Information Notice 1993-05, Locking of Radiography Exposure Devices

Locking of Radiography Exposure Devices

ML031080041
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	01/14/1993
From:	Cunningham R E NRC/NMSS/IMNS
To:
References
FOIA/PA-2015-0150 IN-93-005, NUDOCS 9301080120
Download: ML031080041 (9)

UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDSWASHINGTON, D.C. 20555January 14, 1993NRC INFORMATION NOTICE NO. 93-05: LOCKING OF RADIOGRAPHY EXPOSUREDEVICES

Addressees

All Nuclear Regulatory Commission industrial radiography licensees

Purpose

This information notice is intended to: (a) alert licensees that the lockingmechanisms on certain industrial radiography exposure devices can be lockedwith the sealed source in the exposed position; and (b) emphasize theimportance of ensuring that the source is secure in a shielded position beforemoving the device. We expect that licensees will review this notice,distribute it to responsible staff, and consider actions, if appropriate, toverify that the source is properly secured at the conclusion of radiographicoperations. However, suggestions contained in this notice do not constituteany new NRC requirements, and no written response is required.

Description of Circumstances

Case 1: A radiographer was overexposed in an incident involving adisconnected source when he failed to conduct a survey after each exposure.After investigating the incident, it was discovered that the radiographer hadapproached the device without a survey instrument, locked the device,disassembled the source guide tube, and left the drive controls connectedbefore moving the device from one location to another. The radiographer hadincorrectly assumed that in locking the exposure device, he had secured thesource in a shielded position. In fact, the sealed source remained in theguide tube because the pigtail had disconnected from the drive cable. Theradiographer's error was further compounded when the drive cable was notremoved before moving the device, which would have allowed him to identify theabsence of the source pigtail within the shielded assembly.Case 2: A radiographer was performing radiographic exposures of welds on aseries of pipelines that were located approximately 6.1 meters (20 feet) aboveground. The radiographer used a 1.8-meter (6-foot) guide tube with collimatorand a 7.6-meter (25-foot) control cable. The radiographer hung the devicefrom the pipeline to perform the work with the control cables hanging down tothe ground. After an exposure, the radiographer retracted the source, placedthe control cables on the ground, and used a hydraulic lift to get to thecamera.9301080120 L4'6 fD C fe -2?- 0AIkCct

IN 93-05January 14, 1993 Because the camera was suspended above the lift, the radiographer had to movethe camera to reach the locking mechanism. He moved the camera by graspingthe control cables with his right hand and locking the camera with his lefthand. He continued with his left hand to disconnect the guide tube from thecamera. At this point, he noticed that the sealed source was protrudingapproximately 10 centimeters (4 inches) from the camera port. (Note: Hisalarming ratemeter did not sound because it was not turned on. This violationof 10 CFR 34.33, which can result in a civil penalty, is addressed inInformation Notice 91-49: "Enforcement of Safety Requirements forRadiographers").Reenactments of the incident showed that when the radiographer turned thedevice, the crank handle could drag on the ground, exposing the sealed source.The radiographer was then able to lock the device over the drive cable, withthe sealed source protruding approximately 10 centimeters (4 inches).Analysis of the locking mechanism after the event did not identify any obviousdefects with the mechanism. Tests performed showed that the device couldstill be locked with the source in the exposed position.NRC Evaluation:The findings in both of these cases raised concern among NRC staff that, undercertain conditions, radiographers could have false confidence in the lockingmechanisms. If exposure devices can lock when the source is outside of theshielded position, then radiographers could incorrectly believe that they areprotected from exposure when, in fact, the source is not in its fully shieldedposition. We are also concerned that exposure devices are moved while thedrive cables are still connected.To evaluate the effectiveness of the locking mechanism on radiography exposuredevices and to determine whether radiographers commonly move the devices withdrive cables still connected, NRC inspectors observed licensee equipment testsand interviewed radiography personnel. From the data collected, we determinedthat a majority of exposure devices can be locked when the source is in avariety of positions, rather than only when the source pigtail is properlyseated, with the source in the fully shielded position. Many source pigtailsinclude a "locking ball," designed to prevent the source from moving forwardwhen the lock is engaged; however, our observations show that some exposuredevices may be locked both when the source is not fully retracted and whilethe drive cable is seated under the locking pin, thereby circumventing thelocking-ball feature. This may result in a source being positioned where itis not fully shielded.Many radiographers acknowledged to NRC inspectors that they often leave drivecables connected when moving an exposure device from one location to anotherat temporary job sites. In addition, some acknowledged leaving the guide tubeconnected. One licensee stated that this practice had resulted in a sourcebeing forced out of the exposure device while the device was carried to a newlocation at a temporary job site. This licensee noted that the device waslocked at the time, but the source had not been fully retracted before lockingthe device.

Attachment 1IN 93-05January 14, 1993 LIST OF RECENTLY ISSUEDNMSS INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to93-0493-0392-8492-72Investigation and Re-porting of Misadministra-tions by the RadiationSafety OfficerRecent Revision to10 CFR Part 20 andChange of Implementa-tion Date toJanuary 1, 1994Release of PatientsTreated with TemporaryImplantsEmployee Trainingand Shipper Registra-tion Requirements forTransporting RadioactiveMaterialsEmergency ResponseInformation Require-ments for RadioactiveMaterial ShipmentsUranium HexafluorideCylinders -Deviationsin Coupling WeldsImplementation Date forthe Revision to the EPAManual of ProtectiveAction Guides and Pro-tective Actions forNuclear IncidentsImplementation of theDeliberate Misconduct Rule01/07/9301/05/9312/17/9210/18/9208/24/9208/12/9205/12/9205/08/9292-62All U.S. Nuclear RegulatoryCommission medicallicensees.All byproduct, source, andspecial nuclear materiallicensees.All Nuclear Regulatory Com-mission Medical Licensees.All U.S. Nuclear RegulatoryCommission Licensees.All U.S. Nuclear RegulatoryCommission Licensees.All fuel cycle licensees.All holders of OLs or CPsfor nuclear power reactors,non-power reactors andmaterials licensees author-ized to possess largequantities of radioactivematerial.All Nuclear RegulatoryCommission Licensees.92-5892-3892-37 Attachment 2IN 93-05January 14, 1993 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to93-0493-0393-02Investigation and Re-porting of Misadministra-tions by the RadiationSafety OfficerRecent Revision to10 CFR Part 20 andChange of Implementa-tion Date toJanuary 1, 1994Malfunction of A Pres-surizer Code SafetyValveAccuracy of Motor-Operated Valve DiagnosticEquipment Manufacturesby Liberty TechnologiesUnexpected Restrictionto Thermal Growth ofReactor Coolant PipingPotential Failures ofEmergency Core CoolingSystems Caused byForeign Material Blockage93-0101/07/9301/05/9301/04/9301/04/9312/24/9212/23/9212/17/9212/18/92All U.S. Nuclear RegulatoryCommission medicallicensees.All byproduct, source, andspecial nuclear materiallicensees.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All Nuclear RegulatoryCommission Medical LicenseesAll holders of OLs or CPsfor nuclear power reactors.92-8692-8592-84Release of PatientsTreated with TemporaryImplants88-23,Supp. 4Potential for GasBinding of High-Pres-sure Safety InjectionPumps during A DesignBasis AccidentOL = Operating LicenseCP = Construction Permit

K)IN 93-05January 14, 1993 Discussion:All licensees are reminded of the importance of ensuring that the sources usedin radiography exposure devices are properly secured and fully shielded beforemoving the device. Radiographic exposure devices manufactured and newequipment acquired by licensees after January 10, 1992, must meet new designrequirements in 10 CFR 34.20. These require that, among other safetyfeatures, the device must automatically secure the source assembly when it iscranked back into the fully shielded position within the device. However,many radiographic exposure devices currently in use do not include the newersafety features, and licensees are not required to use devices that complywith 10 CFR 34.20 requirements until after January 10, 1996. Certaihradiogiraphv exposure devices still in use today may be able to be locked withthe source in the exposed position.Experience has shown that when an older exposure device is in use, the lockingmechanism is not an indicator that the source is fully retracted and secured.The use of engineered safety features, like the lock mechanism, MUST BEcoupled with a proper survey (10 CFR 34.43) AND use of an alarm ratemeter(10 CFR 34.33), to prevent the unintentional exposure of personnel. Surveysmust be sufficient to detect a change in exposure readings taken at the sourcetube outlet, to determine whether the source is fully retracted to a shieldedposition (10 CFR 34.43). Alarm ratemeters serve as an additional warningmethod. Additionally, it is recommended that radiographers disassemble thesource guide tube, remove the drive controls, and install the safety plugs orcovers, before moving the radiography exposure device to another location.The failure to do so has been identified as a contributing factor in theunintended exposure of personnel, as well as in incidents where radiographersfailed to notice that the source was not retracted into the device.Sealed sources for radiography are capable of delivering significant exposuresto radiography personnel and to members of the general public, when handled byindividuals who are inattentive to radiation safety procedures. It isrecommended that all workers understand the consequences of improperlyhandling radiographic devices, and that workers be encouraged to use necessaryprecautions when working with these devices.

IN 93-05January 14, 993No written response is required by this information notice.questions about this matter, please contact the appropriateoffice or the personnel listed below.If you have anyNRC regional( Richard E. Cunningham, DirectorDivision Industrial andMedical Nuclear Safety, NMSSGary Shear, Region III(708) 790-5620Technical contacts:Charles Cain, Region IV(817) 860-8186Scott Moore, NMSS(301) 504-2514Attachments:.1. List of Recently2. List of RecentlyIssued NMSS Information NoticesIssued NRC Information Notices

IN 93-05January 14, 1993 :93-05.INDOCUMENT NAME:

IN 93-January , 1993 : G:LOCKING.SWM

IN 92-December , 1992 : G:LOCKING.SWM