ML20090M820

From kanterella
Jump to navigation Jump to search
Ro:On 731109,routine Surveillance Test Identified Suppression Chamber to Reactor Bldg Check Valve Dwv 8-1 Not Operating Freely.Caused by Slight Misalignment Between Stuffing Box & Valve Housing
ML20090M820
Person / Time
Site: Monticello Xcel Energy icon.png
Issue date: 11/19/1973
From: Mayer L
NORTHERN STATES POWER CO.
To: Oleary J
US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9105090417
Download: ML20090M820 (3)


Text

.__ . _ _ _ _ _ _ _ _

Regulatory Donet gj;g Ngy NORTHERN STATES POWER COMPANY MIN N E A PO Li e MIN N E SOTA B5409 November 19, 1973 T 7 @ -? ! "' . ' .

. p ,, - - .,

Q'\ '

t

,U .

'l / '

1 D00KETD USMC a

G- 4. 9' ,-'

1 l

f,  ; - '

C. 4k

~ ~.- \..

Mr. J F O' Leary, Director 5

. n,

,md* ' 4 "3 C #

'N ,h.< 21

'*a

.,,,'.7-Directorate of Licensing Office of Regulation f -'1-'"

,,$xg g, ,j t ,,

~ , , .3 . ',.' .Q, % V

~

s.

U S Atomic Energy Comission 0 ,4 ' '

Washington, D C 20545 - -

Dear Mr. O' Leary:

MONTICELLO NUCLEAR GENEPATING PIANT Docket No. 50-263 License No. DPR-22 Malfunction of Suppression Chamber to Reactor Building Primary Containmnt Check Valve A condition occurred at the Monticello Nuclear Generating Plant which we are reporting to your of fice in accordance vitt. Section 6.7.B.1, Abnormal occurrence Reports, of Appendix A, Technical Specifications of Provisional Operating License DPR-22.

On November 9, 1973, a routine surveillance test identified a suppression chamber to reactor building check valve, DWV 8-1, which would not operate freely. The valve is a twenty inch counterbalanced swing check and is mounted in series with an air operated "T" ring sealed butterfly valve.

These valves function to provide both vacuum relief and primary containment isolation. Failure of the check valve to operate freely threatened to render the valve incapable of performing its dual function.

An investigation indicated that the problem was caused by a slight misalign-ment between the stuffing box and the valve housing.

To correct the problem, a 10 mil. cut was taken on the bore of the teflon bushings to provide a greater tolerance for slight misalignments and slight manufacturing errors. A local leak rate test was performed by pressurizing between the vacuum breaker valves, A0 2380 and DWV 8-1. The test results showed the valves to have a combined leakage of 2.89 SCFH as compared to a Technical Specification li2ait of 17.2 SCFH for each valve.

l l

l l 9105090417 731119 PDR ADOCK 05000263 g PDR r)()h / '

s. l

N O R*. ERN STATES POWER CO %NY 2

A similar valve in the redundant vacuum relief line, DW 8-2, was stroked several times at the time of the occurrence and was found to operate freely.

To assure that a similar failure does not occur in the future, weekly exercising of DW 8-1 and DW 8-2 will be conducted until additional con-fidence is established in the reliability of these valves. This is the first incident of this tyre experienced with these valves.

Yours very truly, ha f '

! L 0 Mayer, PE /

Director of Nuclear Support Services LOM/br cc: J G Keppler G Charnoff Minnesota Pollution Control Agency Attn. K D up,an

,a uta a n i nv 4 A v.i t v.t rnnt av t>OCKET MATERIAL (TEMPORARY FORM) CONTROL NOL 8401 b '

FILE:

i FROM: DATE OF DOC DATE REC'D LTR MEMO RPT OTHER Northern States Power Company i,

Minnsapolis, Minnesota 55401 11-19-73 11-23-73 X j L. O. Mayer j To: ORIG CC OTHER SENT AEC PDR X i J. F. O' Leary 1 signed SENT LOCAL PDR X CLASS UNCLASS PROP INFO INFUT NO CYS REC'D DOCKET NO:

XIX 40 50-263 DESCRIFTION: ENCLOSURES:

I Ltr reporting an abnormal occurrence on 11-9-73,

, regarding malfunction of suppression chamber to ACKN0,u,,,w7mGED ..

recctor bldg primary containment check valve to

operate freely.................

l DO NOT RDIOVE PLANT NAME : Monticello 11-23-73 GC FOR ACTION /INFORMATION BUTLER (L) SCIMENCEF(L) -EIDiANN(L) REGAN(E)

] W/ Copies W/ Copies W/ 7 Copies W/ Copies CLARK (L) STOLZ(L) DICKER (E)

W/ Copies W/ Copies W/ Copies W/ Copies

GOLLER(L) VASSALLO(L) KNIGHTON(E)

W/ Copies W/ Copics W/ Copics W/ Copies KNIEL(L) SCHDiEL(L) YOUNGBLOOD(E)

W/ Copies W/ Copies W/ Copies W/ Copies INTERNAL DISTRIBUTION t, REG FI W TECH REVIE'J DC; TON A/T IND l gjETPDR L,HENDRIE GRILLES LIC ASST BRAIDiAN

.X)GC, ROOM P-506A SCHROEDER CAMMILL VT)IGGS (L) SALi'ZMAN t

!UNTZING/ STAFF A1ACCARY KAS7NER GEARIN (L) B. HURT

,)dSE u vKNIGHT BALLARD GOULBOURNE (L) pgg

[ GIAMBUSSO /PAWLICKI SPANGLER LEE (L)

BOYD *d3HA0 MCDONALD MAIGRET (L) DUBE MOORE (L)(INR) A TELLO ENVIRO SERVICE (L)

DEYOUNG(L) (FWR) /HOUS70N MULLER SHEPPARD (E) INFO v5KOVHOLT (L) 410VAK DICKER SMITH (L) C. MILES 4

P. COLLINS JOSS KNIGHTON TEETS (L) y B. KING (RO)

.APPOLITO YOUNGBLOOD WADE (E)

REG OPR /TEDESCO REGAN WILLIAMS (E)

, " FILE & REGION (3) ,/1.,0NG PROJECT LDR WILSON (L)

d MORRIS ,vLAINAS v'STEELE < BENAROYA HARLESS

/VOLIMER Idi EXTERNAL DISTRIFUTION

, s1 - LOCAL PDR Minneapolis. Minn.

i v1 - DTIE(ABERNATHY) (1)(2)(10). NATIONAL LAB'S 1-PDR-SAN /LA/NY s1 - NSIC(BUCHANAN) 1-ASLBP(E/W Bldg,Rm 529) 1-GERALD LELLOUCHE l 1 - ASLB(YORE /SAYRE/ l-W. PENNINGTON, Rm E-201 GT BROOKHAVEN NAT. LAB WOODARD/"H" ST. 1-CONSULTANT' S 1-AGMED(Ruth Gussman)

A6 - CYS ACRS MIXXEX.I SENT TO LIC. ASST. NLWiARK/BLUME/AGBABIAN RM- B-12 7. GT.

11-23-73 DIGCS 1-GERALD ULRIKSON. . . ORNL l-RD.. MULLER..F-309 GT l

l

_ , . - . . - - - -. - - . . - --- - - - . . - -