Information Notice 2000-10, Recent Events Resulting in Extremity Exposures Exceeding Regulatory Limits

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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

Template NRR-052 To receive a copy of this document, indicate in the box: "C"= Copy without attachment/encl. "E" = Copy with attachment/encl "N" = No

copy *See previous concurrence pages

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