ML20236U059

PN-75-004:on 750320,plant Was Operating at 100% of Full Power,Two Hydraulic Snubbers (Grinnell,Figure 200/201) Were Found Inoperable

ML20236U059
Person / Time
Site:	Three Mile Island
Issue date:	03/21/1975
From:	Jennifer Davis, Dreher F, Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PN-75-004, PN-75-4, NUDOCS 9807290278
Download: ML20236U059 (1)

Text

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PDR Cul/ x a G(l1 /,  ?

PRELIMINARY NOTIFICATION - NOT FOR FUBLIC DISCLOSURE I ivM I '

i PN-75-04 j' March 21, 1975 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE 50 '

Co ~5 f)

This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by OIE staff as of 3:00 p.m. on date of this notification. IT SHOULD BE SPECIFICALLY NOTED THAT THIS NOTIFICATION MAY CONTAIN INFORMATION THAT LATER MAY BE DETERMINED TO

• BE INACCURATE OR INCONSISTENT. AN OFFICE OF INSPECTION AND ENFORCEMENT '

30TIFICATION OF AN INCIDEST OF OCCURRENCE (BLUE SHEET) SUBSEQUENTLY

. . , , , WILL BE ISSUED IF WARRANTED.

Facility - Metropolitan Edison (Three Mile Island)

Subj ect - FAILURE OF HYDRAULIC SHOCK SUPPRESSORS AT THREE MILE ISLAND 1 On March 20, 1975, while the plant was operating at 100% of full power, two hydraulic snubbers (Grinnell, Figure 200/201) were found inoperable.

The suppressors had been removed from main steam lines for testing and overhaul and were found defective during testing. Investigation revealed  !

that the snubber valve (Lindco Model No. BH 1226) on each* unit was defective, i.e., during the piston displacement test, snubber lockup could not be

~ achieved. The problem was corrected by replacing the snubber valve.with N

i g one of a different type (Lindco Mod'el No. BH 1224).

It appears that a generic problem exists with the snubber valve (Lindco '

Model No. BH 1226). The licensee found this problem during performance of the snubber seal replacement program, as previously committed to the Commission. The licensee has identified an additional 13 snubbers con-taining the subject valves. These are also located on the main steam lines inside containment, and replacement of these units is being ac-complished on a priority basis. Inspection findings for these units should be known on 3/24/75. An IE bulletin is being considered.

No press release is being considered.

Contact:

FADreher, IE x7261, HDThornburg, IE x7353, JGDavis, IE x7541 Distribution:

Chairmay-Anders --

Commissioner Mason Secretary . .

Commissioner Gilinsky Commissioner Rowden JCAE Commissioner Kennedy Congressional Liaison  !

/ .

R. V. Gossick, EDO D. F. Knuth, IE J. A. Harris, PA O/

E. G. Case, NRR H. H. Brown, ISP

/

H. Larson, NMSS H. K. Shapar, GC pf o 2-  !

t, '

9807290278 750321 i

PDR I&E i PN-75-OO4 PDR l

PRELIMINARY NOTIFICATION - NOT FOR PUBLTC DT4rinR1'W

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