Information Notice 2000-15, Recent Events Resulting in Whole Body Exposures Exceeding Regulatory Limits
| ML003753235 | |
| Person / Time | |
|---|---|
| Issue date: | 09/29/2000 |
| From: | Cool D NRC/NMSS/IMNS |
| To: | |
| Psyk L | |
| References | |
| IN-00-015 | |
| Download: ML003753235 (6) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555
September 29, 2000
NRC INFORMATION NOTICE 2000-15:
RECENT EVENTS RESULTING IN WHOLE BODY
EXPOSURES EXCEEDING REGULATORY LIMITS
Addressees
All radiography licensees.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to alert
addressees to recent events that resulted in radiographers receiving occupational whole body
doses in excess of the 0.05 sievert (5 rem) total effective dose equivalent limit specified in 10 CFR 20.1201(a)(1). It is expected that recipients will review this information for applicability to
their facilities and consider actions, as appropriate, to avoid similar problems. However, suggestions contained in this information notice are not new NRC requirements; therefore, no
specific action nor written response is required.
Description of Circumstances
In March of this year, the NRC was notified that several radiographers had exceeded the
annual whole body dose limit of 0.05 sievert (5 rem) for calender year 1999. The following
describes the two cases:
Case 1:
A licensee reported that four radiographers received total effective dose equivalents of 7.224,
6.534, 6.104, and 5.112 cSv (rem) for 1999. The licensee stated that the exposures arose from
an unprecedented workload during 1999. Radiographers were using daily pocket dosimeters, although readings did not reflect the exposures expected for a larger workload. The reason for
this discrepancy was not determined, although improper use of the daily pocket dosimeters may
have been the cause. Dosimetry records for the fourth quarter of 1999 were not received until
late February 2000. Thus, the licensee did not realize that its employees had exceeded
exposure limits until the dosimetry reports arrived. The dosimetry processor stated that the
delay in dosimetry record returns was caused by computer difficulties, which it encountered
when upgrading its system for year 2000 compliance.
The licensee took several corrective actions. It now has a database program, allowing it to
determine the total personal pocket dosimeter readings at any given time. On a monthly basis, the licensee will review the pocket dosimeter readings to ensure that radiographers are not
approaching a dose limit. If an individual receives a personal dosimetry reading of greater than
0.4 cSv (rem) in any month, the individual will be notified and a plan will be developed for
keeping the dose within limits.
Case 2:
A licensee reported that two radiographers received annual doses that exceeded the yearly
limits for 1999. One individual received 2.14 cSv (rem) during the last quarter of 1999, which
put his total dose at 5.23 cSv (rem) for the year. Another individual received 0.93 cSv (rem) for
the last quarter of 1999, which made his total year dose 5.16 cSv (rem).
The licensee was slow to return the badges to be processed, sometimes delaying returning
badges up to 6 weeks after receiving them from the field. The control badges were not being
returned with the employee badges, further delaying the process time. Also, the dosimetry
processor had computer problems that delayed the generation of dose reports. The licensee
did not receive one radiographers 1999 fourth-quarter badge results until late February 2000,
and the second radiographers quarterly badge results until March 2000. The provisions in 10 CFR 34.47 (a)(4) require that, after replacement, each film badge or TLD must be processed as
soon as possible.
The dosimetry processor notified the licensee that an employee had exceeded his/her ALARA
level for the second quarter of 1999. The licensee did not document or follow up this
notification.
The licensee also stated that there were discrepancies between the weekly dosimeter records
and the quarterly film badge results from the processor. Pocket dosimeters were being used
and recorded weekly, although the licensee did not review the records. The licensees weekly
records indicated that one radiographer had exceeded the yearly limit of 0.05 sievert (5 rem) in
August 1999, but no action was taken to remove the individual from duties involving exposure
to radiation. At year end, the weekly pocket dosimeter records indicated 6.905 cSv (rem) for
one individual and 1.678 cSv (rem) for the other individual, which differs significantly from the
film badge results of 5.156 cSv (rem) and 5.233 cSv (rem). Although dosimeter sharing was a
possibility, this could not be determined. The provisions in 10 CFR 34.47(a)(2) require that each
film badge and TLD must be assigned to, and worn by, only one individual.
Three major causes contributed to these overexposures: 1) the licensee did not return
employee badges and control badges together to the processor; 2) the licensee did not return
the badges to the processor in a timely manner; and 3) the licensee did not review pocket
dosimeter results.
The licensees corrective actions included: 1) shipping the badges to the processor using an
express mail carrier; 2) documenting telephone notifications from the dosimetry processor that
quarterly ALARA dose levels are exceeded; 3) reviewing the weekly pocket dosimetry reports;
and 4) retraining personnel and emphasizing that the sharing of dosimeters is an unacceptable
practice.
IN 2000-15 Page 3 of
Discussion:
Some of the contributing causes of these exposure events can be summarized as follows:
ÿ
Licensee failed to monitor pocket dosimetry results;
ÿ
Dosimetry badges not mailed to the processor in a timely manner by the licensee;
ÿ
Dosimetry badges and controls were not mailed together to the processor;
ÿ
Dose determined solely on the results of quarterly dosimeter records;
ÿ
Radiographers were assigned jobs before knowing their current cumulative doses;
ÿ
Impact of the workload was not assessed regarding its impact on exposures.
All licensees using radiography devices are reminded of the importance of:
ÿ
Tracking doses on a timely basis, to ensure that an individual is not approaching a
dose limit;
ÿ
Timely return of badges and controls, together, to the dosimetry processor;
ÿ
Obtaining reports from dosimetry processors in a timely manner;
ÿ
Training employees on the importance of not sharing pocket dosimeters and badges;
ÿ
Assessing increased workload and its impact on employee exposures;
ÿ
Not allowing work pressures and workloads to interfere with appropriate radiation safety
practices and the radiation safety program; and
ÿ
ALARA programs reflecting appropriate and timely actions.
Licensees are ultimately responsible for ensuring that their workers do not exceed the annual
dose limits in 10 CFR Part 20. Licensees may wish to consider actions to improve the tracking
and control of worker doses.
This information notice requires no specific action nor written response. If you have any
questions about the information in this notice, please contact the technical contact 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 Contact:
Linda M. Psyk, NMSS
(301) 415-0215 E-mail: lmp1@nrc.gov
Attachments:
1. List of Recently Issued NMSS Information Notices
2. List of Recently Issued NRC Information Notices
ML003753235 C:\\Ticket7886 IN Radiographer ~.wpd
OFC
MSIB
E
MSIB
TECH ED
IMNS
NAME
JHickey
EKraus
DCool
DATE
8/2/00
9/20/00
8/3/00
9/25/00
Attachment 1 LIST OF RECENTLY ISSUED
NMSS INFORMATION NOTICES
_____________________________________________________________________________________
Information
Date of
Notice No.
Subject
Issuance
Issued to
_____________________________________________________________________________________
2000-12
Potential Degradation of
Firefighter Primary Protective
Garments
9/21/2000
All holders of licenses for nuclear
power, research, and test
reactors and fuel cycle facilities
2000-11
Licensee Responsibility for
Quality Assurance Oversight of
Contractor Activities Regarding
Fabrication and Use of Spent
Fuel Storage Cask Systems
8/7/2000
All U.S. NRC 10 CFR Part 50 and
Part 72 licensees, and Part 72
Certificate of Compliance holders
2000-10
Recent Events Resulting in
Extremity Exposures
Exceeding Regulatory Limits
7/18/2000
All material licensees who
prepare or use unsealed
radioactive materials, radio- pharmaceuticals, or sealed
sources for medical use or for
research and development
2000-07
National Institute for
Occupational Safety and
Health Respirator User Notice:
Special Precautions for Using
Certain Self-Contained
Breathing Apparatus Air
Cylinders
4/10/2000
All holders of operating licenses
for nuclear power reactors, non- power reactors, and all fuel cycle
and material licensees required to
have an NRC approved
2000-05
Recent Medical
Misadministrations Resulting
from Inattention to Detail
3/06/2000
All medical licensees
2000-04
1999 Enforcement Sanctions
for Deliberate Violations of
NRC Employee Protection
Requirements
2/25/2000
All U.S. Nuclear Regulatory
Commission licensees
2000-03 High-Efficiency Particulate Air
Filter Exceeds Mass Limit
Before Reaching Expected
Differential Pressure
2/22/2000
All NRC licensed fuel-cycled
conversion, enrichment, and
fabrication facilities
2000-02
Failure of Criticality Safety
Control to Prevent Uranium
Dioxide (UO2) Powder
Accumulation
2/22/2000
All NRC licensed fuel-cycled
conversion, enrichment, and
fabrication facilities
____________________________________________________________________________________
OL = Operating License
CP = Construction Permit
Attachment LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
_____________________________________________________________________________________
Information
Date of
Notice No.
Subject
Issuance
Issued to
________________________________________________________________________________
2000-14 Non-Vital Bus Fault Leads to
Fire and Loss of Offsite Power
9/27/2000
All holders of licenses for nuclear
power reactors
2000-13
Review of Refueling Outage
Risk
9/27/2000
All holders of OL for nuclear
power reactors
2000-12
Potential Degradation of
Firefighter Primary Protective
Garments
9/21/2000
All holders of licenses for nuclear
power, research, and test
reactors and fuel cycle facilities
2000-11
Licensee Responsibility for
Quality Assurance Oversight of
Contractor Activities Regarding
Fabrication and Use of Spent
Fuel Storage Cask Systems
8/7/2000
All U.S. NRC 10 CFR Part 50 and
Part 72 licensees, and Part 72
Certificate of Compliance holders
2000-10
Recent Events Resulting in
Extremity Exposures
Exceeding Regulatory Limits
7/18/2000
All material licensees who
prepare or use unsealed
radioactive materials, radio- pharmaceuticals, or sealed
sources for medical use or for
research and development
95-03, Supp 2
Loss of Reactor Coolant
Inventory and Potential Loss of
Emergency Mitigation
Functions While in a Shutdown
Condition
7/03/2000
All holders of OL for nuclear
power reactors except those who
have ceased operations and have
certified that fuel has been
permanently removed from the
reactor vessel
2000-09
Steam Generator Tube Failure
at Indian Point Unit 2
6/28/2000
All holders of OL 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
Effect of Differential
Temperatures on Safety-
Related Pumps
5/15/2000
All holders of operating licensees
for nuclear power reactors
____________________________________________________________________________________
OL = Operating License
CP = Construction Permit