ML19210C814
| ML19210C814 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/10/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19210C807 | List: |
| References | |
| NUDOCS 7911200145 | |
| Download: ML19210C814 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION CONCERNING ADDITIONAL COOLING OF ELECTRICAL E UIPMENT AREAS VITAL TO SAFETY ARKANSAS POWER & LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT NO.1 (ANO-1)
DOCKET NO. 50-313 I.
INTRODUCTION
.The Arkansas Power and Light Company (AP&L) in their reportable occurrence No. 50-313/77-19 of September 20, 1977 describes how a design review for ANO-2 had revealed an oversight in the design of emergency ventilation in several vital equipment areas in the ANO-1 plant.
The corrective actions the licensee proposed to resolve the concerns associated with the design oversight were presented in a program which consists of three phases. The first and imediate phase was to provide temporary emergency ventilation for the electrical equipment areas and was addressed in our letter of November 4, 1977. The second and interim phase, necessitated by the long delivery time associated with the purchase of Class IE equipment, provided for the installation of industrical quality packaged refrigerated cooling units in preparation for 1978 sumer season. These modifications were completed in December 1977.
In their letters of October 31, 1978Iand July 24, 1979, the licensee submitted a proposed design of the permanent installation (the third phase of the corrective actions) for cooling the emer*gency equipment areas.
These modi-fications were completed during the 1978 refueling outage for Cycle 4 operation.
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Our evaluation of these modifications is presented below.
II.
EVALUATION OF PHASE THREE The third phise of the corrective measures provides for the. installation of two independent qualified chilled water cooling systems.
Each system is comprised of a 15 ton chiller unit and three chilled water unit coolers.
The licensee has documented that the ch' iller units and unit. coolers will' be seismically qualified in accordance with IEEE 344-1975 and environmentally qualified for maximum credible accident conditions in accordance with IEEE 323-1974.
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The north chiller unit (VCH4A) supplies chilled' water to the following emergency train 2 electrical equipment areas:
North switchgear room No. 99, unit cooler (VUC2D)
North battery / charger room No. 95', unit cooler (VUC14A)
North electrical penetration room No.150, unit cooler (VUC148).
Chiller unit VCH4A and unit coolers VUC2D, VUC14A and VUC148 are supplied 480V 3 phase 60 cycle power from emergency power train 2.
The south chiller unit (VCH4B) supplies chilled water to the following emergency train 1 electrical equipment areas:
South switchgear room 100, unit cooler (VUC28)
South battery / charger room 109/110, unit c:aler (VUCl4C)
South electrical equipment room 104, unit cooler (VUCl4D)
Chiller unit VCH4B. and unit coolers VUC2B, VUC14C, and VUC14D are supplied 480V 3 phase 60 cycle power from emergency power train 1.
These air conditioning systems are thermestatically controlled and are designed to maintain a maximum temperature of 104cF in each of the following~
rooms:
battery charger rooms, electrical switchgear rooms, and electrical equipment rooms when the turbine building ambient air temperature is 1220F.
We find this a'cceptable.
T' The two chiller units are physically separated from one another; unit VCH4A is located in corridor 98 and unit VCH4B *is located in the south switchgear room.
The room unit coolers are physically separated as described above.
Physical independence and separation of electrical cabling satisfies the~ recommendations of Regulatory Guide 1.75.
We find this acceptable.
III.
CONCLUSION Based on our review of the licensee's design of the permanent cooling installation, we find this solution to the emergency equipment cooling problem to be adequate and acceptable.
Dated:
October 10, 1979 i 3()I4 334
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