Transcript Radiation Protection Program Update

Radiation Protection
Program Update:
The Details
July 2010
2
Update Topics
• Changes mandated by Title 10, Code of
Federal Regulations, Part 835, Occupational
Radiation Protection (10 CFR 835)
• How changes affect your work / dose
• Resources
– Code of Federal Regulations
– Federal Registers
– Guidance Documents
• Additional improvements
3
References
• 10 CFR 835
– new regulations
• ICRP 60/68
– source documents that prompted most of the
changes
• Federal Register, Vol. 72, No. 110 (Friday,
June 8, 2007)
– amendments to 10 CFR 835 promulgated
– See discussion (changes made and why)
• Radiation Protection Programs Guide for
Use with 10 CFR 835
– Implementation Guide (G 441.1-1C)
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Background
• DOE adopted the system of radiation
dosimetry recommended in ICRP
Publication 60 in 2007
– Allows us to assess and record radiation dose
received by DOE workers in accordance with
updated accepted methods
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What Was Changed?
• New dosimetric
terminology based on
ICRP 60/68 in place of
ICRP 26/30
• New ICRP 60 Tissue
Weighting Factors in
place of ICRP 26
Weighting Factors
• New ICRP 60 Radiation
Weighting Factors in
place of ICRP 26
Quality Factors
• Amendments to other
parts of the regulations
that changed as a
result of adopting the
ICRP 60 dosimetry
system and the
resultant ICRP 68 dose
conversion factors
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New Terms
Old Dosimetric Term
Committed effective dose equivalent
Committed dose equivalent
Cumulative total effective dose equivalent
Dose equivalent
Effective dose equivalent
Quality factor
Weighting factor
Total effective dose equivalent
Deleted Terms
(not in ICRP 60/68)
Deep dose equivalent
Shallow dose
equivalent
Lens of the eye dose
equivalent
New Dosimetric Term
Committed effective dose
Committed equivalent dose
Cumulative total effective dose
Equivalent dose
Effective dose
Radiation weighting factor
Tissue weighting factor
Total effective dose
Replacement Terms (not added to
definitions because meaning is clear)
Equivalent dose to the whole body
Equivalent dose to the skin or an extremity
Depth in
Tissue (cm)
1.000
0.007
Equivalent dose to the lens of the eye
0.300
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Definitions
Equivalent dose (HT) - the product of average absorbed dose in a tissue or
organ and a radiation weighting factor (WR). For external dose, the equivalent
dose to the whole body is assessed at a depth of 1 cm in tissue; the equivalent
dose to the lens of the eye is assessed at a depth of 0.3 cm in tissue, and the
equivalent dose to the extremity and skin is assessed at a depth of 0.007 cm in
tissue.
Committed equivalent dose (HT,50)- the equivalent dose received by a tissue
or organ over a 50-year period after the intake of a radionuclide into the body.
It does not include contributions from radiation sources external to the body.
Committed effective dose (E50)- the sum of the committed equivalent doses
to various tissues or organs in the body multiplied by the appropriate tissue
weighting factor
E50 = ΣWTHT,50 + wRemainder HRemainder,50
Where WRemainder is the tissue weighting factor assigned to the remainder
organs and tissues and HRemainder,50 is the committed equivalent dose to the
remainder organs and tissues.
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Definitions
Effective dose (E)
The summation of the products of the equivalent dose received by specified
tissues or organs of the body and the appropriate tissue weighting factor (WT)
E = Σ WT HT
Includes the dose from radiation sources internal and/or external to the body.
For purposes of compliance with this part, equivalent dose to the whole body
may be used as effective dose for external exposures.
Total effective dose (TED)
The sum of the effective dose (for external exposures) and the committed
effective dose.
Cumulative total effective dose
The sum of all total effective dose values recorded for an individual plus, for
occupational exposures received before the implementation date of this
amendment, the cumulative total effective dose equivalent (as defined in the
November 4, 1998 amendment to this rule) values recorded for an individual,
where available, for each year occupational dose was received, beginning
January 1, 1989.
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Q changes to WR
Radiation Type
Q
WR
Neutrons, energy < 10 keV
3
5
Neutrons, energy 10 keV to
100 keV
Neutrons, energy > 100 keV
to 2 MeV
Neutrons, energy > 2 MeV to
20 MeV
Neutrons, energy > 20 MeV
Neutrons, unknown energy
Spectral data are sufficient to
identify the energy of the
neutrons
10
10
10
20
10
10
10
10
Table titled “Quality
Factors for Neutrons”
(10 CFR 835 section 2(b))
5
20
Formula taken from
ICRP 60., appendix
A, paragraph A12.
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Q changes to WR
Radiation Type
X-rays, gamma rays, positrons, electrons
(including tritium beta particles)
Q
1
Photons, electrons and muons, all energies
Protons and singly-charged particles of unknown
energy with rest mass greater than one atomic unit
1
10
Protons, other than recoil protons, energy > 2 MeV
Alpha particles and multiple-charged particles
(and particles of unknown charge) of unknown energy
Alpha particles, fission fragments, heavy nuclei
WR
10
20
20
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New Tissue Weighting Factors (WT)
Tissue/Organ
Gonads
Red bone marrow
Colon
Lungs
Stomach
Bladder
Breast
Liver
Esophagus
Thyroid
Skin
Bone surface
Remainder*
Whole body
Weighting Factor
0.25
0.12
0.12
0.15
0.03
0.03
0.3
1.00
Tissue Weighting
Factor
0.20
0.12
0.12
0.12
0.12
0.05
0.05
0.05
0.05
0.05
0.01
0.01
0.05
1.00
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New Tissue Weighting Factors (WT)
• The remainder is treated differently:
– Remainder = the five other organs or tissues, excluding the skin and
lens of the eye, with the highest dose (e.g., liver, kidney, spleen,
thymus, adrenal, pancreas, stomach, small intestine, and upper large
intestine)
– The weighting factor for each remaining organ or tissue is 0.06
– Remainder = adrenals, brain, extrathoracic airways, small intestine,
kidneys, muscle, pancreas, spleen , thymus, and uterus.
– The equivalent dose to the remainder tissues is normally calculated as
the mass-weighted mean dose to the preceeding ten organs and
tissues. In those cases in which the most highly irradiated remainder
tissue or organ receives the highest equivalent dose of all the organs, a
weighting factor of 0.025 (half of remainder) is applied to that tissue or
organ and 0.025 (half of remainder) to the mass-weighted equivalent
dose in the rest of the remainder tissues and organs to give the
remainder equivalent dose.
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Other Changes
• Revised for consistency with ICRP 68 dose conversion factors and 5
μm default AMAD for particles:
– Appendix A (DAC values for inhalation)
– Appendix C (DAC values for immersion)
– Appendix E (sealed source accountability values and requirements for
posting and labeling radioactive material)
• Clarify transportation exclusion
– Radioactive material transportation not performed by DOE / DOE
contractor is excluded
– Posting and access control is not needed for radioactive material
transportation performed by DOE / DOE contractor under continuous
control or labeled per DOT
– Receipt monitoring is not required for onsite shipments which have been
under continuous control
• Exclude material, equipment, and real property approved for release
in accordance with DOE approved authorized limits
– HS-20 developing guidance
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Other Changes
• Lowers the maximum
amount of radioactive
material which need not be
labeled to 0.1 Ci
– labeling threshold would
otherwise be 16 Ci for
tritium!
• Allows use of thresholds for
recording internal
occupational exposures
– less than 10 mrem per
result
– less than monitoring
threshold per year
• Establishes DAC default
values for radionuclides not
listed in the rule
– Non-alpha emitters with
radioactive half-life greater
than two hours
4 E−11 μCi/mL
– Alpha emitters
2 E−13 μCi/mL
• Appendix D – not
significantly changed
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Full compliance
required by
July 9, 2010!!
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References
•
Slides by Peter V. O’Connell: 10 CFR 835 Amendment, Office of Health and Safety,
U.S. Department of Energy. ISCORS Public Meeting, Washington, DC. October 1,
2008.
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Additional RPP Changes
In addition to the updates needed to be in compliance with
10 CFR 835, additional updates improve the rigor and quality of the
Radiation Protection Program.
Changes include:
• Dosimeter storage racks
• Supplemental dosimetry
• Sealed source custodians and training
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Personnel Dosimeters
Dosimeter Use
•
Keep dosimeter away from all
medical, dental, and airport
radiation exposures
Dosimeter Return
•
Promptly return your dosimeter
at the end of the wear period
Dosimeter Storage
•
Leave your dosimeter on your
assigned rack at the end of the
work day.
•
If your work area does not have
a rack contact your POC or
Henry Tran at ext. 3793.
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Supplemental Dosimeter
Pocket ion chambers (PICs) are prohibited for
supplemental dosimetry because of calibration
requirements.
Do not use a PIC when radiological controls
specify the use of supplemental dosimetry (i.e.
entering a high radiation area).
1.
Return any PICs you have to RPD
2.
Contact RPD at x4299 to request an
electronic dosimeter as needed to monitor
and record your dose
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Sealed Source Training
Sealed source training is dependent on the radionuclide, activity, and exposure rates. The training
requirements are listed in the table below. In addition, sealed source custodians must be appointed by
their supervisor. This can be accomplished by completing a form memo and sending to RPD. Contact
RPD x4299 for details.
Source Exposure Rate
Training required
Dosimetry required
> 5 mR/h @ 30 cm
RWT I
Personnel Dosimeter
> 0.05 mR/h @ 30 cm
GERT
Personnel Dosimeter
< 0.05 mR/h @ 30 cm
GERT
N/A
How this affects you
If you are a sealed source custodian:
Have your supervisor appoint you if you have not done so already.
Brief users on the new training requirements when issuing sources.
If you are a sealed source user:
Check with your custodian or RPD to verify you have the appropriate training.
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Radioactive Materials and Sources
Notify Radiation Protection at ext.
4299 prior to bringing any radioactive
material onsite such as
1. Naturally occurring radioactive
material, including thorium welding
rods and sand blasting media
2. Sealed sources
3. Radiation generating devices such
as radiography units, x ray
generators, and soil density gauges
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Summary
Change
How it Affects You
New dosimetry terminology
Your dose report will look different, but the values are still in mrem.
Limits are unchanged.
New radiation weighting factors
Only affects neutron dose reporting.
New source accountability
classifications
Sealed source custodians and sealed source users will be notified of
any classification or radiological control changes.
New DAC Values
Radiological controls remain unchanged.
Dosimeter use and return
To encourage prompt return, email reminders will be sent to any
dosimeter wearer who has not returned their dosimeter within 15
days after the wear period ends. After 30 days their supervisor will be
notified.
Dosimeter boards
Please leave your dosimeter on the dosimeter board in your area at
the end of the work day.
Supplemental dosimeters
If supplemental dosimeter is required, contact RPD to obtain a new
supplemental electronic dosimeter.
Sealed source training
Sealed source custodians and sealed source users need to verify
they have appropriate training.
RAM Notification
Notify Radiation Protection at ext. 4299 prior to bringing any
radioactive material onsite.