ML20215E264
| ML20215E264 | |
| Person / Time | |
|---|---|
| Site: | Berkeley Research Reactor |
| Issue date: | 07/09/1976 |
| From: | Prussin S CALIFORNIA, UNIV. OF, BERKELEY, CA |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20215E220 | List:
|
| References | |
| FOIA-86-811 7226, NUDOCS 8612190071 | |
| Download: ML20215E264 (4) | |
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CALIFORNIA, BERKELEY pg, SANTA BARBARA
- SANTA CRUZ BEREI2.EY
- DAVIS. tRVINE
- 14$ ANGELES
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- FEREELEY, CALIFORNIA 94720
- COLLEGE OF ENCINEERINC
- DEPARTMENT OF NUCLEAR ENCINEERINC
-July 9, 1976 l
Docket No. 50-224 I
l Director Division of Operating Reactors Office of Nuclear Reactor Regulations U.S. Nuclear Regulatory Commission Washington D. C. 20555
Dear Sir:
For your information I would like to report an unusual occurrence l
on the Berkeley Research Reactor linear power channel during a thermal power calibration on the 6th of July 1976.
The sequence of events are as follows:
1)
On the 28th of June, 1976, for the first time, the reactor was taken to 1 MW after a routine annual fuel measurement and inspection.
t The temperature rise was noted to be 7.4*C/h.
i The BRR standard power coefficient is 7.3*C/h.lMW thermal.
I Since measurement accuracy specified by General Atomic is l
within 5%, we consider this operation within normal limits.
2)
On the 29th of June the linear recorder response was
'd checked with an external current.
The reading indicated a value i
of 7.33 x 10-7 Amp /kW indicated on the linear recorder, which I
corresponded to our standard calibration current.
l l
The reactor was then taken to 800 kW, as indicated on l
the linear recorder for 1/2 hour.
Surprisingly, a temperature I
rise of 3.4*C was noted.
This corresponds to a power coeffi-l cient of 8.5 C/h-1 MW thermal.
This value is approximately 16% higher than the standard 7.3*C/h-1MW thermal.
3)
During the period 30th of June to 2nd of July 1976 I
the linearity of the linear recorder was checked.
It was found l
that the linear recorder functions quite linearily (within + 5%)
~
l for the entire 1 MW range.
l Also, several 500 kW runs, as indicated on the linear recorder, were made.
Results of these runs suggest that the I
new standard calibration current is in the range of:
-7 6.3'to 6.7 x.10 Amps /lkW as indicated on the linear recorder.
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tor,~Div. of Oper. Reactors July 9, 1976 A final.new standard calibration current of 6.44x10-7 Amp /lkW was.then established.
On' July 2, using this new~ standard calibration current a power calibration was again made at 500 kW for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
An average of 3.6*C/h.500kW was noted which corresponds to 7.2*C/h.lMW thermal.
j 4)
Since linearity (within 5%) of the linear recorder was established, the reactor was taken on July 6 to 1 MW for 26 minutes.
The first 20 minute reading indicates the temperature rise of 4
(22. 7 - 19. 3*C) = 3.4 *C/20 minutes at 1 MW indicated on the i
linear recorder or 10.2*C/h at 1 MW indicated on the linear recorder.
The following 5 minute reading indicates a temperature
~
difference of (23.4*C - 22.7*) = 0.7*C/5 min at 1 MW indicated on the linear recorder or 8'.4*C/h at 1 MW indicated on the linear recorder.
3 The reactor was scrammed.
This unusual occurrence was immediately reported to Mr.
J. L. Crews, Chief of Reactor Operations and Nuclear Support Branch, U. S. Nuclear Regulatory Commission, Walnut Creek, Calif.
Our previous experience indicates that temperature rise during the first 30 minutes of the power calibration is always high.
This can be seen from the large difference of the power coefficients during the first 20 minutes, and the next 5 minutes of the experiment run on the 6th of July.
At the present time it is still too early to firmly establish whether we have exceeded our current 1 MU thermal power limit.
Also,.what caused the problem is.still unknown.
It is important to note that during these various power calibrations it was found that the High Voltage was inadvertently connected to 800 V rather than the normal 300 V.
5)
A more conservative measurement will be performed in the coming days to check the linearity and other characteristics of the linear ion chamber itself and other thermal characteristics of the reactor.
6)
A second report will be sent to your office as soon as more information explaining the above occurrence can be gathered.
Very truly yours, St. AG. 9M S. G.
Prussin SGP: irs Reactor Administrator cc:
Mr. J.
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Steiner L. L. Schmelzer t
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Dear Sir:
.en C
For your information I would'like to report an unusual occurrence on the Berkeley Research Reactor linear power channel during.a thermal power calibration on the 6th of July 1976.
The sequence of events are as follows:
3-i v.,1):
On the;28thz of;, June,,1976, for-the first time, the reactor was taken to 1 MW after a routine annual fuel measurement 3
and inspection.
The temperature;risejwas,noted to.be 7.4*C/h.
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..w.r u:. 1, e t r.1 m L-Thef BRR atandard power: coefficie_ t,iis~.7.3'C/h.1MW thermal.
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Since measurement accuracy specified by General Atomic is within.5%,1we-consider this;, operation within normal limits.
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2.-
neneg2). e.Onlthel,29theof J.une the linear recorder response was checked with an external;.. current.
The' reading, indicated a value of 7.33 x 10-7 Amp /kW indicated on the linear recorder, which corresponded to our standard calibration current.
The reactor was then>.taken,to.800; kW,, as indicated on the. linear recorder for 1/2 hour.f Surprisingly, a temperature
~
l
.2 rise;of 3.4*C was noted.g Thi.s, corresponds.to,a power coeffi-
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cient of 8.5'C/h-1 MW thermal.
Th'i~s" val ~ue~is' approximately 16% higher than the standard 7.3*C/h-1MW thermal.
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3)
During the period.30thmof Junetol2nd"of' July.1976
..,,the linearity of the. linear recorder was ' checked'.
It was found that the linear recoi-der functions quite linearily (within + 5%)
for the entire 1 MW range.
Also, several 500 kW runs, as indicated on the linear recorder,'were made.
Results of these runs suggest that the f
i new standard calibration current is in the range of:
-7 6.3 to 6.7 x 10 Amps /lkW as indicated on'the linear recorder.-
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l.EZ i.TA?firial_new f standardicalibration current ~of 'h 6.44x10-7.. Amp /1kWLwas.then established.
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- 'y on July:2nusing this new standard: calibration current a M
D power calibration'was again made at_500 kW for22> hours.e An average of 3.6tc/h.500kW was noted which corresponds:to 1.,
-7.2*C/h.1MW thermal.~
,~
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S 4)
Since linearity (within 5%) of the linear recorder was
~
established, the reactor was taken on July'62to 1 MW for-26: minutes.
-The first 20 minute reading-indicates the temperature rise'of
- (22.7 - 19.3*C) = 3.4*C/20 minutes at 1 MW indicated on the--
linear recorder or 10.2'C/h at 1 MW indicated on the linear recorder. i The following 5 minute reading indicates a temperature ~ ~
difference of (23.4*C - 22.7*) = 0.7'C/5 min at 1 MW indicated on the linear recorder or8.4*C/h at 1 MW indicated on the: linear recorder."..!-
t y 93 ; -
>. a The reactor was. scrammed.
- m.m..
This unusual occurrence was immed'iately reported to Mr.
J. LP Crewsi. Chief of? Reactor.' Operations'and2 Nuclear Support Branch',UF S.lNuclsar' Regulatory' Commission,~ Walnut Creek, Calif.
Our previous experience indicaties' that'/ temperature rise during the firstD30>minutis,%fithe powericalibration is always 4
high.. This can,be.,seenTfrom.ythe',largeldi.fference of-the power coefficients during the#Thsti20Y i'nuths,Cliid*;the next-5 ' minutes N
m of the experiment runlon.the'6th0of July.T z.: m.
At"the @ e'ssnt5$ltis5 t is still;too'early3to firmly establish I
i T
whether we'.have. exceeded our current 1 MW thermal power limit.
.Also, what?caushd1the p'roblem-is still unknown.
It is important to note that" durliis*%es'e*various' power Ecalibrations it was found 1
that the High Voltage'was inadvertently connected to 800 V rather than the normal'300-V.' '- - -
1 5)
A moreN onservatiYe mea'surement will be performed in the
~
~
coming days to. check the linearity.and other characteristics ~of the linear 1 ion chamber'itself and other/ thermal characteristics -
~
1 '~
.,'T'.
of the reactor'..
_ o 6)
A second report will be.sent to your. office as soon as more information expla,ining the above^ occurrence can be gathered.
l m, cc v,y
. m.
Very.truly yours,
.ep4foqG.9 M r
+
- z. c S. G. Prussin SGP: irs Reactor Administrator cc:
Mr. J. L. Crews
..,.H...Steiner 4
L. L. Schmelzer, i
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