through 6 with both boron dilution alarms OPERABLE. During later discussions leading to Amendment 48, the specific LCOs were replaced by a call-out to Table 3.1-1 through 3.1-5. The tables were the samt or more conservative than the words originally proposed under 3.1.2.9.b. The tables prohibit certain charging

' pump combinations under various k situations, becoming more restrictive (i.e.,fewerchargingpumpsallow$btobeOPERABLE)ask,ff increases.

Those tables restrict the maximum amount of primary water makeup possible.

The call-out to the Tables 3.1-1 through 3.1-5 moved them into the realm of the LCO, rather than the exclusive realm of the ACTIONS. Unconditionally adding these tables to LCO 3.1.2.9 causes a conflict with LCO 3.1.2.4 which requires at least two independent OPERABLE charging pumps while in MODES 1 through 4. Table 3.1-1 and 3.1-2 prohibit LCO 3.1.2.4 from being fulfilled while in MODES 3 and 4 if k were high enough. The problem is acute when bringinganewcorecriticafforthefirsttime, f

i.e., a high k while slowly moving from MODS 3 to MODE 2. Theattempttosimplify3?ff2.9.b inadvertently caused a conflict with 3.1.2.4.

LP&L proposes to reword the LCO to clarify the logical "and" and "or" presently there. The proposed change installs the proper restrictions on the number of charging pumps assuming the boron dilution alarms are OPERABLE. Specifically, the addition to 3.1.2.9.a does not mention MODE 3.

The result is that during MODE 3, either two boron dilution alarms are OPERABLE or operators isolate the primary water makeup path and follow restrictions on Tables 3.1-1 through 3.1-5. Lacking either condition, operators would enter the applicable ACTION statement. For example, while in MODE 4, if an operator chooses to comply with LCO 3.1.2.9 by isolating primary water makeup, the operator must also keep the plant out of the 2

!W3P89'-1544 A4.05' l

configurations en Tables 3.1-1 through 3.1-5. The revised LCOs give double j assurance against a boron. dilution event that could reduce shutdown margin before an operator can act. This re-wording of 3.1.2.9 ends the conflict with 3.1.2.4. The shutdown CEAs withdrawn 145 inches can insert enough negative reactivity to overcome any boron dilution event.

Safety Analysis The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any of the following areas:

1. Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequence of any accident previously evaluated?

i Response: No FSAR 15.4.1.5 summarizes the boron dilution event. A boron dilution event is a moderate frequency incident. Here LP&L assumes a chemical and volume control system malfunction allowing unborated water to enter the reactor coolant system at the maximum possible rate. For this to occur, one or more charging pumps must be operating, the primary water makeup water pumps must be opera:1ng, and the demineralized water supply system must be aligned to supply water to the charging pump suction via the volume control tank. Because at least three simultaneous equipment malfunctions would be needed to produce the above conditions, the incident could only be the result of improper operator action accompanied by a single equipment malfunction. The proposed change to Specification 3/4.1.2.9 continues to ensure the probability of a sustained or erroneous dilution event is very low.

The proposed change will continue to ensure that enough time exists to l prevent a total loss of SHUTD0k'N MARGIN should an inadvertent boron dilution event occur. The proposed LCO 3.1.2.9 follows recommendations based on Combustion Engineering analyses of Waterfard 3 boron dilution events. The boron dilution event probability remains as conservatively low as currently analyzed in the FSAR for both Cycle 3 and Cycle 4.

Therefore, the proposed change will not involve a significant increase in the probability or consequences of any accident previously evaluated.

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[ A4.05 2.- Will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No This proposal does not involve a physical change to plant systems, structures, or components. Nor will it affect how any safety-related equipment mitigates anticipated operational occurrences or accidents.

It does ensure enough time exists to prevent a total loss of SHUTDOWN MARGIN should an inadvertent boron dilution event occur.

Therefore, the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?

Response: No The plant safety margins come from limiting conditions for operation, limiting safety system settings, and safety limits presently given in the technical specifications. LCO 3.1.2.9 ensures enough time exists to prevent a loss of~ SHUTDOWN MARGIN should an inadvertent boron dilution event occur. The proposed change ensures operators have (1) recognize a decrease in boron concentrat1on and

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enough time tot (2) take appropriate corrective action without total loss of SHUTDOWN MARGIN.

The proposed 3.1.2.9 reduces conservatism in the current 3.1.2.9 which, under certain readings, could make reactor startup a technical specification violation. Amendment 48 to Waterford's technical specifications over-sirplified the precautions to take during MODE 3 and 4. This request asks the NRC to reconsider Amendment 48, to correct an unintended error. This proposal correctly implements the recommendations in Waterford's bgron dilution event analysis. The analysis applies to both Cycle 3 and Cycle 4.

l Therefore, the proposed change will not involve a significant reduction in a margin of safety.

l Safety and Significant Hazards Determination Based on the above Safety Analysis, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92; and (2) there is a reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment an described in the NRC Final Environmental Statement.

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I ATTACHMENT A I

NPF-38-101 i

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