ML20004F908

From kanterella
Jump to navigation Jump to search
Forwards Revised Response to Draft Power Sys Branch Position 8.3.5 Re Reactor Containment Electrical Penetrations
ML20004F908
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 06/24/1981
From: Colbert W
DETROIT EDISON CO.
To: Kintner L
Office of Nuclear Reactor Regulation
References
EF2-53793, NUDOCS 8106260164
Download: ML20004F908 (3)


Text

-

i .

Deholt M]SCn NY!!U *i" June 24, 1981 _

EF2-53793, Rev. A /IF '

, f).

^ '/ .

\

[ Q 6

. \.3 > 9fY fi

\

Mr. L. L. Kintner V f' Division of Project Management , N\ p/,g - 6 Office of Nuclear Reactor Regulation Q

~U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Reference:

Enrico Fermi Atomic Power Plant Unit #2 NRC Docket No. 50-341

Subject:

PSB Position (8.3.5) -

Reactor Containment Electrical Penetrations

Dear Mr. Kintner:

Please find attached Detroit Edison's revised response to the draf t PSB position (PSB-2) on Reactor Containment Elect 1Acal Penetrations.

Sincerely, 7M f b William F. Colbert Technical Director Enric Fermi Unit #2 RB/w OOl lll

'810 e 2 a o/(s 9' g

8 ,

l[ 4' Juna 22, 1981

~

EF2-53793 Rev. A ATTACHMENT. .

POSITION ON REACTOR CONTAINMENT PRIMARY ELECTRICAL PENETRATION PROTECTION ,

-The. Detroit Edison. Company Fermi 2 Project, .has made a review of the

-Reactor' Containment Primary Electrical. Penetrations. The main objective 0 Lof this' review wassto-determine that the electricalipenetration1

assembliescare designed to withstand, without the;1oss of mechanical integrity, the ' maximum available. fault current versus time ' conditions

~

that could occur,~given single random failures of circuit overload-

. devices-as recommended by Regulatory Guide 1.63, Revision 1.

'" Electrical Penetration Assemblies in Containment Structures for

. Water-Cooled Nuclear Power Plants".

In making the review,'the fol?owing assumption was primary:

-The I 2t characteristics of the penetration conductors as #urnished by Conax Corp. were used as a basis #or determining integrity. It is realized, however, that the I t'2 curves as furnished by Conax Corp.

r -are conservative in nature and that the I E t curve points are not necessarily 1the points of damage to the mechanical integrity of the penetrations.

However,-in our. review, we followed this conservatism, giving additional assurance that-potential-damage ~to the penetration is thereby reduced to nilJif properly protected.

- -The lfollowing positions. are taken by Detroit Edison, based on the results of this review. These positions are in line with the guidelines set forth 'in Regulatory Guide'l.63..

For-low-energy penetrations, maximum fault current does not approach the I 2tsof the penetration conductor;'no, backup or redundant protection is provided.

On;1ow-voltage oower penetrations where maximum fault current versus time will i exceed the I t of the penetration conductor (considering single random failure l- of the primary pcocection) backup protection will be provided by one of the two following methods:

,; 1. cIf adequate backup pratection can be obtained from the feeder

[ . position and the fault can be cleared in sufficient time to

[

prevent reaching the I 2t of the penetration conductor - no L additional ~ redundant protective devices will be provided. ,

I-l' l-I, '

l -

l:

1 1

1.~ .. . _.. ..-4 . _ -. . ;- -; _.~.3- . _ , . - , , . . . _ . . - - , , , , ,-.J._, . . . . . . - . _ . , - - . . - . . . - ,-

~.

1,...

'Juna 22, 1981 EF2-53793 Rev. A

2. Where the feeder position cannot provide adequate clearing time, an additional protective device, fuse or breaker'as necessary, will be provided.

~ There are only two medium voltage power penetrations. These are used for the Reactor Recirculation Pump Motor MG set output from the generator to

- the pump motors. In ?hese cases the primary protection is provided by tripping the main MG set motor drive incoming circuit breaker. positions.

- Backup protection is provided by tripping che generator field breakers.

-Proper relaying assures operati.on of the field breaker.

Loads 'to the primary containment not necessary for reactor operation, i.e.,

lighting and welding will be naintained in a deenergized condition.

.- Although every effort will be made to complete the installation of necessary-redundant devices in time for fuel load, we do commit to completing all such work by. time of the first refueling outage.

9 0

r 5__ _a

_