ML19347B605
| ML19347B605 | |
| Person / Time | |
|---|---|
| Site: | Vallecitos File:GEH Hitachi icon.png |
| Issue date: | 10/13/1980 |
| From: | Darmitzel R GENERAL ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8010150428 | |
| Download: ML19347B605 (5) | |
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G E N E R A L h; E LE CTR IC
" * ' ^ " ' " " " "
ENGINEERING GEWERAL ELECTRIC COMPANY. P.O. box 460, PLEASANTON, CAllFORNIA 94566 DIVISION October 13, 1980 I
l Mr. Robert A. Clark, Chief Operating Reactors Branch #3 l
Division of Licensing l
S. Nuclear Regulatory Commission i
- k. tington, D.C.
20555 n
Subject:
Responses to Additional Information Request Regarding 1
l Seismic Scram System for the General Electric Test Reactor (GETR) - License TR Docket 50-70
Dear Mr. Clark:
Attached are responses to the additional information request regarding i
the ability of the GETR seismic scram system to operate following a postulated 0.25g pulse of short duration during the first 250 milli-seconds of an earthquake.
Additional records of the Parkfield and Imperial Valley earthquakes were also requested and are enclosed.
These records confirm previous conclusions that no significant ground motion occurs during the first 500 milliseconds following actuation of the seismic recorder.
Very truly yours, h
O'l R. W. Darmitzel, Manager Irradiation Processing Operation
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Attachment i
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h AFFIRMATION t
The General Electric Company hereby submits the " Responses to Additional Information Request Regarding Seismic Scram Systen for the General Electric Test Reactor".
i To the best of my knowledge and belief, the information contained f
herein is accurate.
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- C2 0 An Z Y
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R. W. Darmitzel, Manager Irradiation Processing Operation f
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Sub tted and sworn efore me this 13th day of October, 1980, j'
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, Notary Public in and
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t Response to Additional Information Request Regarding Seismic Scram System for the General Electric Test Reactor The following information is furnished in response to a postulated condition where a short duration seismic pulse occurs in the 0.25-second interval after seismic trip in which the GETR scram circuitry must operate satisfactorily. ' (The only pulse of this nature that was observed in the 87 records previously examined occurred after 0.5 seconds and was about 0.25g.)
Seismic Switch The seismic switch is accurate to 5% and will be set to actuate upon a ground motion of 0.01g.
The length of time required to operate the switch is 0.005 seconds. This equipment has been demonstrated to operate when cabinet mounted after exposure to a 0.5g event.
Control Building The basic structure of the control building has been investigated and is capable of withstanding accelerations above 0.39 The appurtenances (ceilings, partitions, lighting, etc.) may require minor modifications to insure they will not interfere with the seismic scram systems during,a 0.25g pulse.
These modifications, if required, will be completed prior to restart of the GETR.
Control Consoles Analysis'will be performed to confirm the adequacy of the cabinets and relay mount frames.
It appears the cabinets will require a few additional anchor bolts.
In the event cabinet strengthening is required, braces will be added.
The relay mount screws appear satisfactory and will be checked by calculation.
The bundled wires will be tied down if necessary.
Additional Seismic Record Review One additional Parkfield array and six additional Imperial Valley arrays were examined, and all were found to be within the bounds of the previously submitted values.
The maximum acceleration values within the noted time intervals are given in the following table and confirm the previous conclusion that no significant acceleration values occur within the first 0.5 seconds after initiation of the seismic recorders.
It was further determined that the seismic records do not start until at least 0.08 seconds after the seismic switch is tripped.
This adds to the conservatism and allows an additional 0.08 seconds for the scram system to function prior to the occurrence of significant ground motion.
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l Sumary The components of the seismic scram system are very sturdy and capable i
of withstanding short pulses of up to 0.25.
All observations will be 9
confirmed by calculation.
Any fixes required will likely be minor and will be completed prior to restart.
Additional seismic records were examined, and the results are within the limits of the data previously submitted (letter, R. W. Darmitzel to i
R. A. Clark, September 16,1980).
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..t TABLE 1.
Maximum Acceleration at Different Intervals After Trigger at 0.01g Station Component 0.25 sec.
0.5 sec.
1 sec.
2 sec.
i Parkfield Array-2 H
.0143
.0205
.0227
.0680 06/27/?6 V
.0324
.0324
.0599
.1902 Imperial Valley (IV)
H
.0116
.0116
.0116
.0140 r
V
.0080
.0205
.0205
.0374 j
g 4
(IV) Array-2 H
.0032
.0052
.0073
.0186 10/15/79 V
.0262
.0655 '
.0813
.1104 (IV) Array-3 H
.0027
.0072
.0072
.0099 10/15/79 4
V
.0426
.0783
.0783
.0783 (IV) Array-11 H
.0040
.0074
.0074
.0147 10/15/79 Y
.0179
.0327
.0482
.0482 (IV) Array-12 H
.0046
.0046
.0085
.0109 10/15/79 Y
.0160
.0227
.0325
.0325 (IV) Array-13 H
.0074
.0075
.0109
.0121 10/15/79 V
.0203
.0203
.0203
.0203 l
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