U.S. Nuclear Regulatory Commission

... Dissolved Noble Gases in Liquid Effluents and Compliance With Technical Specifications 3.11.1

HPPOS-212 PDR-9111220007

Title: ... Dissolved Noble Gases in Liquid Effluents and

Compliance With Technical Specifications 3.11.1

See the memorandum from L. J. Cunningham to F. J. Hebdon

(and others) dated July 12, 1987. The TS limit for

dissolved or entrained noble gases in liquids is 200

picocurie/ml total activity. This limit is independent of

other nuclides. There is no need to include noble gases in

the MPC summation formula in Note 1 of Appendix B to 10 CFR

Part 20 (§§20.1-20.601). The health physics position was

written in the context of 10 CFR 20.106, but it also

applies to Section 20.1302 and Appendix B, Note 4, of the

"new" 10 CFR Part 20 (§§ 20.1001-20.2401).

Standard Technical Specification 3.11.1 states: "The

concentration of radioactive material released in liquid

effluents to UNRESTRICTED AREAS ... shall be limited to the

concentrations specified in 10 CFR Part 20, Appendix B,

Table II, Column 2 for radionuclides other than dissolved

or entrained noble gases. For dissolved or entrained noble

gases, the concentration shall be limited to 200

picocurie/ml total activity."

In response to an inquiry from a licensee, RPB said that

the staff does not consider Part 20, Appendix B to give

limits for noble gases in water. Specifically, the

footnotes addressing "nuclides not listed above" do not

apply to the noble gases because the noble gases are listed.

RPB also said that the technical specification limit for

noble gases is independent of the concentrations of other

nuclides. That is, the LCO is satisfied if noble gas

concentration does not exceed 200 picocurie/ml and the

concentrations of other nuclides do not add up to more than

one MPC equivalent using Note 1 to Appendix B to 10 CFR

Part 20 (§§20.1-20.601) [or one DAC equivalent using Note 4

to Appendix B of 10 CFR Part 20 (§§20.2001-20.24010].

Hence, there is no need to include the noble gases in the

Part 20 summation formula [i.e., the DAC summation formula

in Note 4 of Appendix B to §§20.1001-20.2401].

Regulatory references: 10 CFR 20.106, 10 CFR 20.1302,

Technical Specifications

Subject codes: 7.3, 9.2

Applicability: Reactors