ML20248D792
| ML20248D792 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 09/25/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20248D784 | List: |
| References | |
| NUDOCS 8910040404 | |
| Download: ML20248D792 (4) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NOS.102 AND 79 TO FACILITY OPERATING LICENSE N05. DPR-70 AND DPR-75 PUBLIC SERVICE ELECTRIC & GAS COMPANY PHILADELPHIA ELECTRIC COMPANY DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY SALEM GENERATING STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-272 AND 50-311
1.0 INTRODUCTION
By letter dated July 9,1987, Public Service Electric & Gas Company requested an amendment to Facility Operating License Nos. DPR-70 and DPR-75 for the Salem Generating Station, Uni +. Nos. I and 2.
The proposed amendments would modify the Salem Units 1 and 2 Technical Specifications by:
1.
Changing the channel description format of Table 3.3-3, Item 7.a Loss of Voltage, to specify that the total number of channels is 1 per bus.
2.
For Table 3.3-3, Item 7.b.
Sustained Degraded Voltage, changing the Total Number of Channels, Channels to Trip and Minimum Channels Operable to 3 per bus, 2 per bus and 3 per bus, respectively.
3.
For Table 3.3-4 Item 7.b.
Sustained Degraded Voltage, changing l
the Trip Setpoint to greater than or equal to 91.6 percent of bus voltage for less than or equal to 13 seconds and changing the Allowable Values to greater than or equal to 91 percent of l
bus voltage for less than of equal to 15 seconds. c.
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2.0 EVALUATION 1.
T/S Table 3.3-3=ftenL 7.a i
The licenses has proposed to revise this item to be consistent with the channel description format used for other items in this table.
The staff finds this change to be an editorial change and acceptable.
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T/S Table 3.3-3 Item 7.b The licensee has redesigned the second level of undervoltage protection system for Salem Units 1 and 2 as a result of an event which occurred at Salem Unit 2 on August 26, 1986. A reactor trip occurred which was followed by a safety injection actuation and a subsequent loss of offsite power. Immediately following the reactor trip, the Unit 2 vital buses began flip-flopping between the No. 21 and 22 Station Power Transformer (SPT) until they eventually separated from the offsite power system. The original design provided for the transfer of a 4ky Class IE bus to the alternate SPT whenever the secondary voltage for its designated SPT drops below 91% of the rated bus voltage for greater than 10 seconds. This transfer function is controlled by two relays on each 4ky Class IE bus. These relays are positioned such that they monitor the secondary voltage of each of the SPT. A separate relay monitors 4ky Class IE bus voltage and provides an input to each of the three Safeguards Equipment Controllers (SEC) such that, for a sustained degraded voltage (less than 91% for greater 13 seconds) condition on 2 out of 3 4ky Class IE buses, all vital buses are separated from the offsite source and safe shutdown loads are sequences onto the emergency bus. This design was unacceptable because 2 out of 3 Class IE buses must have degraded voltage before they are separated from the offsite source and the potential exists for damaging safety related motors as a result of frequent starts or start attempts during flip-flopping of the Class IE buses between the SPTs Nos. 21 and No. 22.
The proposed design eliminates this transfer function of the 4ky Class IE bus to the alternate SPT at 91% of the rated bus voltage.
It includes two levels of undervoltage protection for e6ch Class IE bus (Note: This design has already been implemented at Salem Units 1 and 2 since 1986 but T/S changes have not been implemented as yet.)
The first level actuates at 70% of nominal bus voltage and is designed to protect against complete-loss-of-voltage conditions.
This system consists of 3 inverse time undervoltage relays per 4kv Class IE bus. One undervoltage relay monitors bus voltage, the other two undervoltage relays monitor the,. secondary voltage of the respective station power transformer (SPT). When SPT secondary voltage falls below 70%, a transfer is (nitiated to place the affected bus (es) on the alternate SPT. A transfer permissive logic is completed by the undervoltage relay of the alternate SPT prior to the transfer which indicates acceptable bus voltage on the alternate SPT prior.to th ttransfer. If the alternate SPT transfer permissive is not coinpleteTwith~in 13 seconds, the second level of voltage protection system transfers the affected buses from offsite power system to their respective emergency diesel generators. The single undervoltage relay which monitors bus voltage will transfer all safety buses from offsite power source to their respective diesel generators on a 2-out-of-3 logic.
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The second level of undervoltage protection consists of three undervoltage relays per bus set at 91.6% of the bus voltage. Each of the three relays monitors bus voltage directly and inputs to a two-out-of-three logic for the individual bus.
If the bus voltage falls below 91.6% for 13 seconds, then the affected bus is disconnected form the offsite source (SPT) and connected to its emergency onsite power source. Based on the revised design of the second level of undervoltage protection scheme, the licensee has revised Item 7.b of Table 3.3-3 to reflect the new change and the staff finds this change to be acceptable.
3.
T/S Table 3.3-4, Item 7.b The licensee has proposed to revise this table to incorporate the revised setpoint for the second level of undervoltage protection system relays setting and to correct the allowable value for the second level of undervoltage protection relays. The new relay trip setpoint of 91.6% with an allowable value of 91% of the design voltage is based on the results of detailed analyses of the Salem Generating Station electrical distribution system transient response of the Salem existing electrical system distribution configuration.
On this basis, the staff finds the new relay settings to be acceptable.
4 An editorial change was included by the licensee to Table 3.3-3, Item 4.b.
Four Loops Operating, under CHANNELS TO TRIP and MINIMUM CHANNELS OPERABLE in the Unit 2 Technical Specifications to be consistent with existing Unit I word.ing. The word "in" was deleted from the referenced listings. The staff finds this to be acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change to a requirement with respect to the installation or use of a facility component" located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. The staff has determined that the amendurants involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increasp in individual or cumulative occupational radiation exposure. The Conunission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public coment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR51.22(c)(9_).-Pn4pantto10CFR51.22(b),noenvironmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
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4-4.0 CONCLUSIO_N
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The Comission made a propcsed determination that the amendments invo1ve no significant hazards consideration which was published in.the Federal Register (54 FR 3510)).on August 23, 1989 and consulted with the State of New Jersey. ' No public comments were received and the State of New Jersey did not have any coments.
The staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comission's regulations and the issuance of the amendments will not be inimical to the common defense and security nor to the health and safety of the public.
Principal Contributor:
O. Chopra Dated: September 25, 1989 Se e
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