ML20136E584
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l Safety Evaluation by the Office of Nuclear Reactor Reaulation
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Rg)ated to."_.V = r.t No. 215 to Fat:~.ity Doeratina License NPF-16 Florida Power and Licht C - any (FPL)
St. Lucie. Unit 2 l
Gocket No. 50-389 I
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1.0 INTRODUCTION
By letter dated August 16, 1995, Florida Power and Light (FPL) Company l
(licensee) submitted a request for changes to the St. Lucie Unit 2, Technical l
Specifications (TSs).
The requested changes would revise TS 3.6.6.1, " Shield Building Ventilation system (58VS)," to more effectively address the design i
functions performed by the S8VS for both the Shield Butiding (secondary i
containment) and the F ai Handling Building.
2.0 THE SHIELD BUILDING VENTILATION SYSTEM DESCRIPTION
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i The containment system of St. Lucie 2 consists of a free-standing steel j
primary containment and a reinforced cor.cete :,hield building that encloses i
the primary containment. The function of the SBVS is to collect and filter l
radioactive airborne fission products that may leak from the primary containment to the annulus formed by these structures in the event of a loss of coolant accident (LOCA). Upon receipt of a Containment Isolation Actuation Signal (CIAS), the S8VS will automatically actuate to remove the fission product that result following a LOCA.
The S8VS consists of two independent, redundant, full-capacity fan and filter subsystems (trains).
Each train of the SBVS is also connected, via normally closed motor-operated butterfly valves, to the corresponding exhaust duct of the Fuel Handling Building Ventilation System (FHBVS). Upon receipt of a high radiation signal from the spent fuel storage pool area, the normally operating FH8VS will automatically de-energize and appropriate isolation dampers will close, the FH8VS-to-SBVS cross tie valves will open and the SBVS will automatically actuate to evacuate and filter air from the spent fuel storage pool area. The SBVS thereby provides the fission product removal function that is assumed for the postulated fuel handling accident.
To limit offsite radiation exposures that could result from either a LOCA or a fuel handling accident, assuming single active failure criteria, Limiting Condition for
~ Operation (LCO) 3.6.6.1 requires two independent SBVS to be operable during all modes of operations involving movement of irradiated fuel within the spent fuel storage pool or crane operations with loads over the spent fuel storage pool with irradiated fuel in the spent fuel storage pools.
3.0 DESCRIPTION
AND ANALYSIS OF PROPOSED TECHNICAL SPECIFICATION CHANGES Section 3.6.6.1 Limiting Condition for Operation for the two independent SBVS is currently written in three distinctive statements. An applicability statement and two action statements. The licensee proposed changes clarifies these statements and portrays them in a two distinct sections.
The applicability section and one action section. The existing single applicability statement is a single run-on sentence that could result in misinterpretation of the plant conditions that requirc the availability of an operable SBVS. The proposed applicability section is written as two distinct 9703130242 970301 DE 485 PDR i
. statements to clearly reflect the separate, but overlapping plant conditions that ie: quire an operable SBVS.
As for the action statement, the existing statements are in two parts:
the first statement addresses modes 1 through 4 and the second action statement addresses modes S and 6.
The way it is currently stated may unnecessarily penalize the licensee since it requires the transition to cold shutdown if the inoperable SBVS train is not restored to operable status within seven days.
This action is appropriate for a condition where the SBVS is unable to perform its design safety function for mitigating the effects of a LOCA. However, the specified action provides no compensatory measures for the probable concurrent condition where the SBVS cannot perform its design safety function for mitigating a fuel handling accitient. Additionally, should a condition develop in the FHB during modes I through 4 that impact only the SBVS capability to mitigate a fuel handling accident, the specified action could result in unnecessary unit shutdown and cooldown without requiring the proper compensatory measures until entering mnde 5.
The proposed action statement consists of three parts:
Part a - distinguishes between the actions required for the condition where only the SBVS capability to perform the fuel handling accident safety function is affected, and the i
case where both the fuel handling accident and the LOCA safety functions are affected. We find that this proposed change provides clear direction to the operators.
Parts b and c are consistent with the previously approved existing specification.
It clarifies that the compensatory measures are mode independent and assures availability of the LOCA mitigation safety function in part b, and the fuel handling accident safety function in part c, consistent with the plant safety analysis and NUREG-1432, LC0 3.6.13, " Shield Building Exhaust cleanup System (SBEACS)" (for part b), and LCO 3.7.14, " Fuel Building Air Cleanup System (FBACS)" (for part c).
CONCLUSION The NRC staff concludes that the proposed changes are administrative in nature and provide a clearer and more concise direction to the FPL operators.
The changes are consistent with the format and content of the current plant TS as well as the technical substance of the corresponding specifications in NUREG-1432. Thus, we find the proposed changes acceptable.
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