05000266/LER-1997-027, :on 970521,non-environmentally Qualified Matl Existed in Containment Hatch Applications.Caused by Inadequate Design Review.Mods Will Be Performed to Remove Existing Teflon Material

:on 970521,non-environmentally Qualified Matl Existed in Containment Hatch Applications.Caused by Inadequate Design Review.Mods Will Be Performed to Remove Existing Teflon Material

ML20148N666
Person / Time
Site:	Point Beach
Issue date:	06/19/1997
From:	Malanowski T WISCONSIN ELECTRIC POWER CO.
To:
Shared Package
ML20148N659	List: 05000266/LER-1997-027, :on 970521,non-environmentally Qualified Matl Existed in Containment Hatch Applications.Caused by Inadequate Design Review.Mods Will Be Performed to Remove Existing Teflon Material
References
LER-97-027, LER-97-27, NUDOCS 9706270353
Download: ML20148N666 (4)

LER-1997-027, on 970521,non-environmentally Qualified Matl Existed in Containment Hatch Applications.Caused by Inadequate Design Review.Mods Will Be Performed to Remove Existing Teflon Material

Event date:
Report date:
2661997027R00 - NRC Website

text

r j

NWC FORM 366 U.S. NUCLEAR REGULATORY CONMISSION APPROVED BY OM8 NO. 3160-0104 (4-95)

EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH I

THIS INFORMATION COLLECTION REQUEST: 50 0 HRS.

REPORTED LESSONS LEARNED ARE INCORPORATED LICENSEE EVENT REPORT (LER)

INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY.

FORWARD COMMENTS REGARDING BURDEN ESTMATE TO THE INFORMATION AND (See reverse for required number of RECORDS MANAGEMENT BRANCH (T-6 F 33).

U.S.

digits / characters for each block)

NUCLEAR REGULATORY COMMISSION, WASHINGTON.

1 DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT j

l FACILITY NAME (1)

DOCKET NUMBER (2)

PAGE (3)

Point Beach Nuclear Plant, Unit 1 05000266 1OF4 I

TITLE (4) 1 NON-ENVIRONMENTALLY QUALIFIED MATERIAL IN CONTAINMENT HATCH APPLICATIONS EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7) 01HER FACILITIES INVOLVED (8) l SEQUENTIAL REVISION FACILITY NAME DOCKET NUMBER l

1 MOPTH DAY YEAR YEAR NUMBER NUMBER MONTH DAY YEAR PBNP Unit 2 05000301 l

l l

FACILITY NAME DOCKET NUMBER l 05 21 97 97 027 --

00 06 19 97 05000 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 4: (Check one or more) (11)

MODE (9)

N l 20.220 m 20.2203aH2Hv) 50.73iaH2Hi) 50.73(a)i2Hvm)

POWER 20.2203(aH1) 20.2203(aH3)h) 50.73(aH2)Di) 50.73(aH2Hx) j LEVEL (10)

OQQ 20.2203(aH2)h) 20.2203(aH3Hn) 50.73(aH2Hm) 73.71 j

i l

20.2203(a)(2)hi) 20 2203(aH4) 50.73(aH2Hiv) oTHER I

20.2203(aH2Hm) 50.36(cH 1)

X 60.73(aH2Hv)

Specifv m Absusci below i

20.2203(a H 2Hiv) 50.36tcH2) 50.73(aH2)(vn) or m NRC Form 366A LICENSEE CONTACT FOR THIS LLR (12) lNAME TELEPHONE NUMBER Unclude Area Code)

Thomas G. Malanowski, Senior Project Engineer (414) 221-3950 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE

CAUSE

SYSTc COMPONENT MANUFACTURER REPORTABLE TO NPROS M

TO NPRDS I

SUPPLEMENTAL REPORT EXPECTED (14) l PECTED U

YEAR l

YES SUBMISSION (if yes, complete EXPECTED SUBMIESION DATE).

X NO DATE (16) t ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewntten lines) (16)

As a result of a review of operating experience information from another utility for applicability to the Point Beach Nuclear Plant, it was determined that the pressure equalizing valves in the containment personnel hatches utilized a Telfon material in various applications which is not qualified for the worst case post-accident radiation environment.

In addition, packing material associated with a small window in the containment hatch doors is also believed to contain Telfon.

Unit 1 is presently being maintained in cold shutdown.

Unit 2 is presently being refuelad.

Under the present conditions, containment integrity is not required for either unit.

The valves and windows will be replaced or modified to replace the Telfon with a suitable material prior to j

containment integrity being required.

WRC FORM 366 14 951 9706270353 970619 PDR ADOCK 05000266 S

PDR i

.---___~.--.--_-__..~n

_~...,. _.. -

. -.. ~

9U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACluTY NAME tu DOCILET NUMBER (2)

LER NUMBER 16)

PAGE (3)

YEAR SEQUENTIAL REVISION l

Point Beach Nuclear Plant, Unit 1 05000266 NUMBER NUMBER 2OF4 j

97 027 00 l

TEXT tu more space is reausres use easirionar copes or ivsc Form :166A) (11)

Event Description

Point Beach Nuclear Plant, Unit 1 is presently being maintained in cold shutdown.. Unit 2 is being refueled.

During review of operating experience information from another utility, it was determined that the pressure equalizing ball valves utilized Telfon in various applications.

This material is not qualified for use in the worst case post-accident radicion environment.

l r

INPO Nuclear Network item OE 8390 reported that the shaft seal assemblies on valves used in the containment access hatch systems at the Ginna Station have Telfon packing.

An evaluation at Ginna concluded that the inner door seals could be subjected to radiation levels that could cause the seal to fail, i

A review of containment personnel hatch design at the Point Beach Nuclear Plant was performed.

It has been determined that the prescure equalizing ball valves used on the upper and lower containment personnel access hatches utilize Telfon in various applications.

The inner valves are shielded from containment by 3/4" steel.

In addition, the outer door on upper personnel access is shielded by a lead bulkhead, reducing the exposure to the outer boundary.

In addition, based upon discussions with the manufacturer it has been determined that there is a high likelihood that the material utilized to seal a small window in the hatch doors also contains Telfon.

The radiation threshold for Telfon is 10E4 to 10E5 rads.

The predicted radiation levels in containment following the design basis loss of coolant accident as documented in the Final Safety Analysis Report are approximately 1.5E8 rads.

The Telfon material is likely to degrade to an unacceptable degree in the post-accident radiation environment.

Degradation of the Telfon material in the existing applications in the post-accident containment radiation environment, could result in a direct pathway for leakage of containment atmosphere to the environment.

Safety Assessment

This condition may impact the ability of the hatches, particularly of thel

tU.S. NUCLEAR REGULATORY COMMISSION l

(4-95) j

~

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION Point Beach Nuclear Plant, Unit 1 05000266 NUMBER NUMBER 3OF4 t

97 027 00 TEXT tit more space os requored, use additional copies of IVRC Forrn 366Al (1 D inner door, to perform their safety function.

The upper hatches are equipped with a lead bulkhead and door which would reduce the radiation exposure to the outer door components.

The lower hatches are not shielded.

Under worst case post-accident conditions, the Telfon material could degrade such that a direct leakage pathway from the containment atmosphere to the environment is created.

Csuse The cause of this event has been determined to be an inadequate original design review in that the environmental conditions were apparently not 1

considered when selecting the Telfon material for use in these applications.

i Component and System Description:

The Point Beach Nuclear Plant primary reactor containment structures are designed and constructed with two containment personnel access hatches.

Each personnel access hatch is a double door (airlock), welded steel assembly.

The airlocks are designed to withstand all containment design conditions with either or both doors locked closed.

Both doors open toward the interior of the containment and are therefore sealed under containment pressure.

The volume between the doors is pressurized to test for leak tightness.

Quick-acting type equalizing valves are provided to connect the personnel lock with the interior and exterior of the containment vessel for the purposes of equalizing pressure when entering or leaving containment.

The doors and valves are interlocked to prevent both doors and/or both valves from being opened simultaneously during periods when containment integrity is required.

The pressure equalizing ball valves are two-inch, full port WKM Dyna Seal valves.

The valves contain Telfon seats, stem gaskets, seat cup, tail piece gasket and pacring.

The containment hatch windows are original construction and were manufactured by Pressure Products Company.

Corrective Actions

l l

l A review was performed of the component instruction manuals, drawings and CHAMPS to identify possible uses of Telfon in PBNP hatches.

The review NriO FORM 366A (4-95)

~~

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

NRC FORM 36TA U.S. NUCLEAR REGULATORY COMMIS$10N (4 95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION i

FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (31 YEAR SEQUENTIAL REVISION Point Beach Nuclear Plant, Unit 1 05000266 NUMBER NUMBER 4OF4 j

97 027 00 i

TEXT tot more space is requeed, use additional copies of NRC form 366A) (1 11 l

found the above use of Telfon.

I Modifications will be performed to remove the existing Telfon material and l

replace it with material qualified for the post-accident radiation i

environmen t.

l Appropriate 1eak rate testing wi11 be performed fal1owing modifications to l

ensure the integrity of the e ntainment boundary.

I i

These actions will be completed prior to establishing conditions that require containment integrity.

A root cause evaluation is being completed.

Additional corrective actions

will be taken as determined appropria to from recommendations contained in l

the root cause evalua tion.

i

Reportability

l This condition is being reported in accordance with 10 CFR

50. 73 (a) (2) (v) (D), "Any event or condition that alone could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident."

l Similar occurrences l

l None.

l EIIS System and Component Identifiers I

Valve, Isolation ISV j

l F