U.S. Nuclear Regulatory Commission

10 CFR 50.59 Safety Evaluations for Changes to Radioactive Waste Treatment Systems

HPPOS-086 PDR-9111210238

Title: 10 CFR 50.59 Safety Evaluations for Changes to

Radioactive Waste Treatment Systems

See IE Circular No. 80-18 entitled as above and dated

August 22, 1980. For changes in a facility radioactive

waste system as described in the SAR, a safety evaluation

is required per 10 CFR 50.59. It also provides detailed

guidance on application of 10 CFR 50.59 to radwaste systems.

Recent inspections at operating power reactors have

revealed numerous instances in which licensees have failed

to perform adequate safety evaluations to support changes

made to the design and/or operation of facility radioactive

waste treatment systems. These safety evaluations are

required by 10 CFR 50.59 whenever changes are made in the

facility as described in the Safety Analysis Report (SAR).

The inadequacies of the evaluations have caused

radiological safety hazards to occur unidentified and

therefore to remain unevaluated and uncorrected. In two

particular cases, the inadequately evaluated system changes

resulted in system failures that caused an uncontrolled

release of radioactivity to the environment. In each of

these situations, a proper 10 CFR 50.59 safety evaluation

would have identified and corrected deficiencies in the

system modification and/or operation and would have

prevented the inadvertent release of radioactivity.

NRC follow-up examination of the situation indicates that

the inconsistency and/or inadequacy of licensee safety

evaluations may be widespread. A wide range of opinions

seems to exist among licensees as to what constitutes an

appropriate 10 CFR 50.59 safety evaluation, particularly

for radwaste systems. Therefore, discussion and guidance

are provided for licensee use in preparing future 10 CFR

50.59 safety evaluations to support changes in the design

and/or operation of the radioactive waste treatment systems

of licensed facilities.

Although the detailed discussions of this guidance document

are specifically directed to radioactive waste systems, the

general principles and philosophy of the 10 CFR 50.59

safety evaluation guidance are also applicable to facility

design and operation as a whole; thus, the application of

10 CFR 50.59 should reflect a consistent approach.

Regulatory references: 10 CFR 50.59, Regulatory Guide

1.21, Final Safety Analysis Report

Subject codes: 5.0, 9.0

Applicability: Reactors