ML20215E297
| ML20215E297 | |
| Person / Time | |
|---|---|
| Site: | Berkeley Research Reactor |
| Issue date: | 03/17/1969 |
| From: | Mark H CALIFORNIA, UNIV. OF, BERKELEY, CA |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20215E220 | List:
|
| References | |
| FOIA-86-811 1005, NUDOCS 8612220056 | |
| Download: ML20215E297 (2) | |
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- 2 2. y UNIVERS11T OF CAL 1 <ORNIA, BERKELEY BERKELEY
- DAVIS. IRVINE
- LOS ANCELES. BIVER$1DE
- SAN DIECO. SAN FRANCISCO e
SANTA BARBARA
- SANTA CBUZ g369 COLLECE OF ENGINEERINC BERKELEY. CALIFORNIA 94720' O
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_ _ DEPARTMENT OF 2WCLEAR ENGINEERING ghCENG e
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Director Division of Reactor Licensing O
U. S. Atomic Energy Commission Washington, D. C.
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Dear Sir:
In order to provido the Commission with additional information in support of our request for Change #2, license R101, dated April 18, 1968, a series of pool temperature measuromonts woro made at IhM with different rod banks.
All measuromonts were taken with the secondary sido of the heat exchange secured and the linear channel indicating 1hM.
Our original thermal calibration of the reactor pool indicated a 0.38 C/ hour rise with a 52KW heat input.
Extrapolating to lhM would give 7.3 C/ hour.
At the same time that those temperature readings were being taken, the Safety Channel output was recorded.
Those data are tabulated below:
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DATE ROD BANK LINEAR CIIANNEL hr 9/26 Balanced I hM 89-93 7.3 10/2 Shim in 1 hN 84-87 6.9 10/7 TR in 1 LM 84-86 7.2 10/17 Balanced 1 LM 97-98 7.3 11/6 Balanced 1 AM 105-10G 7.3 12/11 Balanced I hM 103-10G 6.6 12/17 Rog. in 1 hM 88-99 7.2 2/6 Balanced 1 hM 101-103 7.3 3/13 Rog. in 1 hM 88-90 7.1 The temperature measuromonts indicate that the core is never operating at greator than IhM (7.3*C.'3r) and, depending on the rod bank, also that the core is never operating at more than 9.G% loco than 1hM (G.G C/hr.).
By contrast, the Safety Channel shows variations as great as 26% at IhM as determined on the linear channel.
In order to comply with our licenso as presently written, the oporator is required to adjust the set point on the Safety Channel overy time he goes critical and not loss than onco por hour.
This is a procedure which wo do not consider consistent with good safety practico.
8612220056 861216 e
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l One method of rectifying this situation would be to install a cocond compensated ion chamber with accompanying electronic readout cnd scram circuit.
The present Safety Channel electronics could not be used, since the Safety Channel detector.is a gamma chamber chich is also used to record the peak power in a pulse, and as such
-has an extremely low sensitivity.
We have not been able to find a compensated chamber that has a wide enough range to serve this dual function.
The addition of a second separate channel represents considerable expense and modification of the existing system; more than we feel desirable to undertake.
We have also considered the possibility of re-locating the Safety Channel detector in the hope that we might find a position where it would more closely track the linear chamber, We feel that this is an unsatisfactory solution in that the detector would have to be above the top grid plate (it is presently about six inches below the bottom grid plate).
This would require attaching some kind of positioning fixture to the detector since location of the detector above the top grid plate would mean that it would only be supported by a bracket attached to the bridge.
Attaching this fixture would pose a serious potential for radiation exposure since the detector has been in the core since startup and is intensely radioactive.
It is also possible that repositioning the detector would not solve the problem in that a position above the core would allow the control rods to shadow it much as the fuel followers do in its present position.
We therefore submit this data in support of'our request for an amendment to our license.
We fool that this amendment provides the b3st solution to the present situation which we feel needs correcting.
Sincerely, Hans Mark Reactor Administrator HM:1b State of California)
)
County of Alameda
)
Defore me personally appeared Hans Mark, to me known to be the person who signed the foregoing instrument in my presence, and made oath before me to the allegations set forth therein, on the seventeenth day of March, 1969.
Witnessed my hand and seal Margaret A. Hardy Notary public I
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