05000289/LER-1977-023, RO 77-23/1T:on 770920,both Doors of Reactor Bldg Emergency Personnel Access Hatch Open Simultaneously.Caused by Personnel Error.Doors Closed.Forwards LER 77-23/1T

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RO 77-23/1T:on 770920,both Doors of Reactor Bldg Emergency Personnel Access Hatch Open Simultaneously.Caused by Personnel Error.Doors Closed.Forwards LER 77-23/1T
ML19261F309
Person / Time
Site: Crane Constellation icon.png
Issue date: 10/05/1977
From: Herbein J
METROPOLITAN EDISON CO.
To:
Shared Package
ML19261F310 List:
References
GQL-1319, NUDOCS 7910250771
Download: ML19261F309 (4)
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LER-1977-023, RO 77-23/1T:on 770920,both Doors of Reactor Bldg Emergency Personnel Access Hatch Open Simultaneously.Caused by Personnel Error.Doors Closed.Forwards LER 77-23/1T
Event date:
Report date:
2891977023R00 - NRC Website
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V CESCRIPTION ENCLOSU RE 3p Licensee Event Report (RO# 77-23/lT) on 9-20-77 concerning oppening of both doors of ti the reactor /dddtdiffddi building di/tMd emergency personnel access hatch at the same time..........

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POST OFFICE BOX 542 READING, PENNSYLV ANI A 19603 TELEPHONE 215 - 929-3601 October 5, 1977 GQL 1319 Mr. Boyce H. Grier, Directer Office of Inspection and Enforcement,

- fg Region 1 U. S. Nuclear Regu' atory Ccnmission 7

631 Park Avenue King of Prussia, Pennsylvania 19hC6

Dear Sir:

Docket No. 50-289 Operating License No. DPR-50 In accordance with the Technical Specifications of our Three Mile Island Nuclear Station, Unit 1 (TMI-1), we are reporting the folleving reportable occurrence. This report is being submitted one day late ner telecen with your Mr. Fasano.

1)

Report Number: 77-23/1T 2a)

Required Report Date: October h, 1977 2b)

Date of Occurrence:

September 20, 1977 3)

Facility: Three Mile Island Nuclear Station, Unit 1 h)

Identification of Occurrence:

Title:

Both decrs of the Reactor Building Energency Personnel Access Hatch vere open at the same time.

Tyne:

A reportable occurrence as defined by Technical Specifications 6.9.2.a(2) in that both doors of the Reacter Building Emergency Personnel Access Hatch were open at the same time, thus leading to a loss of centainment integrity as stated in Section 1.7 when the conditions were as stated in Section 3.6.1 of the Technical Speciff cations.

5)

Conditions Pricr to occurrence-Power:

Core:

0 M'it Elec:

0 K4e 1482 023

?tr. Boyce H. Grier, Director Octe - 5,1977 101 6

RC vlow: ho x 10 lb/hr RC Pressure:

550 psig 0

RC Temp:

350 F PRZR Level: 100 inches 0

PR2R Temp:

L35 F 6)

Descriptien of Occurrence:

A =aintenance man, while exiting the Reacter Building, opersted the cuter decr handvheel instead of the inner decr handvheel. When he noted his mistake, he turned the outer door handvheel back to its closed position nuo realizing that the cuter decr had bounced off of its closed position before the latching bar engaged.

He then opened the inner door, entered the hatch, and reclcsed the inner door, not taking note that the inner door had also bounced cff cf its seal.

The interlock, controlled by latching bar position, was ncy satisfied even though both dcors were open.

The man noted that both decrs were open and i==ediately notified the Shift Foreman. The doors were returned to their closed position within ten (10) minutes after breaking containment integrity.

7)

Causes of Occurrence:

The causes of this cccurrence have been determined to be faulty design, untrained persennel, and lack of guidance in that:

1.

Improper (too rapid) door usage in the past has bent the shafts en the door closing mechanisms, alleving excessive decr free travel.

These shafts need additional supppcrt after re-align =ent.

( Change Madification No. 90h).

2 There are no prc=inent signs to caution operators against using the oppcsite door handwheel.

3 The operator was not adequately trained in the proper Operation of the Reactor Building doors.

8)

Analysis of Occurrence:

Both decrs were open fer less than ten (10) =inutes before personnel re-established centainnent integrity.

Due to the lov energy plant conditicn and the short time during which centainment integrity was not maintained. This occurrence did not constitute a threat to the health and safety of the public.

1482 024

Mr. Boyce H. Grier, Director October 5. 1977 GQL 1319 9)

Corrective Action

In=ediate:

1.

Returned doors to their closed positiens.

Long Ter=:

1.

An additional interlock device (Change Modification 904) vill be installed to prevent the docr latch interlock frc= being satisfied unless the doors are fully shut.

2.

Prc=inent warning signs will be placed near the handvheels that operate the opposite door.

3.

Additional support bearings vill be f abricated and installed on each of the four (h) Reactor Building door hinge shaft extensions to prevent binding the shafts and excessive free play.

h.

All maintenance personnel vill be reinstructed in the proper operation of the Reactor Building doors. Additienally, proper Reaccer Building decr operation vill be covered in the annual General Employee Training Program.

The Plant Operations Review Cc==ittee and Unit Superintendent have reviewed and approved the above corrective action and have taken steps to assure its cc=pletien.

10) Failure Data:

Manufacturer: Chicago Bridge and Iron Cc=pany Contract No.:

68-2631U Specification: GAI-S?5h89 Hinge Shaf t Extension - 2" steel shaft is part of hinge a;se=bly.

Similar Occurrences:

Th-ll, Th-32, and 77-07 Sincerely, J. G. Herbein Vice President JGH:DGM:tas Attach =ent: Licensee Event Report 148;! 025

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