ML22024A018

Breakout Questions - Trp 19 - Steam Generators

ML22024A018
Person / Time
Site:	Oconee
Issue date:	01/19/2022
From:	Angela Wu NRC/NRR/DNRL/NLRP
To:
Wu A, 301-415-2995
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Download: ML22024A018 (9)

Text

Oconee Nuclear Station, Units 1, 2, and 3, Subsequent License Renewal Application (SLRA)

TRP 019: Steam Generators

1. SLRA SLRA Question / Issue Why are we asking?

Section Page 1 3.1 3-193 SLRA Table 3.1.2-4, Reactor Vessel, The NRC staff is seeking Reactor Internals, and Reactor Coolant clarification on if the auxiliary System - Steam Generators - Aging feedwater nozzle flanges are Management Evaluation, cites AMR Items insulated, and on the use of 3.4.1-103 and 3.4.1-104 for managing loss industry standard Note A.

of material and cracking of the stainless steel auxiliary feedwater nozzle flanges exposed externally to indoor uncontrolled air by the One-Time Inspection program.

These AMR items are for insulated stainless steel piping, piping components, and tanks.

However, the NRC staff was unable to verify that the auxiliary feedwater nozzle flanges are insulated.

SLRA Table 3.1.2-4 cites industry standard Note A, Consistent with NUREG-2191 item for component, material, environment, and aging effect. AMP is consistent with NUREG-2191 AMP, for cracking of the stainless steel auxiliary feedwater nozzle flanges exposed internally to treated water, however, no NUREG-2191 item or NUREG-2192 Table 1 were cited.

Please confirm that the auxiliary feedwater nozzle flanges are insulated and clarify the use of industry standard Note A..

2 3.1, 2.3 3-195, SLRA Table 3.1.2-4 states that the intended The NRC staff is seeking 2-67 functions for the steel baffle assemblies are clarification on the intended flow distribution and structural support, function(s) of the steel baffle however, SLRA Table 2.3.1-4, Steam

Generators, states that the intended assemblies and on the use of function of the baffle assemblies is structural industry standard Note A.

support only.

SLRA Table 3.1.2-4 cites industry standard Note A for the following:

• Cumulative fatigue damage of steel baffle assemblies exposed externally to secondary feedwater, however, the AMR cited is for steam generator components:

top head, steam nozzle and safe end, upper and lower shell, feedwater and auxiliary feedwater nozzle and safe end, feedwater impingement plate and support

• Loss of material of steel baffle assemblies exposed externally to secondary feedwater, however, the AMR item cited is for steam generator tube bundle wrapper and associated supports and mounting hardware Please clarify the intended function(s) of the steel baffle assemblies and clarify the use of industry standard Note A.

3 3.1 3-19 SLRA Table 3.1.2-4 includes an aging The NRC staff is seeking management evaluation for nickel alloy and clarification on the material(s) of steel primary manway and inspection the primary manway and opening covers and backing plates. inspection opening covers and backing plates, and the use of SLRA Table 3.1.2-4 cites industry standard industry standard Note A.

Note A for the following aging management evaluations for the primary manway and inspection opening covers and backing plates:

• Cracking of nickel alloy exposed internally to reactor coolant, however, the AMR item cited is for steel (with stainless steel or nickel alloy cladding) primary side components: upper and lower heads, and tube sheet welds

• Cumulative Fatigue Damage of nickel alloy exposed internally to reactor coolant, however, the AMR item cited is for once-through steam generator components: primary size nozzles, safe ends, welds

• Loss of material of nickel alloy exposed internally to reactor coolant, however, the AMR item cited is for piping, piping components, flanges, heater sheathes and sleeves, penetrations, thermal sleeves, non-reactor vessel shells, heads, nozzles, nozzle safe ends, welds

• Loss of material of steel exposed externally to uncontrolled indoor air, however, the ARM item cited is for piping and piping components Please clarify the material(s) of the primary manway and inspection opening covers and backing plates and the use of industry standard Note A.

4 3.1 3-193 SLRA Table 3.1.2-4 cites industry standard The NRC staff is seeking Note A for the following: clarification on the use of industry standard Note A.

• Cumulative fatigue damage of steel auxiliary feedwater nozzle inlet header exposed internally to treater water, however, the environments for the cited

AMR item are secondary feedwater and steam

• Loss of material of steel main feedwater nozzle inlet headers exposed internally to secondary feedwater, however, the AMR item cited is for steam generator components: shell assembly

• Cracking of steel (with stainless steel cladding) primary nozzles exposed internally to reactor coolant, however, the AMR item cited is for primary side components: upper and lower heads and tube sheet welds

• Loss of material of steel secondary manway and handhold opening covers exposed externally to uncontrolled indoor air, however, the AMR item cited is for piping and piping components

• Cumulative fatigue damage of steel secondary manway and handhold opening covers exposed internally to secondary feedwater, however, the AMR item cited is for steam generator components: top head; steam nozzle and safe end; upper and lower shell; feedwater and auxiliary feedwater nozzle and safe end; feedwater impingement plate and support

• Loss of material of steel secondary manway and handhole opening covers exposed internally to secondary feedwater, however, the AMR items cited are for treated water or steam, and steam generator components: shell assembly

• Loss of material of steel secondary side nozzles (vent, drain, and instrumentation)

exposed internally to secondary feedwater, however, the ARM item cited is for steam generator components: shell assembly

• Loss of material of steel shell assembly exposed externally to uncontrolled indoor air, however, the AMR item cited is for piping and piping components

• Loss of material of steel steam outlet nozzle exposed internally to steam, however, the AMR item cited is for steam generator components: shell assembly

• Cumulative fatigue damage of nickel alloy tube plugs exposed externally to reactor coolant, however, the AMR item cited is for tubes and sleeves

• Loss of material of nickel alloy tube plugs exposed externally to reactor coolant, however, the AMR item cited is for piping, piping components; flanges; heater sheaths and sleeves; penetrations; thermal sleeves; nonreactor vessel shells, heads, nozzles, nozzle safe ends; welds

• Cumulative fatigue damage of steel tube support plate assembly (spacers, nuts, keys, and wedges) exposed externally to secondary feedwater, however, the AMR item cited is for steam generator components: top head; steam nozzle and safe end; upper and lower shell; feedwater and auxiliary feedwater nozzle and safe end; feedwater impingement plate and support

• Loss of material of steel tube support plate assembly (spacers, nuts, keys, and

wedges) exposed externally to secondary feedwater, however, the AMR item cited is for steam generator: tube bundle wrapper and associated supports and mounting hardware

• Loss of material of nickel alloy tubes exposed internally to reactor coolant ,

however, the AMR cited is for piping, piping components; flanges; heater sheaths and sleeves; penetrations; thermal sleeves; nonreactor vessel shells, heads, nozzles, nozzle safe ends; welds

• Loss of material of steel tubesheet exposed externally to secondary feedwater, however, the AMR item cited is for steam generator: tube bundle wrapper and associated supports and mounting hardware

• Loss of material of steel with nickel alloy cladding tubesheet exposed externally to uncontrolled indoor air, however, the AMR item cited is for steel piping and piping components

• Cumulative fatigue damage of nickel alloy tube-to-tube sheet welds exposed internally to reactor coolant, however, the AMR item cited is for tubes and sleeves

• Cracking of nickel alloy tube-to-tube sheet welds exposed externally to secondary feedwater, however, the AMR item cited is for tubes and sleeves

• Loss of material of nickel alloy tube-to-tube sheet welds exposed externally to secondary feedwater, however, the AMR item cited is for tubes and sleeves

• Cumulative fatigue damage of steel (with stainless steel cladding) upper and lower heads exposed internally to reactor coolant, however, the AMR item cited is for once-through steam generator components: primary side nozzles, safe ends, welds Please clarify the use of industry standard Note A.

5 3.1 3-201 SLRA Table 3.1.2-4 cites industry standard The NRC staff is seeking Note E, Consistent with NUREG-2191 item clarification on the use of for material, environment, and aging effect, industry standard Note E.

but a different AMP is credited or NUREG-2191 identifies a plant-specific AMP, for the following:

• Cracking of stainless steel tube support plate assembly (support rod) exposed externally to secondary feedwater, however, no NUREG-2191 item or NUREG-2192 Table 1 are cited

• Cracking of stainless steel tube support plate assembly (tube support plates) exposed externally to secondary feedwater, however, no NUREG-2191 item or NUREG-2192 Table 1 are cited Please clarify the use of industry standard Note E.

6 B2.1.10 B-92 The SLRA states that the Oconee SG The NRC staff is seeking program is consistent with AMP XI.M19 in clarifications on corrective GALL-SLR. SLRA Section B2.1.10 provides actions in accordance with the a description of Oconees SG program. The corrective action program and NRC staff made the following observations: evaluations for continued acceptability.

• The operating experience section includes several examples related to the Oconee corrective action program, including adjusting the growth rate assumptions in the operational assessments. However, the description of the program only discusses corrective actions and the corrective action program with regards to tube plugs with indications of aging. AMP XI.M19 in GALL-SLR discusses corrective actions and the corrective action program with regards to tube integrity not being maintained for the operating interval before the next inspection, non-conservative operational assessments, and acceptance criteria not being met. Please confirm in these instances that corrective actions will be taken in accordance with the corrective action program during the subsequent period of extended operation.

• A discussion that an evaluation for continued acceptability are performed on a case-by-case basis for SG components such as, tube-to-tubesheet welds, heads, tubesheets, and secondary side internals is not included. Please confirm that evaluations for continued acceptability will be performed for these components during the subsequent period of extended operation.

7 The NRC staff noted that SLR-ONS-AMPR- The NRC staff is seeking XI.M19, Steam Generators AMP Evaluation clarification on the discussion of Report, makes several statements sleeving in the SG program regarding sleeves. For example, Section evaluation report.

4.2.c states, in part, All tubes requiring

repair are plugged or sleeved It is the staffs understanding that sleeving is not an NRC approved repair method at Oconee.

The staff did note that the SLRA does not refer to SG sleeves.