ML20088A564

Final Deficiency Rept U-72 Re Penetration Seal Installation & Insp.Initially Reported on 840313.Reinsp & Necessary Repairs Will Be Completed by 840422 on All Silicone foam-filled Wall & Floor Penetrations

ML20088A564
Person / Time
Site:	Callaway
Issue date:	04/04/1984
From:	Schnell D UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
U-72, ULNRC-786, NUDOCS 8404120216
Download: ML20088A564 (2)

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3mb UNION ELECTRIC COMPANY 1901 GRATIOT STREET ST. Louts. MissOURS DOAALD F. SCHNELL vsca ensaiosNT d ( 4 h84 50 9 8 ST. LOUIS, WSSOURI SalGG Mr. James G. Keppler Regional Administrator USNRC Region III 799 Roosevelt Road Glen Ellyn, IL 60137 ULNRC- 78 6

Dear Mr. Keppler:

FINAL 10CFR50. 55 (e) REPORT U-72 PENETRATION SEAL INSTALLATION AND INSPECTION CALLAWAY PLANT On March 13, 1984, Union Electric informed the NRC Region i III of a potential significant deficiency under 10CFR50.55(e) regarding silicone foam penetration seals. The deficiency 3 involves three hour fire rated floor and wall penetration seals constructed of Dow Corning 3-6548 silicone RTV foam by B&B Insulation. Penetration seals are one of the components governed i by the Union Electric Fire Protection QA Program. Deficiencies

in these seals could prevent the Fire Protection design from

meeting its design function. A Union Electric audit of B&B Insulation inspection and installation methods revealed the following inadequacies.

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1. Floor penetration seals were found to have gaps or separations between the foam and the penetrating items and/or penetration liner. The occurrence of gaps (beyond the design criteria) after acceptance

can be attributed to normal shrinkage due to curing, temperature related expansion and contraction of the foam, or misinterpretation.of the inspection requirements. To prevent this from recurring, .

the time allowed for curing has been extended from one to seven days, an additional sealing caulk has been applied at the seal interface, and the

inspectors have been retrained.

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2. Penetration seal depths were less.than the design criteria due to inadequate inspection methods and in some cases insufficient allowance for shrinkage.

i Inspection methods utilized failed to assure com- I pliance with the minimum seal depth criteria. To I assure proper depth, installers have been instructed I on the proper method for ensuring adequate depth l prior to installing silicone foam material. T.he penetrations are being slightly overfilled to allow -

for any shrinkage due to curing and the inspectors g have been instructed on an appropriate method of ghF)]

verifving seal depth.

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840412O216 840404 APR 61984 PDR ADOCK 05000483 S PDR ff$

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Mr. Jakes G. Keppler  ;

. Page TUo April 4, 1984 is l

3. B&B Insulatio.n's. method for installing wall seals involved damming both sides of the penetration and i pumping silicone foam in from the top. With this

method, cable tray and pipe in the penetration

notentially obstruct the free flow of silicone  ;

' foam into allsarcas of the cavity. Voids were l created throughout some seals, thereby not meeting i

! the criteria for a three hour fire rating. In '

addition, expansion of the silicone caused the  !

damming material to bulge outward in certain cases.

' Some of these seals were then damaged by attempts

! to trim away excess silicone foam resulting in less than the required depth of fill. To assure

adequate penetration seals, the installation method i j

has been modified to pump silicone foam into several l locations through the damming material for proper i

distribution. In addition, the installers and inspectors have been reinstructed as to proper installation technique and acceptance criteria.

J Reinspection and any necessary repairs will be complete i by April 22, 1984 on all silicone foam-filled wall and floor l

) penetrations. We believe the measures taken and planned to identify and repair the deficiencies in the penetration sealing program will assure a Fire Protection design capable of meeting j its design function.

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1 j Ver truly yours, l 1 f

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g Donal~d E Schnell l

. JJM/sla l cc: B.-L. Forney,'NRC Region III j Richard DeYoung, Director I&E t Missouri Public Service Commission NRC Resident Inspectors Callaway Plant (2) l l

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