ML20236H661

Special Study Rept on Radiation Overexposure Events Involving Industrial Field Radiography

ML20236H661
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Issue date:	10/31/1987
From:	Pettijohn S NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
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ML20236H652	List: ML20236H650 ML20236H661
References
TASK-AE, TASK-S703 AEOD-S703, NUDOCS 8711040254
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.Special Study Report  !

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1 Radiation Overexposure Events Involving Industrial Field Radiography i

i by the Office for Analysis and Evaluation of Operational Data October 1987 l

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Prepared by:

Sanuel L. Pettijohn  ;

Note: This report documents results of a study completed to date by the Office for Analysis and Evaluation of Operational Data with regard  !

to particular operating events. The findings and recommendations do not necessarily represent the final position or requirements of the responsible program office or the Nuclear Regulatory Commission 8711040254 871022 3 PDR ORG NEXD PDR l

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c 1. _ INTRODUCTION 6 1  ; Radiation overexposure events that_ involve industrial ra'diography arel reported to the NRC under the requirements of 10 CFR 20.403 " Notification of Incidents,"

'and 10 CFR 20.405 " Reports of 0 overexposure and Excessive Levels and Concentrations." These reports are nomally submitted to 'the NRC' Regional offices., The reports are reviewed-at the Regional office and actions taken T as' required. Copies of the reports are sent to AE0D where they are reviewed

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and enter.ed:into a data base.

Industrial radiography overexposure events are reported to Agreement States

.under compatible Agreement State regulations.

This report is a tabulation and review of radiation overexposure ever ts involving industrial radiography that were reported .to the NRC for the period

. January 1981 - December 1986 and events reported to Agreement States for the ].

period January 1981 - June 1984 (data from Agreement States for July 1984 - l December 1986 were not available). The information on events from NRC licensees was.taken from the AE0D NRER data base. Information on the. events from AgreementLStates was 'taken from semi-annual event reports prepared by the ~I Office of State Programs = (These semiannual reports were discontinued after  !

June 1984.).

AE00/NRER undertook the review of radiography overexposure events in order to characterize NRC and Agreement State data'on this type of event in view of the I current rulemaking addressing the regulation of radiography operations being done by the Office of Research (RES).

The report is organized as follows: Section 2 presents background information 1 on industrial radiography; Section 3 contains a discussion of data on NRC licensee events and Agreement State licensee events; and Section 4 contains the report finding and conclusions. Appendix A contains a sumary description of events reported by NRC licensees and Appendix B contains a summary description of events reported by Agreement State licensees.

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2. BACKGROUND 2.1 General J

Industrial radiography involves the use of sealed radioactive sources usually of iriduim-192 or cobalt 60, in nondestructive testing. There are two general types of radiography operations licensed by NRC and Agreement States: fixed site radiography and field radiography. Fixed site radiography is usually done inside a permanent or semi-permanent enclosure that is sufficiently shielded to limit the exposure of personnel outside of the enclosure. In the normal operation of the facility, the source is not exposed with personnel inside the enclosure. In this regard, NRC regulation 10 CFR 34.29 (and compatible Agreement State regulations) states in part that "Each entrance that is used for personnel access to the high radiation area in a permanent radiographic installation to which this section applies shall have both visible and audible warning signals to warn of the presence of radiation. The visible signal shall be actuated by radiation when the source is exposed. The audible signal shall be actuated when an attempt is made to enter the installation while the source is exposed." Because access to the enclosure containing the exposed radioactive source is controlled, the risk of unintentional personnel exposures is greatly reduced. This is not the case in field radiography operations.

In most cases field radiography is characterized by the use of distance to i attenuate radiation doses from relatively large radioactive sources. I Radioactive sources used in field radiography are contained in exposure devices that allow the source to be cranked out of the device to an exposed position while the radiographer is at a relatively safe distance. However, because distance provides the only attenuation of the radiation from the source, many opportunities for personnel exposures can result from the failure of personnel to follow established procedures; for example, the failure to make adequate surveys to insure that the source has been retracted into the shielded exposure device.

The following paragraph taken from the NRC report " Radiographic Safety Performance Criteria," prepared by the Task Force on Equipment Safety Q j

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Performance Criteria, A. Tse, Chairman, gives additional relevant information

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on industrial radiography operations:

l The U.S. Nuclear Regulatory Commission reports that a total 1,116 licenses have been issued to firms which authorize industrial j radiography. The licensees are distributed between Agreement states and the NRC on a 2 to I ratio respectively. Licensed firms employ an estimated 5000 radiographer on full or part time basis. These radiographer utilize an estimated 2000 radiographic exposure devices to produce tens-of-millions of radiographs per year and expend in excess of $20 million for film.

In addition to film, radiographic firms have initial investments  !

in equipment totaling $100 million (radiographic equipment, approximately $10 million; trucks, approximately $90 million). 4 Annual expense to maintain and replace equipment is estimated at $25 million/ year (radiographic equipment, approximately $5 million/ year; trucks, approximately $20 million/ year).

Tse, et al, reviewed the accident experience for industrial radiography with representatives from the states of California, Louisiana and Texas, which account for 1/3 of the total licensees. This data indicated 22 accidents involved injury over the last decade for these states. (Injury is defined as a hand burn and/or whole body exposure in excess of 25 rem.) Based on one accident in California in 1978 and another in Texas in 1980, two catastrophic accidents per decade were estimated for the U.S. Further, an average of 25 accidents per year involving serious overexposure greater than 10 rem whole body were estimated to occur annually.

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l 2.2 Health Effects Health effects of radiation can be broadly divided into early and late effects.

Early effects result from relatively large doses of radiation (generally hundreds of rads) and manifest themselves within hours to months following radiation exposure. These effects include, but are not limited to, death due I

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to irradiation of blood forming organs, the lungs and the gastrointestinal tract; radiation induced sickness resulting from whole body irradiation; lung function impairment; functional impairment of the thyroid gland; skin burns resulting from skin contamination by radionuclides; transient and permanent sterility; and cataract induction. All these effects are threshold effects; 1.e., they would not manifest themselves below a certain dose and the severity of an effect increases with increasing dose. It is unlikely that anyone would die from a whole body dose of 100 rad. A significant fraction of people receiving acute doses of 400 rads would die, and it is very unlikely that lj anyone could survive an acute whole body dose of 1,000 rad. Most radiography overexposure are below the threshold for early effects. ,

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Late effects are those associated with increased risk of future somatic and I genetic effects, somatic (mainly cancer) being those affecting the irradiated '

individual and genetic being those affecting the offspring of the irradiated individual. Both of these effects are random in nature and only the probability of occurrence increases with increased dose, not the severity. j Radiation induced cancers and genetic effects are indistinguishable from those /

occurring from other causes and can only be inferred on the basis of increased incidence in irradiated populations, t 2.3 Causes of Radiography Events

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NUREG/BR-0024 "WorkinD Safely in Ganrna Radiography (A Training Manual for Industrial Radiographer) states that:

Radiography accidents usually happen after the radiographer has made three separate mistakes:

- The radiography source is left out of the camera when it sb,J1d not be.

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- A required radiation survey to ensure that the source has been retracted to its shielded container is omitted or the survey is not done properly.

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- The radiography soLrce is not locked into place once it has been retracted into the safe shielded position. )

The usual result of the radiographer making these errors is a whole body or 1

extremity exposure that exceeds the regulatory limit (1.25 or 3* rem / quarter l whole body and/or 18.75 rem / quarter extremity). The exposures can be sufficiently high to cause minor to severe injury to the radiographer. )

l In addition to human errors leading to radiography overexposure, equipment i failure (source disconnect, source stuck in the source guide tube, etc.) has l been found in a number of cases to have been the initiating event that led to I the radiographer overexposure. NUREG/BR-0024 contains a review of 48 events ,

reported by NRC licensed radiography companies between 1971 and 1980. From the abstracts of these events reported in NUREG/BR-0024 we found that 16 of the 48 events, or approximately 30%, indicated that equipment problems may  !

have contributed to the cause of the event.

3. DISCUSSION 3.1 General The review of radiography events contained in this report is limited to field radiography events. Two groups of data on radiography overexposure events were reviewed: events reported by NRC licensees for the period January 1981 -

December 1986, and events reported by Agreement States licensees for the period January 1981 - June 1984. We did not have complete information on events from i Agreement States for the perioo July 1984 - December 1986. A total of 86 events were reviewed: 34 events from NRC licensees, and 52 events from Agreement State ,

licensees.

• The 3 rem / quarter limit applies if the exposure history of the person is documented (see 10'CFR 35 20.201).

i The 34 NRC licensee events were reported over a 6 year period, giving an average of about 6 events per year. The 52 Agreement State licensee events were reported over a 41 year period, giving an average of about 11 events per year.

The ratio of the average number of events reported anneally by NRC licensees to j the average number of events reported annually by Agreement State licensees, j is about the same as the ratio of NRC licensed radiography facilities to  !

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The significance of the reported radiography events is that they led to personnel overexposure. The personnel overexposure associated with the events reported by NRC licensees ranged from 1.3 to 40 rem whole body and from 22.50 to 50 rem extremity. The average whole body exposure was 7.8 rem.

The personnel overexposure associated with the events reported by Agreement State licensees ranged from 2.2 to 63.2 rem whole body and from 19.66 to 15000 rem extremity. The average whole body exposure was 11.5 rem. )

Very high whole body and extremity exposures can occur because of the relatively lerge (typically 20 curie to 100 curie) unshielded sources that are used in field radiography. In addition to the less frequent but very significant high whole body and extremity doses that are reported by radiography licensees, the average individual dose reported for radiographer is higher than for licensees involved in most other operations licensed by NRC with the exception of commercial power plants. Table 1, based on data from Table 3.1 of NUREG-0713, Vol. 6 "0 occupational Rediation Exposure at Commercial Nuclear Power Reactors and Other Facilities 1984," shows exposure data for certain categories of licensees.

From the table we see that the average measurable dose per worker reported for licensees involved in the manufacture and distribution of radioactive materials is about 24% lower than the average measurable dose per worker reported for r& biographers; for licensees involved in fuel fabrication and processing the average measurable dose per worker reported was about 1/3 the average measurable

• The NRC report " Radiographic Safety Performance Criteria" gives this ratio as 1 to 2.

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dose per worke'r reported for radiographer licensees. On the other hand, the average measurable dose per worker reported for workers 'at commercial light -

water reactors is about 35% higher than the average measurable dose per worker reported for radiographer licensees.

TABLE 1 Comparative Exposure Data for Certain Categories of Licensees (average of values for 1982-1984)

License Avg Measurable Dose l Category Avg Person-rems)

(Collective Dose Per Worker (rem) i Radiography 2624 0.47 l Manufacturing and 785 0.38 Distribution Fuel Fabrication 828 0.15 Commercial Light 54799 0.64 Water Reactors Radiography. Events Reported by NRC Licensees  !

i Thirty four events of radiography exposures that were reported to NRC for 1981-1986 were reviewed. Table 2 shows 'the number of events ascribable to various causes.

In seven of the events, the overexposure generally were received over a 13 week I (calendar quarter) period, as incremer.tal occupational doses that, when summed over the quarter, exceed the regulatory limit. In other words, there was not a i I

single identifiable event that led to the overexposure. Of the remaining 27 events, )

13 were ascribed ta equipment problems, and 9 were ascribed to personnel errors. l A cause of five events could not be determined from the available information. l TABLE 2 l

Radiography Personnel Overexposure  !

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Cause Number of Events i

Occupational Exposure 7 j Equipment Problem 13 l

Personnel Error 9 i

Unknown 5 e Total 34 l

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The causes of events attributable to equipment problems or personnel error were further categorized by type of equipment problem (Table 3) .and type of personnel error (Table 4) that caused the overexposure event.

TABLE 3 Summary of Equipment Problems Type of Problem Number of Events Source Disconnect 7 Lock Mechanism failed 2 Miscellaneous 4

- crimp in guide tube

- exposure device damaged

- survey meter not working )

- unspecified equipment failure TOTAL 13 TABLE 4  !

Summary of Personnel Errors Type of Error Number of Events Source not Retracted 4 Source not Fully Retracted 3 Failure to Connect Source 2 TOTAL 9 l

From Table 3, " Summary of Equipment Problems" we see that 7 of the 13 events ,

(54%) resulted from source disconnects. For two of these events, the licensee's report indicated that the disconnect occurred as a result of a failure involving the guide tube connection. The cause or mechanism of the source disconnect I was not given for the other five events.

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A failure of the locking mechanism. accounted for two events, and four of the i events were ascribed to miscellaneous causes: crimp in guide tube; exposure device damaged; _ survey meter malfunctioned; and unspecified equipment failure.

From Table 4,'" Summary of Personnel Errors," we see that about half (4 out of

9) of the events resulted from the source not being retracted. That is, the radiographer or assistant radiog apher did not attempt to retract the source.

A failure to fully retract the source (that is, an attempt was made to retract the source but the source was only partially retracted and was not in a shielded position) accounted for three everits. A failure to connect'the source to the drive cable accounted for two events. Based on information in the licensees' reports, equipment failure was not a factor for any of the above events involving " personnel error." j Radiography Events Reported by Agreement State Licensees Fifty two events involving radiography exposures reported to Agreement States for January 1981 - June 1984 were reviewed. From the review, one event resulted from routine operational exposures, that is, incremental exposures over 13 weeks (a calendar quarter) that exceeded the regulatory limit. Of the remaining 51 events,18 were ascribed to equipment problems and 12 were ascribed to personnel errors. The cause of 21 events could not be determined from the information available. (see Table 5) l TABLE S ,

i Radiography Personnel Overexposure {

1 Cause Number of Events Occupational Exposure 1 l Equipment Problems 18 j Personnel error 12 i Unknown 21 l TOTAL 52 l 1

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i The cause of events attributed to equipment problems and personnel error were further categorized by type of equipment problem and type of personnel error that i caused the overexposure. event. . Tables 6 and 7 respectively show the results.

TABLE 6 Summary of Equipment Preblems Type of Problem Number of Events Crimp in Guide Tube 8 Source disconnect 4 Failure of Lock Mechanism 3 i Miscellaneous 3

- damaged exposure guide tube

- exposure device damaged

- drive cable sileath detached TOTAL 18 TABLE 7 Summary of Personnel Errors Type of Error Number of Events Source not Retracted 7 Source not Fully Retracted 4 Failure to Connect Source 1 TOTAL 12 ___

From Table 6 " Summary of Equipment Problems" we see that 8 of the 17 events (47%)resultedfromacrimpinthesourceguidetube. The usual result is that the source becomes stuck in the source guide tube. None of the licensees' reports discussed the cause of the crimp in the source guide tubes.

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From our review of general radiography. operations, it. appears that crimps in  ;

guide tubes sufficient to cause'the source to stick could be related to -

-improper handling and/or maintenance of equipnent, or dimage to equipment. >

l Four of the' equipment-related events were ascribed to source disconnects. In  ;

one case, the' source disconnect'was caused by the guide tube becoming disconnected.

In two cases, the drive cable broke (corrosion was: listed as a factor in one event),

and in another case,-the disconnect was ascribed to a damaged nipple on the camera.

1 Of the remaining overexposure events attributed to equipment failure,'three were-ascribed to a failure of the lock mechanism, and three were ascribed to miscel-

.laneous causes: damaged exposure guide tube; exposure device damaged by. heavy

. equipment; and the drive cable sheath.became detached.

l From' Table 7. " Summary of Personnel Errors;" we .see that seven of the 12 events

-(58%) resulted .from the source not being retracted. That is, an attempt was not, made to retract the source (the radiographer apparently forgot to retract the source), i e i Of the remaining.five events, four.resulted from the source not being fully  !

retracted; that. is, an attempt was made to retract the source but (unknown to the radiographer) the source .was only partially retracted. One of the events resulted from a failure to connect the source.

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Based on information in the licensee's reports of these events, equipment failure was not a factor in any of the above events involving " personnel error." l A review of the circumstances involving virtually all of the events showed that, notwithstanding thk' identified equipment problems and personnel errors, the events' probably/could have been prevented if the radiographer'or assistant ,

radiographer had made proper surveys.

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j . ihadiogiaphy personnel.ex Aures ts'ceived as a result of the equipment problems K- p,d/or personnel errors 'descrihet aboveoccurMo in one of three ways

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4. ' . lj Adrsonny)we.rgworf. ting in dgproximity to an unshielded source (changing '

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-- personnel were attemptJng to rechver d lbcsh ~or stuck source'.

' Thejway that the radiographer (or assistantgradiographer) was exposed was usually rd)'ttpd, to the type of error cf eoppment problems that caused the e posure. For a >< exas;,9, overexposure that rEsulted from source disconnects (about 14% of the'

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s y , p tnjal events) mostly occugd. /

J while persornel f wefe attempting w recover the r

g y '/cose source. On the othef hand, overexposure 4

tdt resulted fr'om ,s iiilure of ...

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N j }th1 radiographer to retract the source Wr retract the source tot>tiafe psition) 4 (about 20% of the events) mostly occurrtd while the radiographer wrked around a the exposed source or handled the radiography equipment, pnawarh that the Fource 9 y e c

was exposed. Overexposure that involveo a crfmped'tqur:e gtidd, tube (about 10%

j oftheevents)occurredaboutequallyfromthese'Ujee'b*t'abongYorking,in u p '

close proximity to an unshielced sIurce; handling rdd,oraphy equipment with 1 o

, the source exposed; or recovering a loose or stuck'so6 reb. s Y

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[j yUnderlying Causes of the Reported Events y/ - '

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@ Qere not able to determftw the underlying cause(s) of the equipment failures, , d N h.b., design, maintenance, abus$ d gt::,, fdom the licensQs' *${dr'ts,However,

> QUREG/SR-0024, " Working Safely in hmma Radiography," tsptember 1982, indicated

'$ ' tpat equipment failures may result from improper maintenance or use of equipment:

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,m , , Considering the 48 accidents mentioned earlier, there did not seem to 79 // ' be any cases where a camera failed that was properly operated and '

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. l maintained.... Even in those cases where there was some equipment' failure, failure'could be traced to some error on the.part of the radiographer in operating the equipment or the equipment was not properly maintained or repaired when damaged.  ;

l FINDINGS l Based on our review of the radiography overexposure events reports to NRC for 1981-1986 and Agreement States for January 1981-June.1984, we found that:

(1) The data indicate that equipment problems are involved in about 40% of 4

radiography overexposure events.

(2) Identified' personnel errors and equipment problems notwithstanding, virtually- j all of the events could have been prevented by the radiographer having made  :

proper radiation surveys.

(3) Many reports of radiography events are not sufficiently detailed to allow a determination of the cause of the event nor to identify the type make and model number of equipment involved, t

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APPENDIX A

SUMMARY

DESCRIPTION OF EVENTS REPORTED BY NRC LICENSEES

1. A radiographer received a 7.010 rem whole body dose on February 5,1981.

The exposure was received while the radiographer took about 30 exposures during a four hour period. Off-scale dosimeter was disregarded and proper surveys were not performed during the work.

2. While performing radiography a radiographer received a 9-450 rem dose to the fingertips of the left hand. The overexposure resulted when the j radiographer forgot to retract the source, did not perform a survey and  !

began to set up for the next exposure. l 1

3. Two radiographer received whole body doses of 1.290 and 0.690 rem. An Automation Industries model S20 camera had been locked with the sou'ece j extended and.a survey was not performed. The survey meter (Ludlum model 4) '

was not functioning.

4. A radiographer received a 3.39 rem whole body dose in the first quarter of I 1981. The radiographer had failed to cease work when his dosimeter went off-scale while performing work in January 1981, and failed to prepare a utilization log. Equipment malfunction was a contributing factor.

5. A radiographer received a 3.05 rem whole body dose in the second quarter of 1981 which was in excess of the 3 rem limit which was applicable.

6. As a result of a source disconnect, a radiographer received a hand dose of 33 rems. The radiographer uncoupled the source guide tube and recoupled it with the source in the guide tube near his hand.

7. A radiographer working at the St. Croix, Virgin Islands field site received a total exposure dose of 1.380 rem in the second quarter of 1982. Failure to perform required rad survey led to the OE.

8. Two workers received exposures of 5.3 and 6.5 rem respectively while per-forming field radiography. A radiography exposure device containing a 60 Ci Iridium-192 source fell 12 feet; workers continued to use device and did not survey the guide tube. The source was not fully retracted into the fully shielded position. j 9.- A radiographer's assistant received an occupational exposure of 4.61 rem in Oklahoma during first auarter of 1982.

10. A radiographer received a whole body exposure during April 1982. The amount of the overexposure was not given.

11. A radiographer received a whole body dose of 3.64 rem and a second radi- '

ographer apparently received a whole body dose of 8.94 rem during October 1982.

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12. A source pigtail was locked in the out position prior to the last exposure.

This resulted in a radiographer receiving 1.826 rem, and an assistant receiving 4.725 rem.

13. A radiographer did not hook the source to drive cable. The source could f not be returned to the shielded position. ine radiographer received 60 rem ]

to the middle finger, l

14. A radiograph crew made exposures during field operations and failed to return the source to the shielded position. Individual, assistant radio-  !

grapher, received whole body dose of 4.78 rem during the period from 01/06/83 I to 02/06/83.

15. A radiographer failed to attach cable to pigtail. The source subsequently was pushed out of the camera resulting in an estimated exposure to radio-  :

grapher personnel of 20-40 rem.

16. A 24.1 Ci iridium-192 source was not properly connected, or not connected i to the control cable,-or disconnected in guide tube. The radiographer  ;

attempted to locate the source. Failing to follow company procedures, he ,

received an extremity (thumb.and fingers of both hands) dose of 33.445 rem. j 17 A radiographer received a whole body radiation dose of 8.2 ren.

18. A Gamma Century model SA camera had one roll pin missing and another had l worked ~out enough to permit the lockbox assembly bushing to turn. A disconnect resulted from operating the device. A radiographer picked up the source thinking it was a broken cable. Calculated dose of 72 rem to '

hand.

19. Two radiographer were overexposed when a source became stuck in a crimped guide tube. The event involved a 63 Ci Ir-192 source. Exposures were .

1.28 rem (no NRC Fonn 4) and 4.37 rem total.

20 A radiographer received a whole body dose of 7.96 rem when another radio-grapher failed to retract the source following an exposure. l

21. A radiographer received a whole body exposure of 3.21 rem. The individual l was not authorized to work as radiographer by.NRC. J

22. Radiographer and assistant radiographer were overexposed (8 rem, 34 rem l whole body respectively) when the source (107 Ci Ir-192) became stuck in  !

guide tube. j

23. Source became disconnected (Gamma Century model A2A camera). A radiographer  !

placed source in camera, pushing it into place with palm of hand. Hand l dose of 22.5 rem calculated af ter reenactinent. l

24. An assistant radiographer received a radiation dose of 1.275 rem.

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25. A radiographer working at Bailly Station received a hand dose of 65 rem (estimated). Film badge showed 1.66 rem. The source was not fully retracted.

26. Assistant radiographer received greater than 1.2 rem radiation dose.

27. Two radiographer received whole body doses of 27 rem and 9 rem during source disconnect event. Twenty-eight Ci Ir-192 source remained at end of guide tube for two days, i

28. Radiographer receive'd 3.26 and 4.5 rem respectively. They failed to make surveys.

29. Radiographer received 2.510 and 0.390 rem. The source was not fully retracted.

30. A radiographer received 15.59 rem whole body. A failure to retract the source was the cause of the event.

31. Two Level I radiographer were overexposed to radiation when the survey meter was not used. The source was not connected to the drive cable with result being an overexposure to personnel involved (3.541 and 4.555 rem whole body respectively).

32. A radiographer's assistant was possibly overexposed to radiation while using a 71-curie, iridium-192 source. He noticed the control cable was visible when he went to disconnect the guide tube, indicating that the source had not returned to its shielded position.

33. Two radiographer performing radiographic operations were exposed to radiation, 2.660 rem and 2.610 rem, respectively. Latter individual's quarterly exposure was 3.010 rem. The survey meter they were using was i' not operating properly.

34. A radiographer received an estimated 3.8 rems to the whole body and 72 rems to the left hand as a result of a source disconnect. The radiographer picked up and carried the pigtail which contained a 70 curie Ir-192 source.  !

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1 APPENDIX B Sl4 NARY DESCRIPTION OF EVENTS REPORTED BY AGREEMENT STATE LICENSEES i

1. Two radicgraphers received radiation exposures of.12 rem and 6.78 rem whole body respectively and one of the radiographer received a dose of 19.66 rem to the left hand. The exposures resulted from activities involved in recovering a disconnected source (the drive cable broke). l

2. A radiographer received a dose of 5.5 rem. The cause of the radiation exposure was not determined.

3. Two radiographer received doses of 26.08 rem and 3.64 rem respectively. 1 The cause(s) of the radiation exposures were not determined. 1

4. A radiographer received a dose of 3.5 rem while trying to recover a source i that failed to retract because 'of a crimp in the source guide tube, i I

5. Two radiographer received 4.7 and 19 rem doses respectively. The cause of l the radiation exposure was not determined. -

6. A radiographer received a dose of 5.87 rem. The cause of the radiation 'j exposure was not determined.

7. A radiographer received a dose of 2.19 rem which resulted from the source coming out of the rear of the camera because the drive cable sheath became i detached from the projector body.

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8. A radiographer received doses of 11 rads to the gonads, 234 rads to the i right hand and 177 rads to one leg as a result of a source not being fully I retracted. A survey meter was used; however the survey meter apparently failed and did not give a true indication of the radiation level.

9. A radiographer received a radiation dose of 6.3 rem. The cause of the I radiation exposure was not determined. j

10. An assistant radiographer received a radiation dose of 14.5 rem as a result of not cranking in the source before going to change the film and failing to make a survey. j

11. A radiographer received a dose of 6.67 rem as a result of a source disconnect.

The disconnect resulted from a damaged nipple on the camera.

12. During radiography work off shore a source disconnect occurred resulting in a high radiation level and excessive whole body dose to an individual.

(The amount of the exposure was not given in the report.) The source guide tube disconnected from the exit port of the exposure device.

13. A radiographer received a 6 rem whole body dose and a 13 rem gonad dose i and an assistant received <1 rem as a result of the source not being cranked back. Loose foreign materTal found in the control cable housing may have l led to a false indication that the source was retracted. In any event I the radiographer apparently failed to make a survey as required.

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14. A radiographer received a dose of 9.5 rem. The cause of the radiation exposure was not determined.

15. A radiography device was severely damaged when a barge on which it was being used tilted and the device rolled under a heavy piece of equipment.

The lock box was sheared off and the source became separated from the device. The source and device were handled by the barge captian and the radiographer resulting in radiation doses of 10 rem WB (captain and the radiographer) and an extremity dose to the radiographer of between 3000 and 5000 rem. The extremity dose to the captain was not reported. The radiographer's helper who was nearby received a dose of 2 rem.

16. A radiographer received a radiation dose of 13 rem. The cause of the radiation exposure was not determined.

17. A radiographer received a dose of 6.16 rem as a result of the source not being fully retracted. The licensee reported that the source tube ]

being used was crimped which may have prevented the source from being 3 fully retracted.

18. A radiographer received a radiation dose of 10 rem. The cause of the radiation exposure was not determined.

19. A radiographer received a radiation dose of 5.22 rem. The cause of the radiation exposure was not determined.

20. A radiographer received a dose of 21.5 rem as a result of not performing a proper survey. The source was in the unshielded position.

21. A radiographer received a dose of 11.7 rem. The cause of the radiation exposure was not determined.

22. Two radiographer received doses of 53 rem and 6 rem respectively as a result of a failure to retract the source before handling the camera and failing to make adequate surveys that would have detected that the source was not retracted.

23. Two radiographer received doses of 7.2 rem and 2.3 rem respectively while 3 retrieving a source stuck in the J tube of a camera. The J tube was 3 homemade and had been used many times. Cause of the jamming was found to I be spots of solder in the "J" tube. l

24. A radiographer received a 300 millirem whole body dose and a 500 rem extremity dose as a result of a failure to fully retract the source and 3 make adequate surveys that would have detected that the source was not j fully retracted. Also the source became disconnected when the source tube was disconnected from the camera.

25. A radiographer received a dose of 5.566 rem. The cause of the radiation exposure was not determined.

l

• 26. A radiography source used in a Multitron Model 898 ~ camera with a Gamma Industries model 520 crank assembly became disconnected, apparently as a result.of corrosion induced separation of the drive cable. Three persons .

received doses of 890,. 690, and 590 millirem while recovering the source.

27. A radiographer received a 14 rem dose asia result of failing to fully retract the source.and to make adequate surysys that would have detected that the source was not retracted.

28. A radiographer received a 43.9 rem dose. After completing radiography the radiographer noticed that the 30 C1 Ir 192 source being used was not fully retracted.

29. A radiographer received a dose of 6 rem. The cause of the radiation exposure was not determined.

30. As a . result of a failure to connect a source to the drive. unit by a radiographer trainee, a radiographer and the trainee ' received doses of 13.453 and,8.471 rem respectively. The survey meter indication of high radiation was discounted by the radiographer.

31. Two radiographer received doses of 5.826 and 3.071 rem respectively.

The radiographer stated that they received the dose while retracting a hard to retract source. The source was hard to retract because of l the excessive angle of the camera and the guide tube. l l

32. Two radiographer received doses of 4 rem whole body and 3 rem whole body j respectively, and one of the radiographer received an extremity dose j of 360 millirem. Inspectors found a damaged exposure guide tube and a i malfunction in the survey meter to have contributed to the exposures.

l

33. A radiographer received a dose of 7.5 rem. The cause of the radiation I exposure was not determined.

34. Two radiographer received whole body doses of 2.6 rem and I rem and l extremity doses of 64.352 rem and 6.5 rem as a result of recovering a 1 66 curie Ir 192 source that had become stuck inside a crimped guide i tube. The guide tube was crimped when the guide. tube detached from a

' suction cup holding it and struck a scaffold. ,

1

35. A radiographer received a' dose of 5.89 rem, probably as a result of not using the survey meter properly. During the period of the exposure the H radiographer made 240 shots each of 8 seconds duration. I

• Although (according to the licensee's report) this event did not result in personnel overexposure, it was included because it represents a type of equipment problem that could result in personnel overexposure.

t

?6. A radiographer received a dose of 5.2 rem. The cau'se of the radiation exposure was not determined.

37. A radiographer received a dose of 6.8 rem. The cause of the radiation exposure was not determined.

38. A radiographer received a dose of 9.66 rem. The cause of the radiation exposure was not determined.

39. An individual not . licensed to work as a radiographer who was performing radiography received a dose of 14.3 rem. The radiation exposure resulted from a failure of the individual to perform a survey before approaching the exposure device.

40.. Two radiographer received 13.5 rem and 2.5 rem doses respectively as a result of not performing the required' survey of the camera before approaching the camera to change film, etc.

41. A radiographer received a dose of 10.05 rem. The cause of the radiation exposure was not determined.

42. As a result of attempting to straighten a source guide tube containing a 100 Ci Ir 192 source, a radiation safety officer received a 15000 rad dose to the right hand. The crimp in the source tube caused the source pigtail to be lodged in the tube.

43. A radiographer and an assistant radiographer received doses of 7.32 rem and 7.45 rem respectively. The cause of the radiation exposures was not determined.

44. A radiographer received a dose of 7.14 rem. The cause of the radiation exposure was not determined.

45. Three radiographer received doses of 14.19 rem 9.6 rem, and 4.12 rem as a result of failing to crank in the source or perform radiation surveys that would have indicated that the source was not cranked in before approaching the source.

46. A radiographer received a 5.385 rem dose. The cause of the radiation exposure was not determined.

47.

A radiographer and an assistant radio 9.18doses finger) rem and 63.2rem of 3013 rem and and extremity (graphe 5348 '

rem respectively as a result of failing to perform a radiation survey prior to approaching an exposure device. The two workers spent 2.5 to 5 minutes near a 35 curie iridium 192 source and both touched the end of the source tube.

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