ML19351D720
| ML19351D720 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/31/1977 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19351D718 | List: |
| References | |
| NUDOCS 8011170482 | |
| Download: ML19351D720 (3) | |
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WN UNITED STATES
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- 4 NUCLEAR REGULATORY COMMisslON
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C ASHIN1 ton, I. C. 20555 54. - -
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%,,*.... j' SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION I
SUPPORTING AMENDMENT NO. 35 TO FACILITY OPERATING LICENSE NO. DPR-3 I
YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION (YANKEE-ROWE)
DOCKET NO. 50-29 ip
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p Introduction By application dated January 18, 1977, Yankee Atomic Electric Company (the licensee) proposed a change in the Technical Specifications appended to License No. DPR-3 for the Yankee-Rowe reactor. The proposal relates to the surveillance requirements for the charging pumps.
Specifically, it involves the deletion of the requirement for verification of a specific pump discharge pressure in excess of the reactor coolant system pressure when determining the capability to achieve a minimum charging pump flow rate with the reactor coolant system at the pressure associated with the specific operational mode of the reactor when the test is performed as specified.
Discussion The Yankee-Rowe facility has three motor driven positive displacement charging pumps in the reactor charging and volume control system. The charging pumps are designed to deliver a maximum flow of 33 gpm at a raximum operating pressure of 2500 psig. Any pump can be isolated from the system for repairs. All pumps are provided with a high pressure relief valve. The charging pumps are used to deliver sufficient concentrated boric acid solution to the reactor cooling system for providing the necessary slow reactivity control during all modes of reactor operations.
In addition, the charging pumps are used for long term coolant recirculation in the depressurized reactor cooling system following a LOCA. To meet the assumptions in the accident analysis a charging flow of 26 gpm from one pump is sufficient.
To meet redundancy requirements, at least two pumps must be operable for all modes of reactor operation, except during cold shutdown; at least one pump must be operable during cold shutdown.
Surveillance requirements were added to the new format Technical Specifications for Yankee-Rowe which became 8011170
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_2-effective on January 1, l'<77.
They require periodic verification
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that each charging pump 's capable of delivering at least 26 gpm to the reactor cool,ing system at a pump discharge pressure 30 psig greater than
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the reactor' cooling system pressure.
In its January 18, 1977 application the licensee proposed the deletion of this specific pressure verification s'
provision in the charging pump flow surveillance requirement.
Evaluation i
The charging pump surveillance requirements in the new format Yankee-Rowe specifications were patterned after the standard Technical Specifications i:
for Westinghouse facilities. The standard Technical Specifications are based on the use of centrifugal charging pumps which require flow versus pressure measurements for operability verification. This is necessary for centrifugal type pumps to identify performance degradation by a shift of the measured flow versus pressure operating point from the original pump performance curve. The performance characteristics of the Yankee-Rowe positive displacement pumps are different from those of centrifugal pumps.
By design they are capable of displacing a constant volume of fluid at any pressure up to the setpoint of the pump discharge relief valves. Any possible degradation of these pumps can be identified by measuring pumped flow to verify that the specified flow requirement is met.
Flow rate for these pumps is varied by changing the pump speed but is essentially independent of system pressure.
In any case the speci-fications provide for minimum flow verification at the nominal reactor coolant system pressure essociated with the operational mode of the reactor in which the charging pump flow verification is required to be perfonned.
Accordingly, the charging pumps that are required to be operable would be flow tested about every 15 days, except every 31 days during cold shutdown condition of the reactor. The specified frequency of these tests and the
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implicit requirement to verify the minimum flow rate against the pre-vailing nominal reactor coolant system pressure provides an acceptable degree of confidence that the charging pumps will be capable of delivering the required flow when needed and to demonstrate that the charging pump motors are capable of carrying the load without tripping. Therefore, specific pressure verification for the charging pump operability surveillance is not necessary.
We find that the licensee's proposal would delete a specific pressure verification from the charging pump surveillance require-ments which is not applicable to Yankee-Rowe. We also find that the pump flow verification at the prevailing nominal reactor coolant pressure will assure the availability of at least a minimum flow rate from any charging pump required to be operable consistent with the assumptions in the accident analyses, does not reduce the level of safety of this facility and is there-fore acceptable.
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[N 3-f.]
We have determined 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
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action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental 1mpact
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statement or negative declaration and environmental impact appraisal need
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not be prepared in connection with the issuance of this amendment.
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Conclusion
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We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: January 31, 1977 o
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