United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Contamination of Nonradioactive System and Resulting Potential for Unmonitored, Uncontrolled Release of Radioactivity to the Environment

HPPOS-079 PDR-9111210213

Title: Contamination of Nonradioactive System and

Resulting Potential for Unmonitored, Uncontrolled Release

of Radioactivity to the Environment

See IE Bulletin No. 80-10 entitled as above and dated May

6, 1980. Action Item 3 of this bulletin states that if a

nonradioactive system becomes contaminated and it is

considered necessary to continue operation, an immediate

safety evaluation must be performed in accordance with 10

CFR 50.59.

An auxiliary boiler had been operated for an extended

period of time with contaminated water containing up to

2x10-2 micro-Ci/ml. The contamination was caused by a tube

leak in a temporary hose connecting the auxiliary boiler to

a radioactive waste evaporator concentrate tank. Upon

cooling and condensation of steam in the hose, contaminated

water siphoned from the concentrate tank back to the

auxiliary boiler. Because of additional and continuing

leaks in the heat exchanger of the waste evaporator, the

licensee's efforts to decontaminate the auxiliary boiler

feedwater were ineffective. Maintenance of proper boiler

chemistry was difficult because blowdown options were

restricted due to contamination. As a result, 100 mCi of

radioactive material were released off-site in steam via

the auxiliary boiler fire box and smokestack. The release

resulted in increased environmental levels of cesium and

activation products being detected eight miles downwind

from the site boundary.

Actions to be taken by licensees with operating licenses to

preclude the described situation include:

1. Review facility design and operations to identify

systems considered as nonradioactive (or described as

nonradioactive in the FSAR) that may become contaminated by

radioactive systems. Consideration should be given to the

following: auxiliary boiler system, demineralized water

system, isolation condenser system, PWR secondary water

clean-up system, instrument air system, and sanitary waste

system.

2. Establish a routine sampling / analysis program for

these systems to detect radioactive contamination.

3. If nonradioactive systems are or become

contaminated, further use of the system shall be restricted

until the cause is identified, corrected, and

decontaminated. However, if it is considered necessary to

continue operation with the contaminated system, an

immediate safety evaluation of the operation of the system

as a radioactive system must be performed in accordance

with the requirements of 10 CFR 50.59. The 10 CFR 50.59

safety evaluation must consider the level of contamination

and any potential releases of radioactivity to the

environment. The relationship of such releases to the

radioactive effluent limits of 10 CFR 20

[§§20.1001-20.2401], the facility's Technical

Specifications, and to the environmental radiation dose

limits of 40 CFR 190 must also be evaluated. The record of

the safety evaluation must set forth the basis and criteria

on which the determination was made.

4. If it is determined in the 10 CFR 50.59 safety

evaluation that operation of the system as a radioactive

system is acceptable, provisions must be made to comply

with the requirements of 10 CFR 20.201 [or, at present, 10

CFR 20.1501], General Design Criterion 64 to 10 CFR 50,

Appendix I to 10 CFR 50, and the facility's Technical

Specifications. Specifically, any potential release points

must be monitored and all releases must be controlled and

maintained to ALARA levels described in 10 CFR 50 Appendix

I and within the corresponding environmental dose limits of

40 CFR 190. If in the 10 CFR 50.59 determination it is

concluded that operation of the system as a radioactive

system constitutes an unreviewed safety question or

requires a change to the Technical Specifications, the

system shall not be operated as contaminated without prior

commission approval.

Regulatory references: 10 CFR 50.59

Subject codes: 5.0, 7.3, 9.2

Applicability: Reactors

Page Last Reviewed/Updated Thursday, March 29, 2012