ML20085L649

AO 50-267/75/9:on 750329,leak in Mechanical Seal of Helium Circulator B Discovered.Caused by Foreign Matl on Sealing Surfaces.No Corrective Actions Planned

ML20085L649
Person / Time
Site:	Fort Saint Vrain
Issue date:	04/07/1975
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
AO-50-267-75-9, NUDOCS 8311020201
Download: ML20085L649 (7)

Text

, -

s

()public Service CompanyQ Cf Odonds

, P. O. Box 361, Platteville, Colorado 80651 April 7, 1975 .

Mr. E. Morris floward, Director APr. Ssl97f Nuclear Regulatory Commission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 REF: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Iloward:

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/75/9, final, submitted per the requirements of the Technical Specifications.

Very truly yours,

\ x\., rl .. e o s. ..

11. Larry Bref Superintendent-Operations Fort St. Vrain Nuclear Generating Station-IILE:il cc: Mr. Angelo Giambusso

~

8311020201 750407 P.DR ADOCK 05000 .

'C.

ry .  : -

)'April-7, 1975^

~ f3 d

ABNORMAL OCCURRENCE REPORT DATE:

OCCURRENCE DATE:

March 29, 1975 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO  !

P. O. BOX 361' PLA'ITEVILLE, COLORADO 80651 REPORT No. 50-267/75/9 Final IDENTIFICATION OF OCCURRENCE:

On Saturday, March 29, 1975, it was noted that there were indications that the This is reportabic mechanieni seal on "B" helium circulator might bc Icaking.3 as an-Abnormal Occurrence per definition 2.1.c of the Fort St. Vrain Technical Specifications.

CONDITIONS PRIOR Routine Shutdown TO OCCURRENCE:

Steady State Power Routine Load Change-Hot Shutdown X Cold Shutdown Other (specify) .

Refueling Shutdown-

~ Routine Startup-The major plant. parameters at the time of the event were as follows:

Rtr. O MWth Power Elect. O MWe Secondary Coolant. Pressure ~ 300 .psig .)

) Condensate pressurG Temperature 85 '- 'F. ) on steam-

) generators Flow- 0 . #/hr. ) .

Pressure- 86 paia-Primary _ Coolant Temperature 133-F. Core Inlet 133' 'F Core Outlet-Flow- 'O- #/Hr..

G g --i_--

s L-- .- -

I

O O race 2 DESCRIPTION OF OCCURRENCE:

"B" circulator van cleared to construction to install blind flanges in the normal hearing water lines to and from the circulator bearing circuitry.

This was required to circulate bearing water around the circula. tor to maintain water cleanliness.

When the normal bearing water inlet flange was loosened, water and gas began blowing from the flange and the pressure decreased very slowly. At the same time the Buffer-Mid buffer indication (local and remote) indicated = 10" positive.

"0".

The flange was tightened up and buffer-mid buffer indications returned to The above occurred at 2100 on 3-29-75.

APPARENT CAUSE OF OCCURRENCE: Design Unusual Service Cond.

Including Environ.

Manufacture Component Failure Installation /Const. X Other (specify)

Operator Procedure The circulator seal is leaking, probably due to some foreign material on the sealing surfaces. l l

ANAINSIS OF OCCURRENCE:

It was determined that the circulator static seals are a primary closure and as such should fall under LCO 4.2.9, which allows a maximum leakage from each circulator of 400 lb/ day of helium at 10 psid. The leak rate has been determined to be = 54.0 lb/ day at 10 paid, the base specified by the Technical Specifications. An abnormal degradation of a primary coolant boundary has occurred but no violation of the Technical Specifications has resulted.

It should be mentioned that during normal operat ion of the helium circulator, this mechanical seal performs no sealing function and therefore no leakage as reported occurro.

Leakage through this seal will only occur if the hellun circulator is removed from service and isolated from the bearing and buffer helium auxiliaries.

' . . ~

- ,~

t

's -)

\-l '

page 3, CORRECTIVE ACTIO;::

No corrective action is planned at this time. If the Icakage rate increases and approaches the Technical Specification limit, mechanical repairs will be undertaken.

FAILURE DATA / .

SIMILIAR REPORTED OCCllRRENCES:

Abnormal Occurrence 50-267/74/10 was a similar leakage problem.

PROGRA?ctATIC IMPACT:

None CODE IMPACT:

None Approved:

Ws -) w-q

11. Larry Brcy ( \

Superintendent-Operations Fort St. Vrain Nuclear Generating Station IlLE:11 6

^

3

,8 O April 7, 1975 Q. ABNORMAL OCCURRENCE g ' REPORT DATE:

~

OCCURRENCE DATE: March 29, 1975 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF. COLORADO

$pg'dl,l$ y P. O. BOX 361 -,

. PLATTEVILLE, COLORADO 80651 l REPORT No. 50-267/75/9 Final-1 IDENTIFICATION OF OCCURRENCE:

On Saturday, March 29, 1975, it was noted that there were indications that the mechanical seal _on_"L" helium circulator _might be leakingy This is reportable as an Abnormal Occurrence per definition 2.1.c of .the Fort St. Vrain Technical Specifications.

CONDITIONS PRIOR Routine Shutdown TO OCCURRENCE: Steady State Power Routine Load Change ~

Hot Shutdown X Cold Shutdown Other (specify)

Refuelius Shutdowa .

Routine Startup The major plant parameters at the time of the event were as follows: .

rs MWth Rtr. O Power Elect. O MWe

~ 300 psig )-

Secondary Coolant Pressure

) Condensate pressurc Temperature

~

85 'F ) on-steam

).

Flow 0 f /hr. ) generators Pressure 86 psia Primary '.cciant Temperature 133 . *F. Core Inlet 133 'F Core _ Outlet

. Flow- 0 ~f/Hr.

O O Pigs 2 gGg"'

DESCRIPTIO" 0F OCCURRENCE:

"B" circulator was cleared to construction to install blind flanges in the normal bearing water lines to and from the circulator bearing circuitry.

This was required to circulate bearing water around the circulator to maintain water cleanliness.

When the normal bearing water inlet flange was loosened, water and gas began blowing from the flange and the pressure decreased very slowly. At the same time the Buffer-Mid buffer indication (local and remote) indicated = 10" positive.

"0".

The flange was tightened up and buffer-mid buffer indications returned to The above occurred at 2100 on 3-29-75.

APPARENT CAUSE OF OCCURRENCE: Design Unusual Service Cond.

Including Environ.

Manufacture Component Failure Installation /Const. X Other (specify)

Operator

. Procedure The circulator seal is leaking, probably due to some foreign material on.

the scaling surfaces.

• ANALYSIS OF OCCURRENCE: .

It was determined that the circulator static seals'are a primary closure and as such should fall under-LCO 4.2.9, which allows a maximum Icakage frem each circulator of 400 lb/ day of helium at 10 psid. The leak rate has been determined to be = 54.0 lb/ day at 10 psid, the base specified by the Technical Specifications. An abnormal degradation of a primary coolant boundary has occurred but no violation of the Technical Specifications'has resulted.

It should be mentioned that during normal operation of the helium circulator, this mechanical seal performs no sealing function and therefore no. leakage as reported occurrs.

Leakage through this seal will only occur if the helium circulator is removed from service and isolated from the bearing and buffer helium auxiliaries.

e 4

~

l O

~

O PIgn 3

[W*

• CORRECTIVE ACTION:

No corrective action is planned at this time. "If the leakage rate increases and approaches the Technical Specification limit, mechanical repairs will be undertaken.

FAILURE DATA /

SIMILIAR REPORTED OCCURRENCES:

Abnormal Occurrence 50-267/74/10 was a similar leakage problem..

PROGRAMMATIC IMPACT:

None CODE IMPACT:

None Approved: .'(._ bbi M

\

H. Larry Brey \

Superintendent-Operations Fort St. Vrain Nuclear Generating Station

, HLB:11

{

e 4