Information Notice 2009-05, Contamination Events Resulting from Damage to Sealed Radioactive Sources During Gauge Dismantlement and Non-Routine Maintenance Operations

Contamination Events Resulting from Damage to Sealed Radioactive Sources During Gauge Dismantlement and Non-Routine Maintenance Operations

ML090370785
Person / Time
Issue date:	02/03/2009
From:	Robert Lewis NRC/FSME/DMSSA
To:
Sepulveda, L
References
IN-09-005 IN-09-005
Download: ML090370785 (8)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF FEDERAL AND STATE MATERIALS

AND ENVIRONMENTAL MANAGEMENT PROGRAMS

WASHINGTON, D.C. 20555 February 3, 2009 NRC INFORMATION NOTICE 2009-05 CONTAMINATION EVENTS RESULTING FROM

DAMAGE TO SEALED RADIOACTIVE SOURCES

DURING GAUGE DISMANTLEMENT AND NON-

ROUTINE MAINTENANCE OPERATIONS

ADDRESSEES

All U.S. Nuclear Regulatory Commission (NRC) materials licensees. All Agreement State

Radiation Control Program Directors and State Liaison Officers.

PURPOSE

The U.S. Nuclear Regulatory Commission is issuing this Information Notice (IN) to alert

addressees of recently reported events that occurred during gauge dismantlement or non- routine maintenance operations that involved the handling or removal of sealed radioactive

sources. During these events, sealed radioactive sources were damaged or ruptured, leading

to both facility and personnel contamination. It is expected that recipients will review the

information for applicability to their facilities and consider actions, as appropriate, to avoid

similar incidents. However, the suggestions contained in this information notice are not new

NRC requirements; therefore, no specific action, or written response is required. The NRC is

providing this IN to the Agreement States for their information and for distribution to their

licensees as appropriate.

DESCRIPTION OF CIRCUMSTANCES

In the last three years, NRC has received five event reports, three of them recently, involving

gauge dismantlement/disassembly or non-routine maintenance operations of devices that

involved the handling or removal of sealed radioactive sources. Four of these events occurred

while personnel were attempting to remove a source holder from a gauge or removing a source

from its source holder for the purposes of source disposal. One of the events involved non- routine maintenance of a calibration device. The specific circumstances of these events are

discussed below.

Event 1 An NRC service provider licensee was dismantling gauges for the purpose of source removal

and consolidation for disposal. A licensee employee attempted to dismantle a frame-type beta

gauge containing an approximately 2.29 GBq (62 mCi) strontium-90/yttrium-90 source. The

gauge was over 20 years old and had been in storage at the licensees facility for over 5 years.

The employee performing the dismantlement had not previously worked with the particular type

of gauge or radioactive source. The employee removed the source holder from the gauge and

then attempted to remove the radioactive source from its source holder. The strontium-90/

yttrium-90 source, designed to emit beta particles, had a 0.076 mm (0.003 inch) stainless steel

window. A leak test performed prior to dismantlement did not reveal the presence of removable

contamination. In an attempt to remove the radioactive source from its holder, the employee

physically impacted the source window with a screwdriver and also impacted the source holder

containing the source onto an unyielding metal surface. Following these actions, an in-process

leak test revealed the presence of large amounts of removable contamination.

As a result of the damage to the source, the employee performing the dismantlement activities

had considerable external contamination, including on the hands, face, and clothing. During on- scene personnel decontamination activities, it was found that the employee also received an

intake of strontium-90, as evidenced by the detection of radiation inside the nostrils. Three

other licensee employees were externally contaminated to a lesser extent. The employees

decontaminated themselves prior to leaving the licensees facility. The employee performing

the dismantlement was taken to a local health care facility for medical evaluation as a

precautionary measure and provided several days of urine and fecal samples for bioassay

analysis. The other three employees provided urine samples for bioassay analysis. The dose

assessment for the employee performing the dismantlement revealed a total effective dose

equivalent of 14.4 mSv (1.44 rem). The radiation doses to the other three employees were

considerably lower. The licensees facility was extensively contaminated and strontium-90/

yttrium-90 was found to be dispersed widely throughout the interior of the licensees facility, considerably beyond the area where the disassembly had been performed or where

contaminated individuals had walked within the facility. Decontamination activities were

performed by an appropriately licensed contractor and were completed three months after the

event.

Event 2 During disassembly operations at the facilities of an Agreement State gauge manufacturer and

distributor licensee, an employee attempted to remove a radioactive source from its source

housing for the purpose of disposal. The industrial density/level fixed-type gauge had originally

been manufactured by the licensee over 30 years prior and at the time of the incident contained

an 11.1 GBq (300 mCi) cesium-137 sealed source. The source was damaged or breached as a

result of an employees attempt to remove it from the gauge housing using a saw. Prior to

commencing the dismantlement activities, the employee was unaware that the gauge internals

had been custom-configured. Therefore, when the gauge was cut open with the saw, the

sealed radioactive source was not in the area where the employee expected, and as a result, the radioactive source itself was damaged by the saw. As a result of the damage to the source, cesium-137 was dispersed throughout the licensees

source disposal room, contaminating the area with microspheres. Emergency procedures were

activated by the licensee, and no contamination was detected on the floor outside the source

disposal room. The employee that damaged the source exhibited contamination on one hand

and one leg; a second employee exhibited contamination on both hands and clothing. The

employees were decontaminated onsite and sent for medical evaluation as a precautionary

measure. The two employees provided urine samples for bioassay analysis and also

underwent lung counting. Calculated doses for the two employees were less than 50 uSv

(5 mrem). Decontamination activities were performed by an appropriately licensed contractor

and were completed two months after the event.

Event 3 During disassembly operations at an Agreement State gauge manufacturer and distributor

licensee, radioactive sources in two different continuous level fixed-type gauges were breached

on the same day, resulting in personnel and facility contamination. In the first incident, a

0.41 GBq (11 mCi) cesium-137 sealed source in a gauge was breached when an employee cut

into the source with a band saw. In the second incident, a 0.96 GBq (26 mCi) cesium-137 sealed source in a gauge was breached when the same employee, using a drill, broke the drill

bit when it became stuck in the source capsule. In both cases, the employee that was

dismantling the gauges did not have a clear understanding of the location of the sources within

the gauges.

Radioactive contamination was detected on the employee, throughout the source handling area, and in other portions of the licensees restricted area, including the gauge manufacturing area.

The employee involved in the incidents was decontaminated onsite although some

contamination remained on the fingertips. The employee was sent for medical evaluation as a

precautionary measure. Contamination on the employees hands, arms, hair, and clothing was

estimated to be 0.37 GBq (10 mCi). Urine samples from the employee were collected for

bioassay analysis. Whole body counting of the employee was also performed. Calculations

indicated a committed effective dose equivalent (CEDE) to the employee ranging from 21.3 to

19.4 uSv (2.13 to 1.94 mrem). The licensees facility was decontaminated by an appropriately

licensed contractor.

Event 4 An employee of an Agreement State manufacturer and distributor licensee attempted to remove

an approximately 12 GBq (325 mCi) cesium-137 sealed source from the source housing of a

density/level fixed-type gauge. At the time of the event, the gauge was approximately 19 years

old. Previous attempts had been made to remove the source from the gauge but were

unsuccessful. The employee then attempted to gain access to the source by drilling next to

where the source was believed to be located. However, the drill nicked and damaged the

radioactive source.

As a result of the damage to the source, radioactive material was dispersed in the licensees

facility, contaminating the immediate work area. The licensee estimated that less than

0.37 MBq (10 uCi) of cesium-137 was dispersed, contaminating various surfaces, including the drill press, work bench, and floor. The licensees facility was decontaminated. The highest

radiation dose to an individual was calculated by the licensee to be 10.9 mSv (1.09 rem).

Event 5 An employee of Agreement State instrument calibration service provider attempted to modify or

perform non-routine maintenance on a piece of calibration equipment that contained a

radioactive source. At the time of the incident, the calibration device contained a 1.85 GBq

(50 mCi) cesium-137 sealed source. The device had previously been designed and built by the

licensee for their own use. The employee used a grinder to grind what was believed to be a

metal spacer inside of the calibration device. When contamination was detected by another

employee in the vicinity of the work area, the employees recognized that the piece of metal that

had been ground actually contained a radioactive source.

As a result, the licensees machine shop became contaminated. Also, due to the tracking of

radioactive contamination by personnel, some other areas of the licensees facility became

slightly contaminated. The licensee performed some decontamination activities themselves and

retained the services of an appropriately licensed contractor to complete the decontamination

activities. The licensee identified four individuals that might have been exposed to the

contamination event. All four individuals underwent whole body counting. Three individuals

were estimated to have received less than 0.1 mSv (10 mrem) CEDE. The fourth individual, who performed the grinding of the source, is estimated to have received 2.99 mSv (29.2 mrem)

CEDE.

DISCUSSION

The events described above each occurred during gauge dismantlement or non-routine

maintenance operations that involved the handling or removal of sealed radioactive sources. In

each event, radiation sources were damaged or breached, resulting in both radioactive

contamination of individuals and licensee facilities. In each event, radioactive contamination

was confined within the licensees facility, with no detectable release of radioactive material into

the public domain. However, some licensee facilities were contaminated significantly, leading to

long periods of time of facility closure and in most cases, necessitating decontamination

services provided by a contractor. Also, in each case, licensee personnel were contaminated, often with both external radioactive contamination and some level of intake of radioactive

material. Some employees with a suspected intake of radioactive material were sent for

medical evaluation as a precautionary measure. Additionally, special dose analysis and

assessment methods were necessary in some cases, including urine and fecal bioassay and/or

lung or whole body counting.

Common causal factors have been identified in the events described above that may have

contributed to the damage to the radioactive sources, the subsequent release of radioactive

material, and the resultant contamination of licensee facilities and personnel. The common

causal factors have been identified as follows: 1. Dismantling/disassembling gauges or performing non-routine maintenance of devices

based on intuition rather than reviewing the information contained in the sealed source

and device registry (SS&DR) safety analysis or other information available from the

source or device manufacturer or vendor.

2. For an unfamiliar radioactive source or device, or in the absence of specific information

about the configuration of the radioactive sources within the gauges or devices, licensees did not develop, document, and implement their own procedures to perform

the dismantlement or non-routine maintenance activities.

3. For the incidents that involved dismantlement or disassembly of gauges, the aged and

potentially deteriorated condition of the gauges and/or radioactive sources at the time of

dismantlement/disassembly was not taken into consideration by licensee personnel that

were handling the sources or devices.

This IN serves as a reminder of the importance for licensees to exercise caution when

performing licensed activities that involve the handling or removal of sealed radioactive sources

in gauges or devices. Prior to the start of any such activity, licensees should review specific

information about the gauge, source holder, and/or device. This includes, as appropriate, information available in the SS&DR or other information from the manufacturer or vendor. In the

absence of such information, licensees should themselves develop, document, and implement

appropriate procedures, as well as train personnel on the procedures.

When developing procedures, licensees should consider conducting dismantlement/

disassembly and other non-routine maintenance activities in a deliberate, stepwise manner, including conducting routine monitoring for radioactive contamination to promptly detect

potential problems. Additionally, procedures should take into consideration actions that might

be necessary to mitigate the consequences of radioactive source damage/rupture incidents.

The availability of appropriate radiation detection equipment would assist personnel in

determining the scope and extent of radiological contamination; which would, in part, help

determine the necessary level of response.

Regarding training, licensees might remain mindful that a successful training program should

thoroughly familiarize employees with actions to take to limit the spread of contamination within

licensee facilities and actions to take to successfully decontaminate personnel. Licensees

should consider having appropriate supplies available in the event that the decontamination of

personnel is necessary. Furthermore, a successful training program would help employees

recognize actions that may be necessary to prevent the spread of radioactive contamination into

the public domain. Finally, licensee employees should be trained to recognize conditions under

which it might be necessary to seek external assistance, or notify as appropriate, NRC or other

appropriate regulatory agencies.

CONTACT

S

This IN 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 regional office.

/RA/

Robert Lewis, Director

Division of Materials Safety

and State Agreements

Office of Federal and State Materials

and Environmental Programs

Technical Contacts: Lymari Sepulveda; FSME

(301) 415-5619 E-mail: Lymari.Sepulveda@nrc.gov

Janine F. Katanic, Ph.D., CHP; FSME

(817) 860-8151 E-mail: Janine.Katanic@nrc.gov

Enclosure: List of Recently Issued

FSME/NMSS Generic

Communications

CONTACT

S

This IN 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 regional office.

/RA/

Robert Lewis, Director

Division of Materials Safety

and State Agreements

Office of Federal and State Materials

and Environmental Programs

Technical Contacts: Lymari Sepulveda; FSME

(301) 415-5619 E-mail: Lymari.Sepulveda@nrc.gov

Janine F. Katanic, Ph.D., CHP; FSME

(817) 860-8151 E-mail: Janine.Katanic@nrc.gov

Enclosure: List of Recently Issued

FSME/NMSS Generic

Communications

ML090370785 OFFICE DMSSA/ASPB DMSSA/LB DMSSA/ASPB

NAME JFKatanic: sxg6 LSepulveda ADWhite

DATE 01/08/09 01/09/09 01/09/09 OFFICE DMSSA/LB DMSSA/RMSB DMSSA

NAME PRathbun AMcIntosh RLewis

DATE 02/03/09 02/03/09 03/03/09 OFFICIAL RECORD COPY

IN 2009-05 List of Recently Issued Office of Federal and State Material and Environmental Management Programs

Generic Communications

Date GC No. Subject

Addressees

05/13/08 RIS-2008-10 Notice Regarding Forthcoming Federal All U.S. Nuclear Regulatory Commission

Firearms Background Checks licensees, certificate holders, and applicants for

a license or certificate of compliance who use

armed security personnel as part of their

physical protection system and security

organization. All Radiation Control Program

Directors and State Liaison Officers.

06/16/08 RIS-2008-13 Status And Plans for Implementation of All U.S. Nuclear Regulatory Commission

NRC Regulatory Authority for Certain materials licensees, Radiation Control Program

Naturally Occurring and Accelerator- Directors, State Liaison Officers, and the NRCs

Produced Radioactive Material Advisory Committee on the Medical Uses of

Isotopes

07/18/08 RIS-2008-17 Voluntary Security Enhancements for All U.S. Nuclear Regulatory Commission

Self-Contained Irradiators Containing Materials Licensees Authorized to Possess Self- Cesium Chloride Sources Contained Irradiators Containing Cesium

Chloride (CsCl) ; all Agreement State Radiation

Control Program Directors and State Liaison

Officers; all members of the Advisory Committee

on the Medical Uses of Isotopes.

10/03/08 RIS-2008-23 The Global Threat Reduction Initiative All U.S. Nuclear Regulatory Commission

(GTRI) Domestic Threat Reduction Materials Licensees authorized to possess

Program & Federally Funded Voluntary Category 1 or Category 2 quantities of

Security Enhancements For High-Risk radioactive materials. All Agreement State

Radiological Material Radiation Control Program Directors and State

Liaison Officers. Members of the Advisory

Committee on the Medical Uses of Isotopes

10/03/08 RIS-2008-24 Security Responsibilities Of Service All U.S. Nuclear Regulatory Commission

Providers and Client Licensees licensees that hire service providers to install, service, repair, maintain, relocate, exchange, or

transport radioactive materials in quantities of

concern, service provider licensees, Agreement

State Radiation Control Program Directors, and

State Liaison Officers

12/22/08 RIS-2008-10, Notice Regarding Forthcoming All U.S. Nuclear Regulatory Commission

Suppl. 1 Federal Firearms Background Checks licensees, certificate holders, and applicants for

a license or certificate of compliance who use

armed security personnel as part of their

physical protection system and security

organization. All Radiation Control Program

Directors and State Liaison Officers

Note: This list contains the six most recently issued generic communications, issued by the Office of Federal and State Materials

and Environmental Management Programs (FSME). A full listing of all generic communications may be viewed at the NRC public

website at the following address: http://www.nrc.gov/reading-rm/doc-collections/gen-comm/index.html