ML19339A424
| ML19339A424 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 07/15/1976 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19339A422 | List: |
| References | |
| NUDOCS 8011030783 | |
| Download: ML19339A424 (2) | |
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WASHINGTON, D. C. 20566 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 28 TO FACILITY OPERATING. LICENSE NO. DPR-3 YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION (YANKEE-ROWE)
DOCKET NO. 50-29 Introduction By letter dated April 21, 1976, Yankee Atomic Electric Company (the licensee) requested, pursuant to 10 CFR Part 50, Section 50.59, authori-
- ation to add a pulsation dampener on the Charging Pump No. 3 discharge header. The action is requested because it involves changes to descriptive pages in Section 203 " Charging and Volume Control System" in the Final Ha:ards Summary Report which is incorporated in the Technical Specifications appended to License No. DPR-3 for the Yankee-Rowe facility.
Evaluation The Yankee-Rowe charging rid volume control system includes three motor driven positive displacement pumps.
Each pump is capable of delivering 33 gpm against a discharge head of 2,100 psig. Any of those high pressure chrrging pumps can be isolated for repair.
Limiting conditions for operation of Yankee-Rowe require two of the three charging pumps to be operable.
Operating experience has shown that because of the unique piping arrangement at the discharge of Charging Pump No. 3 (more piping and pipe bends oriented in different directions compared to the piping arrangements of Charging Pump Nos.1 and 2) the normal pressure pulses during operation of Charging Pump No. 3 cause significant vibration of its discharge piping.
This has resulted in a few recent occurrences of weld cracks in the Charging Pump No. 3 discharge piping attributable to vibration induced fatigue failure by continuous operation of this pump.
The weld defects were acceptably repaired and each occurrence was reported to the NRC.
In the April 21, 1976 submittal, the licensee proposes to install a pulsation dampener in the Charging Pump No. 3 discharge header for minimi:ing potential piping vibration to eliminate recurrence of weld de fe cts. The ' dampener would absorb the energy of the pressure pulses during operation of Charging Pump No. 3 by compression of a bladder precharged with nitrogen.
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' The standards of quality of the components involved in the proposed addition of the pulsation da=pener will be at least equal to the quality level of the existing charging system and will be verified by the NRC's Office of Inspection and Enforcement.
The pulsation dampener will be located upstream of t'wo check valves in series, capable of isolating the charging system from the reactor coolant system.
Further, Charging Pump No. 3 can be isolated from the charging system.
We therefore find that even if an unlikely failure of the dagener were assumed it would not usult in unacceptable con-sequences.
From our review of the infor=ation submitted by the licensee we have determined that the addition of the pulsation dampener as proposed will not affect the performance capability of the Charging Punp No. 3 for the intended functions and that it is an acceptable feature for the necessary correction of a potential condition during operation of the Charging Pump No. 3 that has adversely affected the integrity of the discharge header associated with the pump. We have therefore concluded that the addition of a pulsation darpener is acceptable as proposed.
We have deter-ined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR S 51.5(d)(4) that an environmental statement, negative declaration, or environmental impact appraisal need not be prepared in connection with the' issuance of this amendment.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the change does not involve a significant inemase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the change does not involve a significant hazards considerations, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed canner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this acendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: July 15, _1976