ML17194B110
| ML17194B110 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, 05000000 |
| Issue date: | 05/19/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17194B108 | List: |
| References | |
| NUDOCS 8206040402 | |
| Download: ML17194B110 (3) | |
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DPR~29, AND AMENDMENT NO. 71 TO FACIL ITV OPERATING LICENSE NO, DPR-30 COMMONWEALTH EDISON COMPANY AND IOWA-ILLINOIS GAS AND ELECTRIC COMPANY DRESDEN STATION UNIT NO. 2 DRESDEN STATION UNIT NO. 3 QUAD CITIES STATION UNIT NO. 1 QUAD CITIES STATION UNIT NO. 2 DOCKET NOS. 50-237, 50-249, 50-254; 50-265 l.0 INTRODUCTION The criteria and staff positions pertaining to degraded grid voltage protection were transmitted to Commonwealth Edison (CE) by NRC Generic Letter dated June 3, 1977.
In response to this, by letters dated July 27, 1977, June 26, 1980, October l, 1980, October 28; 1981, January 6, 1982 and March 4, 1982, the licensee proposed certain design modifications and changes to the Technical Specifications. A d~tailed review and technical evaluatiori ~f these proposed modifications and changes to the technical specifications'were*performed by EG&G, under contract to the NRC, and with general supervision by NRC staff. This work
- is reported by EG&G in "Degraded Grid Protection for Class lE Power Systems Dresden Station, Unit Nos. 2 and 3, 11 dated March 1982, and "Degraded Grid Protection for* Class lE*Power Systems Quad Cities Station Unl't Nos. l and 2,"
dated March.. 1982*; '.(Attachments l and 2 to this Safety Evaluation).
We have reviewed these Technical Evaluation Reports (TER) and concur. in the conclusion that the proposed electrical design modifications and technical specification changes are acceptable.
2.0 BACKGROUND
The criteria used by EG&G in its technical evaluation of the proposed changes include GDC-17 ("Electric Power Systems") of Appendix A to 10 CFR 50; IEEE Standard 279-1971 ("Criteria for Protection Sys terns for Nu cl ear Power Generating Stations"); IEEE Standard 308-1977 ("Voltage Ratings for Electrical Power Systems and Equipment - 60 Hz"); and staff positions defined in NRC Generic Letter to CE dated June 3, 1977.
- 2.:.
3.0 *PROPOSED CHANGES, MODIFICATIONS AND.DISCUSSION The following electrical system design modifications and technical specifications changes were proposed by CE.
- l. *Installation of a second level of underVoltage protection cin each 4160 volt Class.IE bus.
This,protective relaying will consist of relays connected in a two-out-of-two logic (per bus) such that when the 4160 volt Class lE bus voltage falls below setpoint, (3784V maximum 3708V minimum) for longer than 7 (+ l.4) seconds it will deenergize the second level undervoltage relays and activate a series connected timer (setpoint 5 minutes).
At the end of five minutes, the offsite power source breakers will be tripped, th~ diesel* generator is started, load shedding will be initiated,~nd th~Cla~s lE loads will be sequenced on the emergency di es el generator when satt.S factory vo 1 tage and frequency is achieved *.
- If a safety irijection signal (SIS) is generated by the reactor protection system concurrent with the degraded voltage condition or at any time during the operation of the five minute ti'mer, the SIS will automatically start the onsite emergency diesel generators and bypass the five minute timer.
The ftve~minute tfme delay is of sufficient duration to prevent spurious operatto~ of th~ second level loss of voltage relays during short bus voltage disturbances fh~t maj
- result from starting of large motors br short term grid distunbances.
Additionally, this time delay will all ow operator action to attempt restoration of grid voltage by means available to him.
- 2.
Modify the load shedding circuitry such that once the diesel generator is supplying its associated bus, load shedding is blocked by a 11 b 11 contact of the diesel generator breaker. If th.e onsite emergency diesel generator breaker should*be tripped, load shedding and load sequencing will be reinstated.
- 3.
Additions and changes to the plant technical specifications including th~ surveillance requirements, allowable limits for the relay setpoint and time delay ~hve been provided by the licensee. *An analysis to substantiate the limiting conditions for operation and minimum and maximum setpoint limits were included as part of the modification~
pro~osed. The chariges and additions to technical specifications have been reviewed and found acceptable.
4.0
. *'EVALUATION AND
SUMMARY
We have reviewed the EG&G Technical Evaluation Report and concur in its findings that:
- 1. The proposed degraded grid modifications will protect the Class TE equipment and systems from sustained degraded voltage of the offsite power system.
- 2.
The proposed technical specification changes and additions Bre acceptable.
- 3. Spurious operation of the second level degraded grid voltage relays will not occur during the sta~ting of large motors.
We, therefore, find the Dresden Station, Units 2 and 3 and.the Quad Cities Station, Units l and 2 design to be acceptable with respect to degraded grid voltage protection for the Class lE system.
5.0 ENVIRONMENTAL CONSIDERATION
S We have determined that the amendments do 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 amendments involve an action which is insigni-ficant from the standpoint of environmental impact and, pursuant to 10 CFR
§51.5(~)(4),-that an environmental impact statement, or negative de~laration and environmental impact appraisal need not be prepared in connection.with the issuance_of these amendments.
- 6. 0 CONCLUSION We have concluded, based on the considerations di~cussed *above, that: (1) because the amendments do not involve a significant increase in the pro-bability or consequences of accidents previously considered and d6 not
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involve a significant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reaso~able 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 these amendments will not be inimical to the common defense and se<:;urity or to.the health and.safety of the public.
Attachments-1 and 2:
TER' s for Dresden 2 and 3; Quad Cities l and 2 Date:
May 19, 1982