ML20055H367
| ML20055H367 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 07/19/1990 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | NORTHEAST NUCLEAR ENERGY CO. |
| Shared Package | |
| ML20055H365 | List: |
| References | |
| NUDOCS 9007260108 | |
| Download: ML20055H367 (10) | |
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i UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMIS$10N In the Matter of i
NORTHEAST NUCLEAR ENERGY COMPANY, ET AL )
Docket No. 50 336 i
Millstone Nuclear Power Station, Unit No. 2 REVOCATION OF EXEMPTION i
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l The Northeast Nuclear Energy Company, et al. (the licensee), is the holder
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of Facility Operating License No. DPR-65 which authorizes operation of the Millstone Nuclear Power Station, Unit No. 2, at a steady state power level not in excess of 2700 megawatts thermal. The facility is a pressurized water
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reactor located at the licensee's site in the town of Waterford, Connecticut.
The license provides, among other things, that it is subject to all rules, regulations and orders of the Nuclear Regulatory Commission (the Comission) now or hereafter in effect.
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On November 19, 1980, the Commission published a revised Section 10 CFR l
50.48 and a new Appendix R to 10 CFR Part 50 regarding fire protection featuresofnuclearpowerplants(45FR76602). The revised Section 50.48 and t
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. Appendix R became effective on February 17, 1981.
Section 111 of Appendix R contains 15 subsections, lettered A through 0, each of which specifies requirements for a particular aspect of the fire protection features at a nuclear power plant. On April 15, 1986, the Commission granted exemption to the requirements of two of these 15 subsections, Ill.G and !!!.L. Subsection III.G.2 requires that one train of cables and equipment necessary to achieve and maintain safe shutdown be maintained free of fire damage by one of the following means:
Separation of cables and equipment and associated non-safety circuits of a.
redundant trains by a fire barrier having a 3-hour rating. Structural steel forming a part of or supporting such fire barriers shall be protected to provide fire resistance equivalent to that required of the barrier; b.
Separation of cables and equipment and associated non safety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening conbustibles or fire hazards, in addition, fire detectors and an automatic fire suppression system shall be installed in the fire area; or Enclosure of cables and equipment and associated non safety circuits of c.
one redundant train in a fire barrier having a 1-hour rating.
In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.
Subsection Ill.G.3 and Ill.L of Appendix R also requires that the alternate shutdown capability be independent from the specific fire area.
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. The exemptions specify that a complete area wide automatic fire suppression would not be required for the Closed Cooling Water Pump Area, the Boric Acid Pumps, Spent Fuel Pool Heat Exchanger Area, the Boric Acid Batch Tank-Chemical Addition Tank Area, the Cable Vault, the Main Control Room, the intake Building, and the Charging Pump Room. Other specific exemptions to the deviations from the requirements of Appendix R were permitted as noted in Section IV. All of the Exemptions, except that related to the auxiliary feedwater pumps located in the Auxiliary Feed Pump Pit, are the subject of this Revocation of Exemption, 111.
By letter dated May 29, 1987, as supplemented by letter dated April 22, 1988, the licensee provided an updated evaluation of the plant's compliance with the requirements of 10 CFR 50, Appendix R.
In that submittal, the licensee elected to review the fire protection afforded the plant on a fire area basis and proposed modifications and analyses that precluded the need for Exemption in seven of the eight areas where Exemption was previously granted.
The acceptability of the revocation of exemption for each of the seven areas is addressed below. Details are contained in the NRC staff's related Safety Evaluation (SF).
The fire areas related to the seven revocations of exemptions are:
1.
Closed Cooling Water Pump Area (new area - A-13, old area - A-18) 2.
BoricAcidPumps-SpentFuelPoolHeatExchangers(newarea-A-12, old area - A-14) 3.
Boric Acid Batch Tank-Chemical Addition Tank Area (new area - A-2, old area - A-24) (Partially revoked, certain areas retained) 4 CableVault(newarea-A-4 old area - A-10) 5.
Main Control Room (new area,- A-1, old area - A-42) 6.
Intake Building (new area 1, old area 1) 7.
Charging Pump Room (new area - A-18, old area - A-9)
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Revocation of Exemption 1 - Closed Cooling Water Pump Area (FireAreaA13)
The exemption allowed the licensee to eliminate the need for automatic fire suppression in the Closed Cooling Water Pump Area as would be required by Section !!!.G of Appendix R.
The licensee noted in the updated compliance review of May 29, 1987, that 3-hour protection was afforded the cables for the charging pumps. This eliminates the need for an exemption for charging pumps B and B-swing since, the 3-hour cable protection complies with the requirements of Section
!!!.G.2.a of Appendix R.
j The licensee also chose not to erect a marinate shield around the Train A l
Reactor Building Closed Cooling Water (RBCCW) pump and motor as required by the exemption. Therefore, the RBCCW Pump will no longer be available during hot standby and must be repaired or replaced for cold shutdown.
The staff has concluded that the RBCCW pump is not needed for hot shutdown based on the-licensee'sevaluationofacceptableReactorCoolantPump(RCP) seal integrity without cooling (see Section 2.3.1). Therefore, the fire protection as related to the RBCCW pumps meets the criteria of Section III.G.1.b of Appendix R.
However, the licensee will be required to effect RCP seal cooling i
in acccMance with the resolution of Generic Issue 23 once that issue is resolve.
Based on the forgoing, the exemption is no longer needed from the requirements of Appendix R for fire area A-13.
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. i Revocation of Exemption 2 - Boric Acid Pumps - Spent Fuel Pool Heat Exchangers (Fire Area A-12)
The exemption of the requirement for an area-wide fire suppression system was granted based on the rerouting of the power cables for Charging Pump A and A(swing)outsidethefireareaandtheenclosureoftheverticalrunof 4
Charging Pump A and A (swing) cables in a 1-hour barrier together with the installation of a marinate board radiant energy shield around the vertical
- cables, i
in lieu of the proposed modifications that supported the exemption, the licenseereroutedthepowercabasfortheB(swing)chargingpumpoutsidethe fire area.
This rerouting meets the Appendix R.Section III.G.2 separation criteria and makes the B (swing) charging pump available through the post fire shutdown period in the event of a fire in this area. Thus an exemption is no longer needed from the requirements of Appendix R for fire area A-12.
Partial Revocation of Exemption 3 - Boric Acid Batch Tank and Chemical Addition Tank Areas (Fires Area A-2)
The exemption of the requirement for a total area-wide automatic suppression system was granted based upon rerouting of some Diesel B cables outside the fire area, installing a water curtain in the west end of the fire area to segregate the remaining Train B cables and motor control center from Train A cables the protection of the cables passing through the water curtain with a 1-hour wrap and sprinkler protection.
In lieu of the proposed modifications, the licensee did the following:
(1) Chose to rely on backfeed for AC power and, thus, did not reroute tne Train B diesel cables.
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. (2) Those cables intended to pass through the water curtain were either rerouted or were wrapped in a 3-hour protected fire barrier.
(3) The water curtain was installed as a water spray on MCC B61.
The use of backfeed for AC power eliminated the need for rerouting of Diesel B cables. Therefore, this portion of the exemption in fire area A-2 is 4
no longer needed.
The remaining Train B cables do not require exemption from the requirements of Appendix R since some were rerouted in accordance with Section III.G.1.a of Appendix R or were wrapped with a 3-hour barrier in accordance.
with the requirements of Section !!!.G.2.a of Appendix R.
Therefore, this portion of the exemption in fire area A-2 is no longer needed.
The water curtain established as a water spray on MCC B61 is a deviation from the requirements of Section Ill.G of Appendix R.
Therefore, this portion of the exemption is retained.
Revocation of Examption 4 - Cable Vault (Fire Area A-4)
The exemption of the requirement for a complete. area-wide automatic fire i
suppression system and for the separation by a 1-hour fire-rated barr.ier or by more than 20 feet with no intervening combustible material of certain redundant shutdown cables was granted based on the extension of an automatic wet-piped sprinkler system to include diesel power cables Train A and application of passive 1-hour fire-rated barriers between redundant trains of
~i safe shutdown cables at the crossover points, in lieu of protecting the diesel power cables, the licensee will depend a
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upon backfeed of AC power from Unit I to Unit 2 for emergency AC power, will utilize the fire shutdown panel and will protect selected cables by 3-hour barriers. This was found acceptable since it complies with the provisions of Appendix R, Section !!!.G.2. Thus, an exemption is no longer needed from the l
requirements of Appendix R for Fire Area A-4 Revocation of Exemption 5 - Main Control Room (Fire Area A-1)
The exemption from the requirement of a complete area-wide fixed fire suppression system, the adequate physical separation between redundant shutdown divisions and a shutdown capability independent of the main control room was based on existing fire protection capability and implementation of modifications that would provide for instrumentation signals to a new remote FireShutdownPanel(FSP),disconnectdevicestoassureclosureofcertain valves during a control room fire, the capability to align Unit 1 emergency AC power to the Unit 2 emergency buses, manual / air ope. rated valves in the auxiliary spray flow paths to control Reactor Coolant System (RCS) level and pressure control for cold shutdown, protection against hot shorts in the pressurizer and the reactor head vent control circuits in the event of cortrol room fires, a remote FSB in Fire Zone T3 and procedures to assure safe shutdown in the event of fires in and outside of the control room.
In the licensee's May 29, 1987, Updated Fire Hazards Analysis, the licensee revised the previous approach to safe shutdown which was based upon-the assumption of loss of some panels in the control room to a loss of all panels. Under this assumption, the licensee will rely on use of the FSP installed in Fire Area T-3 m
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' for safe shutdown after a control room fire in accordance with Sections
!!!.G 3 and 111.L of Appendix R.
The licensee installed a bottle-up panel outside of the control room to assure closure of valves in the RCS and main steam system which could be used to isolate the RCS and the SG coolant inventories. The FSP will utilize the AC power backfeed from Unit I to satisfy the criteria of Appendix R, Sections 111.G.3 and III.L.
Thus, an exemption is no longer needed from the requirements of Appendix R for fire Area A 1.
Revocation of Exemption 6 - Intake Building (Fire Area I-1)
The exemption from the requironent of certain shutdown systems not separated by a 3-hour fire-rated barrier and an area-wide automatic fire suppression system was based upon the modification to provide 1-hour fire-rated barriers for all cabling / conduit associated with service watar pump train "A", the modification to provide diking / curbing around Service Water Pump "A" and the installation of an automatic water curtain spray system around Service Water Pump "A."
The licensee reported in the updated Fire Hazards Analysis of May 29, 1987, that none of above modifications were implemented. Rather, the licenses will rely on backfeed of AC power from Unit I for provision of power to Unit 2 in lieu of providing a Unit 2 SW pump to cool a Unit 2 Emergency _ diesel generator. Also, the licensee noted that if a fire did effect the SW pump _and cabling for a SW pump, the pump and cabling would be replaced for bringing the plant to cold shutdown. This was found to be acceptable since such a repair was
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not postulated as being necessary during the hot standby condition. Therefore, an exemption is no longer needed from the requirements of Appendix R for fire area 1-1, Revocation of Exemption 7 - Charging pump Room (Fire Area A-18)
The exemption from the requirement for an area-wide automatic fire suppression system and separation of the three charging pumps by a complete l
1-hour fire-rated barrier or by a distance of more than 20 feet without 1
intervening combustibles was based on a low fire load in the area, on the modifications providing a 1-hour fire-rated enclosure for A and B train charging pump cable trains and on the installation of a eurb/ dike in front of each charging pump cubicle.
The licensee reported in the updated Fire Harzards Analysis dated May 29, 1987, that a 3-hour fire-rated barrier in the form of a wrap had been provided for both charging pump cable trains anc that the curbs had been installed.
The 3-hour fire-rated barrier conforms to the requirements of Sections Ill.G.2 of Appendix R this making two charging pumps (A and B) available for use throughout the post-fire period in this fire area. Therefore, an excmption is no longer needed from the requirements of Appendix R for fire area A-18.
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' Accordingly, the Commission has determined that the specific exemptions l
from 10 CFR 50.48 granted on April 15, 1986, for the Closed Cooling Water Pump
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l Area (FireArea-A.13)-theBoricAcidPumps-SpentFuelPoolHeatExchangers l
Area (Fire Area - A-12), the Cable Vault Area (Fire Area - A-4), the Main Control l
Room Area (Fire Area - A-1), the Intake Building Area (Fire Area 1) and l
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the Charging Pump Room Area (Fire Area - A-18) are hereby revoked. Also, the 1
exemption related to Boric Acid Batch Tank-Chemical Addition Tank Area
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(Fire Area - A 12), is hereby partially revoked and certain areas as discussed are retained. This revetation provides protection of the public adequate health and safety since it resultr in compliance by the Licensee with the l
l Commission's regulations.
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This revocation of exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/e g'a, Direc i
l Division of Reactor Pro ts - 1/11 Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 19th day July,1990.
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