ML020170227
| ML020170227 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/14/2002 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Pulsifer R M, NRR/DLPM, 415-3016 | |
| References | |
| Download: ML020170227 (1) | |
Text
EXCERPTS FROM THE VERMONT YANKEE NUCLEAR POWER STATION TECHNICAL SPECIFICATIONS (TS) AND BASES LIMITING CONDITION FOR OPERATION TS LCO 3.7.A, "PRIMARY CONTAINMENT" states:
- 1.
Whenever primary containment is required, the volume and temperature of the water in the suppression chamber shall be maintained within the following limits:
- a.
Maximum Water Temperature during normal operation - 90 OF.
- b.
Maximum Water Temperature during any test operation which adds heat to the suppression pool - 100 OF; however, it shall not remain above 90 °F for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
- c.
If Torus Water Temperature exceeds 110 °F, initiate an immediate scram of the reactor. Power operation shall not be resumed until the pool temperature is reduced below 90 OF.
- d.
During reactor isolation conditions, the reactor pressure vessel shall be depressurized to less than 200 psig at normal cooldown rates if the torus water temperature exceeds 120 OF.
BASES FOR TS 3.7.A The maximum temperature at the end of blowdown tested during the Humbolt Bay and Bodega Bay tests was 170 °F and this is conservatively taken to be the limit for complete condensation of the reactor coolant, although condensation would occur for temperature above 170 OF.
Using a 50 OF rise in the suppression chamber water temperature and a minimum water volume of 68,000 ft3, the 170 OF temperature which is used for complete condensation would be approached only if the suppression pool temperature is 120 OF prior to the DBA-LOCA. Maintaining a pool temperature of 90 OF will assure that the 170 OF limit is not approached.
SURVEILLANCE REQUIREMENT SR 4.7.A.1 requires the suppression pool average temperature to be within the applicable limits and be verified daily AND every 5 minutes when performing testing that adds heat to the suppression pool.