ML20083R710

AO 4-2-6:on 740125,control Rods Did Not Withdraw from Core to Insertion Limit in Conformance W/Tech Specs.Boron Added to Coolant Sys & Procedures re-emphasized to Personnel

ML20083R710
Person / Time
Site:	Indian Point
Issue date:	02/08/1974
From:	Cobean W CONSOLIDATED EDISON CO. OF NEW YORK, INC.
To:	Oleary J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20083R713	List: ML20083R710 ML20083R718
References
AO-4-2-6, NUDOCS 8304040614
Download: ML20083R710 (2)

Text

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February 8, 1974 k Re Indian Point Unit No. 2 AEC Docket No. 50-247

{ 4 8)O /Sg Facility Operating License A

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Mr. John F. O' Leary, Director Directorate of Licensing Office of Regulatic,n 4

U. S. Atomic Energy Commission Washington, D. C. 20545

Dear Mr. O' Leary,

The following report is provided pursuant to the requirements of Section 6.12.2 (a) of the Technical Specifications to Facility Operating License No. DPR-26.

On January 25, 1974, the Indian Point Unit No. 2 reactor was brought critical in preparation for placing the plant back in service following completion of repairs associated with No. 22

, steam generator feedwater line. Criticality was achieved with

' the "C" bank of control rods 43 steps withdrawn from the core, "B" bank 175 steps withdrawn and "D" bank fully inserted. The position of the control rods was approximately 27 steps below the insortion limit for criticality shown on Figure 3.10-1 of the Technical Specifications. At the time of the occurrence, the reactor coolant system pressure and temperature were 2235 psig and 540 0F respectively. All four reactor coolant pumps were in service, and the boron concentration was 1125 ppm. Immediately upon noting that the positions of the control rods was not in con-formance with Technical Specifications requirements, boron was added to the Reactor Coolant System and the rods were further with-drawn until their positions satisfied the requirements of Figure '

3.10-1.

The 27-step differential represents approximately .26% reactivity.

Minimum boron concentration required to maintain the stipulated shutdown margin (Figure 3.10-3 of the Technical Specifications)

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Mr. John F. O' Leary February 8, 1974 Ret Indian Point Unit No. 2 AEC Docket No. 50-247 Facility Operating License DPR-26 A.O.-4-2-6 is calculated to be 770 ppm. Therefore, the shutdown margin existing at the time of the occurrence was three times more than that required by Figure 3.10-3.

To insure against recurrence of this incident, the importance of following operating procedures precisely has been reenpha-sized to all licensed Reactor Operators.

Because the operational limitations set forth in Figure 3.10-1 are derived conservatively, qafe operation of Indian Point Unit No. 2 was not adversely affe :ted by this occurrence. With the assumption that one rod is s:uck in its fully withdrawn position, the boron concentration in the Reactor Coolant System was still more than sufficient to shut the reactor down. The cafety im-olications to the occurrence are therefore considered slight. -

Very truly yours, CM GM Warren R. Cobean, Jr., Manager Nuclear Power Generation

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