ML17139C072
| ML17139C072 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 12/12/1983 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML17139C071 | List: |
| References | |
| NUDOCS 8312280082 | |
| Download: ML17139C072 (6) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION AMENDMEN N
PF-14 SUStlUEHANN S
E M ELECTRIC S
TI N, UNIT 1 Introduction The licensee in a letter dated October 20,
- 1983, as amended by licensee letter dated November 7, 1983, proposed changes to Technical Specification Table 4.8. 1. 1.2-2 of the operating license for Susquehanna Steam Electric Station, Unit 1 to modify the start time sequence of two Emergency Service Water (ESW) pumps from 53 and 57 seconds to 44 and 48 seconds, respectively.
The change is proposed to support two unit operation and prevent the potential concurrent starts of the Residual Heat Removal (RHR) or Core Spray (CS) pumps with the ESW pumps due to incorporation of the low vessel pressure interlocks required on the RHR and CS pump initiation signals in order to prevent a
LOCA - false LOCA condition during two unit operation.
Evaluation The ESW pump auto start timer. is initiated from the diesel-generator start signal.
The diesel generators are started by low reactor water level or high drywell pressure or a loss of offsite power.
The RHR and CS pumps are initiated by either low reactor water level or both high drywell pressure and low vessel pressure to distinguish the LOCA in one unit from the false LOCA in the other unit for two-unit operation.
Coincident starts of the RHR or CS pumps with the ESW pumps would result in unacceptable low voltages during the motor starts and unacceptable motor start times.
For the Unit 1 operating
- license, the deletion of the low vessel pressure interlock from RHR or CS pump start logic was approved to prevent the concurrent start of the RHR or CS pumps with the ESW pumps for single unit operation.
The licensee has proposed to reinstate the low vessel pressure interlocks on RHR and CS pump initiation signals for two unit operation in order to prevent a
The staff has reviewed the offsite power supply capability to power the RHR and CS pump start concurrent with the ESW pump start.
The offsite power supply systems have been modified by the installation of two additional ESF transformers.
The licensee has re-evaluated the two-unit offsite power supply voltage study.
The study demonstrates that the two-unit offsite power supply and the diesel generators are capable of supplying adequate power to the loads required for two unit operation and will not be adversely affected by the proposed change.
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Comments on the proposed change were received from Mr. Marvin Lewis by telephone on November 18, 1983.
Mr. Lewis was concerned there was no indication of any testing to be accomplished to verify that the change in ESW pump load sequence timers was conducted properly.
The licensee is requried by Technical Specification 4.0.4 to ensure that entry into an OPERATIONAL CONDITION or other specified applicable condition shall not be made unless the Surveillance Requirements associated with the Limiting Condition for Operation have been performed within the applicable surveillance interval or as otherwise specified.
The intent of this provision is to ensure that surveillance activities have been satisfactorily demonstrated on a current basis as required to meet the OPERABILITY requirements of the Limiting Condition for Operation.
Under Technical Specification 4.0.4, testing of the modified timer settings is required to meet OPERABILITY requirements.
Additionally, the setting of these timers is verified during the conduct of preoperational testing as part of the Unit I/Unit 2 tie-in outage.
The NRC staff believes that this adequately responds to Mr. Lewis's concern about testing.
The second concern of Mr. Lewis dealt with whether the timer settings could be maintained within its proper setpoint range given the plant environment, maintenance level, etc.
Under the provisions of Technical Specification 4.8. 1.1.2.d. 14, verification of each diesel generator loading sequence timer listed in Table 4.8. 1. 1.2-2 to be OPERABLE with its setpoint within + lOX of its design setpoint, is required at least once per 18 months.
Since the issuance of the Unit I license in July 1982, the licensee has not reported any diesel generator loading sequence timer outside the
+ 10K of its design setpoint.
Thus, the staff concludes that there is adequate assurance that the timer settings can be maintained within their proper setpoint range.
The third concern expressed by Mr. Lewis was whether the change in ESW pump load sequence timers had an adverse effect on the ESW pump suction head.
The ESW pumps take a suction directly from the spray pond.
Therefore, the ESW pump suction head is strictly a function of spray pond level, not the load sequence timer setting, and the change in ESW load sequence timers will have no effect on the ESW pump suction head.
The NRC staff has reviewed the licensee's proposed change and the comments
- received, and concludes that the proposed change involves no significant hazards considerations.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated because the two unit diesel generator load sequence study and the two unit offsite power supply voltage study are not significantly affected by the proposed change.
The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated because the proposed change remains bounded by the constraints of previous design and safety analyses.
The proposed change does not involve a significant reduction in a margin of safety because the two unit diesel generator load sequence study and the two unit offsite power supply voltage study are not significantly affected by the change, and no other margin of safety as defined in the basis for any other Technical Specification, is significantly affected by the proposed change.
The NRC staff finds the proposed change acceptable.
Environmental Consideration We have determined that this amendment does not authorize a change in effluent types or total amount nor an increase in power level and will not result 'in any significant environmental impact.
Having made this determination, we have further concluded that this amendment involves action which is insigni-ficant from the standpoint of environmental
- impact, and pursuant to 10 CFR Section 51.5(d)(4), that an environmental impact statement or negative declaration and enviromental 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 amendment does not involve a significant increase in the probability or consequences of accidents previously considered, does not create the possibility of an accident of a type different from any evaluated previously, 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.
Dated:
December 12, 1983
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DATED:
December 12 1983 AMENDMENT NO. 19 -
SUS UEHANNA
'ocument Control 50-387 NRC PDR L
PDR NSIC PRC LB82 File EHylton RPerch
- Wagner, OELD Region I HDenton DEisenhut/RPur pl e DBrinkman, SSPB EL'Jordan, DEQA: IE
- JMTaylor, DRP: IE
- LJHarmon, IE (2)
JSauder WMiller IDinitz
- WJones, QA TBannhar t (4)
- FPagano, IE