ML081990508
| ML081990508 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/31/2008 |
| From: | Sacramento Municipal Utility District (SMUD) |
| To: | NRC/FSME |
| References | |
| MPC&D 08-060 | |
| Download: ML081990508 (3) | |
Text
Rancho Seco License Termination Plan Revision 1 Chapter 3, Identification of Remaining Decommissioning Activities May 2008 3.3.3.1 Reactor Building Some liner decontamination is expected to be required once internal structures are removed.
Cleaning, up to and including paint removal, will be done as necessary to meet the derived concentration guideline level (DCGL).
3.3.3.2 Auxiliary Building Extensive decontamination is planned for rooms below grade level in the Auxiliary Building.
Many of the rooms were exposed to leaking or spraying water systems and decontamination is expected to include extensive surface removal including core boring and sawing. It may be necessary to remove floors or sumps if contamination extends through the concrete. These rooms are currently undergoing removal of obstacles that will interfere with 100% scanning surveys.
3.3.3.3 Spent Fuel Pool Significant decontamination is required for the Spent Fuel Pool. The pool liner has been removed and one interior wall where significant pool liner leakage has occurred is scheduled for removal. Once the wall is removed decontamination of remaining wall and floor surfaces will occur as well as the cleaning of the embedded leak chases and through-wall pipes.
3.3.3.4 Turbine Building The Turbine Building has only minor contamination levels with little decontamination planned with the exception of selected floor drain piping segments and sumps.
3.3.3.5 Embedded Pipe Systems Embedded pipe systems are located in all of the impacted buildings listed above. Most embedded system piping is for floor drains. Cleaning is in progress with an initial high-pressure wash to remove debris followed by an abrasive grit blast process as required. Once cleaned to acceptable limits most embedded piping will be grouted to mitigate reuse or transport of remaining residual activity.
3.3.3.6 Wastewater Systems While most wastewater piping that will remain is believed to be below DCGL levels, the Retention Basins and associated bottom drains will require remediation and/or partial removal.
The radioactive discharge line from the RHUTs to the Retention Basins is expected to be removed. Storm drains that lead directly offsite and storm drains that collect system drainage and lead to the outfall should require no remediation. Some system piping that leads to the storm drains is currently being removed in lieu of extensive surveys. Cleaning is currently underway on the oil/water separator. Oil and sludge will be removed and a FSS will be performed.
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Rancho Seco License Termination Plan Revision 1 Chapter 3, Identification of Remaining Decommissioning Activities May 2008 3.3.4 Non-Radiological Activities 3.3.4.1 Outbuilding Demolition The demolition of temporary outbuildings continues. The remaining concrete pads will be surveyed as a part of the FSS process.
3.3.4.2 Site Grading Once Phase I site release is obtained, low areas will be filled and graded for drainage. These areas include the cooling tower basins and canal, the spray ponds and the below grade portion of the Turbine Building including the circulating water lines. Other grading and landscaping may occur.
3.3.5 Control Mechanisms to Ensure No Recontamination Due to the large scope of remaining structures and systems to be decontaminated and the need for some FSS activities to be performed in parallel with dismantlement activities, a systematic approach to controlling areas is established. Upon commencement of the FSS for survey areas where there is a potential for re-contamination, isolation and control measures will be implemented as described in Section 5.2.4.4 of this LTP.
3.3.6 Deferred Activities 3.3.6.1 Storage of Class B and C Waste It is the decision of District management that acceptable waste disposal options for Class B and C waste do not exist at this time. As a result, the waste will be stored in the IOSB until such time as an acceptable waste disposal site is available. Once a solution is available, waste will be shipped and the building will be decontaminated as required.
3.3.6.2 Final Status Survey of IOSB Once the IOSB is decontaminated a FSS will be performed in accordance with this LTP and a final release from the Part 50 license will be requested. The time frame for that request is currently scheduled for 2028, but depends of factors outside of District control. The request is expected to occur prior to the decommissioning of the ISFSI.
3.4 Radiological Impacts of Decontamination and Dismantlement Activities 3.4.1 Occupational Exposure Figure 3-1 provides Rancho Seco cumulative site dose and estimates for the decommissioning project. These estimates were developed to provide site management ALARA goals. The goals are verified by summation of actual site dose, as determined by appropriate dosimetry. ALARA estimates are a compilation of work plan (radiation work permit) estimates for the period. This information is in addition to information gathered for reporting of yearly site dose in accordance with the Rancho Seco Quality Manual (RSQM), Appendix A. The annual report of occupational dose meets the guidance of NRC Regulatory Guide 1.16, Reporting of Operating Information-Appendix A Technical Specifications, [Reference 3-8]. The total nuclear worker exposure during decommissioning is currently estimated to be less than 200 person-rem. This Page 3-10
Rancho Seco License Termination Plan Revision 1 Chapter 3, Identification of Remaining Decommissioning Activities May 2008 estimate is significantly below the 1,215 person-rem estimate of the FGEIS for immediate dismantlement and below the ten-year SAFSTOR estimate of 664 person-rem.
3.4.2 Public Exposure Continued application of Rancho Secos current and future Radiation Protection, Radioactive Waste, Radiological Effluent Technical Specification and Radiological Environmental Monitoring Programs assures public protection in accordance with 10 CFR Part 20 and 10 CFR Part 50, Appendix I. Section 8.6.2 of this LTP contains an evaluation of estimated public exposure as a result of decommissioning activities including the transportation of radioactive waste as compared to the FGEIS.
3.4.3 Estimate of Quantity of Radioactive Material to be Shipped for Disposal or Processing Rancho Seco has shipped for radioactive disposal approximately 5,560 cubic meters (196,325 cubic feet) through December 31, 2005. The estimate of remaining waste is 11,730 cubic meters (414,206 cubic feet), most of which is very low activity concrete debris from the Reactor Building interior. This volume of waste is bounded by NUREG-0586, (FGEIS) volume for the reference pressurized water reactor of 18,343 cubic meters (647,700 cubic feet).
3.4.4 Solid Waste Activity and Volume Rancho Secos Annual Radioactive Effluent Release Report, submitted in accordance with the RSQM and 10 CFR 50.36(a), includes a report on solid waste activity and volumes. This report is submitted before May 1st each year. A summary of solid waste disposal for 1997 through 2005 is provided in Table 3-2. Future updates may be obtained from Rancho Seco for inspection.
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