ML20038B851

Forwards Addl Info Re Responses to IE Bulletin 80-06 Re HPCI & Reactor Core Isolation Cooling Sys,Per 811005 Request

ML20038B851
Person / Time
Site:	Browns Ferry
Issue date:	12/04/1981
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	Ippolito T Office of Nuclear Reactor Regulation
References
IEB-80-06, IEB-80-6, NUDOCS 8112090172
Download: ML20038B851 (5)

Text

- _ __

1 TENNESSEE VALL.FY AUTHORITY CH ATTANOOGA. TENNESSEE 374ol 400 Chestnut Street Tower II December 4, 1981 fgm.

Director of Licensing -2 W

' x Attention: Mr. Thomas A. Ippolito, Chief q-! q '

Operating Reactors Branch No. 2 L pf

b_ ,'Id L U.S. Nuclear Regulatory Commission i E -

, Washington, DC '20555 3 DE08 s

1981 d -

pion

Dear Mr. Ippolito:

W5'%dsat .],!

N

) Docket No. 50-259 In the Matter of the

/)is\\,8 Tennessee Valley Authority' ) 50-260 50-296

' Your letter to H. G. Parris dated October 5, 1981 requested that TVA provide additional information regarding our responses to IE j Bulletin 80-06. As discussed with your staf* in a November 9, 1981 telephone conversation, enclosed are our responses to the questions identified in the October 5, 1981 letter.

Very truly yours, TENNESSEE VALLEY AUTHORITY h.crszt

. M. Mills, Manager Nuclear Regulation and Safety J . Subscrib d d sworn to be ce me this day of _1981.

l . ,

Notary Public My Commission Expires Enclosure cc: Mr. D. Hackett (Enclosure)

EG&G, Inc.

P.O. Box 204 /

San Ramon, California 94583-9983 3 1

l l

8112090172 811204*

PDR ADOCK 05000259 G PDR An Equal Opprn turnty Employer

. __ .= _

-1 ENCLOSURE

~

REQUEST FOR ADDITIONAL INFORMATION

. OIE BULLETIN 80-06 L

BROWNS FERRY NUCLEAR PLANT (DOCKET NOS. 50-259, -260, -296) t i I

! T. A. Ippolito's letter to H. G. Parris dated October 5, 1981 requested that TVA provide additional information regarding our responses to the subject bulletin. The specific requests and their responses are as follows.

1. Have all systems serving a safety-related function been reviewed?

Resoonse The review of all systems serving a safety-related system was completed in October 1980 and the results were transmitted by L. M. Mills' letter to J. P. O'Reilly dated December 3, 1980.

2. Provide a schedule for the required testing of all systems serving a safety-related function, or provide the results of the test if it has been completed.

Response

The required testing on unit 1 has been satisfactorily completed.

No additional modifications required by the subject bulletin were identified.

The required testing on unit 2 is scheduled to be performed during the next refueling outage (summer 1982), and the unit 3 testing is scheduled to be performed during the current refueling outage.

3 Concerning the RHR system (Raf: Licensee's letter dated September 10, 1980): Do valvet ?CV-74-53 and FCV-74-67 change

states (go shut) upon reset of an ESF signal? Which ESF signal (s) are involved? What is reset switch 10A-532A7 What do valves FCV-74-53, FCV-74-67, FCV-74-47, and FCV-74-48 control? ,

I

-_ . _ _ _.,m,_ . ,_.-_>_ _._._,_ _ . . _

---,.r... ., .. . _ . , , ,_ , , ,, . , , . . . _ , - - - , _..,y .,, , ,_ , .n.. .

-1

Response

, Valves FCV-74-53 and FCV-74-67 do not change states (go shut) on

. reset of ESF signal. The ESF signals involved are (1) reactor vessel low-water level, (2) reactor low pressure, and (3) no .

auto-close signal. Reset switch 10A-532A should be listed as 10A-S32A and is used to reset the auto-close signal to FCV-74-53 and FCV-74-67. FCV-74-53 is the inboard recirculation injection valve for RHR and LPCI loop I. FCV-74-67 is the same as FCV-74-53 except it is in loop II. FCV-74-47 (outboard) and FCV-74-48 (inboard) are the series isolation valves in the RHR shutdown cooling suction piping from-the reactor vessel.

4. "Concerning the RCIC system (Ref: Licensee's letters dated August 11, 1980 and September 10, 1980): Is the turbine trip solenoid number "XY-71-9" or "XX-71-9?"

Response

The turbine trip solenoid number is XX-71-9.

5. Concerning 480-Volt Load-Shed logic (Ref: Licensee's letter dated January 14, 1981): What are the results of your further-evaluation of the 480-V Load-Shed logic? What loads are retied to the 480-V shutdown boards upon ESF reset?

Response

A detailed analysis was performed by TVA's Division of Engineering Design to determine if the diesel generators could be overloaded upon reset of the ESF signal, resulting in automatic restarting of certain loads whic;1 had been shed previously. The results of the analysis showed that the diesel r,enerators would not be overloaded.

The following loads are retied ' the 480-V shutdown boards upon ESF reset.

1. Reactor water cleanup demineralizer holding pumps 1A and 1B

2. 250-V battery chargers 1, 2A, and 2B 3 Shutdown board room exhaust fan 1A

4. Shutdown board room emergency supply ran 1B

5. Diesel generators A, B, C, and D; Air Compressors A and B

6. Several standby gas treatment loads will restart if the PSF signals are reset in less than 40 seconds after initiation. ,

-1 t

I 6. What is your schedule for modification? Provide a complete,

[ narrative description of the modifications that will or have been implemented. Include a commitment to test the modifications after installation.

Resoonse As a result of our Bulletin 80-06 drawing review, the need for a modification to the traversing incore probe (TIP) was identified.

No additional modifications were identified as a result of testing unit 1. If modifications are deemed necessary after testing units 2 and 3, information concerning modifications will be transmitted at that time.

The emergency mode for the isolation valve associated with the TIP probe tube is closed. However, the isolation valve could change states if the ESF were reset with the system in manual mode and the drive mechanism in forward drive. This condition would only exist approximately once every we?k for a two-hour period.

The addition of a momentary eset switch with latching relay logic is proposed to resolve this concern. The relay would unlatch on containment isolation initiation and prevent energizing of the TIP system withdrawal enable circuits; therefore, the isolation valve wfll remain closed.

This modification is scheduled to be worked in December 1984.

Postmodification testing will be done to ensure the relay functions properly. The TIP guide tubing system is a closed system inside the primary containment. If the TIP ball valves inadvertently opened on ESF reset, the only path for fission products to escape from primary ccntainment by way of the TIP system penetrations would be through damaged TIP tubing. Additionally, most accident events involving fission product release will not allow ESF reset due to a high drywell pressure. We believe the probability of these conditions occurring simultaneously is small enough to justify delay of this modification until 1984.

-l 4_

\

l

' Additional Information The' isolation logic on the high pressure coolant injection (HPCI)

~

and reactor core isolation cooling (RCIC) steam supply isolation valves merits some additional discussion regarding the applicability.

of'IE Bulletin 80-06. Two valves each in the HPCI (FSV-73-2, -3) and RCIC (FSV-71-2, -3) systems do not remain closed on reset of HPCI or RCIC system line isolation signal.

The subject HPCI and RCIC steam supply valves will isolate on a HPCI or RCIC system isolation signal. The valves may be reopened automatically (provided an initiation signal is present) by successfully resetting the original isolation signal using two reset switches. The intent of IE Bulletin 80-06 is met in that the two isolation switches control only these two steam supply valves.

Furthermore, the existing logic arrangement has some advantages in allowing the system to quickly recover from a spurious system

-isolation.

9