ML20236K940

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PNO-77-021:during Facility First Refueling Outage in in Progress,Visual Exam of 11 Fuel Assemblies Revealed Blisters on Some Poison Pins.Blisters Appear to Be Caused by Hydriding & Some Appear to Be Perforated
ML20236K940
Person / Time
Site: Calvert Cliffs Constellation icon.png
Issue date: 02/03/1977
From: Dreher F, Roy G, Thompson D
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-021, PNO-77-21, NUDOCS 9807100148
Download: ML20236K940 (1)


Text

f cd 11s C l PRELIMINARY NOTIFICATION

f?lQ February 3, 1977 PRELIMINARY N0'TIFICATION OF EVENT OR UNUSUAL OCCURRENCE-PNO-77-21

/

Thispreliminarynotificationconstitutes'EARLYnobceofaneventof POSSIBLE safety or public interest significance. The information

' presented is as initially received withobt verification or evaluation and is basically all that is known by IE staff on this date. ~

Facility: Calvert Cliffs Unit 1 (DN 50-317)

Baltimore Gas and Electric Company

, ,jiubject: HYDRIDING OF POISON PINS During the facility's first refueling outage, currently in progress, l

visual examination of eleven fuel assemblies has revealed blisters '

on some poison pins. The blisters appear to have been caused by hydriding, and some appear to be perforated.

Additional visual inspection of these assemblies is planned as well 1 as inspections of additional assemblies. These inspections will be performed by the fuel supplier (Combustion Engineering) who is now  !

on site.

M The licensee-is planning to present the results of these inspections and a course of action to NRR in the near future. The problem appears similar to the hydriding noted at St. Lucie Unit 1, PNO-76-122.

5 The effect of this problem on the outage schedule is not known at this time.

Media interest is possible but is not expected at this time.

The State of Maryland has been informed. A press release is not planned.

NRC, Region I (Philadelphia) received notification of this occurrence by telephone from the Nuclear Plant Engineer at 1:05 p.m., on February 3, 1977.

Contact:

FADreher, IE x27261 GWRoy, IE x27261 DThompson, IE x27541 Distribution: '

Chairman Rowden Commissioner Kennedy S. J. Chilk, SECY Commissioner Gilinsky C. C. Kammerer, CA G. F. Murphy, JCAE L. V. Gossick, EDO K. R. Chapman, NMSS R. G. Ryan, OSP S. H. Hanauer, EDO E. Volgenau, OIE J. A. Harris, PA '

B. C. Rusche, NRR H. K. Shapar. ELD T. J. McTiernan, OIA Transmitted: PBlds  ; H St. N  ; MNBB Y  ; Luge  ; -

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k PRELIMINARY NOTIFICATION fp.yfDskV N. NN '

9807100148 770203 PDR 1&E PNO-77-021 PDR _