ML22357A076
| ML22357A076 | |
| Person / Time | |
|---|---|
| Issue date: | 12/31/2022 |
| From: | Gabe Taylor NRC/RES/DRA/FXHAB |
| To: | |
| References | |
| Download: ML22357A076 (5) | |
Text
REVIEW / COMMENT DOCUMENTATION Reviewer: NRC-2022-0096 (87 FR 29396) Date: 2022
Title:
Draft Modified IEEE Hazard Report Document Number Review Comments (Print)/Basis for Comment No. Proposed Resolution Comment Disposition / Resolution Section / Paragraph Comment (1)
Page xi COVID is misspelled Correct spelling Corrected Spelling ML22165A208 IEEE 1584-2018 Appendix G.7.6 describes the minimum working Any model predictions that are less than 12 inches (0.3m) is not included in the report.
distance of 12 inches is due to being This is noted as N/A in the ZOI tables within the range of the arc plasma starting on page 4-2. The footnotes for the cloud and metal droplets. No tests were ZOI tables communicate that the results are not applicable due to the ZOI being less than performed at such short working 0.3 m (12 in). Your comments identify that distances. A minimum working distance treatment in this manner is a non-of 12 inches was used because the conservatism and as such, the report has plasma cloud is not considered to have been corrected to replace N/A with the models limiting distance 0.3 m [12 in]. Your exceeded a radius of 12 in. The plasma Reevaluate applicability of methodology and comment also identifies that the level of cloud size and effect of direct contact include clear bounds of use, including non conservatism / non-conservatism is unknown (2) applicability to use in PRAs due to Section 2.2.1 with it should be considered in future since there isnt sufficient research to ML22165A208 arc-flash model revisions. The arc flash conservatism. evaluate model prediction capabilities within the plasma region.
boundary is not simply based on the limits for sustaining injury to humans, it While this is a conservative assumption, it is a limitation of the testing. Target does not take into consideration the ensuing response within the plasma cloud could enclosure fire, which likely encompasses this be substantially different than target limiting ZOI.
response outside the plasma cloud.
Further justification should be provided As such, additional text has been added in to apply a model outside the validation section 2.2.1 to clarify that the ZOI is limited to 0.3 m (12 in.) when the model predicted range (less than the minimum 12 inch damage is less than 1-ft.
distance).
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REVIEW / COMMENT DOCUMENTATION Reviewer: NRC-2022-0096 (87 FR 29396) Date: 2022
Title:
Draft Modified IEEE Hazard Report (3) Section 2.2.2 There is no clear basis for excluding Reevaluate applicability of The sub-section title (electrode configuration)
ML22165A208 insulated conditions, and this is methodology and include clear likely caused confusion in the draft report.
therefore not realistic for cases with bounds of use, including non These are terms used in the initial model to insulated bus bars. applicability to use in PRAs due identify how the electrodes are oriented to the targets and enclosure configuration. There is to conservatism.
no relation to insulated conductors. The insulation referred to the enclosure. As such, wording has been added to clarify the configuration. Based on these clarifications, the comment is not valid since both insulated and non-insulated conductors are applicable.
(4) Page 3-15 HCB and VCB are not adequately Include explanation and Discussion on configuration is added, along ML22165A208 explained, and the chosen approach justification. with justification for using it in the sensitivity was not sufficiently justified. study.
(5) Section 3.4.2 The medium voltage equation on page Clarify applicability of equation Comment is accurate, however, the typical ML22165A208 3-10 is written such that it is assumed and reevaluate applicability of HEAF involves all three phase. Typical event that all three phases contribute to the methodology and include clear progression involves a single-phase to ground fault. This is therefore not applicable bounds of use, including non or phase-to-phase arc that rapidly propagate to all three phases. This has been observed for cases with two phases, or phase-to applicability to use in PRAs due in OE, even for events involving insulated ground. to conservatism. buses. There have been a limited number of A single phase-to-ground fault, events that do not involve all three phases but for example, would have less energy. are considered a less common scenario.
The current PRA framework does not provide a means for establishing when a HEAF will not involve all three phases. Because of these reasons, it is common practices to assume all three phases are involved in a HEAF.
(6) Section 3.6 In the arcing power equation on page 3- Specify terminal voltage or Arc voltage is the voltage across the arc. It is ML22165A208 13, it is unclear if the arc voltage is the system voltage. discussed in appendix A. A reference to terminal voltage or system voltage. appendix A has been added.
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REVIEW / COMMENT DOCUMENTATION Reviewer: NRC-2022-0096 (87 FR 29396) Date: 2022
Title:
Draft Modified IEEE Hazard Report (7) Figure 17 The Total Energy Release is linear with Revise the figure with an The comment identifies a heat flux (power)
ML22165A208 fault duration, but ZOI due to radiation appropriate relationship or relationship for a black body emission source.
is to the 4th power which would not be provide justification for the That relationship predicts power (heat flux) linear. There is no basis given for a linear relationship.
based on the temperature of the emitting object. Power (heat flux) can be integrated to linear increase in ZOI.
derive energy.
The Figure presents the zone of influence which has a dependency on energy, distance, target fragility. Figure 17 presents the results of the model which is empirically derived and includes other forms of heat transfer than just radiation. Since the model encompasses all forms of heat transfer registered by the measurement device, it is unclear how this comment as written is relative to the figure.
(8) Page 4-2 In the ZOI tables, the difference Specify the ZOI in different The model can be used to provide ML22165A208 between Aluminum and Steel is not directions. directionally dependent ZOIs by choosing the substantial. It would be useful to have applicable configuration (HCB or VCB).
the ZOI in different directions specified.
However, this requires detailed knowledge of the equipment lineup. Since this is unique to the equipment and plant configuration, the decision was made to not include this level of complexity and keep the application of the model as a first order approximation.
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REVIEW / COMMENT DOCUMENTATION Reviewer: NRC-2022-0096 (87 FR 29396) Date: 2022
Title:
Draft Modified IEEE Hazard Report (9) Page A-1 Arc voltage is smaller (20% of open Correct the X/R ratio.
ML22165A208 circuit voltage) because high fault current generates large voltage drop (80%) through impedance in transformer and cables.
Based on Figure 19, there does not appear to be a phase shift (the phase voltage sinusoids have the same period with no significant offset due the fault) Changed purely resistive to highly resistive from the open circuit condition to the The model doesnt require an X/R ratio, and fault condition. The transformer source as such is not discussed.
is highly inductive (large X/R ratio) and the cable has a moderate X/R ratio. If the arc was purely resistive with no reactance, there would be a phase shift.
The arc fault likely has a similar X/R ratio (reactance to resistance ratio) to the open circuit impedance and is likely not purely resistive.
(10)
Front / PDF page 9 Type in Figure 15 title approxiation should be approximation Corrected in List of Figures ML22165A134 Consider adding a summary table of the bias (11) Section 3 / PDF page factor and standard deviation for each model Added summary table to Section 3.7 and Missing summary table ML22165A134 20 to the end of this section as a quick reference made changes to section title.
for the end user.
(12) Section 3.4 / PDF Figure 8. Does Arc Duration = Fault Duration These are the same. Discussion added to Terminology should be consistent/clarified.
ML22165A134 page 26 from section 5 tables? clarify what arc duration is.
(13) Section 3.6 / PDF Typo in Figure 15 approxiation should be approximation Corrected in Figure Caption ML22165A134 page 33 Page 4 of 5
REVIEW / COMMENT DOCUMENTATION Reviewer: NRC-2022-0096 (87 FR 29396) Date: 2022
Title:
Draft Modified IEEE Hazard Report It is unclear how the ZOI results can be applied to HEAF modeling. Some brief (14) Section 4 / PDF page discussion should be included for picking Add clarification. Clarification added ML22165A134 37 the correct ZOI. For example, should Fault duration be Fault Clearing Time estimated on a per plant basis.
IEEE SA notes that the research information letters are based on NRC research that is dissimilar to that performed as a part of the IEEE/NFPA All references to the base model and IEEE These new models would not be the IEEE Collaboration Research. The procedures, 1584 have been either removed or replaced.
(15) IEEE SA General 1584 model, and could not be referred to as configurations, measurements, The new model is referred to as the final such.
equipment, and tests differ. Of course, model. Report title has also been changed.
with these differences, it is understood that results, conclusions, and any derived models will also differ.
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