Resolution of Generic Safety Issues: Item B-67: Effluent and Process Monitoring Instrumentation ( NUREG-0933, Main Report with Supplements 1–35 )

DESCRIPTION

According to NUREG-0471,³ the nature of this problem is described as follows:

"Monitoring of radioactivity in gaseous and liquid effluent streams from nuclear power plants is required for several purposes: (a) assessment of the adequacy of process and waste treatment systems, (b) the control of releases of radioactivity to the environment so that they do not exceed the limits of 10 CFR 20 and 10 CFR 50, Appendix I, and (c) the evaluation of environmental impact. This task involves improving current guidance to applicants and reviewers in the areas of radiation monitoring for process and effluent systems and reviewing the effluent monitoring systems for selected operating BWRs and PWRs to determine their effectiveness in meeting the effluent release limits of 10 CFR Parts 20 and 50."

A subsequent ETSB memorandum¹¹⁹ described the problem in each specific subtask of Item B-67 and its proposed resolution as well as the current status of each subtask and recommendations concerning them.

One subtask of this issue is to develop criteria for the design, quality assurance, and performance of process and effluent radiological monitors. This part of the issue is the same as TMI Action Plan Item III.D.2.1⁴⁸ (Radiological Monitoring of Effluents), which is an evaluation of the value and impact of requiring improved effluent monitoring, and Item II.F.1.1⁴⁸ (Noble Gas Effluent Monitoring), which is a requirement for high-range monitoring capability during accidents.

A second subtask of this issue is that certain parts of systems designed to control effluents could malfunction and result in unplanned releases of radioactive material or have a potential for such releases. These include gaseous as well as liquid releases from off-gas systems and fires in charcoal delay systems as well as from overflow from outside tanks or heat exchanger tube failures. Several studies, including NUREG-0442¹²⁰ and the evaluation of the Tsuruga, Japan, unplanned release of radioactive materials, as well as guidance to the utilities in IE Bulletin No. 78-03¹²¹ and SRP¹¹ Section 11.3 have effectively resolved this problem.

A third subtask of this issue was that worst-case generic analyses were to be performed using SRP¹¹ Section 15.7.3 for both BWRs and PWRs located on lakes, rivers, or oceans, for those plants which received their licenses prior to the issuance of the SRP.¹¹ It has been concluded, however, on the basis of experience with plants licensed since the issuance of the SRP,¹¹ that even with the extremely conservative assumptions of SRP¹¹ Section 15.7.3 it has been a rare case that the projected concentrations would exceed the 10 CFR 20 values in Appendix B, Table II, Column 2, for those plants licensed before the issuance of the SRP.¹¹

The final subtask of this issue was that an industry-wide survey was to be performed to determine the extent to which nuclear plants could not process wastes in accordance with the BTP ETSB 11.3.¹¹ The NRR requirement for an operable installed solid radwaste system has since changed and SRP¹¹ Section 11.4 now allows for the use of portable/mobile solidification systems through contractual arrangements with vendors and the dewatering of resins without solidification. The NRR position is consistent with that in the proposed 10 CFR 61 and the license conditions of burial ground operators.

CONCLUSION

In view of the assessment presented in which reports, BTPs, appropriate changes in the SRP,¹¹ as well as reevaluations of some of the concerns originally included in this issue have been identified, this issue is essentially complete except for the one subtask which is covered in TMI Action Plan Item III.D.2.1.¹¹

REFERENCES

0003. NUREG-0471, "Generic Task Problem Descriptions (Categories B, C, and D)," U.S. Nuclear Regulatory Commission, June 1978. 0011. NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants," U.S. Nuclear Regulatory Commission, (1st Ed.) November 1975, (2nd Ed.) March 1980, (3rd Ed.) July 1981. 0048. NUREG-0660, "NRC Action Plan Developed as a Result of the TMI-2 Accident," U.S. Nuclear Regulatory Commission, May 1980, (Rev. 1) August 1980. 0119. Memorandum for K. Kniel from W. Gammill, "Need for Generic Issue B-67, Control and Monitoring of Radioactive Materials Released in Effluents and Performance of Radwaste Systems," November 20, 1981. [8201130493] 0120. NUREG-0442, "Technical Report on Operating Experience with BWR Offgas Systems," U.S. Nuclear Regulatory Commission, April 1978. 0121. IE Bulletin 78-03, "Potential Explosive Gas Mixture Accumulations Associated with BWR Offgas System Operations," U.S. Nuclear Regulatory Commission, February 8, 1978. [7909050232]