ML19208B524
| ML19208B524 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/17/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19208B523 | List: |
| References | |
| NUDOCS 7909200496 | |
| Download: ML19208B524 (2) | |
Text
.
SAFETY EVALUATION ADDITIONAL COOLING 0F VITAL AREAS (PHASE-III)
ARKANSAS NUCLEAR ONE, UNIT 1 (ANO-1)
I.
INTRODUCTION The Arkansas Power and Light Company (AP&L) in their reportable occurrence No. 50-313/77-19 c September 20, 1977 describes hcw 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 here 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 reviewed and reported in the staff's safety evaluation of October 24, 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 industrial quality packaged refrigerated cooling units in preparation for 1978 summer season.
Our safety evaluation for this installation was prepared on August 9,1978.
In their letters of October 31, 1978, and July 24, 1979, the licensee submitted a proposed design of the pennanent installation (the third phase of th9 corrective actions) for cooling the emergency equipment areas. Our evaluatic, of this design is presented below.
II. EVALUATI0h JF PHASE THREE The third phase 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 chiller 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.
The north chiller unit (VCH4A) supplies chilled water to the following emergency train 2 electrical equipment areas:
North switchgear room No. 99, unit cooler (VUC20)
North battery / charger rcom No. 95, unit cooler (VUC14A)
North electrical penetration room No. 150, unit cooler (VUCl4B)
Chiller unit VCH4A and unit coolers VUC20, VUC14A and VUCl4B are supplied 480V 3 pnase 60 cycle power from emergency power train 2.
190920 f 972315
.... The south chiller unit (VCH4B) supplies chilled water to the following emergency train 1 electrical equipment areas:
South switchgear room 100, unit cooler (VUC2B)
South battery / charger room 109/110, unit cooler (VUCl4C)
South electrical equipment room 104, unit cooler ( :Cl4D)
Chiller unit VCH4B rnd unit coolers VUC2B, VUC14C, and VUCl4D are supplied a
480V 3 phase 60 cycle powe from emergency power train 1.
These air conditioning systems are thermostatically controlled and are designed to maintain a maximum temperature of 1040F 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 acceptable.
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 recomendations 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.
8723?6
-. _