ML20071E128

Forwards Response to Item 87 from Franklin Research Ctr Rept,Per NRC 830111 Safety Evaluation for Environ Qualification of safety-related Electrical Equipment, Justifying Continued Operation

ML20071E128
Person / Time
Site:	Browns Ferry
Issue date:	03/07/1983
From:	Kammer D TENNESSEE VALLEY AUTHORITY
To:	Vassallo D Office of Nuclear Reactor Regulation
References
NUDOCS 8303140036
Download: ML20071E128 (15)

Text

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TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 400 Chestnut Street Tower II March 7, 1983 Director of Licensing Attention: Mr. Domenic B. Vassallo, Chief Operating Reactors Branch No. 2 U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Vassallo:

In the Matter of the ) Docket Nos. 50-259 Tennessee Valley Authority ) 50-260 Please reference your letter to H. G. Parris dated January 11, 1983, subject, " Safety Evaluation for Environmental Qualification of Safety-Related Electrical Equipment" and L. M. Mills' letter to you dated February 28, 1983 Enclosed is our response regarding item 87 (presented in Franklin Research Center's Technical Evaluation Report (TER)) for which justification for continued operation was not previously submitted.

If you have any questions, please call Jim Domer at FTS 858-2725.

Very truly yours, TENNESSEE VALLEY AUTHORITY os M D. S. Kammer Nuclear Engineer Subscribed a sworn to ber e j me th a 7' day o 8/Jd/v 1983 hl e i Notary Public p p My Commission Expires /" "O Enclosure cc: See page 2 hF vL 8303140036 830307 PDR ADOCK 05000259 An Equal Opportunity Employer P PDR x

Mr.-D. B. Vassallo March 7, 1983 cc (Enclosure):

U.S. Nuclear Regulatocy Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30303 Mr. R. J. Clark Browns Ferry Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 i

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. W BRCHNS FERRY UMTS 1 Am 2 1

i Jtistification for Continued Opention

! r TER radrrnent It-orn No. 87 Resolution of Deficiency

'IER item 87 concerns General Electric series 100 modular electrical penetrations in the drywell room O. 'there are three of this type

', penetration in both the unit-1 and unit-2 drywells. The TVA penetration ~

i designations are EA, EF, and EG, for each unit and the penetrations are j used for low voltage power and control circuitry. The deficiencies noted j .in the TER are:

1. - Criteria regarding spray not caticfied (not addressed).

2. Criteria regarding irradiation not satisfied (test irradiation is less than identified by '1VA SCEN sheet for gama and beta plateout not considered.)

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The GE series 100 penetrations have substantial steel junction boxes j  ;

i mounted on the drywell end which encloses and protects all important  ;

penetration parts (seals, pigtails, splices) from any spray impingement.  :~

Furthermore, the penetration pressure seals are low moisture absorbtion epoxy and the crosslinked polyethlene insulated GE vulkene SIS pigtails and

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l Raychem heat shrink tubing are well documented for operation in wet or i submerged conditions, so any minor incursion of spray into_the box that i might occur would have no more effect than condensed steam would.

Prototype series 100 assemblies have been IDCA tested as documented in GE  :

100 Series Electrical Penetrations Low Voltage Qualification Test Report dated January 1974, and the presence of a spray system in the Browns Ferry containnent does not effect the penetration qualification.

E i Although the junction boxes enclose and protect the penetration parts, the boxes and the conduits exiting them are not ' sealed at IDCA pressures. Beta plateout within the box can occur with the integrated 1 year accident beta dose conservatively calculated to be 2.4 X 109 rads.

i j Both the primary and secondary penetration conductor seals are shielded from all beta radiation, including that due'to plateout, by the steel module shell and the conductor transition connection epoxy potting.

Recalculation of the gama dose to the penetration seals taking into account the location of the seals at the outboard end of a relatively long

- nozzle shows the 10-year plus IDCA dose is less than 2.6 X 107 rads .

The seals have been qualified to 5 X 107 rads gama as documented in the

! previously referenced GE test report. Therefore, these penetrations are l qualified to maintain containment integrity before, during, and after a

IOCA after 10 years (minimum) of normal operation, not'40 years as indicated in the original 'IVA 79-OlB Report environmental worksheets.

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2 BROWNS FERRY UNITS 1 and 2 <

I Justification for Continued Operation I

'1he penetration pigtails are GE Vulkene SIS switchboard wire which has been qualified to 6.9 X 10 7 rads gamma by Wyle Laboratories Report 43854-3, Qualification Test Report on Eight Cable Splice Assemblies. Calculations show the total beta and gamma dose, including beta plateout, will not exceed 6.9 X 107 rads until 30 minutes into a LOCA after 10 years (minimum) of normal operation. Althotigh unlikely, it will be assumed that all pigtails can fail 30 minutes into a IOCA and Attachment A is the safety -

evaluation report of this condition.

Since, as indicated in Attachment A, all necessary electrical safety functions can be completed prior to electrical failure and the subsequent failure will not degrade any safety function or mislead the operator, continued operation is justified.

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BPOC.$7 FERRY UUCLEAR PLTRf Units 1 and 2 Failure Analysis

1. Dilur_e Mechanigmt Following a IDCA, the en<rorrnental conditions currounding cable penetrations EA, EF, and EG will be such that the insulation on all cables routed through these penetrations 'could asstrne to be Icst after 30 minutes.

2. Failure MQd21 With a loss of insulation, the cables passing through these penetrations could short together or short to ground in any of mny possible configurations. It is unpossible to predict the final configuration.

3.

The 480V ac, 3 phase power cables for the

.Consmuences of FailvIci valves listed belga pass through these penetrations. The possibility exists, although highly remote and unlikely, that a direct short could occur between an energized 3 phase circuit cnd an unenergized 3 phase circuit in the right sequence (i.e., A phase to A phase or C phase, B phase to B phase, C phase to C phase or A phase), cauaing one or niore of these valves to move from its required closed / opened position to the open/ closed position. It is so unlikely that such a fault could occur that further analysis is not required.

The valves involved are (penetrations are in parentheses):

FCV-68-3 (EF) FCV-68-79 (EA) FCV-74-48 (EA)

FCV-74-78 (EA) FCV-69-1 (EA) FCV-73-2 (EA)

FCV-71-2 (EF)

Also, the folloaing devices havs cables routed through these penetrations and are required to be operational following a IOCA:

FSV-76-61 (EF) FSV-76-59 (EP) TE-64-52C (EF)

Virtually any short circuit condition would defeat the proper operation of these devices.

The folleaing is a summary of the potential 480V power sources which could be shorted:

a. Penetration EG - None of the devices listed has cabling in penetration EG. None of the cabling in penetration EG has any possibility of igncting any device of concern.

b. Penetration EA - Th'e folloaing devices have 480V power ccbles routed through penetration EA:

FCV-68-77 FCV-1-55 Drywell Blowers

MEB '83 0 22 2. 221 .

Page 2 of 2

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Shese devices should not be operated following a IOCA, but could be.

FCV-68-33 Nts cables re;ted through this penetration, but they have been disco nected from their power source. ,

c. Penetration 2 - 480V imer cables for the CRD hoist electrical outlets and the recirculation p.r p heaters are routed through penetration EF, and they are energized at all times following a IDCA. 480V power cables for FW-69-1, FC7-69-3, and drywell bloaer also route through ponctration IF, and could be energized although they shouldn't be.

FCV-60-35 453' power cables routed through penetration EF have been j disconnected from their Imer source.

She drywell srp pumps hwe 480V power cables routed through this penetratio. :.nd are lip.ely to be energized during the 100-day period following a m .

d. General - T ere are no other cables routed through any of these penetrations which could under any circumstance impact the devices of concern, i.e., no contrc;l cables which could, because of a short, cause a 480V power source to be energized.

4. conclusions: Spurious operation of the 3 phase electrically operated motor operated valves due to hot shorts of power circuit cables is considered to be incredible; therefore, these valves can be considered to stay in the post IDCA condition. There is a high probability; however, that the solenoid values and tenperature element will not be operable.

Preparedby:d h Date 1-IY'83 Reviewed by: [w !cBDate A- M- /d/

' Approved by: 8M MN Date ) -/M"f3

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