2191 R0 XI.M30

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XI.M30 FUEL OIL CHEMISTRY

Program Description

The program includes (a) surveillance and maintenance procedures to mitigate corrosion and (b) measures to verify the effectiveness of the mitigative actions and confirm the insignificance of an aging effect. Fuel oil quality is maintained by monitoring and controlling fuel oil contamination in accordance with the plant’s technical specifications (TS). Guidelines of the American Society for Testing and Materials (ASTM) Standards, such as ASTM D 0975, D 1796, D 2276, D 2709, D 6217, and D 4057, also may be used. Exposure to fuel oil contaminants, such as water and microbiological organisms, is minimized by periodic draining or cleaning of tanks and by verifying the quality of new oil before its introduction into the storage tanks. However, corrosion may occur at locations in which contaminants may accumulate, such as tank bottoms. Accordingly, the effectiveness of the program is verified to provide reasonable assurance that significant degradation is not occurring and that the component’s intended function is maintained during the subsequent period of extended operation. Thickness measurement of the tank bottom is an acceptable verification program.

The fuel oil chemistry program is generally effective in removing impurities from areas that experience flow. The Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report identifies those circumstances in which the fuel oil chemistry program is augmented to manage the effects of aging for subsequent license renewal (SLR). For example, the fuel oil chemistry program may not be effective in stagnant areas. Accordingly, in certain cases as identified in this GALL-SLR Report, verification of the effectiveness of the fuel oil chemistry program is conducted. As discussed in this GALL-SLR Report for these specific cases, an acceptable verification program is a one-time inspection of selected components at susceptible locations in the system.

Evaluation and Technical Basis

1. Scope of Program: Components within the scope of the program are the diesel fuel oil storage tanks, piping, and other metal components subject to aging management review that are exposed to an environment of diesel fuel oil.

2. Preventive Actions: The program reduces the potential for (a) exposure of the component internal surfaces to fuel oil contaminated with water and microbiological organisms, reducing the potential for age-related degradation in other components exposed to diesel fuel oil; and (b) transport of corrosion products, sludge, or particulates to components serviced by the fuel oil storage tanks. Biocides or corrosion inhibitors may be added as a preventive measure. Periodic cleaning of a tank allows removal of sediments, and periodic draining of water collected at the bottom of a tank minimizes the amount of water and the length of contact time. Accordingly, these measures are effective in mitigating corrosion inside diesel fuel oil tanks. Coatings, if used, prevent or mitigate corrosion by protecting the internal surfaces of components from contact with water and microbiological organisms.

3. Parameters Monitored or Inspected: The program is focused on managing loss of material due to general, pitting, and crevice corrosion; and microbiologically influenced corrosion (MIC) of component internal surfaces. The aging management program (AMP) monitors fuel oil quality through receipt testing and periodic sampling of stored fuel oil. Parameters monitored include water and sediment content, total particulate concentration, and the levels of microbiological organisms in the fuel oil. Water and microbiological organisms in the fuel oil storage tank increase the potential for corrosion. Sediment and total particulate content may be indicative of water intrusion or corrosion. Periodic visual inspections of tank internal surfaces and thickness measurements of the bottoms of the tanks are conducted as an additional measure to provide reasonable assurance that loss of material is not occurring.

4. Detection of Aging Effects: Loss of material due to corrosion of the diesel fuel oil tank or other components exposed to diesel fuel oil cannot occur without exposure of the tank’s internal surfaces to contaminants in the fuel oil, such as water and microbiological organisms. Periodic multilevel sampling provides assurance that fuel oil contaminants are below unacceptable levels. If tank design features do not allow for multilevel sampling, a sampling methodology that includes a representative sample from the lowest point in the tank may be used.

At least once during the 10-year period prior to the subsequent period of extended operation, each diesel fuel tank is drained and cleaned, the internal surfaces are visually inspected (if physically possible) and volumetrically-inspected if evidence of degradation is observed during visual inspection, or if visual inspection is not possible. During the subsequent period of extended operation, at least once every 10 years, each diesel fuel tank is drained and cleaned, the internal surfaces are visually inspected (if physically possible), and, if evidence of degradation is observed during inspections, or if visual inspection is not possible, these diesel fuel tanks are volumetrically inspected. The external surfaces of tank bottoms for outdoor tanks exposed to soil or concrete and indoor tanks exposed to periodically wetted concrete or exposed to soil are volumetrically inspected in accordance with GALL-SLR Report AMP XI.M29, Table XI.M29-1, Footnote 1.

Prior to the subsequent period of extended operation, a one-time inspection (i.e., GALL-SLR Report AMP XI.M32) of selected components exposed to diesel fuel oil is performed to verify the effectiveness of the Fuel Oil Chemistry program. Certain one-time inspections are not conducted subject to the following:

• For components constructed of the same material as the fuel oil storage tank, when the fuel oil storage tank is not coated on its internal surface, one-time inspections are not conducted.
• For components constructed of materials other than the fuel oil storage tank (when the tank is not internally coated), one-time inspections are not conducted when the SLR application states the basis for why water pooling or separation is not possible for a specific material type.

5. Monitoring and Trending: Water, biological activity, and particulate contamination concentrations are monitored and trended in accordance with the plant’s technical specifications or at least quarterly. Where practical, identified degradation is projected until the next scheduled inspection. Results are evaluated against acceptance criteria to confirm that the timing of subsequent inspections will maintain the components’ intended functions throughout the subsequent period of extended operation based on the projected rate of degradation.

6. Acceptance Criteria: Acceptance criteria for fuel oil quality parameters are as invoked or referenced in a plant’s TS. Additional acceptance criteria may be implemented using guidance from industry standards and equipment manufacturer or fuel oil supplier recommendations. ASTM D 0975 or other appropriate standards may be used to develop fuel oil quality acceptance criteria. Suspended water concentrations are in accordance with the applicable fuel oil quality specifications. Corrective actions are taken if microbiological activity is detected. Any degradation of the tank internal surfaces is reported and is evaluated using the corrective action program. Thickness measurements of the tank bottom are evaluated against the design thickness and corrosion allowance.

7. Corrective Actions: Results that do not meet the acceptance criteria are addressed in the applicant’s corrective action program under those specific portions of the quality assurance (QA) program that are used to meet Criterion XVI, “Corrective Action,” of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the corrective actions element of this AMP for both safety-related and nonsafety-related structures and components (SCs) within the scope of this program.

Corrective actions are taken to prevent recurrence when the specified limits for fuel oil standards are exceeded or when water is drained during periodic surveillance. If accumulated water is found in a fuel oil storage tank, it is immediately removed. In addition, when the presence of biological activity is confirmed, or if there is evidence of MIC, a biocide is added to fuel oil.

8. Confirmation Process: The confirmation process is addressed through those specific portions of the QA program that are used to meet Criterion XVI, “Corrective Action,” of 10 CFR Part 50, Appendix B. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the confirmation process element of this AMP for both safety-related and nonsafety-related SCs within the scope of this program.

9. Administrative Controls: Administrative controls are addressed through the QA program that is used to meet the requirements of 10 CFR Part 50, Appendix B, associated with managing the effects of aging. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the administrative controls element of this AMP for both safety-related and nonsafety-related SCs within the scope of this program.

10. Operating Experience: The operating experience (OE) at some plants has included identification of water in the fuel, particulate contamination, and biological fouling. In addition, when a diesel fuel oil storage tank at one plant was cleaned and visually inspected, the inside of the tank was found to have unacceptable pitting corrosion (>50 percent of the wall thickness), which was repaired in accordance with American Petroleum Institute (API) 653 standard by welding patch plates over the affected area.

The program is informed and enhanced when necessary through the systematic and ongoing review of both plant-specific and industry OE including research and development such that the effectiveness of the AMP is evaluated consistent with the discussion in Appendix B of the GALL-SLR Report.

References

10 CFR Part 50, Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants.” Washington, DC: U.S. Nuclear Regulatory Commission. 2016.

API. 653, “Tank Inspection, Repair, Alteration, and Reconstruction.” Washington, DC: American Petroleum Institute. April 2009.

ASTM. ASTM D 0975-13, “Standard Specification for Diesel Fuel Oils.” West Conshohocken, Pennsylvania: American Society for Testing Materials. 2004.

_____. ASTM D 1796-11, “Standard Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method.” West Conshohocken, Pennsylvania: American Society for Testing Materials. 1997.

_____. ASTM D 2276-00, “Standard Test Method for Particulate Contaminant in Aviation Fuel by Line Sampling.” West Conshohocken, Pennsylvania: American Society for Testing Materials. 2000.

_____. ASTM D 2709-96 (Reapproved 2011), “Standard Test Method for Water and Sediment in Middle Distillate Fuels by Centrifuge.” West Conshohocken, Pennsylvania: American Society for Testing Materials. 1996.

_____. ASTM D 4057-06 (Reapproved 2011), “Standard Practice for Manual Sampling of Petroleum and Petroleum Products.” West Conshohocken, Pennsylvania: American Society for Testing Materials. 2000.

_____. ASTM D 6217-11, “Standard Test Method for Particulate Contamination in Middle Distillate Fuels by Laboratory Filtration.” West Conshohocken, Pennsylvania: American Society for Testing Materials. 1998.

US NRC. Regulatory Guide 1.137, “Fuel-Oil Systems for Standby Diesel Generators.” Revision 2. Agencywide Documents Access and Management System (ADAMS) Accession No. ML12300A122. Washington, DC: U.S. Nuclear Regulatory Commission, June 2013.

_____. “Safety Evaluation Report Related to the License Renewal of Three Mile Island Nuclear Unit 1, Section 3.0.3.2.12, Fuel Oil Chemistry–Operating Experience.” ADAMS Accession No. ML091660470. Washington, DC: U.S. Nuclear Regulatory Commission. June 30, 2009.

Generic Aging Lessons Learned - The US NRC GALL Report is NUREG-1801. The US NRC Subsequent License Renewal GALL is NUREG-2191

Subsequent License Renewal - The extension of the original license from 40 years to 60 years is known as License Renewal. Extensions of the license beyond 60 years are known as Subsequent License Renewal.

Microbiologically Influenced Corrosion - A degradation mechanism of corrosion influenced by microorganisms.

Aging Management Program

Quality Assurance

Operating Experience

United States of America

Nuclear Regulatory Commission - The US federal government agency that regulates nuclear power plants

Agency wide Documents Access and Management System - The official recordkeeping system, through which the U.S. Nuclear Regulatory Commission (US NRC) provides access to the "libraries" or collections of publicly available documents