ML15324A443
| ML15324A443 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 11/19/2015 |
| From: | Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML15324A443 (12) | |
Text
Ice Condenser
Ice Condenser 2
Purpose Ice Condenser Overview TS Surveillances - Proposed Change History - Basis for Change Questions
Ice Condenser Overview Passive Heat Removal System Contains at least 2,750,700 lbs of ice Two main regions Ice Bed and Upper Plenum Ice bed separated from containment by lower inlet doors Ice bed separated from upper plenum by intermediate deck doors Upper plenum separated from containment by top deck doors 3
Ice Condenser Overview (Cont.)
4
Ice Condenser Overview (Cont.)
5
Ice Condenser Overview (Cont.)
6 Lower Door Turning Vanes
Ice Condenser TS Surveillances 7
Three Lower Inlet Door Surveillances (3.6.12.3, 4, & 5) 3.6.12.3 - Visually inspect each door 3.6.12.4 - Torque to begin to open door 3.6.12.5 - Torque to open & close door Frequency Once per 3 months in first year Once per 18 months
Ice Condenser TS Surveillances (Cont.)
8 Proposed change allows first cycle operation until the end of the cycle aligned with the power ascension program Approximately 10 month long cycle Surveillance changes SR 3.6.12.3 Verify, by visual inspection, each inlet door is not impaired by ice, frost, or debris.
Twice during the first cycle after receipt of the license AND 18 months
Ice Condenser TS Surveillances (Cont.)
9 SR 3.6.12.4 Verify torque required to cause each inlet door to begin to open is 675 in-lb.
Twice during the first cycle after receipt of the license AND 18 months SR 3.6.12.5 Perform a torque test on a sampling of 50% of the inlet doors.
Twice during the first cycle after receipt of the license AND 18 months Surveillance changes (cont.)
Ice Condenser Basis For Change Basis for Change Doors simple & highly reliable Nine Ice Condenser Units with 20 to +30 years of operation Operating experience shows very few failures First cycle failures SR 3.6.12.3 - None SR 3.6.12.4 - 2 (1975 & 1978)
SR 3.6.12.5 - 1 (1996)
Prevents an otherwise unnecessary plant shutdown Three month Specification frequency was used to establish an operating history for new plant type design 10
Summary 11 Revise Frequency for Surveillances 3.6.12.3, 4, & 5 Doors simple and highly reliable Supported by many years of operating experience Prevents an unnecessary plant shutdown
Ice Condenser Questions 12
Ice Condenser
Ice Condenser 2
Purpose Ice Condenser Overview TS Surveillances - Proposed Change History - Basis for Change Questions
Ice Condenser Overview Passive Heat Removal System Contains at least 2,750,700 lbs of ice Two main regions Ice Bed and Upper Plenum Ice bed separated from containment by lower inlet doors Ice bed separated from upper plenum by intermediate deck doors Upper plenum separated from containment by top deck doors 3
Ice Condenser Overview (Cont.)
4
Ice Condenser Overview (Cont.)
5
Ice Condenser Overview (Cont.)
6 Lower Door Turning Vanes
Ice Condenser TS Surveillances 7
Three Lower Inlet Door Surveillances (3.6.12.3, 4, & 5) 3.6.12.3 - Visually inspect each door 3.6.12.4 - Torque to begin to open door 3.6.12.5 - Torque to open & close door Frequency Once per 3 months in first year Once per 18 months
Ice Condenser TS Surveillances (Cont.)
8 Proposed change allows first cycle operation until the end of the cycle aligned with the power ascension program Approximately 10 month long cycle Surveillance changes SR 3.6.12.3 Verify, by visual inspection, each inlet door is not impaired by ice, frost, or debris.
Twice during the first cycle after receipt of the license AND 18 months
Ice Condenser TS Surveillances (Cont.)
9 SR 3.6.12.4 Verify torque required to cause each inlet door to begin to open is 675 in-lb.
Twice during the first cycle after receipt of the license AND 18 months SR 3.6.12.5 Perform a torque test on a sampling of 50% of the inlet doors.
Twice during the first cycle after receipt of the license AND 18 months Surveillance changes (cont.)
Ice Condenser Basis For Change Basis for Change Doors simple & highly reliable Nine Ice Condenser Units with 20 to +30 years of operation Operating experience shows very few failures First cycle failures SR 3.6.12.3 - None SR 3.6.12.4 - 2 (1975 & 1978)
SR 3.6.12.5 - 1 (1996)
Prevents an otherwise unnecessary plant shutdown Three month Specification frequency was used to establish an operating history for new plant type design 10
Summary 11 Revise Frequency for Surveillances 3.6.12.3, 4, & 5 Doors simple and highly reliable Supported by many years of operating experience Prevents an unnecessary plant shutdown
Ice Condenser Questions 12