ML19210A128

Event Rept 76-23/1T:on 760604,improper Incorporation of Fuel Densification Penalty Into Cycle 2 Tech Specs Found.Error Could Have Permitted Reactor Operation in Manner Less Conservative than Assured in Safety Analysis

ML19210A128
Person / Time
Site:	Three Mile Island
Issue date:	06/18/1976
From:	Arnold R METROPOLITAN EDISON CO.
To:
References
ER-76-23-17, ER-76-23-1T, GQL-0890, GQL-890, NUDOCS 7910240845
Download: ML19210A128 (4)

Text

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i Ltr. trans the followk1g. . . . . . - Reportable Occurrence # 76-23/1T,on 6-4-76 Concerning Improper incorporation of fuel densif-i

. icatiun penalty into cycle # 2 Tech. Specs,wh'ich i affec+ figures 2.1-1,2.1-3 and 2.3-1.....

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Mr. J. P. O'Reilly U s if a Nuclear Regulatory Commission ngT[

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Dear Sir:

Docket No.59-289 Operating License No. DPR-50 In accordance with the Technical Specifications of our Three Mile Island Nuclear Station Unit 1 (TMI-1), ve are reporting the following reportsble occurrence.

(1) Report Number: ER 76-23/lT (2a) Report Date: June 18, 1976 (2b) Event Date: June 4, 1976 (3) Facility: Three Mile Island Nuclear Station Unit 1 (h) Identification cf Event:

Title:

Improper incorporation of fuel densification penalty into cycle 2 technical specifications, which affect figures 2.1-1, 2.1-3 and 2.3-1.

Type: A reportable occurrence as defined in Technical Specification 6.9 2.A(8) in that this error in an analysis described in the basis for Technical Specifications might have permitted reactor operation in a manner less conservative than assured in the safety analyses.

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1490 007 .

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Mr. J. P. O'Reilly June 18, 1976 GQL 0890 (5) Conditions Prior to Event:

Various normal operating conditions.

(6) Description of Event:

On June 4, 1976, it was discovered that:

a. The fuel densification penalty was not properly incorporated into technical specifications prepared for cycle 2.

b. Proper incorporatien of this penalty would affect D:TB based pressure-temperature limit curves such that they would be more restrictive.

c. Babcock & Wilcox calculations confirmed that elimination of the internal vent valve bypass flow penalty, as authorized by Iluclear Regulatory Commission letter of March lo, 1976, would more than compensate for this error.

Thus, elimination of the internal vent 7alve flow penalty will allow continued use of present pressure temperature curves.

(7) Designation of Apparent Cause of Event:

This event was caased by personnel error in that an incorrect heat flux term was used in the incorporation of the fuel densification penalty into cycle 2 technical specifications.

(8) Analysis of Event:

This event did not constitute a threat to the health and safe.y of the public in that it has been calculated that the present technical specifications are adequately conservative since eliminstion of the reactor internals vent valve penalty more than ecmpensates for the consequences of the fuel densification error.

(9) Corrective $ction:

I=.ediate: At the time the licensee was informed of the error ccccerning the fuel densification penalty, it had been determined that elimination of the reactor internals vent valve penalty would more than compensate for this error, therefore, continued operation using present technical specifications was deemed safe.

1490 008

Mr. J. P. O'Reilly June 18, 1976

, GQL 0890 Long Term: A draft of Technical Specification Change Request No.

36 has been submitted. This change revises the affected curves to correctly reflect the fuel densification penalty, and the elimination of the vent valve bypass flow penalty, and includes tent valve surveillance re quirements.

(10a) Failure Date: Not Applicable (10b) Similar Events:None Very truly yours, g,

I R. C. nold Vice President RCA:rk 1490 Oh09