ML051740372

RAI - Application of Alternate Source Term

ML051740372
Person / Time
Site:	Columbia
Issue date:	06/22/2005
From:	Bhalchandra Vaidya Office of Nuclear Reactor Regulation
To:	Coleman D Energy Northwest
vaidya B, NRR/DLPM, 415-3308
References
TAC MC3203
Download: ML051740372 (2)

Text

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REQUEST FOR ADDITIONAL INFORMATION COLUMBIA GENERATING STATION APPLICATION OF ALTERNATE SOURCE TERM Technical Specifications (TS) 3.8.2, 3.8.5, and 3.8.8 (which are currently applicable in Modes 4, 5, and during movement of irradiated fuel assemblies in the secondary containment) required, in part, immediate suspension of movement of irradiated fuel in secondary containment when both offsite preferred sources, redundant safety related electric onsite power sources, or redundant safety related distribution systems are no longer operable. The proposed change would allow, without TS restrictions, the movement of irradiated fuel assemblies that have decayed at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when there is no offsite power, when there is no onsite power, or when there is no ac and dc electric power through the electric distribution system to safety related loads.

Technical Specifications Task Force (TSTF)-51 guidelines for system removed from service during movement of irradiated fuel that has decayed for two days or more and during core alternations state that:

'During fuel handling/core alternations, ventilation system and radiation monitor availability (as defined in NUMARC 91-06) should be assessed, with respect to filtration and monitoring of releases from the fuel. Following shutdown, radioacitivity in the fuel decays away fairly rapidly. The basis of the Technical Specification operability amendment is the reduction in doses due to such decay.

The goal of maintaining ventilation system and radiation monitor availability is to reduce doses even further below that provided by the natural decay. A single normal or contingency method to promptly close primary or secondary containment penetration should also be developed. Such prompt methods need not completely block the penetrations or be capable of resisting pressure. The purpose of the 'prompt" methods" mentioned above is to enable ventilation systems to draw the release from a postulated fuel handling accident in the proper direction such that it can be treated and monitored."

Justify movement of irradiated fuel assemblies that have decayed at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without the availability of power source to any safety systems such as those needed to maintain plant shutdown (as described above in TSTF-51), for monitoring and maintaining the plant status, or to mitigate events postulated during fuel handling accident.