ML17252A847
| ML17252A847 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 02/08/1974 |
| From: | Cobean W Con Edison, Consolidated Edison Co of New York |
| To: | O'Leary J US Atomic Energy Commission (AEC) |
| References | |
| Download: ML17252A847 (2) | |
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Consolidated Edison Company of New York, Inc.
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Mr. John F. o' Leary*, Director Directorate of Liceniing Off ice of Regulation
- u. s. Atomic Energy Commission Washington, D. c.
20545
Dear Mr. O'Leary,
February 8, 1974 Re:
Indian Point Unit No. 2 AEC Docket No. 50-247 Facility Operating License DPR-26 A.0.-4-2-6 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Criticality was achieved with the "C" bank of control rods 45 steps withdrawn from the core, "B" bank 175 steps withdrawn and "D" bank fully inserted.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 insertion 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 5400F 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 wJth-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 2 -
February 8, 1974 Re:
Indian Point Unit No. 2
- AEc Docket No. 50-247 Facility Operating License DPR-26 A.0.-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 reempha-sized to all licensed Reactor Operators.
Because the operational limitations set forth in Figure 3.10-1 are derived conservatively, safe operation of Indian Point Unit No. 2 was not adversely affected by this occurrence.
With the assumption that one rod is stuck in its fully withdrawn position, the boron concentration in the Reactor Coolant System was still more than sufficient to shut the reactor down.
The safety im-plications to the occurrence are therefore considered slight.
cc:
Mr. James P. O'Reilly Very truly yours, c6~
- 12. Gi~ h Warren R. Cobean, Jr., Manager Nuclear Power Generation