ML19319C906: Difference between revisions
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l. | |||
$O Report on C?.DCS 3reaker Cabinet Seis=ic Qualification jv | |||
-l O ) | |||
Thir report, pursuant to 10 CFR 50.53(e) on 'Significant Deficiencies, is to S | |||
document the investigation of the significant deficiency 'in the seis=ic qual-U 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, | |||
Thir report, pursuant to 10 CFR 50.53(e) on 'Significant Deficiencies, is to | floor is inadequate to withstand the SSE acceleration levels. | ||
1 Analysis l | |||
document the investigation of the significant deficiency 'in the seis=ic qual-ification on the Control Rod Drive Control Syste= Trip Breaker Cabinets. | The. Control Rod Drives are trippad by Loss of Power to the Drive Stators. | ||
t f | Pcwer is interrupted by disengaging either the AC or DC CRD breakers. | ||
Should the I | |||
1 Analysis | 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 | |||
t | 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 | 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 | |||
i l | thus considered to be a Significant Deficiency as par 10 CFR 50.55 (e). | ||
i Corrective Acticn l | |||
Breakers Cabinets to the floor could adversely affect safety. This i. roble: is t | 'Ihe attach =ent of the AC Breaker Cabinet to the. floor has been redesigned. | ||
thus considered to be a Significant Deficiency as par 10 CFR 50.55 (e) . | De-l I | ||
Pending upen the arrange =ent at the particular site, either additional bolts | |||
[ | |||
Corrective Acticn | will be included or a fillet veld will be added to increase the attachnent strength, l | ||
)a ] | |||
l' Each plant is being evaluated on an individual basis. | |||
l' j | |||
j | 8008040fST u= | ||
-. = | |||
. = = | |||
_ _ _ _ . = . _}} | _.,.a _, | ||
_ _ _ _. =. _ | |||
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Latest revision as of 19:32, 1 January 2025
| 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 Report on C?.DCS 3reaker Cabinet Seis=ic Qualification jv
-l O )
Thir report, pursuant to 10 CFR 50.53(e) on 'Significant Deficiencies, is to S
document the investigation of the significant deficiency 'in the seis=ic qual-U 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
'Ihe attach =ent of the AC Breaker Cabinet to the. floor has been redesigned.
De-l I
Pending upen the arrange =ent at the particular site, either additional bolts
[
will be included or a fillet veld will be added to increase the attachnent strength, l
)a ]
l' Each plant is being evaluated on an individual basis.
l' j
8008040fST u=
-. =
. = =
_.,.a _,
_ _ _ _. =. _
.