ML20205Q347
| ML20205Q347 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 05/21/1986 |
| From: | ARKANSAS POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20205Q339 | List: |
| References | |
| NUDOCS 8605280266 | |
| Download: ML20205Q347 (2) | |
Text
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3.4 STEAM AND POWER CONVERSION SYSTEM t
Applicability I
Applies to the turbine cycle components for removal of reactor decay heat.
Objective To specify minimum conditions of the turbine cycle equipment necessary to assure the capability to remove decay heat from the reactor core.
Specifications 3.4.1 The reactor shall not be heated, above 280 F unless the following conditions are met:
1.
Capability to remove decay heat by use of two steam generators.
- 2.
Fourteen of the steam system safety valves are operable.
3.
A minimum of 11.1 feet (107,000 gallons) of water is available in Tank T418.
4.
Both EFW pumps and their flow paths are operable.
5.
Both main steam block valves and both main feedwater isolation valves are operable.
3.4.2 Initiate functions of the EFIC system which are bypassed at cold shutdown conditions shall have the following minimum operability conditions:
" low steam generator pressure" initiate shall be operable a.
when the main steam pressure exceeds 750 psig.
b.
" loss of 4 RC pumps" initiate shall be operable when neutron l
flux exceeds 10% power.
" main feedwater pumps tripped" initiate shall be operable c.
when neutron flux exceeds 10% power.
- Except that during hydrotests, with the reactor subcritical, fourteen of the steam system safety valves may be gagged and two (one on each header),
may be reset for the duration of the test, to allow the required pressure for the test to be attained.
Amendment No. 50,90,91 40
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-g,
r pressure" initiate are the only shutdown bypasses to be manually initiated during cooldown.
If reset is not done manually, they will automatically reset.
Main feedwater pump trip bypass is automatically removed above 10%
power.
In the event of loss of main feedwater, feedwater is supplied by the emergency feedwater pumps, one which is powered from an operable emergency bus and one which is powered from an operable steam supply system.
Both EFW pumps take suction from tank T418.
Decay heat is removed from a steam generator by steam relief through the turbine bypass, atmospheric dump valves, or safety valves.
Fourteen of the steam safety valves will relieve the necessary amount of steam for rated reactor power.
The minimum amount of water in tank T41B would be adequate for about 4.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of operation.
This is based on the estimate of the average emergency flow to a steam generator being 390 gpm.
This operation time with the volume of water specified would not be reached, since the decay heat removal system could be brought into operation within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or sess.
A portion of tank T41B is protected from tornado missiles.
The protected volume is sufficient to provide a thirty minute supply of water.
This thirty minute period is sufficient to allow manual operator action, if required,- to transfer suction of the emergency feedwater pumps to service water.
Amendment No. 91 41a
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