ML20197F110
| ML20197F110 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 05/09/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20197F107 | List: |
| References | |
| NUDOCS 8605150431 | |
| Download: ML20197F110 (3) | |
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UNITED STATES 8
- a NUCLEAR REGULATORY COMMISSION
$ d' W / ^ I
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WASHINGTON, D. C. 20555 N
l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR RE
%J SUPPORTING AMENDMENT NO. 41 TO FACILITY OPERATING LICENSE NO. NPF-11 AND AMENDMENT NO. 22 TO FACILITY OPERATING LICENSE NO. NPF-18 COMMONWEALTH EDISON COMPANY LA SALLE COUNTY STATION, UNITS 1 AND 2 DOCKET NOS. 50-373 AND 50-374
1.0 INTRODUCTION
To ensure satisfactory resolution of outstanding concerns regarding adequacy i
of station electrical distribution system voltages, the La Salle operating licenses contain License Condition 2.C.(20) for Unit 1 and 2.C.(11) for Unit
-2 regarding low and/or degraded grid voltage. The license conditions require the Commonwealth Edison Company (licensee) to install a second level of undervoltage protection prior to startup from t'he respective first refueling cutage. The concern was that the original design provided no protection for the engineered safety feature (ESF) buses against a degraded voltage condi-1 tion between the trip setpoint of the normal (first level) of undervoltage relays (60 to 69% of rated voltage) and 90% of rated voltage.
i By letter dated November 13, 1985, the licensee requested amendments to the La Salle, Units 1 and 2 Technical Specifications to include this low and/or i
degraded grid voltage modification. This modification will include two undervoltage relays and a time delay relay to each 4.16 kV bus which provides 2
l protection against degraded grid voltage. The undervoltage relays are con-nected in a two-out-of-two logic arrangement to prevent spurious trips. The 3
undervoltage relays are set to trip at 92% of bus voltage and have a 10 4
second time delay to prevent momentary voltage drops (e.g., motor starts) from actuating the system. The ESF bus will automatically disconnect from the offsite power sources, shed loads, and transfer to the diese1' generator if a degraded voltage condition exists for more than 5 minutes during normal plant conditions or immediately upon receipt of an emergency core cooling system initiation signal (neither time includes the 10 second sensor time delay).
Modifications to all three electrical divisions of Unit 1 will be completed during the present Unit 1 first refueling outage; and modifications to two out of the three divisions, Divisions II and III, have been completed for Unit 2.
Modification to the third division, Division I, will be completed prior to startup after the first Unit 2 refueling as required by License Condition 2.C.(11).
2'. 0 EVALUATION i
The licensee proposed a revision to the Technical Specification Tables 3.3.3-1, 3.3.3-2, and 4.3.3.1-1 to add the second level of undervoltage 8605150431 860509 PDR ADOCK 05000373 P
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protection. Table 3.3.3-1 specifies two undervoltage relays, both of which c
are required to operate for the trip function to occur.
Footnote a is revised to reflect this function.
Since the logic for both the loss of I
voltage ant' degraded voltage is two-out-of-two sensors, the licensee pro-posed reviMon of ACTION 37 and addition of new ACTION 39. The proposed new actior, stateu nt would allow a sensor to be placed in the tripped con-dition with the plant operating for seven days without automatic degraded voltage protection for one ESF division, provided the other two divisions' degraded voltage protection is operable.
In response to our concern for one ESF division having no protection at.
all for degraded voltage if proposed ACTION 39 were impTemented, the licensee proposed to delete ACTION 39 and replace it with ACTION 37 which requires placing sensors in the tripped condition within one hour or declaring the associated diesel-generator inoperable.
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The staff has reviewed the licensee's submittal and concludes that the La Salle Units 1 and 2 degraded grid voltage design conforms to our require-ment and is, therefore, acceptable. The staff has also reviewed the d
licensee's proposed Technical Specification changes and finds that they appropriately address the actuation sensor, trip setpoints and surveillance requirements for the changes made to degraded voltage logic circuit and are, therefore, acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change in the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20 4
3 and changes in surveillance requirements.- The staff has determined that these amendments involve no significant increase in the amounts, and no significant changes in.the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumula-tive occupational radiation exposure. The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public coment on such finding. Accord-ingly, these amendments meet the elioibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), ~ no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
The Commission made a proposed detennination that these amendments involve no significant hazards consideration which was initially published in the i
Federal Register (50 FR 49784) on December 4,1985, and a renotice which l
was published in the Federal Register (51 FR 12226) on April 9,1986. 'No' i
public coments were received on either notice, and the state of Illinois did not have any comments.
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3-We have concluded, based on the considerations discussed above, that:
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(1) there is reasonable assurance that the health and tafety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regula-tions and the issuance of these amendments will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
N. Trehan, EICSB, NRR Dated:
May 9,1986 e
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