United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Health Physics Position on the Controlling of Beam Ports, Thermal Columns, and Flux Traps as High Radiation Areas

HPPOS-235 PDR-9111210349

Title: Health Physics Position on the Controlling of Beam

Ports, Thermal Columns, and Flux Traps as High Radiation


See the memorandum from L. J. Cunningham to J. H. Joyner

(and others) dated May 31, 1991. The narrow radiation

beams from beam ports, thermal columns and flux traps at

reactor facilities may expose major portions of the head

and trunk, and therefore, must be controlled as high

radiation areas. The health physics position was written

in the context of 10 CFR 20.201 and 20.203, but it also

applies to "new" 10 CFR 20.1601 and 20.1902.

This memo clarified the NRC staff position that the subject

areas must be controlled as high radiation areas. A number

of Notices of Violation (NOV) concerning the posting and

control requirements of 10 CFR 20.201 and 20.203 have

occurred at research and test reactors. These licensees

were not properly controlling high radiation areas,

specifically those involving beam ports. [Note: The

posting and control requirements for high radiation areas

are contained in "new" 10 CFR 20.1601 and 20.1902.]

The argument is made by licensees that the radiation

streaming from these beam ports will not cause an exposure

to the whole body. These licensees have taken the position

that narrow beams don't meet the current 10 CFR 20.202 (b)

(3) definition that state in part, " ... a major portion of

the body could receive, in any one hour, a dose in excess

of 100 millirems."

The 10 CFR Part 20 definition of the whole body as

specified in 10 CFR 20.101 (b) (3) includes the head and

trunk; active blood forming organs; lens of the eyes; or

gonads. [Note: The "new" 10 CFR 20.1003 definition states:

"Whole body means, for purposes of external exposure, head,

trunk (including male gonads), arms above the elbow, or

legs above the knee."] Whether these beams are narrow or

not, if they could possibly expose the lens of the eyes,

the gonads or any other major portion of the head and trunk

or active blood forming organs, then the beams must be

controlled as high radiation areas. The revised Part 20

will support this position, and will further clarify it by

avoiding the term "the major portion of the whole body,"

when defining a high radiation area. [Note: The "new" 10

CFR 20.1003 definition states: "High radiation area means

an area, accessible to individuals, in which radiation

levels could result in an individual receiving a dose

equivalent in excess of 0.1 rem (1 mSv) in 1 hour at 30

centimeters from the radiation source or from any surface

that the radiation penetrates."]

Pursuant to 10 CFR 20.203 (c) (5) [or 10 CFR 20.1601 (c)],

if the stated alternatives of 10 CFR 20.203 (c) (2) and (4)

[or 10 CFR 20.1601 (a) and (b)] are not feasible, a

licensee may apply to the Commission for approval of

methods not included in paragraphs 20.203 (c) (2) and (4)

[or paragraphs 20.1601 (a) and (b)] for controlling access

to high radiation areas. If a licensee chooses 10 CFR

20.203 (c) (2) (iii) [or 10 CFR 20.1601 (a) (3)] as the

control option, positive entry control is required.

Methods of positive entry control may include, but are not

limited to, the following:

All entries into high radiation areas are controlled by

requiring issuance of a Radiation Work Permit (RWP) or a

work procedure. This controlling permit or procedure

contains any special instructions and the requirements for

entry into the high radiation area, which may include: a

pre-briefing on the actions to be performed, a review of

current radiation surveys, the requirements of a film badge

or TLD, and a pocket ionization chamber or extremity

dosimeters, signs and barriers to avoid contact with the

beam, and directions not to alter any shielding or

experiment without health physics supervision.

Due to the nature of the potential hazards involved, all

facilities having these types of radiation beams need to

control these areas as high radiation areas. However,

given the diverse nature of reactor types and experimental

configurations in the nonpower reactor community, we could

expect these licensees to implement a wide variety of

practices and controls to satisfy the regulatory

requirement for positive entry control.

This Health Physics Position has been reviewed by all

Regions; the Division of Advanced Reactors and Special

Projects, NRR; the Office of Nuclear Material Safety and

Safeguards; and the Office of Enforcement.

Regulatory references: 10 CFR 20.201, 10 CFR 20.203, 10

CFR 20.1601, 10 CFR 20.1902

Subject codes: 4.1, 4.7

Applicability: Reactors

Page Last Reviewed/Updated Thursday, March 29, 2012