United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 90-47: Unplanned Radiation Exposures to Personnel Extremities Due to Improper Handling of Potentially Highly Radioactive Sources

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF NUCLEAR REACTOR REGULATION
                           WASHINGTON, D.C.  20555

                                July 27, 1990


Information Notice No. 90-47:  UNPLANNED RADIATION EXPOSURES TO 
                                   PERSONNEL EXTREMITIES DUE TO IMPROPER 
                                   HANDLING OF POTENTIALLY HIGHLY 
                                   RADIOACTIVE SOURCES


Addressees:

All holders of operating licenses or construction permits for nuclear power 
reactors, holders of licenses for permanently shutdown facilities with fuel 
onsite and research and test reactors.

Purpose:

This information notice is intended to alert addressees to the hazards of 
unplanned radiation exposures, especially to the extremities, resulting from 
improper handling of potentially highly radioactive sources.  It is expected 
that recipients will review the information for applicability to their 
facilities and consider actions, as appropriate, to avoid similar problems.  
However, suggestions contained in this information notice do not constitute 
NRC requirements; therefore, no specific action or written response is 
required. 

Description of Circumstances: 

FitzPatrick Events 

On March 8, 1990, a radiation control technician (RCT) at the James A. 
FitzPatrick Nuclear Power Plant contaminated himself with sodium-24 (Na-24), 
at a level of at least 120 mR/hr, after picking up a contaminated cap to put 
it back on the empty source vial.  Instead of using handling tools as 
specified in procedures, the RCT used his gloved right hand.  Later, during 
the removal of his gloves, the RCT contaminated his left hand.  This event 
occurred after the preparation of approximately 400 mCi of Na-24 radioactive 
solution for injection into the reactor primary system as part of a system 
flow check.  Calculations performed by the licensee showed that the skin of 
the left thumb had been exposed to approximately 48.8 rems (using 7 mg/cm 2 
as the thickness of the skin as specified in Form NRC-5).  The NRC staff has 
taken escalated enforcement action against the licensee because of this 
event.  See NRC Inspection Report 50-333/90-12 for more details. 

Aside from the skin exposure, this event is significant because the 
corrective actions taken for a similar event that occurred at the same plant 
in February 1987 failed to prevent the occurrence of the above event. 




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Regarding the February 1987 event at the FitzPatrick plant, NRC Inspection 
Report 50-333/87-07 reported that an irradiated instrument dry tube was 
inadvertently removed from the spent fuel pool (SFP) and dropped onto the 
floor.  A worker picked up the tube and threw it into the SFP, thereby 
receiving an overexposure to one hand.  As a result of a licensee and NRC 
review, five violations were identified:  (1) failure to control extremity 
exposure, (2) failure to instruct individuals as to the radiological hazard, 
(3) failure to perform an adequate survey, (4) failure to follow radiation 
protection procedures, and (5) failure to follow operating procedures. 

As a result of the 1987 event, the licensee issued standing orders requiring 
radiation protection supervisory personnel to monitor and review 
radiologically sensitive work.  In addition, the licensee required that 
procedure reviewers use a checklist to address radiological concerns while 
reviewing new or temporary procedures.  Those actions were appropriate, 
however it is necessary for each worker to understand the hazard of 
radiation exposure to the extremities that may result from the improper 
handling of objects of high potential radioactivity.  Listed below are items 
from the licensee's checklist which, if properly addressed, would have 
emphasized to personnel the hazards associated in working with a highly 
radioactive source and could have prevented the 1990 Na-24 event: 
                    
     -    Are personnel qualified and trained to perform the job? - In both 
          events, a common weakness was that the personnel did not 
          understand the magnitude of the hazard associated with the work.  
          Since Na-24 flow testing is not commonly used at nuclear power 
          plants, better training of workers on the proper handling of 
          radionuclides for flow testing could help prevent unnecessary 
          exposures. 

     -    Do the work procedures have radiological hold points to help 
          initiate proper radiological job coverage/oversight? - In both 
          events, hold points were not established to request a survey of 
          unidentified, potentially highly radioactive objects prior to 
          handling the objects.

     -    Do all workers understand what controls have been established for 
          limiting radiation exposure and contamination? - The protective 
          clothing requirements on the Radiation Work Permit (RWP) did not 
          reflect the true nature of the contamination hazard associated 
          with the performance of the Na-24 flow testing.  In addition, at 
          no time during the mock-up training or the pre-job ALARA meeting 
          was there any specific mention of the disposition of the highly 
          contaminated Na-24 source vial and cap.  This contamination 
          incident could have been avoided if the worker had treated the 
          outside of his gloves as contaminated during removal.  For the 
          Na-24 flow test, the absence of more specific contamination 
          information may have resulted in the RCT being less vigilant in 
          his contamination control work practices.

Pilgrim Events 

Other examples of improper handling of highly radioactive sources occurred 
at the Pilgrim plant.  In January 1984, during maintenance work on a control 
rod drive (CRD), CRD parts and miscellaneous debris from the bottom of the 
reactor 
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vessel were placed in a five-gallon bucket of water and left unposted in the 
area for five days.  On the fifth day, after the CRD parts were removed for 
decontamination, a RCT identified the bucket as a source of high radiation 
and proceeded to survey the objects by picking them up to perform the 
measurements. 

Subsequent thermoluminescence dosimeter (TLD) measurements of the objects 
indicated contact dose rates as high as 2880 R/hr, resulting in an exposure 
to the RCT's hand of about 4.5 rem. 

Evidently, lessons learned from this event were not effectively communicated 
to all workers at the plant.  On August 18, 1984, a RCT identified a highly 
radioactive chip of metal in a CRD tool tray (later evaluation indicated a 
contact dose rate of 1120 R/hr).  This information, however, was not 
immediately disseminated to all workers in the area, (i.e., the area was not 
posted).  Later, when a group of workers began to work in the area around 
the CRD tool tray, the RCT, while pointing at the chip with the survey 
meter, yelled through his respirator for the workers to move away from the 
CRD.  One worker, believing that he was being directed by the RCT to remove 
the chip, picked up the chip and threw it away from the CRD.  The extremity 
dose to the worker's hand was estimated to be 1.1 rem for the three seconds 
he was holding the chip. 

The above events indicate that the hazards of extremity exposure are not 
well understood by all radiation workers and that lessons learned from the 
occurrence of a higher than normal exposure to one worker are not 
effectively integrated into the work habits of other workers.  Attachment 1 
gives additional examples in which unplanned exposures occurred due to 
improper handling of potentially highly radioactive sources. 

Discussion:   

Although it may appear obvious that common sense should prevent radiation 
workers from picking up potentially highly radioactive sources, the number 
of identified unplanned radiation exposures of this type indicates that 
"common sense" has not been effective.  Radiation workers have traditionally 
been well indoctrinated in the control of radiation exposures to the 
whole-body.  However, this knowledge is not well translated into the control 
of radiation exposures to the extremities (i.e. hands, forearms, feet and 
ankles).  Because the contact dose rates of radioactive sources can be 
extremely high, handling these objects even for a few seconds can result in 
very high extremity exposures.  The use of remote handling tools can reduce 
the magnitude of unplanned exposures without hindering the completion of the 
tasks involved.  Most licensees evaluate the need for such tools during the 
planning for specific aspects of each job; however their use for an 
unanticipated situation has not always been effectively communicated to the 
workers. 

Because an unidentified highly radioactive object can be picked up with 
little or no advance notice, the presence of a RCT or a line supervisor may 
not prevent an unplanned exposure.  In several events, the RCTs themselves 
erred by directly handling the objects and receiving unplanned exposures.  
Therefore, it is important that all radiation workers understand the hazards 
of high extremity exposures associated with unidentified and possibly highly 
radioactive objects and be well trained in the proper handling of these 
objects.  With 
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proper training, a worker is more likely to survey or request timely surveys 
of suspect objects that could harbor highly radioactive sources.  For these 
types of localized hot sources, including beta sources, routine general area 
radiation survey maps may not be useful in protecting the worker. 

This information notice requires no specific action or written response.  If 
you have any questions about the information in this notice, please contact 
one of the technical contacts listed below or the appropriate NRR project 
manager.  




                              Charles E. Rossi, Director 
                              Division of Operational Events Assessment 
                              Office of Nuclear Reactor Regulation 

Technical Contacts:  Joseph C. Wang, NRR 
                     (301) 492-1848 

                     James E. Wigginton, NRR
                     (301) 492-1059


Attachments:
1.  Summaries of Other Events 
2.  List of Recently Issued NRC Information Notices 
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                                                            Attachment 1 
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                         Summaries of Other Events: 

TMI-2 (September 1989) 

Two workers handled a piece of material believed to be fuel debris.  The 
radiological controls technician (RCT) monitoring the work was unaware that 
the workers had handled the object.  After the RCT surveyed the object, it 
was returned to the reactor vessel because of its high dose rate.  The 
licensee initiated an inquiry when the first worker, on the following day, 
asked another RCT about the health implications of handling fuel debris.  
The calculated skin dose to the left hand of one of the workers was 55 rem.  
(NRC Inspection Report 50-320/89-11, February 8, 1990) 

Point Beach (April 1989)

An inservice inspection (ISI) engineer received a dose to the hand of 4.7 
rem during a closeout inspection of the Unit B steam generator.  The 
exposure occurred when the engineer picked up an object and passed it 
outside the steam generator without knowing that the radiation level of the 
object read 200 R/hr at near contact.  (NRC Inspection Report 50-266/89-15, 
June 21, 1989) 

Rancho Seco (July 1984)

After the completion of a tube plugging job, a worker entered the steam 
generator to vacuum loose debris.  The worker picked up an object that was 
too large to be vacuumed and tossed it out of the steam generator.  The 
object had been earlier identified as part of a high pressure injection 
nozzle thermal sleeve.  The radiation level of the object read 28 R/hr at 
six inches.  A licensee radiation protection investigation concluded that no 
overexposure had occurred.  (NRC Inspection Report 50-312/84-25, October 19, 
1984) 

Sequoyah (August 1982)

Two flow tests of reactor systems performed in August 1982, using Na-24 as a 
tracer, resulted in an extremity exposure to one worker of 10 rem.  Because 
this exposure was higher than those incurred during past flow tests, the 
licensee initiated an investigation to determine the cause of the high 
exposure.  The licensee concluded that because of the high contact dose-rate 
(1.5 R/sec) of the Na-24 source vial, its cap should not be removed by hand 
as was the case in previous tests; instead remote handling tools should be 
used.  The licensee also concluded that, because Na-24 is not commonly used 
at nuclear power plants, health physics management should provide better 
training and pre-job planning to both RCTs and radiation workers with regard 
to the handling of radionuclides, such as Na-24, used in flow testing.  
Based on this event, the licensee determined that prior to 1982, extremity 
dose evaluations for flow testing had underestimated the actual doses, and 
that the extremity monitoring program for the plant should be upgraded.  
However, no overexposures have been reported to the NRC as a result of flow 
testing at Sequoyah.  

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                                                            Attachment 1
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Peach Bottom (October 1981) 

A maintenance worker received an unplanned exposure to the hand while 
visually inspecting the inservice fuel inspection platform at the Unit 2 
spent fuel pool (SFP).  This exposure occurred when the worker picked up 
fuel channel clips from the fuel elevator with his hand.  The area radiation 
monitors alarmed.  A nearby radiation control technician immediately 
instructed the maintenance worker to put down the fuel channel clips.  The 
clips were then placed into a bucket in the spent fuel pool.  Subsequent 
radiological survey of the fuel channel clips indicated a gamma dose rate of 
3.2 R/hr at 1.8 inches.  Exposure to the worker's hand was estimated at 527 
mrem.  (NRC Inspection Report 50-277/82-11, July 13, 1982.) 
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