ML23074A002
| ML23074A002 | |
| Person / Time | |
|---|---|
| Issue date: | 03/08/2023 |
| From: | Navedo T NRC/NRR/DRO |
| To: | Office of Administration |
| References | |
| 88FR13735 00002, NRC-2023-0028 | |
| Download: ML23074A002 (1) | |
Text
SUNSI Review Complete Template=ADM-013 From: Tania Martinez Navedo E-RIDS=ADM-03 To: Michael Eudy Cc: Liliana Ramadan; Sheila Ray ADD: Michael Eudy, Bridget Curran, Solomon Sahle, Mary Neely
Subject:
Comment on DG-1418 Comment (2)
Date: Wednesday, March 8, 2023 8:31:21 AM Publication Date: 3/6/2023 Attachments: image001.jpg Citation: 88 FR 13735 image002.jpg Good morning Mike, I have shared with folks in DEX 1 comment I have on DG-1418. I would appreciate it if they could be added to the comments resolution table for the DG:
Comment:
The last paragraph in the background section states:
IEEE Std. 485-2020, section 4.2.5, Duty Cycle Diagram, states that the total time span of the duty cycle is determined by the requirements of the installation. This duty cycle time depends on the type of production and utilization facility designactive or passive. The duty cycle time is typically discussed in a plant safety analysis report. For facilities that are active, the battery duty cycle should cover both design-basis accidents (DBAs) and station blackout (SBO) scenarios (with a permitted load shedding scheme). For DBAs, since an emergency diesel generator (EDG) or other onsite emergency power source is assumed to be available within approximately 10 seconds to recharge the battery, some facilities have sized the vital batteries considering a duty cycle of less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> duration. However, an EDG or onsite emergency power source may be out of service at the time of an accident concurrent with the loss of offsite power. It may take up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to switch the associated battery charger to an alternate power source. Therefore, for active designs, the vital batteries should be sized for the worst-case duty cycle, consisting of either a minimum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for the DBAs or the analyzed SBO duration (with a permitted dc load shedding scheme). This guidance does not apply to the EDGs or onsite emergency power sources own battery if provided separately (which is exclusively sized based on the starting requirement of the EDG or onsite emergency power source, such as field flash).
This paragraph may cause confusion since passive plants may still need to design for DBA and SBO and this paragraph doesnt state as such - really, it doesnt provide sufficient guidance for passive plants. Passive plants and advanced Rx will have to size their batteries, based on the safety analysis (i.e. for what events they are needed - DBA, SBO, AOO, etc).
I would recommend revising the paragraph as follows:
IEEE Std. 485-2020, section 4.2.5, Duty Cycle Diagram, states that the total time span of the duty cycle is determined by the requirements of the installation. This duty cycle time depends on the type of production and utilization facility design, andactive or passive.
The duty cycle time is typically discussed in a plant safety analysis report. For facilities that are active, the battery duty cycle should cover both design-basis accidents (DBAs) and station blackout (SBO) scenarios (with a permitted load shedding scheme). For DBAs, since an emergency diesel generator (EDG) or other onsite emergency power source is assumed to be available within approximately 10 seconds to recharge the battery, some facilities have sized the vital batteries considering a duty cycle of less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> duration. However, an EDG or onsite emergency power source may be out of service at the time of an accident concurrent with the loss of offsite power. It may take up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to
switch the associated battery charger to an alternate power source. Therefore, for active designs, the vital batteries should be sized for the worst-case duty cycle, consisting of either a minimum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for the DBAs or the analyzed SBO duration (with a permitted dc load shedding scheme).
This guidance does not apply to the emergency diesel generators (EDGs) or onsite emergency power sources own battery if provided separately (which is exclusively sized based on the starting requirement of the EDG or onsite emergency power source, such as field flash).
Happy to discuss further if youd like.
Tania Tania Martinez Navedo, Acting Deputy Director Division of Reactor Oversight Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission e-mail: tania.martinez-navedo@nrc.gov phone: (301) 415-6561