Information Notice 2009-05, 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