ML22024A012
| ML22024A012 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/19/2022 |
| From: | Angela Wu NRC/NRR/DNRL/NLRP |
| To: | |
| Wu A, 301-415-2995 | |
| Shared Package | |
| ML22024A002 | List:
|
| References | |
| Download: ML22024A012 (7) | |
Text
Oconee SLRA: Breakout Questions SLRA Section B2.1.26, Buried and Underground Piping and Tanks TRP: 14
Question SLRA SLRA Background / Issue Discussion Question / Request Number Section Page (As applicable/needed) 1 B2.1.26 B-181 Exception No. 2 - Alternative limiting The subject enhancement (as critical potential. written) applies to all buried steel within the scope of Exception No. 2 states the following in subsequent license renewal, part: but the justification focuses on
- NUREG-2191 recommends the the standby shutdown facility limiting critical potential for diesel engine fuel oil tank.
cathodic protection systems Clarification needed regarding should not be more negative whether this exception is than -1200 mV. The Oconee applicable for instant-off Buried and Underground Piping potential measurements (a) in and Tanks AMP will maintain the the vicinity of the standby instant-off potential of all test shutdown facility diesel engine locations between -850 mV fuel oil tank; or (b) site-wide.
and -2000 mV.
- The cathodic protection system for The staff requests a the standby shutdown facility clarification discussion diesel engine fuel oil tank was regarding how the two part installed in 2010 to replace the system consisting of a high original passive sacrificial anode build epoxy primer and a high system. Due to the location of the build coal tar epoxy finish coat tank and space limitations in the can accommodate voltages area, anodes could not be more negative than -1,200 mV.
installed on the south side of the The -1,200 mV limiting critical tank that is adjacent to the potential is an industry standby shutdown facility building standard value.
wall. Also, the design depth for the anodes on the north side of the tank could not be obtained due to a shallow bedrock layer in the
area. In order to achieve adequate polarization at test locations for the south side of the tank, an instant-off potential more negative than -1200 mV was required for test locations for the north side of the tank.
- The coating used for the standby shutdown facility diesel engine fuel oil tank is a two part system consisting of a high build epoxy primer and a high build coal tar epoxy finish coat. Epoxy coating systems are less susceptible to cathodic disbondment than other coating systems such as tape wrap coatings.
2 N/A N/A Buried Gray Cast Iron Piping-Clarification needed regarding if there is in-scope buried gray The staff reviewed SLR-ONS-AMPR-cast iron piping at ONS.
XI.M41, Buried and Underground Piping and Tanks AMP Evaluation Report, Revision 1, and noted the program address gray cast iron piping. The staff also notes that there are no aging management review items for gray cast iron exposed to a soil environment.
3 Table 3-480 SLRA Table 3.3.1 (item 144) states Clarification needed regarding 3.3.1 stainless steel piping and pipingwhy the subject components components exposed to soil are managed do not cite cracking due to for cracking due to stress corrosion SCC.
cracking (SCC).
The following stainless steel components exposed to soil do not cite cracking due to SCC.
- Valve bodies in the high pressure service water system.
- Piping in the condenser circulating water and siphon seal water systems.
4 Various Various Enhancement No. 1 states [i]nstall a The staff requests a clarifying cathodic protection system in accordance discussion on the following.
with NACE SP0169-2007 for buried carbon steel piping within the scope of the The staffs understanding is program. that cathodic protection will not be provided for buried ductile The SLRA states ductile iron piping iron piping based on the exposed to soil in the High Pressure following reasons: (a) the Service Water and Keowee Fire subject piping is within the Detection/Protection systems will be scope of SLR in accordance managed for loss of material by the with the criteria of 10 CFR Buried and Underground Piping and 54.4(a)(3) [fire protection]; (b)
Tanks program. the subject piping was installed in accordance with SLR-ONS -AMPR -XI.M41 states [b]uried NFPA 24; and (c) preventive piping in the High Pressure Service Water actions beyond those in NFPA System and Keowee Fire 24 (i.e., cathodic protection)
Detection/Protection System is designed are not required based on and installed in accordance with NFPA GALL-SLR Report
- 24. recommendations.
SLRA Sections 2.3.3.4.1, High Pressure Service Water System, and 2.3.3.4.3, Keowee Fire Detection/Protection System, state these systems are within the scope of SLR in accordance with the criteria of 10 CFR 54.4(a)(2) and 10 CFR 54.4(a)(3) [fire protection].
GALL-SLR AMP XI.M41 states [f]or fire mains installed in accordance with
National Fire Protection Association (NFPA) NFPA 24, preventive actions beyond those in NFPA 24 need not be provided if The staff notes that NFPA 24 does not provide recommendations related to cathodic protection.
5 B2.1.26 B-185 Underground-to-soil interface corrosion: The inspection Table 3-1002 SLRA Table 3.3.2-56, Standby Shutdown recommendations for buried 3.3.2-56 Facility Fuel Oil System, cites soil and and underground tanks underground external environments for provided in the enhancement the diesel engine fuel oil storage tank. are consistent with GALL-SLR Report AMP XI.M41 Enhancement No. 9 states [i]nternal recommendations; however, volumetric inspections of the standby these recommendations are shutdown facility diesel engine fuel oil based on tanks being exposed tank will cover at least 25 percent of the to a buried or underground surface area of the tank and include at environment (i.e., not tanks least some of both the top and bottom of with an underground-to-soil the tank. external interface, where there is an increased potential for degradation at interface locations). The staff seeks clarification regarding if inspections of the subject tank will account for the potential for corrosion at the underground-to-soil interface.
6 B2.1.26 B-184 Enhancement No. 7 states [p]erform The number of inspections in visual inspections of at least two Enhancement No. 7 for ten-linear foot sections of buried uncoated stainless steel piping is stainless steel piping at least once every consistent with GALL-SLR ten years Report AMP XI.M41 recommendations; however, GALL-SLR Report Table XI.M41-1, the recommended inspections Preventive Actions for Buried and are based on coatings being
Underground Piping and Tanks, provided. Based on coatings recommends coatings for buried stainless not being provided for buried steel piping. stainless steel at ONS, the staff requests a clarifying GALL-SLR Report AMP XI.M41 states discussion to understand why
[a]dditional inspections, beyond those in two inspections in each Table XI.M41-2 may be appropriate if 10-year interval is appropriate.
exceptions are taken to program element 2, preventive actions. The staff also notes that Table 9-4, Soil Corrosivity Index SLR-ONS -AMPR -XI.M41 provides soil from BPWORKS, of EPRI sampling results from 2008 (average Report 3002005294, Soil values only) for the following soil Sampling and Testing parameters: soil resistivity, chlorides, and Methods to Evaluate the sulfates. Corrosivity of the Environment for Buried Piping and Tanks at Nuclear Power Plants, (this document in on the ePortal) includes the following soil parameters when determining the soil corrosivity for stainless steel piping: soil resistivity, pH, redox potential, sulfides, chlorides, soil moisture, and soil consortia (bacteria). The staff seeks clarification regarding why pH, redox potential, soil moisture, and soil consortia were not considered for stainless steel.
7 A2.26 A-27 The UFSAR states the acceptance GALL-SLR Report Table criterion for cathodic protection system XI-01, FSAR Supplement effectiveness is -850 mV relative to Summaries for GALL-SLR copper/copper sulfate reference Report Chapter XI Aging electrode. Management Programs, states [f]or steel components,
GALL-SLR Report Table XI-01 includes where the acceptance criteria the following statement [w]here the for the effectiveness of the coatings, backfill or the condition of cathodic protection is other exposed piping does not meet than -850 mV instant-off acceptance criteria such that the depth or The cathodic protection extent of degradation of the base metal acceptance criterion in the could have resulted in a loss of pressure UFSAR does not specify boundary function when the loss of instant-off.
material rate is extrapolated to the end of the subsequent period of extended The staff seeks clarification operation, an increase in the sample size regar ding why the quoted is conducted. If a reduction in the number statement to the left is not of inspections recommended in included in SLRA Section GALL--SLR Report, AMP XI.M41, Table A2.26.
XI.M41-2 is claimed based on a lack of soil corrosivity as determined by soil SLRA Section A2.26 does not testing, then soil testing is conducted discuss soil testing; therefore, once in each 10-year period starting 10 it is unclear why Preventive years prior to the subsequent period of Action Category E would be extended operation. applicable at ONS.
GALL-SLR Report AMP XI.M41 states Preventive Action Category E applies when a cathodic protection system has been installed but all or portions of the piping covered by that system fail to meet any of the criteria of Preventive Action Category C piping, provided (a) coatings and backfill are provided in accordance with the preventive actions program element of this AMP; (b) plant-specific OE is acceptable (i.e., no leaks in buried piping due to external corrosion, no significant coating degradation or metal loss in more than 10 percent of inspections conducted); and (c) soil has
been determined to not be corrosive
[emphasis added by the staff].