Information Notice 2000-10, Recent Events Resulting in Extremity Exposures Exceeding Regulatory Limits
| ML003732340 | |
| Person / Time | |
|---|---|
| Issue date: | 07/18/2000 |
| From: | Cool D NRC/NMSS/IMNS |
| To: | |
| DeCicco J, NMSS/IMNS, 415-7833 | |
| References | |
| IN-00-010 | |
| Download: ML003732340 (7) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555-0001 July 18, 2000
NRC INFORMATION NOTICE 2000-10: RECENT EVENTS RESULTING IN EXTREMITY
EXPOSURES EXCEEDING REGULATORY LIMITS
Addressees
All material licensees who prepare or use unsealed radioactive materials, radiopharmaceuticals, or sealed sources for medical use or for research and development.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this Information Notice (IN) to alert
addressees to recent events that resulted in personnel receiving occupational extremity doses in
excess of the 0.5-sievert (50-rem) shallow dose equivalent limit specified in 10 CFR
20.1201(a)(2)(ii). 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 IN are not new NRC requirements; therefore, no specific action nor written
response is required.
Description of Circumstances
Recently, NRC was notified by, and responded to, two licensees facilities where personnel
received radiation exposures to their extremities in excess of the 0.5-sievert (50-rem) limit.
Although both events occurred at commercial radiopharmaceutical facilities, the issues pertain to
all material licensees that may prepare or use unsealed radioactive materials, radiopharmaceuticals, or sealed sources for medical use, or for research and development.
Case 1:
The licensee - a radiopharmaceutical manufacturing facility - notified NRC of an event involving
an employee directly handling an unshielded molybdenum-99/technetium-99m generator
column. The column contained 700 gigabecquerels (19 curies) of molybdenum-99 (Mo-99) and
300 gigabecquerels (8 curies) of technetium-99m (Tc-99m). Event reenactments determined
that the individual may have held the column using his thumb and index finger of his left hand for
as long as 50 seconds while attempting to correct alignment problems with the inlet and outlet
needles. The individual wore a ring badge on the right hand to measure extremity dose, and this
monitor read 0.057 sieverts (5.7 rems). Calculations indicated that the dose to the individuals
thumb and index finger of the left hand may be as much as 25-gray (2500-rad) shallow dose
equivalent.
The licensees investigation into the event identified two additional exposure situations involving
13 other individuals in other areas of the facility.
One situation involved the hand-labeling of product vials that contained approximately 740
megabecquerels (20 millicuries) of indium-111, an accelerator-produced radioactive material.
Ten individuals, over the period between 1995 and 1999, inclusive, held the product vials in
their left hands, with the index fingers on the tops of the vials and their thumbs on the bottoms, in close proximity to the radioactive material, and applied the labels with their right hands. The
individuals all wore their extremity monitors on their right hands. Licensee calculations
determined that the individuals involved in this practice received between 0.5- and 6-sievert (50-
and 600-rem) shallow dose equivalent during calendar years 1995 through 1999. Several
individuals received exposures in excess of 0.5 sievert (50 rems) in multiple years.
The other situation involved three additional individuals who worked in one of the licensees
product testing laboratory. While performing their duties in this laboratory, the individuals
removed aliquots of radioactive material for testing from product vials, using unshielded
syringes, and in some instances, while holding the unshielded vials in their hands. These
individuals received between 0.7- and 1.0-sievert (70- and 100-rem) shallow dose equivalent to
their hands and fingers during calendar years 1997 and 1999. Again, some of the individuals
received exposures in excess of 0.5 sievert (50 rems) in more than 1 year.
The licensee believed that the exposures recorded by the extremity monitors were the doses of
record, and did not recognize the significant difference between the recorded dose and the
actual dose to the fingertips when handling unshielded vials and syringes of radioactive
material. This contributed to the licensee not being fully aware of the extent of inadequate
radiation handling practices. The extremity monitor results for the individuals involved in these
last two situations did not provide any indications that they were receiving doses in excess of
NRC regulatory limits.
Case 2:
A licensee -a commercial radiopharmacy- reported that the fingers of a radiopharmacist may
have received an exposure in excess of the NRC limit. As reported by the licensees dosimetry
processor, the workers extremity monitoring received approximately 0.082 sieverts (8.2 rems),
0.265 sieverts (26.5 rems), 0.131 sieverts (13.1 rems), and 0.12 sieverts (12.0 rems), during
the months of February, March, April, and May, respectively. There had been significant delays
in processing extremity dosimeters and assessment of the results.
The pharmacist did not have prior radiopharmacy experience, and the licensee provided the
pharmacist with training in radiopharmacy operations and procedures, as well as with on-the-job
training. The pharmacist performed routine radiopharmacy tasks, including elution of Mo-
99/Tc-99m generators and formulation of unit doses of Tc-99m, as ordered by local hospitals. To deal with the difficult time constraints and production pressures, in part, the pharmacist used
a lighter syringe shield (without a flange needed to maximize shielding the radiation emanating
from the vial septum) or no shielding. In addition, the pharmacist directly handled dosages
without shielding during dose calibrations, and on many occasions conducted repeat dose
calibrations while attempting to dispense requested activity.
Discussion:
Some of the contributing causes of these exposure events can be summarized as follows:
ÿ Direct handling of unshielded material, or inadequate use of shielding and remote
handling devices;
ÿ Lack of direct supervisory review of work habits and techniques used to minimize
exposure;
ÿ Operational pressures to meet production outputs and deadlines;
ÿ Inadequate attention to As Low As Reasonably Achievable (ALARA) programs;
ÿ Extremity monitoring not being representative of actual dose;
ÿ Delays in the receipt of dosimetry results; and,
ÿ Absence of a questioning attitude toward extremity exposure, or a lack of awareness of
exposure levels in close proximity of radiation sources.
All licensees that work with and handle unsealed radioactive materials, radiopharmaceuticals, and unsealed sources, are reminded of the importance of:
ÿ Training and supervising new employees, to ensure that they understand the hazard
associated with their work;
ÿ Examining the operational procedures and activities for handling materials, and assuring
that they are well understood by the individuals using them;
ÿ Using appropriate shielding, and understanding the gravity of directly touching or
handling unshielded syringes, vials, or other sources;
ÿ Not allowing work pressures and workloads to interfere with appropriate radiation safety
practices and the radiation safety program;
ÿ Extremity monitoring and its proper placement, such that extremity monitor dose results
are representative of the highest exposure expected to any extremity; and,
ÿ ALARA programs reflecting appropriate and timely actions to reduce extremity doses as
well as the total effective dose equivalent (TEDE);
ÿ Selecting an appropriate monitoring interval and processing turnaround time to ensure
that ALARA objectives and regulatory limits are met. This information notice requires no specific action nor written response. If you have any
questions about the information in this IN, please contact the technical contacts listed below or
the appropriate regional office.
/RA/
Donald A Cool, Director
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
and Safeguards
Technical contacts: Jamnes L. Cameron, RIII Dr. Mohamed M. Shanbaky, RI
630-829-9833 610-337-5209 E-mail: jlc@nrc.gov E-mail: mms1@nrc.gov
Attachments:
1. List of Recently Issued NMSS Information Notices
2. List of Recently Issued NRC Information Notices
Attachment 1 LIST OF RECENTLY ISSUED
NMSS INFORMATION NOTICES
_____________________________________________________________________________________
Information Date of
Notice No. Subject Issuance Issued to
_____________________________________________________________________________________
2000-07 National Institute for 4/10/2000 All holders of operating licenses
Occupational Safety and for nuclear power reactors, non- Health Respirator User Notice: power reactors, and all fuel cycle
Special Precautions for Using and material licensees required to
Certain Self-Contained have an NRC-approved
Breathing Apparatus Air emergency plan
Cylinders
2000-05 Recent Medical 3/06/2000 All medical licensees
Misadministrations Resulting
from Inattention to Detail
2000-04 1999 Enforcement Sanctions 2/25/2000 All U.S. Nuclear Regulatory
for Deliberate Violations of Commission licensees
NRC Employee Protection
Requirements
2000-03 High-Efficiency Particulate Air 2/22/2000 All NRC licensed fuel-cycled
Filter Exceeds Mass Limit conversion, enrichment, and
Before Reaching Expected fabrication facilities
Differential Pressure
2000-02 Failure of Criticality Safety 2/22/2000 All NRC licensed fuel-cycled
Control to Prevent Uranium conversion, enrichment, and
Dioxide (UO2) Powder fabrication facilities
Accumulation
99-33 Management of Wastes 12/28/99 All medical licensees
Contaminated With
Radioactive Materials
99-32 The Effect of the Year 2000 12/17/99 All NRC medical licensees
Issues on Medical Licensees
99-31 Operational Controls to Guard 11/17/99 All NRC licensed fuel cycle
Against Inadvertent Nuclear conversion, enrichment and
Critically fabrication facilities
99-30 Failure of Double Contingency 11/8/99 All fuel cycle licensees and
Based on Administrative certificates performing laboratory
Controls Involving Laboratory analysis to determine uranium
Sampling and Spectroscopic content, in support of
Analysis of Wet Uranium administrative criticality safety
Waste controls
Attachment 2 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
_____________________________________________________________________________________
Information Date of
Notice No. Subject Issuance Issued to
________________________________________________________________________________
2000-09 Steam Generator Tube Failure 6/30/2000 All holders of operating licenses
at Indian Point Unit 2 for nuclear power reactors, except those who have
permanently ceased operations
and have certified that fuel has
been permanently removed from
the reactor vessel
2000-08 Inadequate Assessment of the 5/15/2000 All holders of operating licensees
Effect of Differential for nuclear power reactors
Temperatures on Safety- Related Pumps
2000-07 National Institute for 4/10/2000 All holders of operating licenses
Occupational Safety and for nuclear power reactors,non- Health Respirator User Notice: power reactors, and all fuel cycle
Special Precaustions for Using and materiallicensees required to
Certain Self-Contained have an NRC-approved
Breathing Apparatus Air emergency plan
Cylinders
2000-06 Offsite Power Voltage 3/22/2000 All holders of operating licenses
Inadequacies for nuclear power reactors, except those who have
permanently ceased operations
and have certified that fuel has
been permanently removed from
the reactor vessel
2000-05 Recent Medical 3/06/2000 All medical licensees
Misadministrations Resulting
from Inattention to Detail
2000-04 1999 Enforcement Sanctions 2/25/2000 All NRC licensees
for Deliberate Violations of
NRC Employee Protection
Requirements
____________________________________________________________________________________
OL = Operating License
CP = Construction Permit This information notice requires no specific action nor written response. If you have any questions
about the information in this IN, please contact the technical contacts listed below or the appropriate
regional office.
/RA/
Donald A Cool, Director
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
and Safeguards
Technical contacts: Jamnes L. Cameron, RIII Dr. Mohamed M. Shanbaky, RI
630-829-9833 610-337-5209 E-mail: jlc@nrc.gov E-mail: mms1@nrc.gov
Attachments:
1. List of Recently Issued NMSS Information Notices
2. List of Recently Issued NRC Information Notices
Distribution:
INMS r/f NMSS r/f
DOCUMENT NAME: G:extremityin.wpd
Accession Number:ML003732340
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OFC MSIB C MSIB N MSIB C IMNS C
NAME JDeCicco* E Kraus* JHickey* *DCool/RA/
DATE 7/ 17 /00 7/ 17 /00 7/ 17 /00 7/ 18 /00
OFFICIAL RECORD COPY