ML20059L493

Provides Addl Info Re 900713 Tech Spec Change 290 Concerning Hpci/Rcic Steam Line Space Temp Isolations,Per Request

ML20059L493
Person / Time
Site:	Browns Ferry
Issue date:	09/17/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TVA-BFN-TS-111, NUDOCS 9009270056
Download: ML20059L493 (4)

Text

.

[: , j; 4

./ A - *

[e y6 "

a

y. .. > '

ii  : TENNESSEE: VALLEY AUTHORITY ' ,

e , .

P. 0. Box 2000 l Decatur,. Alabama ';

, SEP 171990 .

'i TVA-BEN-TS-111 10 CFR 50.90.

1 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk .i Washington, D.C. 20555~

-Gentlemen:

In the Matter of ) Docket No. 50-260 ,

j Tennessee Valley' Authority )  ;

O l' BROWNS FERRY NUCLEAR PLANT (BFN) - TVA BFN TECHNICAL SPECIFICATION.(TS) NO.

290 HIGH PRESSURE COOLANT. INJECTION-(HPCI)/ REACTOR CORE ISOLATION COOLING

-(RCIC) STEAM LINEl SPACE HIGH TEMPERATURE ISOLATIONS ,

E 4 The subject request for TS change was submitted on July 13,:1990. The- . ,

enclosure provides additional i' ution requested by the NRC staff for the z requested TS change. '

3 There'are no commitments contained in'this submittal.

'.4

.If there are.any questions about this information, please telephone =

fPatrick P. Carier at'(205) 729-3570.

Very truly yours,

, TENNESSEE VALLEY AUTHORIfY -;

e .

i e

• E. G. Wallace, Manager Nuclear Licensing and <

~

Regulatory Affairs cc - 'See page 2 a

9009270056 900917 PDR P ADOCK 05000260 ->

PDC ,

a An Equal Opportunity Employer b

,n

e.

, , i:

81 .. .:

, -U.S. Nuclear Regulatory Commiasion ec.(Enclosure):

'American Nuclear' Insurers Attentions Librarian!

The-Exchange, Suite 245 270 Farmington Avenue Farmington, Connecticut 06032 e

Ms. S. C.-Black, Deputy Director Project Directorate II-4 U.S. Nuclear Regulatory Commission One White Flint, North

-. 11555 Rockville Pike i Rockville, Maryland 20852 Mr. Charles'R. Christopher, Chairman Limestone County Commission P.O. Box 188 Athens, Alabama 35611 Dr. C. E.' Fox State Health Officer State Department of Public Health

" State Office' Building' Montgomery, Alabama 36194

'Mr. J' E.-Jones General Electric Company 735 Broad Street.

Suite 1108 James Building Chattanooga, Tennessee 37402 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12,. Box'637 Athens, Alabama 35609-2r,00 Thierry M. Ross, Project Manager U. S. Nuclear: Regulatory Commissic n i One White Flint, North

~11555 Rockville Pike Rockville, Maryland- 208 Mr. B. A. Wilson, Project Chief U.S. Nuclear Regulatory Commission Region II.

101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

LT,.. <

s ;

!e-ENCLOSURE

. 7, ADDITIONAL INFORMATION REQUESTED BY NRC STAFF - TS 290.

~ Additional Information Reauested-

'(1) >The proposed action statement is: "Within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> restore the inoperable channel (s) to OPERABLE status or place the inoperable-

. channel (s) in the tripped condition." The licensee also proposes to delete the following note in reference to the temperature monitors

" Requires one channel from each' physical location (there are 4

-locations) in.the steam line space." TVA has not provided justification for. changing the action statement and removing the above note. TVA.

should provide the statf with an appropriate justification for these proposed changes to explain their impact on safety.

TVA Response

~

The change to the action statement is proposed to provide a compensatory measure which is consistent with the functional design of the isolation instrumentation and logic. The existing action statement in the BFN TS-requires the function to be repaired in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or the system or component is declared inoperable; The proposed action statement. requires the function (s) to be' repaired within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or place the inoperablo channels in the tripped condition. It is annecessary to declare the-system or component. inoperable since placing the inoperable channel (s) in the tripped condition, restores single-failure tolerance to the isolation function.

Placing the inoperable channel (s) in the tripped condition will create a condition where an additional single failure could prevent the function of the i HPCI or RCIC system. However, neither the HPCI or RCIC systems are themselves' single failure proof. j The deletion of the note is proposed since the existing note does not

- -b

~

accurately describe the design of the HPCI/RCIC High Temperature Isolation- q cInstrumentation. The existing note describes each sensor as a channel. This

~

-is incorrect since the design of the systems provides four channels with each -

channel made up of four sensors. The information in the existing note is revised to correctly describe the makeup of a channel.and-is' relocated to the- ,

bases section.  !

Additional Information Reauested i'

Each channel consists of four temperature monitors-(pump room 1plus three

'(2) l torus areas). The definition of an inoperable channel is not clear.- Is L it the inoperability of any of the four temperature monitors in a given. ,

channel? Furthermore, the proposed action statement does not place a -

time limit on how long an inoperable channel may be placed in the tripped position. It is understood that the tripped position will place j the logic in an appropriate condition to ensure isolation; however, there is the additional concern that protracted operation with the logic in a partially tripped condition will make HPCI and RCIC more vulnerable to spurious isolations. The staff requests TVA to address the above l question and concern.

o'

- T. i . . _

i _

m. Enclosure Page 2 of;2-

['-

LIYf Response LThe proposed bases describes _a channel as follows:

"Each channel contains one temperature switch located in the' pump room and three temperature switches located in the torus area."

-This description is applicable to both HPCI and RCIC instrumentation.

' Application of the' definition of OPERABLE to 'the HPCI/RCIC temperature-switches determines the number of sensors required for the channel to be OPERABLE. It is inappropriate to specifically define in the TS what constitutes an inoperable channel. The TS definition of OPERABLE combined with the description of a channel in the proposed basis provides adequate -

guidance and controls _the OPERABILITY of the involved temperature switches.

The proposed change does not propose to limit the time that an inoperable channel may.be placed in the tripped position. Placing a channel in the tripped position restores the isolation function to a single failure _ tolerant condition. Although-tripping the channel does-result in a condition where a spurious actuation in another channel could prevent the function of the

associated system, this condition is consistent with the' design of the HPCI and RCIC systems since neither of these systems are themselves single failure proof.

Additional Information Reauested (3) TVA addressed spurious actuation as follows: "The setpoints are established above the maximum expected room temperatures to avoid spurious action due to ambient conditions and below the-analytical limits to ensure timely pipe break detection and isolation." TVA's analysis does not_take into account the loss of normal. cooling in monitored areas,= rate of temperature rise, or area temperature alarm setpoints to preclude spurious steam'line supply line isolation. The staff requests.that TVA address these topics.

TVA Resoonse Substantial margin (at least 35' F) exits between the maximum abnormal' temperature expected in each area and the minimuni actuation temperature determined for each temperature switch. The maximum temperature expected

- could occur as a result of outside temperature excursions; temporary, greater

'than' design heat loads; or degraded environmental control system operation.

.With the substantial margin between maximum abnormal-temperatures for the areas and the minimum actuation temperatures of the switches, the maximum abnormal temperatures cannot result in actuation of the switches.

.