W3P89-3094, Application for Amend to License NPF-38,consisting of Tech Spec Change Request NPF-38-98,revising Control Element Assembly Drop Time Limits for facility.C-E Rept, ...Control Element Assembly Drop Time Tech Spec Change... Encl

Application for Amend to License NPF-38,consisting of Tech Spec Change Request NPF-38-98,revising Control Element Assembly Drop Time Limits for facility.C-E Rept, ...Control Element Assembly Drop Time Tech Spec Change... Encl

ML20245J496
Person / Time
Site:	Waterford
Issue date:	08/14/1989
From:	Dewease J LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20245J501	List: ML20245J503 ML20245J507 W3P89-3094, Application for Amend to License NPF-38,consisting of Tech Spec Change Request NPF-38-98,revising Control Element Assembly Drop Time Limits for facility.C-E Rept, ...Control Element Assembly Drop Time Tech Spec Change... Encl
References
W3P89-3094, NUDOCS 8908180050
Download: ML20245J496 (11)

Text

pgn'wvw tt A

~~ "

L.' - 317 Baronne Street P. O. Box 60340

, New Orleans, LA 70160-0340 f[:'

1 A. Tel. 504 595 2781 J G. Dewease Sonor Vce President-p Nucinar Omnahans W3P89-3094 4 A4.05 I QA August 14, 1898-( W1

'U.S. Nuclear Regulatory Commission

'ATTNs Document Control'besk Washington, D.C. 20555

Subject:

.Waterford 3 SES

' Docket No. 50-382 License No. NPF-38

, Technical Specification Change Request NPF-38-98 Gentlemen:

-Attached for your review and approval is a proposed Technical Specification

' change revising the control element assembly (CEA) drop time limits for Waterford 3. The Technical Specification change supports CEA drop time

' testing during the upcoming refueling outage.

Analyses performed by Combustion Engineering demonstrate that drop time testing acceptance criteria are more correctly based on the average CEA

~ drop time (with limits on the maximum individual CEA drop time) rather than on the drop time of the slowest individual CEA. Combustion Engineering previously presented these analyses to the NRC staff in a meeting held April 6, 1989, at the NRC offices in Rockville, Maryland. The assumptions and methodology of the analyses for Waterford 3 are documented in the attached report, which supports the Technical Specification change request.

Louisiana Power & Light evaluated the proposed change in accordance with

'10CFR50.91(a)(3) and determined that these changes involve no significant

' hazards. The bases for these determinations are included in the enclosed submittal.

LP&L requests your prompt review of this amendment since we currently project a Waterford 3 refueling outage commencing in mid-September 1989 with CEA drop time testing in late October or early November 1989. LP&L is pursuing in parallel a Technical Specification change to increa.se the current limit on'the maximum CEA drop time in the event the NRC is unable to complete a review of this proposal in time to appport the upcoming CEA drop time testing.

000l 8908180050 890814 '

PDR ADOCK 05000382 )

p PDC

=xx

gisy ,77mp pp,i (

• k. ,'

m< r-

^

, lAM' . . . . . . . .

'W3P89-3094.

' Technical Specification Change Request NPF-38-98 "e

, '(Page 2=

in

],

Should .you 'have 'any questions or' camments on this matter. . please feel free

'to contact Steven Farkas at (504) 464-3383.

' Very tiruly yours,

., b

..C IDewease

! e for Vice President- . >

') clear Operations-IJGD/SEF/ssf-

Attachments: NPF-38-98.

cc: . Messrs..R.D. Martin F.J. Hebdon

, - - D.LL Wigginton-

. E.L.- Blake -

W.M. Stevenson.

NRC Resident' Inspectors Office

-Administrator Nuclear Energy Division (State of Louisiana)

'American Nuclear Insurers i

f i

i j l

~_i.__.-.i.___I_

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

)

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-38-98;-

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.

s OlAA EO -

. Me'ase~ '

for Vice President-Nuclear Operations STATE OF LOUISIANA)

) ss PARISH OF ORLEANS )

and r the Parish Subscribedandsworntobeforeme,[aNotaryPubli and State above named this //// day of - 4 ,

1989. //

Lo / P otary PubHc My Commission expires V .

/

~

w __ __ - _ _-__ -___ __. _ _ - _ _ _ _ _ _ _ - _ _ - _ - _ _ - _ _ _ _ _ - _.

1

E. , c j l

DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE NPF-38-98 This. proposal justifies revising Technical Specification 3.1.3.4, "CEA Drop Time."

Existing Specifications l

See Attachment A Proposed Specifications See Attachment B Description The proposed change revises the acceptance criteria in Technical Specification 3.1.3.4, "CEA Drop Time," and the associated Bases. The Technical Specification is revised so that the average drop time of all full length CEA's must be less than or equal to the 3.0 second limit currently applied to each individual CEA. The maximum drop time for any individual full length CEA is changed to 3.2 seconds.

The ACTION statement is modified to apply to both the average drop time and the maximum individual CEA drop time. Bases Section B3/4.1.3 has also been modified to include the average drop time.

The methodology that supports th change has been previously discussed in a meeting with NRC, Combustion Engineering, and several utilities on April 6, 1989.

During May 1988 testing, all Waterford 3 CEAs met the current Technical Specification limit of a 3.0 second maximum drop time. However, due to the increased coil decay time of the current technique, little margin exists between the actual measured drop times of some CEAs and the Technical Specification requirements. The potential exists that cycle-to-cycle variations may cause a small number of CEAs to exceed the specification on maximum CEA drop time by a small amount.

Waterford 3 desires to increase the margin to the Technical Specification requirements to ensure that startup after a refueling outage will not be delayed due to normal CEA drop time variations causing the Technical Specification limit to be exceeded. This is done, consistent with safet.y analyses, using the assumption that all CEAs fall at the average drop time.

1

t 4 The current. analysis method assumes all CEAs drop into the core at the same time and at the same rate following a reactor trip, with the insertion governed by the slowest CEA. Hence, the Technical Specifications currently require that all CEAs fall within 3.0 seconds to 90% insertion.

The proposed change accounts for the fact that all CEAs do not actually drop all at the same rate, but instead there is a distribution of CEA drop times. The proposed change requires the average CEA drop time (to 90%

insertion) to be 3.0 seconds or less.

The reactivity worth of a CEA is a direct function of the neutron flux surrounding the CEA. Thus, the worth of all the CEAs at any time during the trip depends on the average flux level seen by all CEAs. During the

- critical part of the trip, the faster CEAs experience a higher flux and thus mak.e a greater relative contribution to the net negative reactivity insertion than do the slower CEAs. Therefore, the negative reactivity insertion for any reasonable distribution of CEAs is more directly correlated to, and can better be represented by, the average CEA insertion rather than by the slowest CEA insertion. A detailed analysis supporting the use of average CEA drop times is presented in the attached report, "Waterford 3 CEA Drop Time Technical Specification Change Justification."

Combustion Engineering has performed a set of 3D HERMITE space time calculations which are described in the attached report. These calculations show that the negative reactivity insertion due to CEAs falling in a reasonable distribution about the average is at least the same as the negative reactivity insertion due to all CEAs dropping into the core at the average rod drop time. Thus, the current Technical Specification limit of 3.0 seconds for all CEAs can be applied to the average of all CEAs. This change assures the actual reactivity insertion is at least equal to that assumed in accident analyses.

The proposed Technical Specification also establishes a maximum drop time limit of 3.2 seconds for the slowest CEA. This limit provides assurance that the distribu'lon of CEA drop times about the average remains consistent with that assumed in the Combustion Engineering analyses.

The 3D HERMITE calculations are a one-time analysis which demonstrates the average CEA drop time conservatively represents actual CEA drop time l

distributions. For future reloads, the safety analysis methodology will be unchanged from the present methods, except that the CEA drop time will be characterized by the average drop time. Cycle specific reverification is not required as long as the fuel management and CEA drop time characteristics are not significantly changed.

S$b)

I 2

g . _ - ___ _ __ -- -_ - _ _ _ - _ - _ _ _ _ _ _ - _

.s. *

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 consequences of any accident previously evaluated?

Response: No The proposed. change to the CEA drop time requirements have been evaluated for impact on Waterford 3 analyses. Analyses show that assuming the negative reactivity insertion of CEAs falling in a reasonable' distribution about the average is the same as the negative reactivity insertion due to all CEAs dropping into the core at the average rod drop time. -Thus, the change is equivalent to the current acceptance criteria because the required negative reactivity insertion must be attained within the sama 3.0 second limit. Since the negative reactivity insertion during reactor trip assumed in accidert analyses is not adversely impacted by assuming all CEAs drop at the rate of the average CEA, the proposed change will not increase the probability or consequences of an accident previously evaluated.

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 The proposed change does not involve any new or modified structures, systems, or components. Rather, the proposed change affects only an

acceptance criteria for confirming the required reactivity insertion

. performance of the existing CEA hardware. Since the new acceptance criteria preserves the safety analyses reactivity insertion assumptions, the proposed change does not create the possibility of a new or different kind of accident from any 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 margin of safety associated with CEA insertion (maximum reactor trip time) is assumed for each of the analyzed events in the Final Safety Analysis Report. Technical Specification 3.1.3.4 ensures actual plant performance stays bounded by the safety analyses assumptions on CEA drop time. As stated above, the proposed change in the CEA drop time requirement is equivalent to the current requirement and will not have any adverse impact upon safety analyses. Therefore, the margin of safety in the analyses is not reduced.

Safety and Significant Hazards Determination Based on the above Safety Analysis, it is concluded that: (1) the proposed 3

i _ ___ _ _ _ _ _ _ _ _ _ _ _ _ - - _ - _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _

n- 4 change does not'censtitute 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 as described in the hTC Final Environmental. Statement.

i 1

4

^

-\

o ATTACHMENT A l NPF-38-98 1.

T.

i_il__.i__________m___________,. _ _ _ _ _ . _ _ _ _ _ _ ,__ _ - - - - . - _ _ _ . - _ _ _ . . _ _ _ _ . _ _ _ . _ . _ . _ _ _ _ . , _ _ _ , _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

o, .

REACTIVITY CONTROL SYSTEMS p[/M

. CEA DROP TIME LIMITING CONDITION FOR OPERATION 3.1.3.4 from a fully withdrawn position, shall be less than or eq from when the electrical power is interrupted to the CEA drive mechanism until the CEA reaches its 90% insertion position with:

a.

T,yg greater than or equal to 520*F, and b.

All reactor coolant pumps operating.

APPLICABILITY: MODES 1 and 2.

ACTION:

a.

With the drop time of any full length CEA determined to exceed the above limit, restore the CEA drop time to within the above limit prior to proceeding to MODE 1 or 2. -

b.

With the CEA drop times within limits but determined at less than full reactor coolant flow, operation may proceed provided THERMAL POWER is restricted to less than or equal to the maximus THERMAL POWER level allowable for the reactor coolant pump combination operating at the time of CEA drop time determination, {

j SURVEILLANCE REQUIREMENTS 1 4.1.3.4 measurement The CEA priordrop time ofcriticality:

to reactor full-length CEAs shall be demonstrated through a.

For all head, vessel CEAs following each removal and reinsta11ation of the reactor b.

For specifically affected individuals CEAs following any maintenance on or modification to the CEA drive system which could affect the drop time of those specific CEAs, and *

c. At each refueling outage.

l l

I

. i l

WATERFORD - UNIT 3 3/4 1-23 AMEN 0 MENT NO. 7 I

I R,EACTIVI.T%. CONTROL SYSTEMS gKtWAU BASES m MOVA8LE CONTROL ASSEMBLIES (Continued)

CEA positions and OPERABILITY of the CEA position indicators are required' to be verified on a nominal basis of once per-12 hours with more frequent veri-fications required if an automatic monitoring channel is inoperable. These verification frequencies are adequate for assuring that the applicable LCO's

, are satisfied.

The maximum CEA drop time . restriction is consistent with the assumed CEA

. drop time used in the safety analyses.

Measurement with T,yg greater than or equal to 520*F and with all reactor coolant pumps operating ensures that the measured drop times will be representative of insertion times experienced during a reactor trip at operating conditions.

The establishment of LSSS and LCOs requires that the expected long and short-tem behavior of the radial peaking factors be determined. The long term behavior relates to the variation of the steady-state radial peaking factors .

with core burnup and is affected by the amount of CEA insertion assumed, the portion of a burnup cycle over which such insertion is assumed', and the expected power level variation throughout the cycle. The short term behavior ~ relates to transient perturbations to the steady-state radial peaks due to radial xenon redistribution. The magnitudes of such perturbations depend upon the expected use of the CEAs during anticipated power reductions and load maneuvering.

Analyses are performed based on the expected mode of operation of the NSSS (base loaded, or load maneuvering) and from these analyses CEA insertions are determined and a consistent set of radial peaking factors defined. The Long

. Tern Steady State and Short Tern Insertion Limits are determined based upon the assumed mode of operation used in the analyses and provide a means of preserving

. the assumptions on CEA insertions used. The limits specified serve to limit the behavior of the radial peaking factors within the. bounds determined from analy-sis. The actions specified serve to limit the extent of radial xenon redistri-bution effects to those accommodated in the analyses. The Long and Short Term Insertion Limits of Specification 3.1.3.6 are specified for the plant which has been designed for primarily base loaded operation but which has the ability to accommodate a limited' amount of load maneuvering.

The Transient Insertion Limits of Specification 3.1.3.6 and the Shutdown CEA Insertion Limits of Specification 3.1.3.5 ensure that (1) the minimum SHUT-DOWN MARGIN is maintained, and (2) the potential effects of a CEA ejection acci-dent are limited to acceptable levels. Long-term operation at the Transient Insertion Limits is not permitted since sucn operation could have effects on the~ core power distribution which could invalidate assumptions used to determine the behavior of the radial peaking factors. Insertion of Reg. Groups 5 and 6 is permitted to be essentially tip-to-tip within the limits imposed by the Tran-sient Insertion Limit Line. This method of insertion is protected from sequence errors by the Core Protection Calculators.

The Part Length CEA Insertion Limits of Specification 3.1.3.7 ensure that adverse power shapes and rapid local power changes which affect radial peaking g factors and DNB considerations do not occur as a result of a part-length CEA group covering the same axial segment of the fuel assemblies for an extended period of time during operation.

WATERFORD - UNIT 3 8 3/4 1-5 AMENDMENT NO. 12

m. '

s 1 >

4.,-  ;. 4 b

ATTACHMENT B NPF-38-98 l

l l

l l l

l'. ,

l

\

l

- - _ - _ - -