ML19319C906: Difference between revisions
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$O jv Report on C?.DCS 3reaker Cabinet Seis=ic Qualification ' | |||
$O jv | |||
Thir report, pursuant to 10 CFR 50.53(e) on 'Significant Deficiencies, is to | Thir report, pursuant to 10 CFR 50.53(e) on 'Significant Deficiencies, is to | ||
-lSUO ) | -lSUO ) | ||
document the investigation of the significant deficiency 'in the seis=ic qual-ification on the Control Rod Drive Control Syste= Trip Breaker Cabinets. | document the investigation of the significant deficiency 'in the seis=ic qual-ification on the Control Rod Drive Control Syste= Trip Breaker Cabinets. | ||
t f Identification of Proble=s A reevaluation of the seis=ic qualification of the control rod drive control i system AC breaker cabinets has found that the attach =ent of the cabinet to the i, floor is inadequate to withstand the SSE acceleration levels. | t f Identification of Proble=s A reevaluation of the seis=ic qualification of the control rod drive control i system AC breaker cabinets has found that the attach =ent of the cabinet to the i, floor is inadequate to withstand the SSE acceleration levels. | ||
1 Analysis | 1 Analysis | ||
* l The . Control Rod Drives are trippad by Loss of Power to the Drive Stators. Pcwer | * l The . Control Rod Drives are trippad by Loss of Power to the Drive Stators. Pcwer | ||
| Line 36: | Line 29: | ||
' f. | ' f. | ||
breaker function be disabled in some =anner, the Control Rods would have to be driven into the core to shut the reactor down. | breaker function be disabled in some =anner, the Control Rods would have to be driven into the core to shut the reactor down. | ||
t O | |||
j In the event of an SSE, the AC Breaker Cabinets could, as per the analysis, i break loose fco= the floor =ounting. With the cabinets unattached, the rando: | |||
t | |||
: | |||
i motion of dancing, bouncing, and even falling over could cause accelerations of the breakers that have not been analyzed or damage to the breakers, wiring, or I | i motion of dancing, bouncing, and even falling over could cause accelerations of the breakers that have not been analyzed or damage to the breakers, wiring, or I | ||
, connections which could conpro=ise the ability of the breakers to trip the | , connections which could conpro=ise the ability of the breakers to trip the f control rods. Analyses cannot show that the failure will always be fail safe. | ||
f control rods. Analyses cannot show that the failure will always be fail safe. | |||
i l Therefore, the deficiency in the design of the structural attach =ent of the AC l | i l Therefore, the deficiency in the design of the structural attach =ent of the AC l | ||
Breakers Cabinets to the floor could adversely affect safety. This i. roble: is t | Breakers Cabinets to the floor could adversely affect safety. This i. roble: is t | ||
thus considered to be a Significant Deficiency as par 10 CFR 50.55 (e) . | thus considered to be a Significant Deficiency as par 10 CFR 50.55 (e) . | ||
i Corrective Acticn l | |||
l - 'Ihe attach =ent of the AC Breaker Cabinet to the. floor has been redesigned. De-I Pending upen the arrange =ent at the particular site, either additional bolts l [ will be included or a fillet veld will be added to increase the attachnent strength, l' )al' | |||
Corrective Acticn | |||
] Each plant is being evaluated on an individual basis. | ] Each plant is being evaluated on an individual basis. | ||
j 8008040fST u= .- - . = . | j 8008040fST u= .- - . = . | ||
. = = .. _. , .a _, | . = = .. _. , .a _, | ||
_ _ _ _ . = . _}} | _ _ _ _ . = . _}} | ||
Revision as of 05:08, 1 February 2020
| ML19319C906 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 10/03/1974 |
| From: | BABCOCK & WILCOX CO. |
| To: | |
| Shared Package | |
| ML19319C884 | List: |
| References | |
| NUDOCS 8003040856 | |
| Download: ML19319C906 (1) | |
Text
.
- l. ,
$O jv Report on C?.DCS 3reaker Cabinet Seis=ic Qualification '
Thir report, pursuant to 10 CFR 50.53(e) on 'Significant Deficiencies, is to
-lSUO )
document the investigation of the significant deficiency 'in the seis=ic qual-ification on the Control Rod Drive Control Syste= Trip Breaker Cabinets.
t f Identification of Proble=s A reevaluation of the seis=ic qualification of the control rod drive control i system AC breaker cabinets has found that the attach =ent of the cabinet to the i, floor is inadequate to withstand the SSE acceleration levels.
1 Analysis
- l The . Control Rod Drives are trippad by Loss of Power to the Drive Stators. Pcwer
! is interrupted by disengaging either the AC or DC CRD breakers. Should the I f
' f.
breaker function be disabled in some =anner, the Control Rods would have to be driven into the core to shut the reactor down.
t O
j In the event of an SSE, the AC Breaker Cabinets could, as per the analysis, i break loose fco= the floor =ounting. With the cabinets unattached, the rando:
i motion of dancing, bouncing, and even falling over could cause accelerations of the breakers that have not been analyzed or damage to the breakers, wiring, or I
, connections which could conpro=ise the ability of the breakers to trip the f control rods. Analyses cannot show that the failure will always be fail safe.
i l Therefore, the deficiency in the design of the structural attach =ent of the AC l
Breakers Cabinets to the floor could adversely affect safety. This i. roble: is t
thus considered to be a Significant Deficiency as par 10 CFR 50.55 (e) .
i Corrective Acticn l
l - 'Ihe attach =ent of the AC Breaker Cabinet to the. floor has been redesigned. De-I Pending upen the arrange =ent at the particular site, either additional bolts l [ will be included or a fillet veld will be added to increase the attachnent strength, l' )al'
] Each plant is being evaluated on an individual basis.
j 8008040fST u= .- - . = .
. = = .. _. , .a _,
_ _ _ _ . = . _