ML20086E583

AO 74-08:on 740525,water Leakage Discovered Along Reactor Vessel Wall.Caused by Leak on Control Rod Drive Hydraulic Sys Return Line to Reactor Vessel.Engineering Review & Assessment Underway

ML20086E583
Person / Time
Site:	Vermont Yankee
Issue date:	05/28/1974
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086E492	List: ML20086E500 ML20086E576 ML20086E583
References
AO-74-08, AO-74-8, VYV-3284, NUDOCS 8312070430
Download: ML20086E583 (2)

Text

r ,

il O -

O i i

q' s

J VERMONT YANKEE NUCLEAR POWER CORPOR ATION SEVENTY SEVcN OROVC STRCCT 1

Ru rLAND, ht.' TON ~r 03701 VYV-3284 "N*

i ,

I P.O. BOX 157 2

VERNON. VERMONT 05354 i

May 28, 1974 I

~

. /e ,, N 3

Director D,7 b Directorate of Regulatory Operations, Region I I.Q "4 United States Atomic Energy Commission 631 Park Avenue

/2/ djk, y i Q,% ]

t -" -

tt ,

King of Prussia, pennsylvania 19406 0 -

. N.mf

\ .3 e ' . '~.-

r

REFERENCE:

Operating License DPR-28

\o 'e .

4s ,'f.D7. .!

Docket No. 50-271 \p

'./,  %, *.' .. vy . ,cN . C'. '

Abnorical Occurrence No. A0-74-08 (24 IIour Report) J

' @ s ].. RM 4 '

4

Dear Sir:

I As defined by Technical Specifications for the Vermont Yankee n.. cia., v n. <. , scor<nn, coc e 4 nn r, 7 , u. .. vonnve 4 ng no e n n n. . .,3 Abnormal Occurrence as A0-74-08 and confirming our telephone conversaticn with your office on May 26, 1974.

At 1440 on May 25,1974, with the reactor operating at approximately 10% power, plant personnel who were performing corrective maintenance on reactor drywell cooling equipment observed water leakage along the reactor vessel wall. Initial investigation indicated that the source of leakage appeared to be from within the biological shield area. An immediate reactor shutdown and cooldown was initiated in order to define the source of the leakage.

' On May 26, 19 74, a water leak was identified on the Control Rod Drive Ilydraulic Systen return line to the reactor vessel. The Icak was located on a 2 1/2" x 3" stainless steel in-line reducing coupling which connects the cysten piping to N-9 vessel noz:1c " safe end" and was determined to be in the area of the' fusion line on the coupling side of the weld. It was concluded that this condition was in violation of Technical Specifications, Section 1.0.A.5 in that it resulted in abnormal degradation of one of the several boundaries designed to contain radioactive natcrials. , s

.. l!

8312070430 740711 - 9 )I PDR ADOCK 05000271 j i S PDR \. f((( <Ni

. x

! +

~

j pupx zNl' REGju)Cg

e f^\ r.

VERMONT YANKC eUCL. CAR POWER CORPORAT!OP 1

Directorate of Regulatory Operations May 28, 1974 Page 2 The ic:cediate program will include an in-depth engineering review and assessment by the Nuclear Services Division which will appropriately define the cause and establish necessary corrective measures and repair in as timely a fashion as possibic.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION s .

B.W. Riley Plant Superintendent WFC/kbd I

l

• E 44, g J