05000289/LER-1980-010, Forwards LER 80-010/01T-0

Forwards LER 80-010/01T-0

ML19318D037
Person / Time
Site:	Crane
Issue date:	06/30/1980
From:	Herbein J METROPOLITAN EDISON CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19318D039	List: 05000289/LER-1980-010, Forwards LER 80-010/01T-0 05000289/LER-1980-010-01, /01T-0:on 800606,licensee Received Ltr Stating FSAR Does Not Assume That Radioactive Release Paths Exist Via Main Safety Valves or Emergency Feed Pump Turbine Exhaust.Caused by Implementation of Small Break Guidelines
References
TLL-294, NUDOCS 8007070248
Download: ML19318D037 (2)

LER-1980-010, Forwards LER 80-010/01T-0

Event date:
Report date:
2891980010R00 - NRC Website

text

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Metropolitan Edison Company g

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Post Office Box 480 Middletown. Pennsylvania 17057 717 944-4041 Wr ter's oirect osai Number June 30,1980 TLL 294 Office of Inspection and Enforcement Attn:

n.11. Grier, Director Region i U. S. Nuclear Regulatory Commission 631 l' ark Avenue King of Prussia, PA 19406

Dear Sir:

Three Mile Island Nuclear Station, Unit I (TMI-1)

Operating License No. DPR-50 Docket No. 50-289 LER 80-010/OlT-0 Attached please find Licensee Event Report 80-010/0lT-0 concernine a nonconservative error in the 1MI-I FSAR.

This event is considered reportable under the requirements of Technical Specification 6.9.2.A(8).

This event is being submitted late based on a telephone conversation between Mrests.

D.

llavercamp of your of fice and D. Mitchell of Met-Ed.

Sincerely,

$gned J. G. Herbein J. G. Herbein Vice President TMI-I JGH:DGM:1ma Attachments cc:

J. T. Collins B. J.

Snyder 00}

D. Dilanni R. W. Reid S

j

/ /

Metropol: tan Edison Company is a Member of the General Pubic Utilities Sys:em 800

,._._70_7_0)pp,...........

TLL 294 LICENSEE EVENT REPORT

NARRATIVE

REPORT TMI-I LER 80-010-01T-0 EVENT DATE-May 6, 1980 1.

EXPLANATION OF OCCURRENCE By letter received from Babcock & Wilcox Company at TMI on Mty 5, 1980, the licensee was informed of the potential reportability of the TMI-I steam generator tube rupture safety analyses. The TMI-I FSAR safety analyses dt. not assume that radioactive release paths exist through the main safety valves or through the emergency feed pump turbine atmospheric steam exhaust.

This nonconservative error in the analysis results in calculated thyroid doses at the site boundary in excess of that reported in the TMI-I FSAR. The estimated dose supplied by B&W is I sed on Anticipated Transient Operating Guideline (ATOC) analyses completed for Arkansas Nuclear One - 1 and TMI meteorological dispersion factors.

Calculated releases for TMI-I would be Icss than that calculated for ANO-1, therefore, the B&W calculation is bounding and is within the limits of 10 CFR 100.11 (2). This event is reportable per Technical Specification 6.9.2.A(8).

11.

CAUSE OF OCCURRENCE This situation was discovered during review of the small break LOCA operator guidelines requiring the Reactor Coolant Pumps to be tripped. This would cause the secondary side to depressurize slower than previously assumed and cause the main steam safety valves to dump steam to the atmosphere. The FSAR incorrectly assumed that on a low pressure reactor trip that all steam header overpressure is relieved by the turbine bypass system.

Additionally, past reactor trip data indicates that main steam safety valves are normally lifted for a period of time less than a minute, which indicates the FSAR analyses were nenconservative prior to implementation of the small break LOCA operator guidelines.

III.

CIRCUMSTANCES SURROUNDING THE OCCURRENCE This unit was in long term cold shutdown with core cooling being provided by the Decay Heat System.

IV.

CORRECTIVE ACTION TO BE TAKEN TO PREVENT RECURRENCE The TMI-I ATOC program, of which the steam generator tube rupture is one of the transients selected for review, will identify any operating guide-lines and procedure changes necessary to minimize potential thyroid dose from the potentially contaminated steam release from main steam safety valve end steam-driven emergency feed pump turbine exhaust. The ATOG review for TMI-I is scheduled for completion in December 1980, before TMI-I projected restart.

V.

COMPONENT FAILURE DATA

N/A I

1 s

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