ML19347C573
| ML19347C573 | |
| Person / Time | |
|---|---|
| Issue date: | 09/15/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | AFFILIATION NOT ASSIGNED |
| References | |
| NUDOCS 8012310117 | |
| Download: ML19347C573 (1) | |
Text
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o UNITED STATES 8
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SUITE 202, WALNUT CREEK PLAZA
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,s-WALNUT CREEK, CALIFORNIA 94506 September 15, "J80 suAKIMI MLt:{ CAL CEgTER 347 AUa<INI 4,
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1 Gentlemen:
The enclosed Information flotice 80-33 is for.iarded to you for information.
If there are any cuestions related to'the suggested actions, please contact i
this office.
Sincerely, i
!.W+~,cCGi i
R. H. Engelken Director i
. Enclosures :
1.
IE Information I otice flo. 80-33 2.
Recently Issued IE Information !!otices l
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l 9c12810117 i.,_,_.....___,.._______.,_.____._._____..__.,_.____.____._....._.._._,-_-...__.-
.s SSINS No.: 6830 Accession No:
8006190078 4
IN 80-33 UNITED STATES NUCLEAR REGULATORY COMMISSION J [f s
" ~9 g 9 WASHINGTON, D.C.
20555
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0FFICE OF INSPECTION AND ENFORCEMENT
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September 15, 1980 IE Information Notice No. 80-33:
DETERMINATION OF TELETHERAPY TIMER ACCURACY Description of Circumstances:
New requipments for full calibration and spot-check measurements of teletherapy One of the determinations required is " timer accuracy" !i!i35.21(b)(45535.21 - 35.25 of units in and 35.22(b)(1).
Recent inspections conducted by the U.S. Nuclear Regulatory Commission (NRC) have determined that many licensees and consultant physicists have misunderstood this requirement. The purpose of this information notice is to clarify the meaning of " determination of timer accuracy (i.e., timer 4
error)" as used in these regulations.
There is a finite error in source output measurements due to the time required for the source shutter mechanism to travel from the full "off" to full "on" condition and return. This error may be positive or negative, depending on when the timer movement starts with respect to source travel.
It is the determination of this " timer error" that is required in the regulations as part of full calibrations and monthly spot-check measurements. The timer error, once determined, may be corrected by adding its value (positive or negative) to the treatment time or exposure time during calibrations and spot-check measurements. Omission of this correction may introduce substantial error into short irradiations.
Further, a significant change in timer error from month to month may indicate a timer malfunction or source movement mechanism failure or both.
The timer error and armpDMc. tc for its determination are described in detail in 54.14 of ANSI Standard f1449.1-1978*. Comparison of the console timer with a stopwatch is not an acceptable substitute for this determination.
ACTION TO BE TAKEN BY LICF'! SEES:
Full calibration and spot check measurements performed on your teletherapy unit should include the determination of timer error as described above.
This information notice should be brought to the immediate attention of the qualified expert (10 CFR Part 35.24) performing these calibrations and measurements.
No response to this information notice is required.
If you need additional information regarding this matter, contact the Fuel Facility and Material Safety Branch of the appropriate NRC Regional Office.
- Copies of ANSI Stanc'ard N449.1-1978 may be obtained from the American National Standards Institute, Inc.,
1430 Broadway, New York, New York 10018.
., ~ _ _. _.,.
1 4
IN 80-33 September 15, 1980 RLCENTLY ISSUED IE IflF0hMATION NOTICES l
i Information Nte of Notice No.
Subject Issde Issued to i
j 80-32 Clarification of certain 8/12/80 All NRC and agreement requirements for Exclu-state licensees sive-use shipments of radioactive materials 80-31 Maloperation of Gould-8/27/80 All light water reactor Brown Boveri Type 480 facilities holding OLs volt type K-600S and or cps
)
K-DON 6005 circuit breakers l
80-30 Potential for unaccept-8/19/80 All boiling water reactor able interaction between facilities holding power 5
the control rod drive scram reactor OLs or cps.
4 function and non-essential control air at certain GE BWR facilities t
80-29 Broken studs on Terry 8/7/80 All light water reactor turbine steam inlet facilities holding flange power reactor OLs or cps
- i Supplement to flotification of 7/29/80 All holders of reactor i
80-06 significant events at and near-term OL operating power reactor applicants i
facilities 80-28 Prompt reporting of 6/13/80 All applicants for and required information holders of nuclear power to NRC reactor cps i
80-27 Degradation of reactor 6/11/80 All pressurized water coolant pump studs-reactor facilities I
holding power reactor i
OLs or cps 80-26 Evaluation of contractor 6/10/80 All Part 50 licensees QA programs 80-25 Transportation of 5/30/80-Material licensees in pyrophoric-uranium priority categories II-A, l
II-D, III-I and.IV-DI;
~
j agreement state licensees in equivalent categories
- Operating Licenses or Construction Permits l
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