ML19275A537
| ML19275A537 | |
| Person / Time | |
|---|---|
| Issue date: | 08/31/1979 |
| From: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | |
| References | |
| RTR-REGGD-8.028, TASK-OH-804-4, TASK-OS REGGD-08.XXX, REGGD-8.XXX, NUDOCS 7910040608 | |
| Download: ML19275A537 (19) | |
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s U.S. NUCLEAR REGULATORY COMMISSION August 1979 7 'i ) + (
0 0FFICE OF STANDARDS DEVELOPMENT Division 8 E
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DRAFT REGULATORY GUIDE AND VALUE/ IMPACT STATEMENT Task OH 804-4 v
s, AUDIBLE-ALARM 00SIMETERS A.
INTRC9UCTION Section 20.201, " Surveys," of 10 CFR Part 20, " Standards for Protection Against Radiation," states that licensees must make or cause_to be made such surveys to evaluate radiation hazards as may be necessary for the licensee to comply with the regulations of Part 20.
Section 20.202, " Personnel Monitoring,"
requires the use of appropriate personnel monitoring equipment to determine whether any radiation dose is being or has been received.
Licensees sometimes supplement such monitoring equipment with electronic pocket dosimeters that have an audible alarm to warn workers that they may be_ receiving more exposure to radiation than they had expected or had planned.
This guide discusses the appropriate use;of audible-alarm dosimeters, including certain conditions under which they should not be relied upon to perform their intended function.
The guide also discusses performance speci-fications that the dosimeters should meet if they are used.
In this guide, the term " audible-alarm dosimeters" refers to electronic dosimeters that alarm when either a preset integrated exposure or a preset exposure rate is reached.
The term also includes " chirpers," those devices that sound a brief " chirp"~ or " beep" every time some small exposure such as 1 milliroentgen or less is recor'ded.
B.
DISCUSSION 1101 109 Several types of= work lend themselves to the advantageous use of audible-alarm dosimeters.
For example, audible-alarm dosimeters may have uses during nuclear power plant maintenance operations.
The alarm can warn a worker that he or she is being exposed unexpectedly.
The alarm can also tell a worker s regulatory guide and the associated value/ impact statement are being istued in draft form to involve the pubile in the early stages of the development of a regulatory position in this area.
They have not received complete staff review and do not represent an official NRC staff position.
Public coments are being solicited on both draf ts, the guide (including an y implementation schedule) and the value/ impact statement. Comments on the value/ impact statement should be accompanied by supporting data.
Coments on both draf ts should be sent to the secretary of the Commission, U.S. Nuclear Regulatory Comission, Washington, D.C. 20sss, Attention:
Docketing and Service Branch, by g Requests for single copies of draf t guides (which may be reproduced) or for placement on an automatic distribution list for single copies of future draf t guides in specific divisions should be made in writing to the U.S. Nuclear Regulatory Commission, Washington, D.C. 2055s, Attention: Director, j-Division of Technical Information and Document Control.
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that he or she is approaching allwab}e levels of radiation exposure and should prepare to leave the area.
In industrial radiography, an audible-alarm dosimeter can warn a radiog-rapher that he or she is approaching an expost.d source.
Ideally, the radiog-rapher's survey meter should nave provided a warning, but in most radiography overexposures that have occurred, the radiographer did not make proper use of the survey meter.
In low-level waste disposal, an audible-alarm dosimeter can quickly warn a worker that a particular package is more than normally radioactive and that he or she should be especially cautious in handling it.
Audible-alarm dosimeters are not generally substitutes for conventional survey meters.1 They provide some redundancy or " defense in depth" where (1) the operator fails to perform a survey, (2) the operator fails to make a fully adequate survey, or (3) the survey meter has malfunctioned, unknown to the operator.
An audible-alarm dosimeter provides a second chance when an operator is distracted or busy.
It becomes an automatic extension of his or her senses.
In these ways, audible-alarm dosimeters supplement the conventional survey meter.
The main difficulties with using audible-alarm dosimeters are related to their reliability or their improper use.
A worker wearing an audible-alarm dosimeter that has stopped working without his or her knowledge may have a false indication of safety.
Unaware that the audible-alarm dosimeter is not working, the worker may neglect other precautions such as performing radiation surveys.
In such a case, the worker could be unaware of radiation exposure levels.
These difficulties can be diminished by using the more reliable types of audible-alarm dosimeters and by following procedures for avoiding misuse.
'These subjects are discussed in the regulatory position.
To evaluate the reliability of audible-alarm dosimeters now commercially available, the NRC contracted with Battelle-Pacific Northwest Laboratory for performance testing of such dosimeters.
The results of these tests are reported IAn exception to this statement, however, can be found in the Standard Technical Specification 6.12.1, "High Radiation Area," for nuclear power plants.
The specification allows an audible-alarm dosimeter to be substituted for a survey meter.
O 1101 110 2
9 in NUREG/CR-0554, " Pocket-Sized Electronic Dosimeter Testing,"2 January 1979, written by Oscar Mulhern, William Bartlett, and C. D. Hooker.
The authors noted that 5 out of 14 models passed a performance test equivalent to that described in the Appendix to this guide.
However, they concluded that, "The pocket-sizer electronic dosimeters tested can probably withstand the polite abuse they might receive in laboratories, universities, and medical facilities.
However, they are not. useful to a radiation protection program for indi.strial radiographers.
The dosimeters tested are not capable of surviving repeated severe punishment such as that which might be encountered in a harsh industrial or outdoor environment."
Because of these limitations, the NRC staff believes that audible-alarm dosimeters are appropriate as secondary devices for surveys or personnel monitoring and then only as long as the precautions and limitations for their use described in the regulatory position are observed.
C.
REGULATORY POSITION 1.
The NRC staff approves of the use of audible-alarm dosimeters as a 9
secondary warning device in certain situations where the audible alarm could prove useful in alerting workers that they are in a radiation field or have reached a preset dose.
For example, in many instances the likelihood of a I
radiation overexposure in industrial radiographic field operations might be l
reduced by use of audible-alarm dosimeters.
As another example, workers per-forming maintenance in a steam generator of a nuclear power plant can be alerted when a preset exposure has been reached.
2.
Audible-alarm dosimeters generally should not be used as the primary warning device.1 Audible-alarm dosimeters are not an adequate substitute for a survey meter.
Instead they are a secondary warning device.
3.
Only audible-alarm dosimeters meeting the performance specifications in the Appendix to this guide should be used.
The specifications in this guide were taken from a May 11, 1979, draft of a standard under development by the Health Physics Society Standards Committee.
2 Copies are available from National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161.
($4.50) 1101 111 3
4.
Audible-alarm dosimei.ers should not be used in the following adverse situations:
a a.
Alarm Inaudible.
When the alarm may not be heard, such as (1) in a high noise environment, (2) when the user has a pronounced hearing loss, (3) when the user is wearing mufflers over the ears, or (4) when the sound from the dosimeter would be muffled by heavy clothing worn over the dosimeter.
b.
Dosimeter Soaked with Water.
When immersion in water or soaking of the dosimeter, such as from rain, is a distinct possibility.
Tests have shown that immersion in water stops all alarm dosimeters from working.
Complete dry-ing and replac ng of batteries will allow some but not all dosimeters to resume proper operation.
c.
Dosimeter Affected by Chemicals. When a salt or corrosive chemical-l uen atmosphere is present.
Salt water quickly caused all audible-alarm dosi:n-eters tested a malfunction.
5.
Each day, before use, audible-alarm dosimeters should be tested for adequate battery strength and should be checked for proper operation with a radiation source.
6.
Care should be taken to avoid dropping alarm dosimeters.
If the dosimeter is dropped, its proper operation should be verified using a radia-tion source before using the dosimeter again.
7.
In industrial radiography and similar jobs where the audible-alarm dosimeter's principal purpose is to warn against the presence of unexpectedly high radiation fields, dosimeters that alarm only when a preset integrated exposure has been reached should not be used.
Instead, " chirpers" or dosim-eters that alarm when a preset exposure rate has been reached should be used.
With this type of dosimeter, the worker would receive less exposure than with an integrating audible-alarm o.imeter.
O 4
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m D.
IMPLEMENTATION O
This section provides information to applicants on the NRC staff's plans for using this regulatory guide.
In cases in which an applicant proposes to use audible-alarm dosimeters as part of his radiation protection program, the selection and use of the audible-alarm dosimeters will be evaluated on the basis of this guide except in tho;e cases in which the applicant proposed an acceptable alternative method.
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APPENDIX PERFORMANCE SPECIFICATIONS FOR POCKET-SIZED AUDIBLE-ALARM DOSIMETERS AND RATEMETERS 1.
SCOPE This appendix establishes performance specifications for pocket-sized chirpers, audible-alarm dosimeters, and audible-alarm ratemeters.
Included within the scope of this appendix are chirpers, pocket-sized dosimeters that alarm at a preset integrated dose, and pocket-sized ratemeters that alarm at a preset exposure rate.
Nonalarming dosimeters are outside the scope of this appendix.
2.
DEFINITIONS 2.1 Chirper -- an instrument that is designed to be carried on the person and produces an audible signal of variable frequency and/or volume as a function of radiation exposure rate.
- 2. 2 Pocket Sized Audible-Alarm Ratemeter -- an instrument that is designed to be carried on the person and provides an alarm at a preset or selectable dose rate.
In addition, it may have a visual display of exposure and/or exposure rate.
2.3 Pocket Sized Audible-Alarm Dosimeter -- an instrument that is designed to be carried on the person and provides an alarm at a preset or selectable exposure.
In addition, it may have a visual display of exposure and/or exposure rate.
2.4 Device -- chirper, pocket-sized audible-alarm ratemeter, or pocket-sized audible-alarm dosimeter.
O 1101 114 6
1 3.
PERFORMANCE SPECIFICATIONS 3.1 Phwical Requirements 3.1.1.
Size Physical dimensions and weight shall not exceed the following:
a.
Width:
8 cm b.
I.ength:
16 cm c.
Thickness:
4 cm d.
Width plus thickness:
11 cm e.
Weight:
300 g 3.1.2.
If provided with a clip, the gripping power shall be sufficient to hold the device to a single layer of 10 oz cotton duck material against a constant force equal to twice the weight of the device.
3.1.3.
Devices shall be designed to withstand three free falls of 1.2 meters onto a flat concrete surface in mutually perpendicular planes.
After this test, the device shall meet all performance specifications.
(Note:
This is a prototype test.
Devices intended for subsequent use should not undergo this test.)
3.1.4.
Switches for power, alarm setpoints, and zero reset shall be pro-tected to prevent inadvertent or accidental mechanical changes of settings.
- 3. 2 Power Requirements 3.2.1.
Devices shall be equipped with a self-contained power supply.
3.2.2.
A warning indication shall be available to ensure that at least eight hours of operation in a 100 mR/h field, including at least 20 manual operations of a visual readout (if provided), remains.
1101 115 7
3.2.3.
Battery life shall exceed 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> when used continuously in a 1 mR/h field, including one manual readout per hour if a visual display is provided.
3.2.4.
If a total exposure memory is provided, the information shall be maintained in the memory for at least two hours after the primary power supply is discharged.
3.3 Controls and Features for Audible-Alarm Ratemeters and Dosimeters
- 3. 3.1.
If a noncontinuous visual display is provided, it shall have a manual readout actuator.
Activation of this actuator shall not reset the device.
Any automatic periodic display shall remain on for at least one second.
3.3.2.
If an audible alarm is supplied, a sound pressure level greater than 75 dBA at a distance of 30 cm from the device shall be provided.
If the device is to be used in a location where the ambient sound pressure level exceeds 80 dBA, provisions may need to be made for other types of warning.
(This also applies to chirpers.)
3.3.3.
If multiple alarm levels are provided, there shall be no setting or combination of settings that will cause the device to fail to alarm.
If multiple switches are used, and if more than one switch is energized, the instrument shall alarm when the lowest level determined by the energized switches is reached.
If no alarm deactivation switch is provided and all alarm switches are in the deenergized mode, the instrument shall alarm at the lowest selectable alarm level.
3.3.4.
Provision shall be made to permit adjustment of response to achieve the calibration accuracy of this appendix, and such mechanisms should be protected from inadvertent alterations in adjustment.
3.3.5.
Clearing of a total exposure memory, if provided, shall be accomplished only by means of a switch designated solely for that purpose.
1101 116 e
s t
S 3.3.6.
A jack may be provided to permit connection of a remote alarm.
Use of this jack shall not disable any other feature, circuit, or output of the device.
3.4 Response Characteristics 3.4.1.
The range of the instrument shall be specified in roentgens, roentgens per hour or submultiples thereof, or equivalent SI units.
3.4.2.
Accuracy for pocket-sized audible-alarm ratemeters and dosimeters in an exposure rate range of 0.1 to 1 R/h shall be within *20 percent referenced to the calibration source.
The calibration source shall be specified by the manufacturer.
3.4.3.
Energy dependence shall be specified and shall be within 130 per-cent over the range from 80 kev to 1.25 MeV for pocket-sized audible-alarm ratemeters and dosimeters at an exposure rate less than 1 R/h.
This paragraph is independent of paragraph 3.4.2 above.
3.4.4.
Exposure rate alarms shall continue to operate in fields up to 3
10 times the highest alarm setpoint.
~
3.4.5.
Exposure rate dependence shall be within 20 percent over the stated tseful range.
3.4.6.
Exposure accumulation shall not be terminated when the alarm is activated.
p 3.4.7.
The maximum exposure display level shall be retained until manually reset.
3.4.8.
Deviation of more than 10 percent from the reference value obtained at 20 C shall not be produced by temperatures within the stated operating tempera-ture range.
1101 117 o
9
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3.4.9.
The device shall operate properly over the relative humidity range of 20 to 90 percent, over the specified temperature range, and when cycled through the dew point at 20 C.
O 1101 118 10
DRAFT VALUE/IT ACT STATEMENT A.
THE PROPOSED ACTION 1.
DESCRIPTION The proposed action is to provide guidance on the selection of reli-able audible-alarm dosimeters and on the appropriate use of such dosimeters by industrial radiographers, nuclear power plant workers, and others as a supplemental warning of exposure to radiation.
2.
NEED FOR THE PROPOSED ACTION At times in the past, industrial radiographers have attempted to improve safety by using audible-alarm dosimeters.
For the most part these attempts have been unsuccessful for two reasons.
First, commercially available audible-alarm dosimeters often are not rugged enough to operate reliably under adverse field conditions.
Comments from some users are given in Attachment 1.
- Second, radiographers using these audible alarm dosimeters have placed less reliance on the use of survey meters.
This has often created a dangerous situation when the radiographer depended on an audible-alarm dosimeter that was not working.
The guidance is intended to allow licensees to select reliable audible-alarm dosimeters and to provide dosimeter manufacturers with criteria they can use in designing their products.
Because reliability and use of alarm dosimeters are so interconnected, they will be treated in the same guide.
B.
VALUE/ IMPACT OF THE PROPOSED ACTION 1.
NRC OPERATIONS Approximately one-half man year of staff time will be required to draft and review a "for comment" guide.
A technical assistance contract ($77,000) with Battelle-Pacific Northwest Laboratories was awarded for testing commer-cially available alarm dosimeters.
Their report was received in March 1979.
7910040b$
11 1101 119
2.
INDUSTRY The guidance will allow licensees (including industrial radiographers, nuclear power plant personnel, low-level radioactive waste disposal facility personnel, and others) to select an audible-alarm dosimeter suitable for their needs and to avoid using dosimeters that are not likely to cerform adequately.
The guidance will also alert licensees to situations where the use of audible-alarm dosimeters is not appropriate.
This will assist licensees in conducting adequate surveys and using appropriate personnel monitoring equipment.
The guidance will also provide dosimeter manufacturers with criteria to use in designing suitable dosimeters.
Some new dosimeter designs are desirable because existing audible-alarm dosimeters have not been sufficiently reliable for field use, as shown in Attachment 1.
An impact of publishing performance specifications is that the market pctential for dosimeters not meeting the specifications will be greatly reduced.
Manufacturers of those dosimeters would probably have to redesign their dosim-eters.
Licensees owning dosimeters not meeting the specifications would be likely to discontinue use of the dosimeters they owned or buy new ones.
3.
WORKERS The use of reliable audible-alarm dosimeters can be beneficial to workers if good dosimeters are used in appropriate situations.
Warning of high radia-tion levels can reduce the frequency of radiation overexposures and can reduce occupational exposure to radiation when radiation levels are higher than expected.
4.
ANSI The Health Physics Society Standards Committee (HPSSC) has formed a work-ing group on audible-alarm dosimeters.
The SD task leader is a member of that committee.
By September 1978, a draft standard for submission to HPSSC had been developed.
The guide is based on the latest version of that d aft standard dated May 11, 1979 The development of NRC guidance proceeded in parallel with the ANSI standard, but the NRC will not wait for issuance of the ANSI standaru before publishing its guidance.
O 1101 120 12
C.
TECHNICAL APPROACH 1.
VALUE/ IMPACT OF THE USE OF AUDIBLE-ALARM DOSIMETERS IN INDUSTRIAL RADIOGRAPHY It is believed that the careful use of audible-alarm dosimeters in indus-trial radiography would ceduce workers' collective dose, but it is not possible to estimate the size of the reduction.
In some cases increased dose could result from reliance on an inoperable alarm dosimeter in place of a survey meter.
The alarm dosimeter would be of most use in accident situations.
It is 1
not known how much of the collective dose in raJiography is caused by accidents, but it is probably no more than 10% of the total dose.
Thus, accidents by NRC-licensed radiographers could account for 310 of 3100 man-rems.
(The collective dose due to -"an.posures totals about 100 man-rems annually, but not all accidents lead to vverexposures.
Assuming the alarm dosimeters could reduce the 310 man-rems by 50%, the dosimeters might save 155 man-rems /yr.
To accomplish this saving, the industry would have to buy 1500 alarm dosim-eters per year (assuming a 2 year life) at a cost of $100 per unit.
Thus, the annual equipment cost would be $150,000 per year.
The cost of maintaining the dosimeters would be at least $50,000 per year for a total cost of $200,000 per year.
This cost would save, at most, 155 man-rems, although 't might save much less.
Thus, the lower limit for the cost per man rem saved by audible-alarm dosimeters is $1300.
The actual cost, however, could be significantly greater.
2.
VALUE/ IMPACT OF THE USE OF AUDIBLE-ALARM 00SIMETERS IN NUCLEAR POWER PLANT MAINTENANCE OR REPAIR Audible-alarm dosimeters generally have a different function in nuclear power plant maintenance or repair th n in industrial radiogr..nhy.
Rather than warning of an accident, they warn when a preset dose limit !.as been reached.
As such, they allow a more precise measurement of a worker's exposure during the course of a job than would otherwise be possible.
Thus, the dosimeters allow the worker to work in the radiation area as long as he can without receiving an overexposure.
Used in this way, the purpose is not to reduce the 13
collective man-rem from a job, but to spread it over enough workers that an overexposure to anyone would be avoided.
Since there is no saving in collec-tive dose, a cost in $/ man-rem saved cannot be calculated.
The dosimeter's value to the licensee is that it allows better use of his manpower.
A savings of man-rems is possible during maintenance or repair work when the size of the area being worked in is large, when the dose rates in the area vary, and when the area contains, " hot spots." An audible-alarm dosimeter with a " chirper" type alarm will immediately warn a worker that he or she is in an area with high doses.
This alerts him or her to the high dose rate and allows avoidance of the area when possible.
Unfortunately, the savings in collective dose from this application will depend so strongly on the particular situation that an estimate of dose savings cannot be made for the general situation.
It is only possible to calculate a savings when the specific circumstances of an individual situation are known.
The value of this guide to the licensee is that it should prevent the use of audible-alarm dosimeters where their use would not be safe and that it would help licensees select dosimeters having adequate performance characteristics where their use is desirable.
D.
PROCEDURAL APPROACH 1.
PROCEDURAL ALTERNATIVES There are four possible procedural approaches; a.
Regulation b.
Regulatory guide developed bu the staff c.
Regulatory guide adopting an ANSI standard d.
NUREG report or other less formal presentation of the criteria 2.
VALUE/ IMPACT OF PROCEDURAL ALTERNATIVES It would seem premature to propose a regulation when the reliability of alarm dosimeters and the actual effect on safety that their use would have are uncertain.
The regulatory guide developed by the staff is the recommended procedural alternative.
A guide can allow considerable flexibility in its application.
A regulatory guide adopting an ANSI standard is not recommended because the standard is a long way from completion.
Awaiting that completion could 1101 122
delay this task greatly.
There could be great delay in producing a suitable standard, or the final s+1ndard might not be suitable at all.
In addition, the ANSI standard will r.ot provide guidance on the use of audible-alarm dosimeters.
A NURFG report or other less formal presentation is not recommended because the performance criteria and recommendations on use will really be guidance and not background information.
The subject also seems important enough to call for a regulatory guide.
E.
SUMMARY
AND CONCLUSIONS A regulatory guide is the recommended procedural alternative.
A guide can allow considerable flexibility in its application.
3 1
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15
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m ATTACHMENT 1 COMMENTS CONCERNING USE OF AUDIBLE-ALARM DOSIMETERS IN INDUSTRIAL RADIOGRAPHY l.
Harold Price, AEC Director of Regulation in a June 16, 1970, letter to R. E. Hollingsworth, General Manager.
"We have discussed the use of audible alarm dosimeters (chirpers) by radiographers with two radiography licensees who have used them.
They indicate that the audible alarm dosimeters now cor.mer.ially available appea, designed for laboratory use and are not rugged and reliable enough to be used effectively by radiographers in the field.
Both have abandoned the project.
One licensee stated that they have invested approximately
$10,000 in audible alarm dosimeters, and most of the dosimeters have been damaged beyond rerair."
2.
John Weiler, Offshore Power Sys tems, letter of August 16, 1976, and telephone conversation of Aprii 19, 1978.
"Most of the audible alar.n dosimeters that I have evaluated will not hold up ur. der !ield radiography conditions such as low /high temperatures, high humidity, severe abuse and shock, and typically beccme inoperative after two or three weeks."
Weiler said he had tried 2 different models.
He said the circuit boards crack especially when they are dropped or are thrown in trucks.
Salt atmosphere shorts out the devices.
The G-M or electrometer tubes are fragile, and the devices become inoperative after being dropped in water.
3.
Joseph Hinton, Thiokol/ Louisiana Division, Shreveport, Louisiana, meeting on April 4, 1978.
G 1101 124 16
He purchased audible-alarm dosimeters and one broke the first time it was dropped.
The dosimeters gave off an intermittent beep that distracted employees.
4.
Harry Harrison, Nuclear Weapons Effects Laboratory, White Sands i
Missile Range, telephone call of April 19, 1978.
They used Chirpers 3/4 in. diameter by 6 in. long.
They were very unreliable.
They would work intermitte=,7tly.
Sometimes they would just stop working and later start aga h for no apparent reason.
5.
Dan B. Harmon, Cities Service Oil Co., Lake Charles, Louisiana, meeting on April 4, 1978.
Their two radiographers use audible-alarm dosimeters, but both devices have required repairs.
6.
vack Dallinger, General Dynamics Electric Boat, telephone call of April 20, 1978.
In two overexposures last year audible-alarm dosimeters were worn under coats and could not be heard.
Some are louder than others.
The older devices seem less loud.
They tried devices with a plastic case once, but the cases would not stand up to the handling.
They would quickly break.
Switches on their devices 7n be accidentally turned off by brushing them.
Hot summer days when men wear "T" shirts are a problem.
There is no place to attach them (devices worn on belt cannot be heard).
They are trying arm bands that hold device near shoulder; also lanyards.
There are problems when crawling through tight openings.
1101 125 17
ri 7.
Ed Bailey, State of Texas, meeting April 18, 1978.
Alarm dosimeters nave a bad failure rate.
Batteries have a short lifetime.
8.
Ronald Wascum, State of Louisiana, meeting February 1, 1978.
Alarm dosimeters were tried by Bayou Testors in Louisiana.
The devices did not stand up under working conditions--hot, high humidity, salt atmosphere, being dropped in water in swamps, being dropped on hard surfaces.
Their use was dis-continued after several months as being too dangerous.
The State also has several alarm dosimeters, but they usually do not work.
9.
Herman B. Jones, Business Manager, Operating Engineers, Local #2, meeting April 25, 1978.
Objected very strongly to the continuous noise from chirpers while working close to cameras.
Said the noise can drive you nuts.
10.
Jack Selby, Battelle-Pacific Northwest Laboratories, letter of October 26, 1977.
"The latest test of four different pocket dose rate and dose integrating pocket alarms indicates that none are satisfactory as a primary control / protective device.
Some of the deficiencies in the four were:
- 1.
Never did work despite two trips back to the factory.
9
~
1101 126 18
- 2.
Despite having the calibration control at maximum, reading errorsvariedfrom-15Nat100mR/hrto-100%at20R/hr.
- 3.
Tht-ee out of five units failed within four months.
r
- 4.
Some components burned out and the instrument was returned to the factory for rework.
After 2.5 months it still had not been returned."
[
11.
Bernard Killion, University of Lowell, conversation during June 1978.
"I was using a 100 curie Co-60 source at the Nevada Test Site in the early 1960's and a survey indicated that the source had returned to its storage location.
But, unknown to me, the source had become disconnected and remained out.
It was later discovered that a concrete block maze had blocked line-of-sight ability to detect the source.
I owe my life to the fact that a " chirper" gave notice 9
that I was about to enter an unsafe area."
12.
Oscar Mulhern, William Bartlett, and C. Hooker, Battelle-Pacific Northwest Laboratory, NUREG/CR-0554, " Pocket-Sized Electronic Dosimeter Testing,"
page 9, January 1979.
"The pocket-sized electranic dosimeters tested can probably withstand the polite abuse they might receive in laboratories, universities, and medical facilities.
However, they are not useful to a ra:iation protection program for industrial radiographers.
The dosimeters tested are not capable of surviving repeated severe punishment such as that which might be encountered in a harsh industrial or outdoor environment.
The fragile nature of these devices may not be appreciated by the user..."
1101 127 19
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