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APPENDIX C

TECHNICAL BASIS FOR OCCUPATIONAL RADIATION SAFETY SIGNIFICANCE

DETERMINATION PROCESS

1 ALARA

Section 1101.(b) of 10 CFR Part 20 states that licensees "shall use, to the extent practical,

procedures and engineering controls based upon sound radiation protection principles to

achieve occupational doses that are as low as is reasonably achievable (ALARA)." The

Statements of Consideration (SOC) published with this regulation (Federal Register, Volume

56, dated May 21, 1991, at 23367) expressed the Commission’s continued emphasis on

the importance of the ALARA concept to an adequate radiation protection program.

However, the SOC clarifies that "compliance with this requirement will be judged on whether

the licensee has incorporated measures to track and, if necessary, to reduce exposures

and not whether exposures and doses represent an absolute minimum or whether the

licensee has used all possible methods to reduce exposures." While admitting that this is

subjective criteria, the SOC goes on to state the expectation that the "level of effort

expended [with regard to ALARA measures] should reflect the magnitude of the potential

exposures...."

Reactor licensees currently have mature ALARA programs to plan significant work, estimate

the resulting collective dose, and make the determination as to what dose reducing

radiological and engineering controls are reasonably achievable. Consistent with the above

regulatory basis, the NRC inspections verify the reasonableness of the licensee’s ALARA

program. The effectiveness of the ALARA program is assessed on a work activity-by-work

activity basis. The actual dose outcome of a work activity is compared to the planned,

intended dose for that work activity. A mismatch between the planned, intended dose and

the actual dose experienced in completing a work activity is an indication of a possible

program weakness or failure. In addition, the SDP employs dose criteria to represent

"magnitudes of exposure" that reflect differences in the level of effort that is reasonably

expected to be applied by the licensee with regard to ALARA measures. These dose

criteria have been selected, based on regulatory experience and typical industry practices,

solely to judge the relative significance of ALARA concerns as they relate to the regulatory

requirement for an ALARA program. The dose criteria should not be construed to imply

a staff position or regulatory guidance beyond their application within the context of the SDP

and the reactor oversight process.

For the purpose of this cornerstone, unplanned, unintended occupational collective dose

is the total sum of the occupational radiation doses (collective dose) received by individuals

for a work activity in excess of that collective dose planned or intended (i.e., that dose the

licensee determined was ALARA) for that work activity. A work activity is one or more

closely related tasks that the licensee has identified as a unit of work for the purpose of

ALARA planning and work controls. Planned, or intended, collective dose can be the results

of a realistic dose estimates (or projection) established during ALARA planning or the dose

expected by the licensee (i.e., historically achievable) for the reasonable exposure control

measures specified in ALARA procedures/planning. These do not include "stretch goals"

set by a licensee to challenge their organization to strive for excellence in ALARA

performance. Collective dose associated with reasonably unexpected changes in the scope

of work, material conditions, or radiological conditions, during a work activity (and for which

measures are implemented to track, and if necessary, to reduce these doses) should also

be considered intended dose.

Situations where the unplanned, unintended collective dose for a work activity does not

exceed 50% of the planned, intended dose, should normally be considered as minor issues

and screened out from SDP consideration (see IMC 0612, "Power Reactor Inspection

Reports," for a discussion of the screening process). This criterion reflects a reasonable
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expectation of the accuracy for the licensee’s ability to predict the collective dose resulting

from a work activity during ALARA planning. In addition, failures that exceed this 50%

criterion for work activities where the actual total collective dose is less than 5 person-rem

should also generally be considered as minor. However, situations where the licensee has

arbitrarily divided the radiological work into very small "work activities" for the purpose of

avoiding inspection findings (i.e., tolerate weaknesses in the program that result in several

or wide-spread failures to plan and control exposures), should be considered more than

minor.

The 5 person-rem criterion represents a level of actual dose associated with a work activity

at which it is reasonably expected that the licensee will, at a minimum, apply measures to

review and plan work, track dose and, if practical, to reduce exposures. Reactor licensees

generally conduct formal ALARA planning and controls at levels below this (typically, one

person-rem). The 5 person-rem dose criterion should not be taken to represent a level of

collective dose that is "risk-significant." However, failure to plan or control work activities

at this level is a possible indication of a more significant weakness in the ALARA program,

and could reasonably be viewed as a precursor to a more significant failure. Thus, a failure

to "establish, maintain, or implement procedures or engineering controls, intended to

achieve occupational doses that are ALARA, and that resulted in unplanned, unintended

occupational collective dose for a work activity" with an actual dose in excess of 5

person-rem will be evaluated as a finding, subject to whether the actual dose also exceeded

the planned, intended dose by more than 50%.

The first decision gate, in the ALARA branch of the SDP, evaluates the significance of the

inspection finding in terms of the licensee’s overall ALARA performance (e.g., the three-year

rolling average collective dose). Inspection findings associated with an ALARA program

that have an average collective dose below the criteria are assessed at no greater than

Green. The criteria in the SDP represents the median industry three-year rolling average

collective doses (as reported at the initiation of the revised ROP). Several factors can

impact a particular licensee’s standing with respect to the collective dose criteria. In some

cases (i.e., overall plant design, or significant plant modifications such as steam generator

replacement) these factors may be independent of the ALARA program performance.

However, the three-year rolling average collective dose is a high level indication of the

radiological challenges the program faces. The SDP is intended to direct NRC inspection

resources to those programs with the largest challenges. This criteria should not be

interpreted as a de-facto definition of ALARA for occupational radiation exposures. Nor,

as stated above, should a Green finding be interpreted as acceptable. It does mean that

the significance of the finding is determined not to warrant further NRC oversight.

The 25 person-rem criterion in the SDP represents a level of actual dose associated with

a work activity at which it is reasonably expected that there will be review and oversight by

licensee management to confirm the adequacy of ALARA measures that are being applied.

Accordingly, a "failure to establish, maintain, or implement procedures or engineering

controls..." at this level of dose is deemed to be of relatively greater significance with regard

to the regulatory basis of the SDP. Therefore, an ALARA concern that involves a work

activity with actual dose greater than 25 rem will be evaluated as a White finding within the

SDP.

If the actual collective job dose associated with the finding was not greater than 25

person-rem, and if there were four or fewer such occurrences in the assessment period,

then the ALARA finding is Green. If there have been five or more such occurrences in the

assessment period, then the finding is White. By its nature, collective dose is the sum of

individual work activity doses. The aggregate impact on the licensee’s overall collective

dose from five, 5 person-rem work activities is the same as one, 25 person-rem activity.

This White finding reflects program performance, and an associated aggregate impact,

where prior licensee management intervention is expected.
Issue Date: 07/28/05 3 0308, Att 3, App C

2 Exposure Control

With the exception of shallow dose limit from discrete radioactive particles, the failure to

control exposures to an individual, resulting in an occupational dose in excess of the 10 |

CFR 20 dose limits, is at least a Yellow finding. Occurrences that result in dose(s) in excess

of five times the 10 CFR 20 occupational dose limits are designated as Red findings. An |

exposure attributable to a discrete radioactive particle which exceeds the shallow dose limit |

in 10 CFR 20, is assessed as a White finding. An exposure to a discrete radioactive particle |

that results in exceeding five times the shallow dose limit in 10 CFR 20, is assessed as a |

Yellow finding. |

Breakdowns in the Radiation Protection Program, or unintended exposures, that do not

exceed a dose limit can still be considered significant if they constitute a "Substantial

Potential for Overexposure". A substantial potential, consistent with the current

Enforcement Manual (NUREG/BR-0195, subsection 8.4.1), is an occurrence in which a

minor alteration of the circumstances would have resulted in a violation of Part 20 limits and

it was only fortuitous that the altered circumstances did not occur. In the SDP, the finding

involving a substantial potential for overexposure can result in a White or Yellow finding

depending on the dose rates (e.g., risk of a serious outcome) associated with the failure.

In a Very High Radiation Area of 500 rads/hr, it can take as little as 3 minutes for a worker

to receive 25 rem. Note that the Enforcement Process (and possible civil penalty) will not

engage unless the event involved an "actual consequence" (in this case an actual

overexposure). The Assessment Process, rather than the Enforcement Process, will

determine further licensee and NRC action for events that do not result in "actual

consequences."

The last decision gate in the Exposure Control Findings portion of the Occupational

Radiation Safety SDP is intended to sort out significant issues and findings related to plant

equipment and facilities. The Assessment Program is a risk informed process, and radiation

dose is the measure of health risk associated with licensee activities. Therefore, this gate

focuses on those issues that could or do compromise the licensee’s ability to assess dose.

Since this gate culls out White findings, it is intended that only significant, programmatic,

failures of radiation monitoring and personnel dosimetry trip this gate. Examples of findings

intended to be addressed by this gate include; (1) the licensee's failure to use a National

Voluntary Laboratory Accreditation Program certified dosimeter processor, (2) a generic

and uncorrected failure of the electronic dosimeters to respond to, or record, radiation dose,

and (3) improper calibration of instruments or monitors (thereby significantly biasing their

response) which are used as a basis for establishing protective controls. An individual

failure to survey or monitor should be considered a failure of a radiation safety barrier and

should be evaluated for its potential for unintended dose or substantial potential for

overexposure, as discussed above.