ML19140A282
| ML19140A282 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 05/15/2019 |
| From: | Bennett Brady NRC/NRR/DMLR/MRPB |
| To: | Gallagher M Exelon Generation Co |
| Bennett B, NRR-DMLR 415-2981 | |
| Shared Package | |
| ML19140A281 | List: |
| References | |
| Download: ML19140A282 (3) | |
Text
Regulatory Basis:
10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the subsequent period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to manage the effects of aging during the subsequent period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. To complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information about the matters described below.
RAI 3.3.2.1.1-1a Background.
A. The May 2, 2019, (ML19122A289) response to RAI 3.3.2.1.1-1 states that, cracking due to SCC [stress corrosion cracking] is not cited as an aging effect requiring management for copper alloy with greater than 15 percent zinc components in the environment of air - indoor, uncontrolled. The response provided a basis for this position citing NUREG-2221, Technical Bases for Changes in the Subsequent License Renewal Guidance Documents NUREG-2191 and NUREG-2192, Table 3-2 SRP-SLR Chapter 2, Scoping and Screening, Differences from SRP-LR, Revision 2 and Their Technical Bases, as follows:
- It is unlikely that leakage from packing, gaskets, seals or o-rings would result in failure of the system to deliver sufficient flow at adequate pressure.
- In regard to leakage, which could affect either the pressure boundary (containment leak boundary) or leakage boundary (spatial) intended functions, licensees routinely conduct tours of the operating spaces. When leakage is detected it is typically promptly entered into the corrective action program. The leakage is corrected by replacing the packing, gaskets, seals, and o-rings as consumables.
Regarding the air-indoor uncontrolled environment, the RAI response states:
It is feasible that trace amounts of ammonia or ammonium compounds could exist in the air - indoor, uncontrolled environment due to (1) incidental leakage from the raw water cooling systems from packing, gaskets, seals, and o-rings, and, (2) incidental leakage from packing, gaskets, seals, and o-rings through insulation where the insulation contains contaminants.
The associated copper alloy with greater than 15 percent zinc components are cited as being consistent.
B. For six of the environments (i.e., air indoor-uncontrolled, air-outdoor, air-dry, treated water, condensation, waste water) cited in the response to RAI 3.3.2.1.1-1, the response states in part that, ammonia or ammonium compounds are not assumed to be present.
Issue.
A. In justifying that potential sources of ammonia are not required to be considered when determining aging effects requiring management, the RAI response misapplied the position documented in NUREG-2221, Table 3-2 regarding why it is not necessary to manage loss of leak tightness for packing, gaskets, seals, and O-rings. Referencing the staff position in the basis documents, the staff concludes that the RAI response basis is not correct as follows:
The technical basis statement associated with leakage from degraded packing, gaskets, seals, and O-rings is in relation to the process flow. There is reasonable assurance that the pressure boundary intended function of the component would not be adversely affected due to leaks from packing, gasket, seals and O-rings; however, that does not imply that leaks from these types of components cannot cause aging effects that adversely affect the pressure boundary intended functions of other components.
The technical basis document statement regarding the replacement of these components as consumables:
o The function of the containment leakage boundary is to provide containment isolation for fission product retention. While packing, gaskets, seals, and O-rings could impact this function, the GALL-SLR Report recommends periodic testing of containment penetrations, which would test these items along with the entire penetration. It is not necessary to separately manage aging effects for packing, gaskets, seals, and O-rings in regard to this intended function.
o The staff recognizes that leakage and spray from nonsafety-related components are associated with the leakage boundary (spatial) intended function. However, as stated in the basis, leaks are typically promptly identified and corrected. As a result, it is the staffs position that recommending management of aging effects associated with packing, gaskets, seals, and O-rings is not warranted. Stating it in another manner, it is not warranted that packing, gaskets, seals, and O-rings be identified as items requiring aging management in the Table 2s of applications.
o These positions do not extend to include an interpretation that this leakage is, not required to be considered when determining aging effects requiring management. In fact, such an interpretation contradicts SRP-SLR Section A.1.2.1, which states:
However, leakage from bolted connections should not be considered as abnormal events. Although bolted connections are not supposed to leak, experience shows that leaks do occur, and the leakage could cause corrosion. In addition, condensation frequently occurs during humid periods of normal plant operation and can also occur during plant shutdown when normally hot components might be below the dew point. The aging effects from leakage of bolted connections and condensation occurring during humid periods of normal plant operations should be evaluated for SLR.
In summary, the GALL-SLR Report and SRP-SLR do not recommend that aging effects be managed for packing, gaskets, seals, and O-rings. However, potential aging effects due to degraded (leaking) packing, gaskets, seals, and O-rings should be evaluated to be consistent with the GALL-SLR Report.
B. The RAI response lacks sufficient clarity on whether ammonia or ammonium compounds are or could be present.
Request A. State the basis for why cracking due to SCC is not cited as an aging effect requiring management for copper alloy with greater than 15 percent zinc components exposed to an environment of air - indoor, uncontrolled.
B. Definitively state whether ammonia or ammonium compounds are or could be present in the following environments: air indoor-uncontrolled, air-outdoor, air-dry, treated water, condensation, and waste water.