ML20069B843

I b-niminn Question 26(a): bre has been some confusion about the revised Part 20 r-;i with respect to controlled The regulations (revised Part 20) allow licensees a certain creas and when individuals are receiving a public or an oc.

amount of discretion in developing a radiation protection cupational dose. Before asking questions involving specific program that is suitable and practical to implement at the exposure scenarios (in parts b, c, and d of this question),

licensee's location and for the licensee's particular set of -

does the NRC staff have any general guidance on these working conditions. For example, licensees are permitted by topics?

the regulations to select the boundaries for restricted areas and controlled areas. (Because licensees are not required by Answer: Anyone attempting to answer questions about 10 CFR Part 20 to have controlled areas they may choose -

which dose limits apply in a particular situation shoukt be -

whether or not to have controlled areas.) When an individ-familiar with the requirements of 10 CFR 20.1201,10 CFR ual is to work in a controlled area or an unrestricted area, 20.1207,10 CFR 20.1208, and 10 CFR 20.1301, and with -

the licensee shouki evaluate the individual's assigned duties

- i the dormitions of the following terms in 10 CFR 20.1003:

and determine whether a does woukt be categorized as a i

occupational dose, public dose, member of the public, re-public dose or an occupational dose in accordance with the i

stricted area, controlled area, and unrestricted area.

definitions of these terms in 10 CFR 20.1003.

1 h - dan.i % va una na==

h following criteria that include both regulatory require-i ments and basic radiation protection philosophy will be used By definition, and with the exceptions given in the def-in the NRC inspection program.

l~

initions of " occupational dose", any dose received by any individual in a " restricted aren" is an " occupational dose."

hatN Area No one in a resencted area is a "snamher of the public."

Outside " restricted areas" (i.e., in " controlled areas" or in When an area satisfies both the dermition of a restricted

" unrestricted areas"), whether the dose to an individual is an area in Part 20 and the defmition of a protected area in

' occupational dose" or a "public dose" depends on whether Part 73,-it is considered to be a restricted area for the dose received by the individual is (as specified in the purposes of compliance with 10 CFR Part 20.'

NURBO/CR-6204 4

1

Questions and Answers Doses are to be categorized as public doses (i.e., public Boundaries of restricted areas may be selected by licen-dose limits apply) whenever reasonable and practical sees but being selected, they shoukt be documented (good practice) (except for occupational doses).

(recorded) (good practice).

In deternunmg whether an individual in a controlled Access to restricted areas must be controlled, e.g., by area is to be categorized as an individual who receives barriers, signs, or guards ($20.1003). Note: Areas an occupational dose or as a member of the general that can have personnel access controlled but that are public, the more difficult decisions concern individuals not being controlled (e.g., because the radiation source who may be occasionally exposed or whose assigned has been removed) are not restricted aream, duties are not closely connected to the licensed activity.

Such individuals include messengers, delivery men and Posting of a restricted area as a restricted area is not women, custodial workers, secretaries, clerical work-required although other posting may be required within ers, hospital volunteers, etc. Usually, such indivkhtals the area (620.1902).

are considered to be members of the public and the doses they receive are well within the limits for mem-Doses received by allindividuals in restricted areas are bers of the public. However, if the assigned duties of occupational doses (520.1003),

these individuals are closely and frequently connected to the licensed activity, and their doses may approach Individuals working in or frequenting a restricted area or exceed the limits for members of the public, the must be provided training, as appropriate (619.12),

doses such individuals receive are better treated as occupational doses.

Individuals entering a restricted area must be informed Only when doses are to be categorized as occupational that they are subject to occupational dose limits.

doses (i.e., occupational dose limits apply) do the fo!-

Effort must be made to maintain all doses ALARA lowing conditions apply:

($20.1101).

- A decision must be mad 3 as to whether monitor-A decision must be made as to whether monitoring is ing is required (620.1502).

required ($20.1502).

- The licensee should have the ability to exercise enntrnlled Area positive control over the individual's activities in a

the controlled area.

Controlled areas are not required (620.1003).

- The licensee should provide appropriate instruc-As indicated in the preceding section, an area that tions.

satisfies both the definition of a restricted area and the definition of a controlled area is considered to be a

- The licensee shouki inform the individual that restricted area for purposes of compliance with 10 CFR he/she is subject to occupational dose limits rather Part 20.

than public dose limits (619.12-this is an implied requirement).

Boundaries of controlled areas may be selected by licensees but shouki be documented (reconfed) (good indiviAn=1 Member = nf tha puhtin practice).

Individuals in controlled areas and unrestricted areas Posting of a controlled area as a controlled area is not are members of the public unless they are receiving an required (120.1902),

occupational dose (620.1003 & 620.1301).

Licensees shoukt apply lower dose limits (public dose Doses received in controlled areas may be occupational doses or public doses. Generally doses will be public limits) to non-workers whenever possible and doses except when the licensee determmes that an reasonable (good practice).

individual receives exposure to radiation "in the course An individual is not a member of the public when they of employment...." [$20.1003, $$20.1301(b)].

enter a restricted area (520.1003).

5 NUREG/CR-6204

Questions and Answers

-I Effort naast be made to achieve doses that are ALARA procedures will not be rescheduled. "Ihe ducts are not used I

o (620.1101),

to ventilate the hot lab.

l

' 2. Individual B is an emergency room nurse employed by i

Question 26 (b): Do occupational dose limits or public the hospital. On frequent occasions she accompames dose limits apply to the doses received by the individnals patients to the nuclear medicine department for emergency described in the following scenanos for nuclear power lung scans.

l plants?

j i

3. Individual C is not employed by the hospital but visits j

1. Assume an indivaal employed by a heensee working at the hospital on a weeklf basis for the purpose of performing

{

a two-unit site (one nuclear plant and one fossil plant) is preventive mamtenance on the gamma cameras. He fro-permanently employed at the fossil plant, which is inside the quently observes the nuclear medicine technologist during.

nuclear plant's controlled area. b individual does not -

patient studies to verify equipment operation.

enter any restricted areas. What dose limits apply to that individual while' working at the fossil plant?

4. Individual D is employed by the hospital as a caretaker.

During the sununer he routinely cuts the grass outside the

2. What dose limits apply to a pregnant taxi driver while hospital. Note: b hot lab has at least one outside wall.

she is picking up and discharging passengers withm the controlled area (outside the restricted area) of a nuclear Answer: Occupational dose limits apply to individuals B.

l power plant?

(emergency room nurse)'and C (who maintams gamma

'l cameras), h assigned duties ofindividuals B and C are J

3L What dose limits apply (a) to construction workers who closely and frequently connected to the hcensed activities, cre building a second nuclear power plant within the con.

Linuts for members of the public apply to Individuals A _

trolled area (outside the restricted area) of the first nuclear (who repairs a ventilation duct) and D (caretaker who cuts power plant at that site and (b) to secretanes in the adminis-grass), h assigned duties ofIndividuale A and D are only l

trative buikling within the controlled area (outside the re-remotely (and, in the case ofIndividual A, infrequently),

stricted aren)?

connected to the licensed activity and it is reasonable and practical to apply the public dose limits.

Answer: For scenarios #1,2, and 3, the dose limits for members of the public apply. However, if turbine shine Question 26 (d):. Do occupational doses limits or public from the nuclear plant is such that the individuals in scen-dose limits apply to the doses received by the individuals -

{

orios #1 (fossil plant workers) and #3 (constmetion workers described in the following scenarios for a radiography com-and secretaries) are likely to exceed the dose limits for pany?

members of the public, the licensee should consider the individual doses to be occupational doses and meet the A large radiography company performs radiography both in requirements for individuals who receive occupational the fieki amt in a hot cell within its plant. b hot cell is doses.

located in the delivery bay. The company shares its physi-cal plant with an affiliated company. UPS deliveries for l

Question 26(c): Do occupational dose limits or gniblic dose both compames come to the same bay area. h radio-limits apply to the doses received by the individuals des-graphy company has dermed its restricted area to be the hot cribed in the following scenarios for a hospital?

cell and its controlled area to be the delivery bay.

A hospital has dermed a controlled area as all areas within

1. Individual E is a secretary employed by the radiography.

the main buikling. These areas can only be accessed by company. Her desk, where she performs all admimstrative doors which open to the outside environment. In addition, assignments, is located in the delivery bay, adjacent to the they have designated the hot lab as a restricted area. b hot cell.

hot lab can only be accessed through the nuclear medicine department.

2. Individual F is a data entry clerk at the affiliated com-pany. He is employed by a temporary agency on a 12-

1. Individual A is a maintenance worker. He is employed month assignment. He is responsible for picking up all UPS by the hospital and has been assigned to repair ventilation shipments (within the controlled area),

ducts in the nuclear medicine (NM) department. b job

. must be performed during normal work hours; patient

3. Individual G is a co-worker of Individual E. He fre-l-

quently enters Individual E's office to use the telephone to l

l L

NUREO/CR-6204 6

l

Questions and Answers make personal calls during the course of a normal work Question 66: his question concerns restricted area

day, limitations. At some sites for nuclear power plants the restricted area has been defmed as the site boundary, in Answer: Individual E (secretary): Assuming that the sec-some areas routine public access was available with the retary's location near a hot cell is essential, the occupational urxlerstanding that, shoukt the need arise, public use of dose limits apply, these areas coukt be prohibited. Examples of this type of access include fishing, visitor centers, and farming. This Indivkhial F (clerk): Limits for the general public apply.

type of use now appears to fall within the intent of the def-bre is only a casual connection between the individual's inition of controlled area and therefore, a new restricted assigned duties and the licensed activity that results in the area boundary located somewhat nearer the plant must be individual's exposure, dermed, in places where such uses exist.

Individual O (co-worker): his indivklual is subject to the b next physical boundary is a single fenced area, roughly dose limits for a member of the general public. He has not corresponding to the security definition of owner controlled entered a restricted area and his assigned duties do not area. Station parking is routinely within this area and ac-involve exposure to radiation and to radioactive material cess is provided through openings in the single fence which from licensed and unlicensed sources of radiation.

are not continuously guarded. These openings are posted,

(

Reference:

"No Trespassing " b direct questions involved are, f

Can this area (single fenced area) qualify as the restrict-a.

Question 40: Assume a licensee has dermed its compliance ed area boundary?

year as January 1,1993 to December 31,1993. What is the mechanism to change its defmition of year? For example, b.

If so, are postings sufficient or woukt guards be the licensee wants to monitor from January 31,1994 to required?

January 30,1995, how shoukt it account for the lost days January 1 - 30, 19947 Is it acceptable to prorate the doses?

c.

If posting is sufficient, what is the acceptable wording?

Answer: No. b question refers to the definition of Answer:

)

" year" in 10 CFR 20.1003. h licensee is not allowed to a.

Yes, access to this area coukt be limited so as to meet j

make the one-step change as postulated in the example in the question because that change involves omitting certain the dermition of a restricted area. However, it shouki be days. Omitting days, even with dose proration, is not recognized that the dose received by an individual in a re-allowed. However, the license coukt accomplish the desired stricted area is an occupational dose that is subject to the change in two steps, one step in each of two consecutive occupational dose limits in Subpart C of tim revised Part 20 years, that wouki give a " year" beginning 1/31 of one calen-(or to the occupational dose limits of 10 CFR 20.101 in the dar year and ending 1/30 of the following year. b first oki Part 20) and the requirements in 10 CFR 19.12 on step, using the example, wouki be a change, at the begin-instructions to workers. (See defmitions of " restricted area" ning of 1993, to a " year" of 1/1/93 to 1/30/94 (13 months).

and " occupational dose.")

The second step wouki be a change, at the beginning of 1994, to a " year" of 1/31/94 to 1/30/95. This two-step b.

Although neither posting nor guards are required speci.

change meets the requirement of " years" that begin in fically, access to a restricted area must, by definition, be January with no day omitted or duplicated in consecutive controlled. In the situation desenhed in the question, access years. (

Reference:

10 CFR 20.1003) control couki be accomplished by posting or use of guards Since posting is not specifically required (see b. above),

Question 57: b definition of a very high radiation area c.

(10 CFR 20.1003) and the requirement for control of access the wording is leR to the discretion of the licensee.

to very high radiation areas specify an absorbed dose of 500 rads in an hour. Is this a deep dose, a shallow dose, or an NOTFh This answer also applies to research and test reac-eye dose?

tors, fuel fabrication plants, and major radioactive materials processors insofar as the conditions desented in the ques.

Answer: The 500-rad dose is intended to be a deep dose, tion for nuclear power plants apply to these other facilities.

evaluated at a tissue depth of I cm (1000 mg/cm').

(

References:

10 CFR 20.1003,10 CFR 20.1201,10 CFR

(

References:

10 CFR 20.1003,10 CFR 20.1602) 20.1206,10 CFR 20.1207,10 CFR 20.1208,10 CFR 19.12) 7 NUREO/CR-6204

Questions and Answers ed due to radiological exposure considerations. This Question 67: This question concerns water approaches to concep is consistent with the revised mle.

nuclear sites. Several sites for nuclear power plants include portions of navigable lakes or rivers within their licensed Will the defmitions of " member (s) of the public" in Generic exclusion areas. Obviously, the utility does not own these Letter 89-01, Supplement 1 (NUREGs 1301 and 1302) be areas. Would such boundaries as dermed in our licenses changed to be consistent with the defimition of " member of qualify as restricted areas, controlled areas, or unrestricted the public" in the revised Part 20?

areas?

Answer: Yes. The NUREGs themselves will not be Answer: b licensee cannot limit access to navigable changed; however, in a forthcoming Generic Letter on lakes or rivers that the licensee does not own; therefore, model Technical Specifications that incorporate provisions these bodies of water cannot be part of a restricted area or of revised Part 20, the definition of " member (s) of the controlled area arxl must be considered to be unrestricted public* will be changed to be consistent with revised Part creas. However, for the dose calculations for airborne ef-

20. See Question 26 and answer in the fourth set of fluents that are required by reactor technical specifications questions and answers for clarification of the definition of and that are related to 10 CFR 50 Appendix I, doses are not

" occupational dose." (

References:

10 CFR 20.1003, required to be calculated over such bodies of water.

NUREG-1301, NUREG-1302).

(

Reference:

Question 93: In the definition of individual monitoring Question 74: Dose rates are used to establish posting devices, is there any reason electmnic monitoring devices requirements for radiation areas, high radiation areas, and are not mentioned?

very high radiation areas. 10 CFR 20.1601(a)(1), " Control of Access to High Radiation Areas." refers to a " deep-dose Answer: No b particular devices inchided in this equivalent" in describing when a control device shouki be dermition are a few examples, not a comprehensive listing, provided to reduce radiation doses below 0.1 rem in one of such devices. (

Reference:

hour, thus implying that the " dose equivalent" in the defmi-tion of a "high radiation area" is the " deep dose equivalent"

[at a tissue depth of I cm (1000 mg/cm2)). Are the " dose Question 94: Why was the " controlled area" defined?

equivalent" in the defmitions of " radiation area" arul "high radiation area" and the " dose" in the definition of "very Answer: h " controlled area," which is not defined or high radiation area" all considered to be at a tissue depth of used in the old Part 20, was defmed and used in the revised 1 cm (1000 mg/cm2)?

Part 20 to provide regulatory recognition of the existence of such areas and to clarify their regulatory status within the Answer: Yes, in addition see Question 57. (

References:

context of 10 CFR Part 20. In a related change, in revised

)

10 CFR 20.1003,10 CFR 20.1601)

Part 20, occupational dose limits no longer apply only in restricted areas, and lower (public) dose limits no longer apply to raervnna outside a restricted area. Es, under the Question 80: The revised Part 20 ($20.1003) provides old Part 20, an individual who receives an occupational dose defmitions of " member of the public," "public dose," and in a controlled area is subject to the same (low) dose limit as

" occupational dose." These definitions are not consistent a member of the public in that same area. Under the revis.

with the definition of " member (s) of the public" dermed (for ed Past 20, an individual who receives an occupational dose nuclear power plants) in Generic Letter 89-01, Supplement in a controlled area is subject to the occupational dose 1 (NUREGs 1301 and 1302).

limits, but a member of the public in the same controlled area is subject to the (lower) dose limits for members of the Consider that typically, one woukt expect any individual public. (

Reference:

entering the " restricted area" wouki be considered to be occupationally exposed and not classified as a " member of the public." All individuals, including utility employees, Question 96: (a) h roentgen (R) is not defined or used in their contractors, and delivery people outside the " restricted revised Part 20; however, many survey instruments and area," in the " controlled area," woukt be considered as computer records show dose rates in terms of "mR/h" or

" members of the public." h only exception is where a "R/h." Will these survey instrument face pieces and com-utility employee or its contractor doing work in a portion of puter forms have to be changed when revised Part 20 is im-the " controlled area" where public access has been restrict-plemented? (b) Most radiation instrumentation is currently NUREG/CR4204 8

Questions and Answers calibrated in units of roentgens rather thaa rads. A roentgen means an individual in a controlled or unrestricted area (not of x-or gamma-radiation in the energy range of 0.1 - 3 an individual in a restricted area). Therefore, the occupa-MeV produces 0.% rad in tissue. Will these instruments tional dose limits (and not the dose limits for individual need to be recalibrated to account for this difference.

members of the public) apply to the dose received by any individual in a restricted area. See related Question 26.

Answer: (a) No. The survey instruments will not need to

(

Reference:

be changed. See Question 428 for acklitional information conceming the use of the unit " roentgen

arxl its subunits.

Question 149: 10 CFR 20.1003 dermes the shallow-dose (b) No. It may be assumed that one roentgen equals one equivalent as the dose equivalent at a tissue deph of 0.007 rem or a more accurate conversion factor may be used.

cm. (a) Does this mean that the dose to the skin of the

(

References:

10 CFR 20.1003,10 CFR 20.2101),

whole body is the sum of the non-penetrating dose equivalent (beta and low energy photons) and the deep dose equivalent? (b) is it proper to calculate the extremity dose Question 119: Is it permissible under 10 CFR Part 20 for a by summmg the dose equivalent nwasured on an extremity bcensee to have a controlled area that is controlled for dosimeter (which may only be worn for part of the prposes of radiation protection but that is not a restricted monitoring period) with the deep dose equivalent?

area?

Answer: General response: 10 CFR 20.1502 requires Answer: No. By definition, in Part 20, a " restricted area monitoring of external dose for individuals who are likely to means an area, access to widch is limited by the licensee for receive, in a year, a dose in excess of 10% of the applicable the purpose of protecting individuals against undue risks limits. Requirements to measure / assess the dose equivalent from exposure to radiation and radioactive materials." As at dephs of 0.007,0.3, and I cm exist under old Part 20 as stated in the answer to Question 26(a) under the heading well as revised Part 20. In oki Part 20, these requirements

" Controlled Area" ".. an area that satisfies both the are included in the instmetions for item 5 of NRC Form 5.

definition of a restricted area and the definition of a la the revised Part 20, these requirements are in Part 20

)

controlled area is considered to be a restricted area for itself, together with new dose limits and special names in purposes of compliance with Part 20." (

Reference:

10 CFR the definitions for the dose equivalents at these three dephs.

i 20.1003)

The only explicit requirements concerning the precision and accuracy of personnel dosimetry are the NVLAP accreditation requirements, which are the same in old Part Question 144: When will licer' sees be permitted to use 20 [10 CFR 20.202(c)] arxl revised Part 20 [10 CFR weighting factors other than one to determine and record 20.1501(c)]. Methods that have been acceptable for extemal whole body dose (effective dose equivalent from measuring / assessing dose equivalent at these three depths in external sources) as the occupational dose of record?

the past shouki continue to be acceptable in the future.

Answer: After the NRC has received and approved an Answers to the specific questions are as follows:

application for the use of weighting factors (W) other than one for obtaining the effective dose equivalent. See the (a) No. The " dose to the skin of the whole body" is the discussion of the comment on the use of effective dose equi-shallow dose equivalent. The shallow-dose equivalent is the 2

valent for external exposure in the Statement of Considera-dose equivalent at a depth of 0.007 cm (7 mg/cm ) from all tions (56 FR 23368, third column arxl 23369, first column).

types of radiation, whether " penetrating" (such as gamma The response to the comment concludes with the statement rays and neutrons) or "non-penetrating" (such as weak beta that "The use of other weighting factors for external radiation and lower energy x-rays).

exposure may be approved on a case-by-case basis upon request to the NRC." (

Reference:

(b) No, not in general. The question does not make it clear whether or not the dose summmg is for dose during the same time period. It is never proper to calculate an ex-Question 148: What is the dose limit for a member of the tremity dose (shallow-dose equivalent) for a particular time pblic in a restricted area?

period by adding a deep dose equivalent to the shallow-dose equivalent. If the question refers to a monitoring period Answer: By definition (10 CFR 20.1003), the dose re-during which an extremity dosimeter (measuring shallow-ceived by an individual in a restricted area is an occupa-dose equivalent) was used only part of the time, but during tional dose. Also, by definition, " member of the public" which a whole-body dosimeter was used all of the time, the 9

NUREG/CR-6204

Questions ard Answers answer deperds on the circumstances of the individual's struction workers, or secretaries (but not the pregnant taxi exposure. It wouki be acceptable to assume, for the times driver) "... are likely to exceed the dose limits for mem-during which the extremity dosimeter is not used, that the bers of the public, the licensee should consider the indivi-extremity dose (shallow dose equivalent) is equel to the dual doses to be occupational doses and meet the requim-shallow. dose equivalent measured by the whole-body dosi-ments for individuals who receive occupational doses." ne meter. If only the deep-dose equivalent is measured by the basis for this answer is the NRC staff's understanding of the whole-body dosimeter, it would be acceptable to assume, intent of the defmition of " occupational dose", specifically, for times during which the extremity dosimeter is not used, that portion which states that " occupational dose means the that the extremity dose is equal to the deep-dose equivalent dose received by an individual... in the course of employ-(measured by the whole-body dosimeter) if it can be shown ment in which the individual's assigned duties involve that types ard levels of radiation to which the extremity was exposure to radiation...." This understanding of the exposed wouki not have resulted in a significantly higher dermition is also expressed in more general terms in the shallow dose equivalent to the extremity than the deep dose answer to Question 26(a). (

Reference:

10 CFR 20.1003) equivalent to the whole body. (

Reference:

Question 413: This question refers to the answers to Questions 66 and 31 under $20.1003 and $20.1201, respec-Question 150: 10 CFR 20.1003 defmes tissue monitoring tively, and to Question 26(d) under $20.1003. Simply depths of 0.007,0.3, and 1 cm for shallow, eye, and deep.

designating an area as a restricted area so you can control dose, respectively; (a) Is it important to measure at (or everyone at occupational dose limits is a perversion of every extrapolate the measurements to) these exact depths? (b) radiation protection principle published. Of course, this is couki the eye and deep-dose both be determmed at 0.3 cm?

just my opinion. I hope NRC will revise its interpretation of this defmition.

Answer: See the " general response" in the answer to Question 149.

For example, a secretary in a nuclear medicine clinic with-out any direct person-to-person contact with patients shouki (2) As under the ok! Part 20, it is important to measure (or not be subject to occupational limits just because she is in a to extrapolate measurements to, or otherwise assess the dose restricted area. Many other examples coukt be cited, and equivalent) at a reasonable approximation of these depths.

some that are more in the gray area shouki be examined carefully. Clearly, there is a significant population of (b) No. The deep < lose equivalent is, by defmition, the exposed persons that are not being hekt to the proper dose equivalent at a depth of I cm, not 0.3 cm. However, standard. The following statement refers to the answer to the dose at 0.3 cm (eye dose) woukt usually be a Question 26(d) concerning " individual E." la spite of the conservative approximation (overestimate) of the dose at I definition of occupational dose, mere geography is not cm (deep < lose). (

References:

10 CFR 20.1003) justification for classifying a person as a radiation worker.

Answer: The questioner appears to object to the dermition Question 412: This question refers to the answer to of " occupational dose" that states that " occupational dose Question 26(b) urder $20.1003. What is the basis for using means the dose received by an individual in a restricted area a dose threshoki to decide whether a person is categorized or...." The NRC cannot change this defmition by as a member of the public or as occupationally exposed?

revising its " interpretation of this definition." The definition The definitions do not specify a dose thresboki.

can only be changed by rulemaking.

Answer: Question 26(b) asked whether occupational or While there may have been a lack of clarity in the referenc-public dose limits apply to individuals, described in three ed answers, our intention is that licensees shouki not engage different scenarios, who are exposed within controlled areas in a practice of " simply designating an area as a restricted J

(outside any restricted areas) at a nuclear power plant.

area so you can control everyone at occupational dose i

These scenarios described (1) a fossil plant worker, (2) a limits." Question 66 asks if a simple fenced area can quali-pregnant taxi driver, and (3) construction workers building a fy as a restricted area and the answer is yes, provided it is second nuclear power plant argl secretaries in the adminis-the licensee's purpose to limit access for the purpose of trative buikling. He answer to Question 26(a) states that controlling radiation exposures. Question 31 asks if stu-the public dose limits apply to the individuals in all three dents and volunteers (such as nuclear medicine students and scenarios, but the answer also states that if turbine shine

" candy stripers" who transport nuclear medicine patients or from the nuclear plant is such that fossil plant workers, con-perform volunteer work in a nuclear medicine department)

NUREO/CR-6204 10

Questions and Answers ere subject to occupational dose limits. The answer to this used in experiments at some research reactor facilities.

question is that these individuals are subject to the occupa.

What values of the quality factor, Q, and the fluence per tional dose limits because, and provided that (as the question unit dose equivalent shoukt be used for " cold" neutrons?

implies), the type of work they are assigned involves ex-j posure to rr.diation; it does not matter where (in which area)

Answer: The values for " thermal neutrons" should be used

]

they are working Question 26(d) asks if the occupational until the use of other values is approved by the NRC.

i doio limits or public dose limits apply to " Individual E," a

(

Reference:

10 CFR 20.1004 Table 1004(b).2) secretary for a radiography company, who works in a

" controlled area" next to a " restricted area" containing a hot cell. The answer is that the occupational dose limits apply),

10 CFR 20.1008 - hnpleinentation again because the type of work assigned presumably in-volves exposure to radiation since it must be perfomied near the hot cell. (

References:

10 CFR 20.1003,10 CFR Question 30: If a license condition ties the licensee to a 20.1201).

section in the old Part 20 and there is no corresponding section in the revised Part 20, does the requirement in the old Part 20 stay in effect after implementation of the revised Question 434: llow are occupational dose limits applied in Part 20.

regard to the revised Part 20 definition of " year"? The purpose of this question is to obtain additional clarification Answer: Yes. See 10 CFR 20.1008(e). The license of the intent and application of the " year" as it is defined in condition that ties the licensee to a section in the old Part 20 the revised Part 20 and discussed previously in Question 40.

remains in force until there is a technical specification Apparently, licensees may establish a year that is other than change, license amendment, or a license renewal that January 1 through December 31 (e.g., Question 40 address-modifies or removes this condition." (

Reference:

10 CFR es a year that is from January 31 of one year through 20.1008(e))

January 30 of the following year). In responding to the question, consider the following example. A worker receives dose sequcntially at facilities of two different Question 58: Before implementing all of the provisions of licensees, the first licensee using a year of January 1 -

the revised Part 20, would a licensee be in violation of 10 December 31 n1 the second licensee using a year of CFR 20.1008(a)if the licensee voluntarily adopted the pro-January 31 - January 30. The worker receives 4 rems total visions of 10 CFR 20.1208 for protection of the embryo /

effective dose equivalent (TEDE) at the facility of the first fetus?

licensee during the period January 1 January 30, and then transfers to the second licensee's facility, arriving for work Answer: No, licensees can voluntarily provide protection on February 1. For work performed at the second licen-for the embryo / fetus in accordance with the provisions of 10 see's facility, is the individual's remaining available TEDE CFR 20.1208 before implementing all of the provisions of I rem or 5 rems?

revised Part 20. Ilowever, licensees wouki have to be clear that they are not " adopting Part 20" because that wouki Answer: Five rems. For a particular licensee, the relevant require it to be adopted in full. (

References:

10 CFR time period for determmmg compliance with an annual dose 20.1008(a),10 CFR 20.1208) limit is the year beginning and ending on the dates specified by that licensee, providing that the time period chosen by the licensee is consistent with the definition of " year" in 10 Question 65: The following question concerns OMB CFR 20.1003. In the example provided, the worker started approval of the information collection requirements of the work at the facility of the second licensee at the beginning revised Part 20. Section 20.1008 indicates that licensees of that licensee's " year" and, therefore, the worker had no shall implement the provisions of all sections of revised Part prior occupational dose during that licensee's " year."

20 on or before January 1,1993 and that if a licensee

(

Reference:

chooses to implement revised Part 20 before then, the licensee shall implement all provisions of revised Part 20 not othmvise exempted by subsection 20.1008(d). How-10 CFR 20.1004 - Units of Radiation Dose ever, section 20.1009 says that the information collection requirements of the revised Part 20 will not becorne effec-tive urJil OMB approves them. Does this mean that before Question 73: Table 1004(b).2 does not include entries for OMB approval is obtamed, a licensee can implement all of "cok!" neutrons, (e.g.,7 x 10* MeV neutrons) which are 11 NUREO/CR-6204

l Questions and Answers the provisions of the revised Part 20 ascent the infonnation of inspections with respect to ALARA and, therefore, no collection requirements?

significant change in the inspection program and proce-dures. NRC headquarters does plan to review all draR '

Answen OMB approval of the infonnation collection notices of violation of 10 CFR 20.1101(b) in order to requirements of revised Part 20 was obtamed on January 24, mosutor proposed enforcement actions in this area to ensure 1992, with the exception of NRC Forms 4 and 5. OMB that a reasonably consistent approach is established. Con-cpproval for these forms is expected in the future.

sistent with current and past policy, the NRC Regional -

(

References:

10 CFR 20.1008,10 CFR 20.1009)

Offices will continue to allocate increased inspection re-sources (e.g., ALARA team inspections) to inspections of poor ALARA performers. (

References:

10 CFR 2.2 - SUBPART B - RADIATION 20.110i(bn PROTECTION PROGRAMS Question 99: b following questions concern the relation-

' ship of emergency plans for nuclear power plants to 10 CFR 10 CFR 20.1101 - Radhtlon Protection 20.1001 (" Purpose") and 10 CFR 20.1101 )" Radiation Progrants Protection Programs").. (a) To what extent do radiation protection programs need to be established such that during emergency conditions, the revised Part 20 can be complied Question 7: Relative to 10 CFR 20.1101, radiation protec-with? (b) For example, in order to comply with the new EPA "Mamial of Protective Actions For Nuclear Incidents" tion programs, what wouki a typical radiography licensee have to do beyond what that licensee is doing now?

October 15,1991, do germanium counting systems need to be established to analyze air samples for iodines and par-Answen Ensure that the pmgram was documented amt ticulates, and computer programs to calculate CEDE, so that review the program's content and hnplementation periodi-CEDE can be added to external dose to get TEDE7 (c) Do cally (at least annually). (See Regulatory Guide 10.6 for emergency smvey/ plume chase teams need to wear breath-additional information). If the licensee does not have a -

ing zone air samplers?

radiation protection program, then such a program must be developed. (

Reference:

10 CFR 20.1101)

Answen (a) In general, the revised Part 20 contains no new requirements that would make ' hanges necessary in c

existing radiation protection programs as they relate to Question 11: Shoukt the Radiation Protection Program be a emergency conditions. 10 CFR 20.1001 includes the sen-stand-alone document or can it be the sum of many docu.

tence, "However nothmg in this past shall be construed as monts or manuals (e.g., a requirement for HP audits includ.

limiting actions that may be necessary to protect public ed as part of a QA audit program document)?

heahh and safety," and the intent of this sentence is discus-sed in the statement of considerations (56 FR 23365, first Answen Section20.1101 requires a documented radiation column). NRC requirements concerning emergencies at protection program. This documentation does not have to NRC-licensed facilities (i.e., nuclear power' plants and fuel-be a stand-alone document but it must be reviewed annually, cycle licensees) are contained in 10 CFR Parts 30,40,50,

(

Reference:

10 CFR 20.1101) and 70, and no conforming changes to these requirements were needed as a result of the revised Part 20. (b)'and (c)

See answer to (a). With regard to the offsite emergency

)

Question 62: With 10 CFR 20.1101(b) makmg ALARA a workers such as fire fighters, law enforcement officers, civil i

requirement ("shall" instead of a "shouk!"), does the NRC defense workers and environmental fiekt team members, the staff' plan or anticipate any significant change in inspection EPA manual provides guidance given in Table 2-2 titled program focus or in enforcement activity with respect to "Ouidance on Dose Limits for Workers Performing Emer.

ALARA for occupational exposure at nuclear power plants?

gency Services." In addition to the refinements in the dose limits, the revised EPA Manual uses the CEDE and the Answen No. In general, the recent performance of the TEDE concept bre are no changes necessary with nuclear power reactor industry has been good with respect respect to the momtoring of the external exposure levels of to efforts to achieve occupational doses that are ALARA.

these workers in the early phase of an accident except as Collective doses (person-rem) for both PWRs and BWRs noted in the referenced table, b question is, therefore,

.l have been declining since the early 1980s. b NRC staff how to account for the inhalation dose of offsite emergency is not planmng any significant change in the depth or scope workers to prevent them from exceeding their limits. Due NUREG/CR-6204 12

Questions and Answers to the urgency of offsite response in the early phase of an Offsite (corporate or contract) audits and evaluations accident, it will not be practical to set up air samplers at shouki be performed to determine whether the radiation numerous locations and analyze those samples in a timely protection program complies with the regulations and manner. Air samples and radiation measurements taken by other requirements and whether plant. wide objectives the fiek! monitoring teams will be valuable to determine the are being met as well as to identify needed program dose to emergency workers after the fact, but will be of improvements. (

Reference:

10 CFR 20.1101) little value during the actual performance of emergency tasks, since some form of real time exposure rate inlication is needed. To create this real time indication, a correction Question 133: 10 CFR 20.1101(b) requires licensees to factor can be developed that when multiplied by the emer-use, to the extent " practicable," procedurea and engineering gency worker's dosimeter reading can provide a conserva-controls based upon sound radiation protection principles to tive estimate of the inhalation dose. The NRC and FEMA achieve dosee that are ALARA. The ALARA concept cre currently investigating this issue. After appropriate emphasizes dose-reduction techniques that are reasonable review the NRC and FEMA will provide guidance for considering costs.

offsite agencies to use. (

References:

10 CFR 20.1001,10 CFR 20.1101,10 CFR 50.47) liowever, " practicable" may imply something that has been proposed and seems feasible but has not been actually tested in use. " Practical" is more consistent with the ALARA con-Question 118: 10 CFR 20.1101(c) requires that each cept because " practical" implies " sensible", " involving good licensee " periodically (at least annually) review the radiation judgement" and " proven success in meeting the demands program content and implementation." A nuclear power made by actual living or use." In making decisions about plant has many reviews and atulits (including quality assur-ALARA procedures and engineering controls, will licensees ance audits) of various aspects of their radiation protection be permitted to interpret " practicable" as " practical"?

programs during a year and reviews are on a schedule that covers all phases of the program on a 2-3-year review cycle.

Answer: In the context of this regulation, the word "prac-la this acceptable to the NRC7 ticable does not have the connotations attributed to it in the question. 10 CFR 20.1003 states that "ALARA... means Answer: Yes, provided that the combination of these making every r=-hla effort to maintain exposures to reviews and audits covers program content and implemen-radiation as far below the dose limits in this part as is tation. Reviews and audits at nuclear power plants should prarteral... * (emphasis added). The discussion of 10 incorporate the following features to assess procedural CFR 20.1101(b) in the preamble to revised Part 20 (56 FR compliance, technical performance, implementation, and 23367) includes the following statement: " Compliance with effectiveness of the facility radiation protection program, this requirement [10 CFR 20.1101(b)] will be judged on whether the licensee has incorporated measures to track Radiation protection supervisoiy reviews and, if necessary, to reduce exposures and not whether exposures and doses represent an absolute minimum or Onsite radiation protection supervisors shouki periodi.

whether the licensee has used all possible methods to reduce cally perform and document reviews of the effective-exposures." Thus the use of the word " practicable" in 10 ness of the radiation protection staffin such areas as CFR 20.1101(b) does not imply procedures and engineering radiological work practices, work monitoring, proco-controls that are unproven. (

Reference:

10 CFR 20.1101) dural compliance, and survey adequacy.

Quality assurance audits Question 134: 10 CFR 20.1101(c) requires a periodic (at least annual) review of the radiation protection program as Quality assurance audits shoukt be performed by the defined in 20.1101(a). 10 CFR 20.1101(a) refers to 10 onsite auditing group. Personnel in the auditing group CFR 20.2102 for recordkeeping requirements. (a) Does the should have sufficient radiation protection training or use of the word " audit" in 10 CFR 20.2102(a) require experience so they can determine whether radiation records for all audits that are performed in addition to the protection functions are being performed as required.

periodic review? (b) Are the reviews required by 10 CFR The quality assurance program audits shoukt meet the 20.1101(c) also considered to be audits that are subject to requirements of Appendix B to 10 CFR Part 50.

the quality assurance criteria specified in 10 CFR Part 50, Appendix B, XVIll?

Corporate or contract audits 13 NUREG/CR-6204

1 Questions and Anawers Answer: (a) No. b recordkeepag requirements of 10 CFR 20.2102(a)(2) apply only to audits and reviews per.

Question 381: (a) For nuclear power facilities does confor-formed by the hcensee to comply with 10 CFR 20.1101. If mance with Regulatory Guides 8.8 and 8.10 fully meet the the review is perfonned annually, then only the records of requirements of 20.1101(b) regarding ALARA programs?

that myiew are required.

(b) If not, does the NRC plan to update these Regulatory guides to confonn to new requirements?

(b) No, b requirements of Parts 20 and 50 am separate l

requirements. However, quabty assurance audits of aspects Answer: No, to both questions.-(a) Regulatory Gua 8.8 cf the radiation protection program at nuclear power plants Rev. 3 is now (in 1993) 15 years old, the second proposed pursuant to the requirements of 10 CFR Part 50, Appendix revision to this guide is now 11 years oki, and Regulatory B, XVIII, may padially satisfy the requirements of 10 CFR Guide 8.10 is 16 years old. These guides do not adequately 20.1101(c). (

Reference:

10 CFR 20.1101,10 CFR cover all the_means that the nuclear power industry has 20.2102).

developed and shown to be practical and cost-effective for

= "N occupational doses ALARA. For example, these guides do not recognize the importance of water -

Question 380: Nuclear power plant bcensees are required chemistry contmis and radiation source and flek! controls to meet the quality assurance criteria in 10 CFR Part 50

' for maintaining doses that are ALARA.

Appendix B. Regulatory Guide 1.33 describes a program '.

acceptable to the NRC staff to demonstrate c-- - ' m with (b) b NRC staff has not yet established a schedule for.

10 CFR 50 Appendix B requirements and includes guidance updating these guides, b staff did issue Draft kegulatory.

mganling the documentation, use of procedume'and periodic Guide DO-8004, " Radiation Protection Programs for myiew of radiation protection programs. Does commitment

' Nuclear Power Plants,' to provide guidance on compliance to and confonnance with 10 CFR Part 50 Appendix B and with 10 CFR 20.1101, ' Radiation Protection Programs,"

Regulatory Guide 1.33 fully meet the requirements of 10 including guidance on the ALARA requirements of 10 CFR CFR 20.1101(a) and (c)? Note: b answer to Question 20.1101(b). However, representatives of the' nuclear power 118 provided previously did not clarify if additional require '

industry stated that this guide was not needed and it has monts are imposed on nuclear power plants by 10 CFR been waimlrawn. (

Reference:

10 CFR 20.1101).

20.1101(a) and (c) that are new or different from the previously applicable requirements.

2.3 SUBPART C - OCCUPATIONAL Answer: No See related question 134 and answer, 10 CFR Part 50 Appendix B and 10 CFR 20.!!01(a) and (c)

DOSE LIMITS cre different requirements.10 CFR Part 50 Appendix B establishes quahty assurance requirements for the operations of nuclear power plant safety-related structures systems al 10 CFR 20.1201 - Occupational Dose Limits components. 10 CFR 20.1101(a) requires each license to for Adults develop, <t~~M and implement a radiation protection program commensurate with the scope and extent of Question 2: What are the reqnirements for including dose licensed activities and sufficient to ensure compliance with from non-NRC-licensed sources (x-rays, accelerators, the provisions of Part 20. 10 CFR 20.1101(c) requires NORM) as part of occupational dose?

periodic reviews of that radiation protection program.

Ahhough for nuclear power plants, there is some overlap Answer: b combined total of the doses from licensed between the requirements of 10 CFR 50 Appendix B and the and unlicensed sources (other than backgre - ' and medical requirements of 10 CFR 20.1101(a) asul (c), they clearly are radiation) must be below the Part 20 occupational dose different requirements. For example, some aspects of the limits. b requirement for inclusion'of doses from non-radiation protection program established pursuant to 10 CFR licensed sources is intended to account for occupational 20.1101 (a) may not be considend " safety related" within doses received while working for activities or with materials the meaning of this term in 10 CFR 50 Appendix B. b that are licensed or controlled by organizations other than reference to 10 CFR Psit 50 Appendix B in the answer to the NRC, e.g., states, DOE, etc. Thus licensees must Question 118 was provided in the context of a discussion of record and add the doses from non-licensed sources to the quality assurance audits and was not an irulication that doses from licensed sources to obtain the total dose for '

" commitment to and conformance with Appendix B and companson with the occupational limit. (

References:

10 I

Regulatory Oukie 1.33 fully meet the requirements of CFR 20.1001,10 CFR 20.1002,10 CFR 20.1003,10 CFR-(20.1101(a) and (c)." (Referencesi 10 CFR 20.1101).

20.1201)

NUREO/CR-6204 14

Questions and Answers need to clearly designate the particular areas in a hospital Question 3: What do you do about hot particles?

that are

restricted areas." (

Reference:

Answer: Until changed by rulemaking, the dose limits in Part 20 (10 CFR 20.1201(a)(2)) apply. Special rulemaking Question 34: What are the applicable radiation limits in a on " hot particles" is still pending. Until rulemakmg is ac-controlled area if the licensee does not allow nwmbers of complished the NRC will continue handling hot particle the public to enter the aren?

enforcement issues in accordance with the stated Enforce-ment Policy published in the Federal Register (55 FR Answer: Occupational dose limits apply to individuals who 31113, 7/31/90) and transmitted to nuclear reactor licensees receive an " occupational dose" in a " controlled area." (See as Attachment 2 to NRC Information Notice 90-48 (8/2/90).

definitions of " occupational dose" and " controlled area" in

(

References:

10 CFR 20.1201, U.S. NRC Enforcement 10 CFR 20.1003.) (

References:

10 CFR 20.1003,10 CFR Policy) 20.1201)

Question 6: What if an NRC licensee hires a DOE em-Question 41: Licensee A questions a new employee about ployee who earlier in the year received an internal exposure outside employment. The employee states that he is only ofless than 5 rems annual effective dose equivalent, but working at that facility. ARet 3 months, the employee starts greater tluun 5 rems committed effective dose equivalent?

working, in the evenings, at another licensed facility (Licensee B). The employee does not tell A about B; Answer: Previous occupational exposures, even those therefore, Licensee A does not take the exposure received received at an unlicensed DOE facility, count against the by the employee at facility B into account when he calcu-limit. - The worker could not be allowed further radiation lates the employees annual total effective dose equivalent exposure for the year (except a planned special exposure).

(TEDE). Will Licensee A be in noncompliance for not Note: There are also beenmi DOE facilities. (

References:

knowing about the dose received by the employee at Licen-10 CFR 20.1201,10 CFR 20.2104) see B7 Iflicensee A was made aware of the exposure at

{

Licensee B aRer-the-fact, must Licensee A go back aral account for this exposure when calculating TEDE7 If Question 31: Are students and volunteers subject to the Licensee A firx!s out about the worker's exposure at Licen-occupational dose limits? For example, nuclear medicine see B after the year's end, and if the sum of the exposures students, or " candy stripers' that transport nuclear medicine exceeded the annual limit, is Licensee A obligated to record patients or perform volunteer work in a nuclear medicine and report the overexposure and deduct it from the 25 rem department.

lifetime PSE limit?

Answer: Occupational dose is defined in revised Part 20 Answer: In order to meet the requirements of 10 CFR as "the dose received by an irxlividual in a restricted area or 20.1201(f), the licensee must establish some means to have in the course of emninymad in which the irmlividual's each employee inform the licensee when that employee is assigned duties involve exposure to radiation...* In the receiving occupational dose from sources outside the licen-question above, the individual's assigned duties do involve see's control. it is not sufficient merely to ask each em-exposure to radiation as a necessary feature of those duties; playee once (as in the example), with no continuing pro-therefore, the students and volunteer are subject to the vision for employee notification. Assuming that Licensee A occupational dose limits. (

Reference:

10 CFR 20.1003,10 made no provision for learmng of the new employees subse-CFR 20.1201) quent concurrent employment in other jobs that resulted in occupational dose, Licensee A would be in noncompliance for not deternumng the dose received on the job at Licensee Question 33: What is the dose limit for visitors entering a B. If Licensee A was made aware of the exposure at Licen-restricted area (e.g., visitors to a hospital, patients' rela-see B aAer-the-fact, Licensee A must go back and account tives, escorted tourists)?

for this exposure when calculating TEDB. If Licensee A finds out about the worker's exposure at Licensee B after Answer: Occupational dose limits apply to all individuals year's end, and if the sum of the exposures exceeded the who enter a " restricted area." This is also the case under annuallimit, Licensee A is obligated to record and report the old Part 20. " Visitors to a hospital, patients' relatives, the overexposure and to deduct it from the 25 rem lifetime escorted tourists" who do not enter a restricted area are not PSE limit. Although the question and preceding answer are subject to the occupational dose limits. Therefore, there is a provided in terms of Licensee A's responsibilities with 15 NUREG/CR-6204

Questions and Answers respect to doses received at Licensee B's facility, Licensee they are doing and regardless of the area they are in outside B has the same responsibilities with respect to doses receiv-a " restricted area." (

References:

10 CFR 20.1003,10 ed at licensee A's facility. (

Reference:

CFR 20.1201).

Question 45: In determmmg the " eye dose equivalent," can credit be taken for shiekling provided by eyeglasses / safety Question 97: 10 CFR 20.1201(b) refers to " doses received glasses?

during accidents, emergencies, and...." Is there any d'f-ference between an " accident" and an " emergency"?

Answer: Yes. (

Reference:

10 CFR 20.1201(a)(i))

Answer: Yes. An accident is an unexpected and undesir-able event. An emergency is a situation or occurrence of a Question 46: Will determination of the " eye dose equiva-serious nature, developing suddenly and unexpectedly, and lent," at a tissue depth of 300 rug /cm, he included in the demadling immediate action. Thus an accident usually 2

NVLAP personnel dosimetry accreditation program?

results in an emergency, but it is possible to have an emer-gency without an accident (e.g., action taken in an emer-Answer: Not until ANSI N13.11, which defines the testing gency inay prevent an accident). In either case, licensees program used in the NVLAP accreditation program, is must account for doses received in excess of the annual revised to inchule tests for the 300 mg/cm depth and this limits in either an accident or an emergency, or both, in 2

revised standard is adopted by the NVLAP program. (Note:

accordance with 10 CFR 20.1201(b). (

Reference:

10 CFR Requirements under the old Part 20 include the determina-20.1201(b)).

2 tion of the dose to the eye at a tissue depth of 300 mg/cm.

See Instructions for Preparation of NRC Form 5, Item 5.

(

Reference:

10 CFR 20.1201(a)(2)(i))

Question 100: (a) is any special TLD monitoring of eye dose equivalent required? (b) Do TLDs for eye dose mea-surement need to be physically located near the eye?

Question 77: Representatives of the nuclear power industry cre concerned that the additional terms provided in the Answer: (a) Individual monitoring of the dose equivalent revised rule to describe the "real estate" in and around to the lens of the eye is required if the eye dose is likely to commercial power plants seems to be overlapping. This exceed, in a year,1.5 rem (10% of 15 rem) for an adult or couki lead to confusion. Access to these various areas may 0.15 rem (10% of 1.5 rem) for a minor. Licensees may use also affect the category to which individuals working within any form of monitoring that is capable of measuring these these areas are assigned. At nuclear power plants, either

doses, the " protected area" or " radiation controlled area" may serve as the " restricted area." Although workers granted (b) The answer to this question depends on the conditions of unescorted access entering the " protected area" may not be exposure, in most cases a licensee will not have to physi-directly monitored for radiation exposure, they nmst be cally place a TLD near the eye. However, there may be considered as " occupationally exposed." At least minimal unusual exposure situations (such as exposure of the eye to

radiation worker" training is required for these workers a narrow beam of radiation) that wouki make it necessary to consistent with the regulations. " Controlled areas" would place a dosimeter near the eye. [ Note: See Questions 45 typically extend to the " site boundary" or " owner controlled and 46.] (

References:

10 CFR 20.1003,10 CFR 20.1201, area." Does the NRC staff have any conunents on this 10 CFR 20.1502).

matter?

Answer: Each licensee shouki carefully document how the Question 123: In 10 CFR 20.1201(a)(1) does " annual licensees local " area" terms corresporxl to the area terms in limit" for dose (s) mean the limit on doses received in a 10 CFR Part 20 (restricted, controlled, and unrestricted

" year" as defined in 10 CFR 20.1003?

creas). Under both oki and revised Part 20, anyone who enters a restricted area is subject to the occupational dose Answer: Yes. (

References:

10 CFR 20.1201,10 CFR limits and must receive appropriate instructions in accor-20.1003) dance with 10 CFR 19.12. Workers can also be occupa-tionally exposed (arx1, therefore, subject to the occupational dose limits) in controlled and unrestricted areas (i.e., areas outside restricted areas) deperxling (in accordance with the definition of " occupational dose") on the nature of the work NUREO/CR-6204 16

i Questions and Answers l'

Question 172: (a) If the annual limit to the head is five rem and/or neck, and few if any shields protect the head from deep dose equivalent, what is the purpose of the 15 rem eye external radiation. Therefore, few shields wouki satisfy the dose equivalent? (b) llow can a person receive 15 rem eye conditions for credit.1lowever, licensees shoukt use shieki-done equivalent without exceeding the annual TEDE limit?

ing as necessary to minimize the area of exposure and keep doses ALARA. (

Reference:

Answer: (a) h purpose of the 15 rem non-stochastic limit to the lens of the eye is to prevent lens opacities (cataracts). The dose limit to the head (a stochastic limit)

Question 176: 10 CFR 20.1201 (a)(2)(ii) states a limit of end the dose limit to the eye (non-stochastic limit) are "A shallow. dose equivalent of 50 rem (0.50 Sv) to the skin measured at different dephs in tissue, I cm tissue equiva-or to any extremity." (a) Can a person receive 50 rem lent desh for deep dose and 0.3 cm for eye dose; and for shallow dose equivalent to the skin of the lower arm (ex-low penetrating radiation (such as beta or low-energy x-tremity) and 50 rem shallow dose equivalent to the upper rays), doses at different tissue dephs can be significantly arm (non-extremity), without having an overexposure? (b) different.

Can a person receive 50 rem shallow dose equivalent to the I

left upper ann, then the same dose to the right upper arm, (b) b 15 rem eye dose equivalent applies to the exposure without having an overexposure? (c) Can a person receive f

to the lens of the eye arxl is measured at a tissue deph of 50 rem shallow dose equivalent to each extremity dunng 0.3 cm. b 5 rem TEDE limit is the sum of the deep dose one year?

l l

equivalent at a tissue deph of I cm arx! the committed l

cffective dose equivalent. In general, a person can receive Anwr* (a) Yes, as long as the total shallow dose equiva-15 rem to the eye (measured at 0.3 cm) without exceeding lent does not exceed 50 rem in either position. b skin of the 5 rem limit on deep dose equave'ent whec tha head is the extremity is not considered in the shallow-dose equiva-exposed to beta or low-energy pheson radiation, although it lent limit to the skin of the whole body. The annual limits wouki be rare. for an individual to receive 15 rem eye dose are a shallow-dose equivalent of 50 rem (0.50 Sv) to the equivalent without exceeding a deep dose equivalent of 5 skin or to any extremity, rem, (

Reference: