ML13031A630

from James Krafty to Josephine Ambrosini: Millstone 2 Service Water Temp

ML13031A630
Person / Time
Site:	Millstone
Issue date:	08/09/2012
From:	James Krafty NRC/RGN-I/DRP/PB5
To:	Josephine Ambrosini, Bellamy R, Joseph Deboer, Brian Haagensen, James Kim, Thomas Setzer, Keighley E Division of Operating Reactor Licensing, NRC/RGN-I/DRP/PB5
References
FOIA/PA-2013-0045
Download: ML13031A630 (1)

Text

Bellamy, Ronald From: Krafty, James Sent: Thursday, August 09, 2012 9:19 AM To: Ambrosini, Josephine; Haagensen, Brian; Bellamy, Ronald; Setzer, Thomas; Keighley, Elizabeth; DeBoer, Joseph; Kim, James

Subject:

Milstone 2 Service Water Temperature Millstone 2 has been in and out of TS 3.7.11 over the past few days. The current concern is that the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> average temperature will exceed 75F. If this happens, they will be required to go to cold shutdown.

Unit 2 monitors service water temperature at the inlet to the 3 vital switchgear coolers. They record the highest of the 3 temperatures hourly and use it in calculating the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> average. Because of instrument error, they use 74.5F as the limit to ensure that they do not exceed 75F. Their current 24 hr average temperature is 73.7F. It increased from 73.4F over the past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Their TS amendment request is asking to use the average of the 3 temperatures instead of the highest reading in calculating the 24 hr average. Using the average of the 3 temperatures, the 24 hr average would be 73.3F, 0.4F lower.

Unit 2's service water takes a suction 15ft below the LI sound surface. Unit 3 takes their UHS temperature form the average temperature at the inlet to the condenser waterboxes. The circ water pumps take a suction 30ft below the LI sound surface which is less susceptible to surface heating.

Jim 1

7Y