Document: NRC Regulatory Guide
Document ID: d812c779-c17b-4eb3-9d66-b532cd68bd03
Document Type: regulatory_guide
Title: Decommissioning Planning During Operations + HISTORY - HISTORY 12/2011 – DG-4014 , Proposed New Guide
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML1115/ML111590642.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.22
CFR Part: 
CFR Title: 

Content:
on. Evaluating these events provided a means for NRC staff to identify the potential for future subsurface contamination at currently operating facilities. The study identified a number of events that could increase decommissioning costs by increasing the possibility of significant soil or ground water contamination and concluded that these events should cause the licensee to reevaluate its decommissioning cost estimate. In particular, slow and long-lasting leaks of radioactive material into the subsurface may eventually produce radiological hazards and significantly increase the cost of decommissioning. The study concluded that the sites with a higher likelihood of becoming legacy sites shared the following characteristics: 1. relatively large volumes of low specific activity radioactively contaminated liquids; 2. large volumes of long-lived radionuclides; 3. large throughput; 4. liquid processes; or 5. processes that involve large quantities of solid radioactive material stored outdoors. Decommissioning regulations require licensees to remediate sites to approved release criteria for unrestricted use (unless they can demonstrate the need for restricted use) without regard to the cost. Early detection of significant subsurface contamination through surveys and monitoring and appropriate response by the licensee is the preferred approach because the regulatory objective is to ensure the licensee and the NRC are aware of contamination that may create conditions that would complicate decommissioning, and possibly create a legacy site. Therefore, essential parts of decommissioning planning are early identification of significant residual radioactivity, estimating the total cost of remediation, and financial planning to ensure that funds are available when needed. This regulatory guide provides a risk-informed, graded approach to implementing the regulation. The risk-informed approach to implementing this rule is illustrated in Figures 1–3. A more detailed discussion