Events Involving Undetected Spread of Contamination

Content

• Introduction
• Notice Summary
• Applicability
• Related Events
• Significance of Events
• Event Causes
• Corrective Actions
• Hazard Reduction
• References

Introduction

This notice is one in a series of publications issued by the Office of Nuclear and Facility Safety to share nuclear safety information throughout the Department of Energy complex. For more information, contact Dick Trevillian, Office of Operating Experience Analysis and Feedback, Office of Nuclear and Facility Safety, U.S. Department of Energy, Washington, DC 20585, telephone (301) 903-3074. No specific action or responses are required solely as a result of this notice.

Safety Notices are distributed to U.S. Department of Energy Program Offices, Field Offices, and contractors who have responsibility for the operation and maintenance of nuclear and related facilities, and to other organizations involved in nuclear safety. Written requests to be added to or deleted from the distribution of Safety Notices should be sent to: BR Richard L. Trevillian, EH-33, Room E-460 GTN, U.S. Department of Energy, Washington, DC 20585.

The ESH Office of Information Management maintains a file of Safety Notices and supporting information. Copies can be obtained by contacting the Office of Information Management at (301) 903-0449 or by writing to the Office of Information Management, U.S. Department of Energy, EH-72/Suite 100, CXXI/3, Washington, DC 20585.

Notice Summary

This notice describes events at DOE and commercial facilities involving personnel who spread contamination to uncontrolled areas, and in some cases beyond facility boundaries, because the contamination was not detected at radiological area exits. The Notice describes the causes and significance of the events, as well as related corrective actions and lessons learned. Information recently issued by the Nuclear Regulatory Commission (NRC) is also described.

Applicability

This notice is applicable to all DOE facilities that contain radiological contamination hazards. The Office of Nuclear and Facility Safety advises operators of applicable facilities to become familiar with the potential consequences of undetected personnel contaminations. No specific action or response is required as a result of this notice.

Related Events

The Occurrence Reporting and Processing System (ORPS) database contains information on numerous events involving spread of radioactive contamination to uncontrolled areas, including off-site areas, caused by failure to detect and respond to contaminated personnel leaving radiological areas at DOE facilities. Some events involved subsequent contamination of areas and items such as parking lots, homes, automobiles, and personal items. The following are descriptions of three such DOE events.

On November 17, 1993, a graduate student working at the Health Research Laboratory (HRL) at Los Alamos National Laboratory (LANL) spilled solution containing phosphorus-32 (P-32) and spread contamination down a hallway, into a lobby, across a parking lot, and into a stairwell.¹ Eight other people were contaminated during the event, including two Radiological Control Technicians (RCTs) who were contaminated while conducting surveys in response to the event. Because contamination was found in a high-traffic area, the whereabouts of 191 employees had to be verified. Some personnel were recalled for monitoring but no further contamination was detected.

The student had been working with a sample containing 100 microcuries of P-32, a beta emitter with a half-life of 14 days. Facility personnel believe that the student spilled resin contaminated with phosphorus-32 while depositing it in a radioactive waste container and then contacted the resin with his shoe. The student did not use secondary containment, such as placing the waste in a plastic bag or other suitable container, and did not monitor the floor of the room. Both omissions were in violation of established procedures. RCTs detected contamination levels of 2,000,000 dpm/100cm² in the area of the waste container and levels up to 21,000,000 dpm/100cm² approximately three feet away. The highest contamination level measured in the hallway was 760,000 dpm/100cmsup² and one spot in the parking lot measured 140,000 dpm/100cmsup².

After the spill occurred, the student left the room and self- monitored at the exit of the Radiologically Controlled Area (hereafter referred to the first RCA) using an HFM-7 monitor. The student was apparently not paying attention and did not notice that the monitor indicated contamination. He then exited the first RCA, walked down the hallway, through the lobby, and across the parking lot to his vehicle. After picking up a change of clothes, he re- entered the building through the same route and went to a second RCA to change his clothes.

As he prepared to exit the second RCA, he self-monitored with an RM- 20, which indicated a very high count rate on his shoe. Deciding to go back to his lab, he exited the second RCA, proceeded up a stairwell to the first RCA, and returned to the lab. At this point, the student realized the extent of the problem, removed his shoes to prevent further spread of contamination, and walked to the first RCA exit point to summon help. In the process, he apparently contaminated the ball and heel of his right foot, where RCTs detected contamination measuring 1,000 dpm/100cm².

On April 22, 1994, a utility operator at the Idaho National Engineering Laboratory (INEL) Test Reactor Area (TRA) spread contamination to five buildings, a concrete pad, and a bicycle after entering a posted contamination area without proper protective clothing and exiting it without performing required surveys.² The operator subsequently left the site with contamination on his trousers. He alarmed a contamination monitor at the site exit, but RCTs did not conduct thorough follow-up surveys. Extensive radiological surveying and decontamination were required as a result of the event. RCTs surveyed on-site buildings, roads, and grounds that may have been contaminated by the operator. They also surveyed buses used to transport the operator and the homes of the operator and another employee that was involved with the same work. No contamination was found on the buses or at either home.

The operator was experiencing difficulties placing the TRA Warm Waste Treatment Facility (WWTF), which is a radiological buffer area, in operation. After determining that an abnormal valve lineup existed, the operator entered posted contamination and high contamination areas without proper protective clothing to return the out-of- position valves to normal. After positioning the valves, he left the radiological buffer area with his shoes highly contaminated and without performing a whole-body survey. Later, the operator alarmed a portal monitor at the TRA exit. RCTs detected contamination on both shoes and confiscated them. They resurveyed the operator in the portal monitor and allowed him to go home, but did not perform a whole-body survey.

Facility personnel recalled the operator for additional surveys after discovering contamination on another operator and on a bicycle used by the operators. RCTs subsequently determined that the operator had left the site with a 1,600 cpm/100cm² loose particle on his trousers.

On March 10, 1993, Michigan State University (MSU) personnel notified Lawrence Berkeley Laboratory (LBL) that an LBL staff scientist had become contaminated during a visit to the MSU Superconducting Cyclotron Laboratory from February 25 to March 3, 1993. He unknowingly spread contamination throughout the facility, to his home and personal effects, the homes he visited, and automobiles.^3,4 On March 9, 1993, MSU personnel identified high-levels of carbon-14 contamination outside controlled areas and traced the source to a radioactive cyclotron target which had been handled by the LBL scientist during his visit.

LBL radiation assessment personnel responded immediately to the scientist's work area at LBL and detected contamination as high as 150,000 dpm/100cm² on numerous items, including work papers, his shoes, and file folders and binders he had brought back from MSU. Contamination as high as 300,000 dpm/100cm²was detected on other items he had worn or handled while at MSU, including a small box, a travel bag, and a sweater. Contamination was also detected on the back seat of his private vehicle where he had worked on some papers.

LBL personnel also surveyed the scientist's home and identified contamination levels up to 20,000 dpm/100cm² on clothing items and two pieces of luggage. No area contamination was found at the home and no skin contamination was identified on the scientist. MSU radiation safety personnel identified contamination levels at the Superconducting Cyclotron Laboratory approximately 20 times the levels detected at LBL.

On March 3, 1994, the NRC issued Information Notice (IN) 94-16, "Recent Incidents Resulting in Offsite Contamination."⁴ The Notice describes three events which resulted in contamination of both individuals and personal property, both on and off the licensees' property. The notice reported the contamination of the staff scientist at LBL. The other two incidents were similar to the event at the Health Research Laboratory in that both involved students working with P-32.

In one of the two incidents, a graduate student working on the weekend accidentally and unknowingly contaminated the floor of the lab with 100 to 500 microcuries of the material. He failed to survey himself or the laboratory before leaving, as required by procedures, resulting in widespread contamination of several floors of a research building, private residences, clothing, and vehicles. In the other event, a post-graduate student, also working on the weekend with P- 32, contaminated himself and failed to survey because of an inoperative survey meter. Subsequent surveys showed that the student had spread contamination to several residences, automobiles, and a church.

Significance of Events

These events illustrate the impact of undetected personnel contaminations. Failure to detect contamination on personnel can result in widespread contamination of facilities, off-site areas, personal effects, residences, automobiles, and other people. Such events result in unnecessary exposure to radioactive contamination by facility workers and the public, which is a violation of DOE-mandated principles of keeping radiation exposure As Low As Reasonably Achievable (ALARA). Depending on the levels of contamination and radionuclides involved, such events could result in serious consequences to the individuals exposed.

In addition to the health, safety, and environmental consequences, significant resources are required to respond to such events. As illustrated above, the response itself can result in additional spread of contamination. Further, the response may include extensive surveying, decontamination, notifications, communications and interface with off-site agencies, event analysis, corrective action development and implementation, and public relations. These activities can consume significant resources and divert manpower needed in other areas. Further, such events can result in a decrease in the public's confidence in DOE's ability to safely control nuclear activities.

Event Causes

A review of these events reveals a number of common contributing causes, mostly involving violations of procedures. In some cases, because of inadequate surveys, spread of contamination was not detected for days, or even weeks, after the original incident occurred. Individuals involved did not check for personal or area contamination before leaving work areas and routine surveys were not conducted in time to prevent widespread contamination. Common contributing causes include:

• Failure to follow applicable radiological protection procedures.

• Failure to adequately perform required surveys, including self-surveys and surveys of the work area.

• Inadequate training for personnel involved in handling and use of radioactive material.

• Failure of radiation protection personnel to properly identify, analyze, and respond to the event.

• Failure to exercise appropriate precautions when handling radioactive material.

• Inadequate supervision or management oversight of activities involving handling and use of radioactive material.

• Inadequate identification of existing contamination.

• Failure to consider the possibility and consequences of off- site contamination as part of contamination event response. Emphasis was placed on facility or laboratory decontamination and resuming normal operations.

The most common contributors to undetected contamination events are failure to follow procedures and failure to adequately perform surveys of the individuals involved and the work area. Failure to follow established procedures was a contributing cause in all of the events. At the HRL, the student violated procedures by not using secondary containment while disposing of contaminated material, by failing to monitor the lab floor before and after the work was completed, and by failing to monitor himself prior to leaving the area. In the TRA event, the operator violated procedures when he failed to read the associated RWP and to notify radiation control technicians that he was working under the RWP, failed to obtain a pre-job brief, failed to wear prescribed protective clothing, and failed to perform required surveys on at least two occasions.

Improper frisking techniques, inattention to detail, and failure to survey for all possible types of contamination have all contributed to incidents involving undetected personnel contaminations. In most cases, contaminated individuals did not adequately survey themselves or their work areas, and in some instances they did not perform surveys at all. In the HRL and TRA events, and in two of the events described in IN 94-16, surveys that would have detected contamination and prevented its spread were not conducted. The reasons for not conducting surveys included inadequate attention to detail, lack of training, lack of awareness of potential consequences, and inoperable survey equipment.

Inadequate training was also a factor in most of the events described in this Notice. In the events described in IN 94-16, training had been provided, but was either inadequate or ignored. At the HRL, training was identified as a contributing cause because the student had not been trained on the research protocol he was using nor had he been trained on the use of the HFM-7 monitor. In addition, training on proper use of the various radiological monitoring equipment and training specific to hazards associated with facility operations and radionuclides involved was determined to be inadequate.

Failure of radiation protection personnel to properly identify, analyze, and respond to the event contributed to the consequences of many of the events. In the TRA event, radiation control technicians, after detecting contamination on the operator's shoes, allowed him to leave the site without detecting contamination on his trousers. In some cases, facility personnel did not adequately consider the possibility and consequences of offsite contamination. In all three of the events described in IN 94-16, the licensee initially indicated that they were confident that no offsite contamination had occurred. However, subsequent surveys identified widespread offsite contamination.

Corrective Actions

Corrective actions implemented in response to these events were extensive and tended to focus on increasing the scope and effectiveness of training. They also emphasized procedure compliance, proper surveying techniques, and increased management oversight of radiological activities. The HRL in particular developed a comprehensive list of specific corrective actions to prevent similar events at that facility, including:

• Develop a formal inspection process to "walk the spaces," unannounced, but on a specified frequency, to identify non-compliant activities.

• Develop and implement a formal process to assess user knowledge of active radiological procedures, including periodic, unannounced inspections of randomly-selected labs within the facility.

• Increase the availability of radiation survey instruments. HRL ordered twenty-five instruments for use by radioactive material handlers.

• Post instructions on how to respond to contamination events at or near radiological buffer areas and controlled exits points.

• Clarify Radiological Worker training requirements and review Radiological Worker training for compliance with the DOE Radiological Control Manual.⁵

• Provide training on proper use of all applicable radiation survey instruments used in the facility.

• Provide facility-specific training that addresses the hazards associated with facility operations and the radionuclides involved. The training will be based on operating experience and will include lessons learned from radiological and non-radiological occurrences at the facility.

Hazard Reduction

The DOE Radiological Control Manual⁵ provides guidelines that, if implemented, can significantly reduce the potential for incidents involving undetected personnel contamination and the resulting offsite contamination. Chapter 3 describes proper conduct of radiological work, including contamination control practices (Appendix 3C) and guidelines for personnel contamination monitoring with hand-held survey instruments (Appendix 3D). Articles 221 and 338 contain specific guidelines for performing contamination monitoring when exiting radiological areas. Article 338.8 requires that instructions comparable to those in Appendix 3D be posted adjacent to monitoring instruments.

Chapter 5, Part 5 of the Manual provides requirements for radiological monitoring and surveying. Chapter 6 establishes qualification and training requirements, including continuing and specialized training, for personnel working at or visiting facilities with radiological hazards. This chapter repeatedly emphasizes the need for site-specific training. Article 612 states: "In establishing local training programs, the standardized core courses shall be presented and site-specific information should be added. For example, training at accelerator facilities should expand course content for high-energy radiation and activation products. Training at plutonium facilities should expand the course content for alpha control." Part 6 lists topics that should be considered for training at certain types of facilities, including plutonium, uranium, tritium, and accelerator facilities.

The events described in this Safety Notice illustrate the importance of properly and thoroughly responding to a potentially significant contamination event. A rush to resume normal operations should be avoided and qualified technical personnel should be promptly assigned to evaluate the extent of the contamination. The potential for offsite contamination should also be included in response procedures for spills and other contamination events and emphasized in continuing training programs.

Facility personnel should periodically evaluate the effectiveness of corrective actions implemented to prevent loss-of-contamination- control events. Where feasible, performance measures related to contamination control can be used to assess the effectiveness of the corrective actions and of the overall contamination control program.

In addition to the Radiological Control Manual, DOE 5480.11⁶ establishes radiation protection standards and program requirements for workers at all DOE facilities.

DOE Order 5480.11 requirements for contractors have been codified in 10 CFR 835⁷, "Occupational Radiation Exposure." As part of the rulemaking, DOE Order 835.101 (g) requires that a radiation protection plan (RPP) be submitted to DOE no later than January 1, 1995, and DOE Order 835.101 (f) requires compliance with the rule no later than January 1, 1996.

The type of incidents described in this Safety Notice could, in the future, be considered violations of 10 CFR 835.404, paragraphs (a), (b), (f), and (g), exposing those involved to fines or other civil penalties. This is similar to the application of 10 CFR 20⁸, "Standards for Protection Against Radiation," which applies to facilities under the jurisdiction of the NRC.

References

1. DOE Final Occurrence Report ALO-LA-LANL-HRL-1993-0006, "Area and Personnel Contamination Resulting from Phosphorus-32 Spill," February 8, 1994.

2. DOE Final Occurrence Report ID--EGG-TRA-1994-0008, "Identification of Radioactive Contamination on Employee's Clothing Off-Site," June 13, 1994.

3. DOE Final Occurrence Report SAN--LBL-LSD-1993-0001, "Offsite Contamination," June 17, 1993.

4. NRC Information Notice 94-16, "Recent Incidents Resulting in Offsite Contamination," March 3, 1994.

5. DOE/EH-0256T, "Radiological Control Manual," Revision 1, April 1994.

6. DOE 5480.11, "Radiation Protection for Occupational Workers," Change 3, June 17, 1992.

7. 10 CFR 835, "Occupational Radiation Protection; Final Rule," December 14, 1993.

8. 10 CFR 20, "Standards for Protection Against Radiation; Final Rule," December 8, 1992.