Radiation Protection Program Update:

The Details

Radiation Protection Program Update:

The Details July 2010

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Update TopicsUpdate 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

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ReferencesReferences

• 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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BackgroundBackground

• 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?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 TermsNew Terms

Old Dosimetric Term New Dosimetric TermCommitted effective dose equivalent Committed effective dose

Committed dose equivalent Committed equivalent doseCumulative total effective dose equivalent Cumulative total effective dose

Dose equivalent Equivalent doseEffective dose equivalent Effective doseQuality factor Radiation weighting factorWeighting factor Tissue weighting factorTotal effective dose equivalent Total effective dose

Deleted Terms (not in ICRP 60/68)

Replacement Terms (not added to definitions because meaning is clear)

Depth in Tissue (cm)

Deep dose equivalent Equivalent dose to the whole body 1.000Shallow dose equivalent

Equivalent dose to the skin or an extremity 0.007

Lens of the eye dose equivalent

Equivalent dose to the lens of the eye 0.300

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DefinitionsDefinitions

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 (E

50)- the sum of the committed equivalent doses to various tissues

or organs in the body multiplied by the appropriate tissue weighting factor

E50

= ΣWTH

T,50 + w

Remainder H

Remainder,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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DefinitionsDefinitions

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 (W

T)

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 WRQ changes to WR

Radiation Type Q WR

Neutrons, energy < 10 keV 3 5

Neutrons, energy 10 keV to 100 keV

10 10

Neutrons, energy > 100 keV to 2 MeV

10 20

Neutrons, energy > 2 MeV to 20 MeV

10 10

Neutrons, energy > 20 MeV 10 5Neutrons, unknown energy 10 20Spectral data are sufficient to identify the energy of the neutrons

Table titled “Quality Factors for Neutrons”(10 CFR 835 section 2(b))

Formula taken from ICRP 60., appendix A, paragraph A12.

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Q changes to WRQ changes to WR

Radiation Type Q WR

X-rays, gamma rays, positrons, electrons (including tritium beta particles)

1

Photons, electrons and muons, all energies 1

Protons and singly-charged particles of unknown energy with rest mass greater than one atomic unit

10

Protons, other than recoil protons, energy > 2 MeV 10

Alpha particles and multiple-charged particles (and particles of unknown charge) of unknown energy

20

Alpha particles, fission fragments, heavy nuclei 20

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New Tissue Weighting Factors (WT)New Tissue Weighting Factors (WT)

Tissue/Organ Weighting Factor Tissue Weighting Factor

Gonads 0.25 0.20Red bone marrow 0.12 0.12Colon 0.12Lungs 0.12 0.12Stomach 0.12Bladder 0.05Breast 0.15 0.05Liver 0.05Esophagus 0.05Thyroid 0.03 0.05Skin 0.01Bone surface 0.03 0.01Remainder* 0.3 0.05Whole body 1.00 1.00

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New Tissue Weighting Factors (WT)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 ChangesOther 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 ChangesOther 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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ReferencesReferences

• 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 ChangesAdditional 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 DosimetersPersonnel 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 DosimeterSupplemental 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 TrainingSealed 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 SourcesRadioactive 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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SummarySummary

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.