ML19239A032
| ML19239A032 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 08/26/2019 |
| From: | Anderson V Nuclear Energy Institute |
| To: | Office of Administration |
| References | |
| 84FR31125 00001, NRC-2019-0118, NUREG-2187 V2 | |
| Download: ML19239A032 (14) | |
Text
Page 1 of 1 SUNSI Review Complete Template = ADM-013 E-RIDS=ADM-03 ADD: Jazel Parks, Nick As of: 8/27/19 7:46 AM Melly, David Stroup, Received: August 26, 2019 Markhenry Salley Status: Pending_Post PUBLIC SUBMISSION COMMENT (1) Tracking No. 1k3-9btt-itt7 PUBLICATION DATE: Comments Due: August 27, 2019 6/28/2019 Submission Type: Web CITATION 84 FR 31125 Docket: NRC-2019-0118 NUREG-2178, Refining and Characterizing Heat Release Rates from Electrical Enclosures during Fire Comment On: NRC-2019-0118-0001 Refining and Characterizing Heat Release Rates From Electrical Enclosures During Fire Document: NRC-2019-0118-DRAFT-0002 Comment on FR Doc # 2019-13893 Submitter Information Name: Victoria Anderson Address:
1201 F Street, Suite 1100 Washington, DC, 20004 Email: vka@nei.org General Comment Industry Comments on Draft NUREG-2187 Volume 2, Refining and Characterizing Heat Release Rates from Electrical Enclosures during Fire Volume 2: Fire Modeling Guidance for Electrical Cabinets, Electric Motors, Indoor Dry Transformers, and the Main Control Board Attachments 08-26-19_NRC_NEI Comments NUREG-2187 Volume 2 https://www.fdms.gov/fdms/getcontent?objectId=0900006483ec1f8b&format=xml&showorig=false 08/27/2019
VICTORIA K. ANDERSON Technical Advisor, Engineering & Risk 1201 F Street, NW, Suite 1100 Washington, DC 20004 P: 202.739.8101 vka@nei.org nei.org August 26, 2019 Office of Administration Mail Stop: TWFN-7-A60M U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Industry Comments on Draft NUREG-2187 Volume 2, Refining and Characterizing Heat Release Rates from Electrical Enclosures during Fire - Volume 2: Fire Modeling Guidance for Electrical Cabinets, Electric Motors, Indoor Dry Transformers, and the Main Control Board; 84 FRN 31125-31126; Docket ID NRC-2019-0118 Project Number: 689
Dear Ms. Jennifer Borges:
The Nuclear Energy Institute (NEI)1, on behalf of its members, submits the following comments on the draft NUREG-2187 Volume 2, Refining and Characterizing Heat Release Rates from Electrical Enclosures during Fire - Volume 2: Fire Modeling Guidance for Electrical Cabinets, Electric Motors, Indoor Dry Transformers, and the Main Control Board. The technical work documented in this draft NUREG represents an important advancement in making Fire Probabilistic Risk Assessment (PRA) models more realistic. Current models of electrical cabinet fires represent a substantial portion of the known conservatism in Fire PRAs. Integration of this new technical work will enable licensees to significantly improve the realism in their models and ultimately allow them to use these models in making operational decisions. Overall, NEI finds this work to be of high quality, and offers minor comments to enhance clarity. NEI urges the NRC to incorporate the comments received on this draft NUREG as soon as practical to support near-term finalization of this important work.
We trust that NRC staff will find these comments useful and informative, while continuing to give priority to finalization of the document. Please contact me at vka@nei.org or (202) 739-8101 with any questions or comments about the content of this letter or the attached comments.
1 The Nuclear Energy Institute (NEI) is responsible for establishing unified policy on behalf of its members relating to matters affecting the nuclear energy industry, including the regulatory aspects of generic operational and technical issues. NEIs members include entities licensed to operate commercial nuclear power plants in the United States, nuclear plant designers, major architect and engineering firms, fuel cycle facilities, nuclear materials licensees, and other organizations involved in the nuclear energy industry.
Ms. Jennifer Borges August 26, 2019 Page 2 Sincerely, Victoria K. Anderson Victoria K. Anderson Attachment c: Mr. Michael Cheok, RES, NRC Mr. Mark H. Salley, RES, NRC Mr. David Stroup, RES, NRC
Attachment:
Detailed Comments on Draft NUREG 2178 Volume 2 "HRRs for electric motors and dry transformers: Appendix G of NUREG/CR-6850 recommended HRRs from 6850 were not bounding/conservative values for bounding/conservative in all instances, 1 (pdf pg 30)
HRRs associated with electric motors as compared to the values presented in and dry transformers based on the 5, recommend rephrasing this statement.
values assessed for electrical cabinet fires. "
The section for Non-suppression floor Add a period to the end of the section on 1 (pdf pg 30) value doesn't end with a period. 'Non-suppression floor value'.
The discussion on 'Non-suppression Recommend including some discussion floor value' doesn't indicate that it is about the non-suppression floor value 1 (pdf pg 30) only applicable to MCR fires, however change being applicable only to the the discussion within the report does MCR.
limit the applicability.
The terms electrical enclosures and electrical cabinets, as used in this report, are inclusive of cabinets, panels, and relay racks as those terms This discussion implies that when used, are used in NUREG/CR-6850 and the term "enclosure fires" does not relate other related FPRA documents and to "electrical enclosures" or "electrical standards.
cabinets" but instead means a fire occurring in a room. However, in many In NUREG/CR-6850 the term 1.3 (pdf pg places of this report the term "enclosure enclosure is used in two other 31; lines 18- fire" is directly used to refer to a fire in an contextsnamely, the regulatory issue
- 25) electrical cabinet (most often in Section of cables and components that share a 4).
common enclosure (e.g., cables routed in the same cable tray), and the This section should be revised to clarify modeling of enclosure fires (i.e.,
that "enclosure fire" is used in 2178, Vol fires that occur within a room as 2 to mean an electrical cabinet fire.
opposed to fires that occur in an open unconfined space). The reader is cautioned not to confuse these unrelated uses of the word enclosure.
"Section 4 provides additional 1.4 (pdf pg Include comma "NUREG/CR-6850, guidance beyond that in NUREG/CR-31; line 39) Appendix S" 6850 Appendix S" If available, provide FDS results for obstructed radiant runs in excel format.
2 This will limit the use of interpolation the analyst needs to perform and therefore reduce uncertainty.
Provide statement on whether or not 2 and 3 obstructed radiation factors can be used if using the point source method.
Obstruction factors greater than 1 will result in ZOIs larger than those predicted 2, 3, and by the FDTs. Clarify whether or not the Appendix B analyst must use ZOIs larger than those produced by the FDTs.
A simplified approach to obstructed radiant ZOI when using damage threshold method would be to apply the 2, 3, and 98th% obstruction factor of a given Appendix B source to all percentiles of the fire since the 98th% obstruction factor will always be bounding. Suggest including this method as a suggested approach.
A simplified approach to obstructed radiant ZOI when using damage threshold method would be to apply the 2, 3, and 98th% obstruction factor of a given Appendix B source to all percentiles of the fire since the 98th% obstruction factor will always be bounding. Suggest including this method as a potential approach.
Chapter 2 establishes that the adjusted FDT is the suggested radiant ZOI model for unobstructed radiation. However, in the main body sections pertaining to obstructed radiation, the values presented use the unadjusted FDT and the adjusted FDT values are maintained in App. B rather than the main report.
2, 3, and Furthermore, the information provided in Appendix B App. B is limited compared to that in the main report. Suggest that for the damage threshold approach documented in the main report, the adjusted FDT be used and App. B should document the unadjusted FDT. Both methods should include full analysis (e.g., obstruction factors, max severity factors, Groups 1-3 approach, etc.)
The surface, S, is dependent on LF and D, not height of target above fire base, H. Equation 2-4 correctly shows this.
2.2.2 (pg 38) Equation 2-2 Update equation 2-2 to replace H with LF. Ensure the graph in Figure 2-4 is using the correct equation.
...size for the cabinet size and door status based on NUREG-2178, i.e.,
2.3.2 (pg 46) Change units from MW to kW.
325 and 1,000 MW for medium and large cabinets, respectively.
Vented / unvented face - A vented cabinet face is a face where there are openings to support substantial air flow The final criteria implies that any panel in or out of the cabinet. These would that does not meet the definition of 2.3.3 (pg 50) include louvers for passive or robustly secured is to be considered mechanical ventilation, areas of wire vented. Define robustly secured (e.g.,
mesh, large areas with no panel guidance from FAQ 08-0042).
present, or a face with an access panel
/ door that is not robustly secured.
A vented cabinet face is a face where The final criteria for a vented face implies there are openings to support that a panel that is well sealed, but not substantial air flow in or out of the necessarily robustly secured (e.g., has a cabinet. These would include louvers simple twist-handle style top-and-bottom-for passive or mechanical ventilation, latches), is to be considered vented.
areas of wire mesh, large areas with 2.3.3 (pg 50) However, the next sentence suggests no panel present, or a face with an that if the face is unvented (i.e., well access panel / door that is not robustly sealed), the panel can be considered secured. An unvented face is a face unvented. Provide clarification on the with no significant openings to support treatment of well sealed panels that do substantial air flow in or out of the not meet the definition of well secured.
cabinet.
For the south and west faces the FDS predicted ZOIs are less than the adjusted FDTs ZOIs for 85% to 92% of These statistics also apply to the east 2.3.3.2 (pg the results. 3% to 8% of the FDS ZOIs wall. Update wording to include the east 54) are greater wall.
19 than 110% of the adjusted FDTs ZOIs.
Update wording:
a solid flame model [3], or the use a solid flame model [3], or the use a of 3 (pg 33) of field model such as the Fire field model such as the Fire Dynamics Dynamics Simulator (FDS) [4, 5].
Simulator (FDS) [4, 5].
Figure 3-1 implies that there is no benefit on the vented cabinet face, but it should Figure 3-1 be implying less benefit. The green and red lines should be separated on the vented face.
Provide definitions of Threshold Approach ZOI Factor or Damage Integral 3.1.1 Approach ZOI Factor prior to Table 3-1 or point to Section 2.3.3.4.
The values within Table 3-2 for TP Thermoset is worse than TP for Medium cables result in less severe Open and large closed for default 3.1.1 consequences than TS cables for loading. Confirm this is correct and (Table 3-2) large, closed (0.76 vs 0.78) and recommend including a note below the medium, open (0.9 vs 0.98) cabinets. table to verify.
Provide all inputs necessary to 3.1.2 (pg 74) determine the ZOI of the example sources.
Identify if the Threshold Approach ZOI 3.1.2 (pg 74) Factor or Damage Integral Approach ZOI Factor is being used in the example.
"Consider a TP electrical cable that is This example states the maximum located 0.25 m (0.8 ft) from the severity factor is 0.10 or 0.07. This is for unvented face of large, closed low fuel loading large cabinets, which is cabinet. For this cabinet Table 3-3, not stated in the example. For default has a maximum severity factor of 0.10.
3.2.2 (3-7) fuel loading cabinets, the maximum is The actual severity factor for the cable 0.25/0.20.
could not be larger than 0.1; however, it could be less. If the detailed tables Specify the appropriate fuel loading in from Section 2 were used, the severity the example.
factor for this cable would be 0.07.
Typically, severity factors less than 0.02 are screened. These tables have values of less than 0.02 (e.g.
Tables 3-3 0.01). Recommend using a screen and 3-4 abbreviation when there is no external impact (e.g. SCRN). This could also be used in Tables 3-1 and 3-2 for clarity.
Recommend addressing the following portion of cabinet to cabinet damage approach discussed in Section S.2 of NUREG/CR-6850: "Assume no damage in the second adjacent cabinet occurs until after the fire propagates to the "No modifications are intended to the adjacent cabinet. Assume damage can existing guidance for determination of 4.1.4 (pdf pg occur earlier if there are large openings functional damage to equipment due to
- 88) in a wall and plenum areas in which a fire affecting cables and components hot gas layer is likely to form."
inside the electrical enclosures."
If damage is not postulated until after ignition, and the rules for ignition are now changing, confirm that the new rules for ignition do not invalidate the previous rule for damage based on ignition.
"3) The guideline and methods Can this be elaborated on? As in, what 4.1.4 (pdf pg described here are not intended to guidance should be followed for HEAF
- 88) apply to high energy arc fault (HEAF) scenarios or is this information expected fire scenarios." to be included in future testing?
4.2.2.1: "Double Wall" Section 9.2 configuration classification 4.2.2.1, should be changed from "Double wall air 4.2.3, & 9.2 9.2: "Cabinet to cabinet fire gap" to "Double Wall" for clarity and (Various propagation can be screened for the consistency with Sections 4.2.2.1 &
pages) following configurations:
4.2.3.
- Double wall air gap" This statement seems to be referring to fire spread along horizontal cable runs from one cabinet to another, however "As a result, for open-top enclosures that is not explicitly clear and could be 4.2.2.2 (pdf fire spread along horizontal cable runs misconstrued to mean open top pg 90) is considered unlikely." enclosures wouldn't ignite horizontal runs of cable that are outside the cabinet. Recommend adding some clarifying words to this statement.
For consistency and additional clarity revise the enclosure classifications to Recommend revising the terminology match between Sections 4.2.2.1, 4.2.3, of the following enclosure and 9.2.
4.2.3 (pdf pg classifications, as listed in 4.2.2.1
- Group 4c: Small Enclosure
- 94) and/or 4.2.3:
- Switchgear & Load Centers
- Small Enclosure Otherwise, "small enclosure" could be
- Switchgear mistakenly be thought to be engineering judgment.
43 "If additional resolution of HRR is required for the exposed cabinet, the As written, this is difficult to understand.
exposed cabinet have HRRs sample It is not clear what is meant by 'if from the upper 50 % of the exposed additional resolution of HRR is required.'
cabinet distribution. For example, if the Recommend rewording to better clarify exposed cabinet is a large, open, that the user has the flexibility to apply thermoplastic (TP) enclosure it could any HRR to the exposed enclosure HRR 4.4.2 (pdf pg be represented by a 1000 kW fire with as long as the HRR is greater than the 99) a severity factor of 1 or as a 1000 kW 50th percentile HRR using the gamma fire with a severity factor of 0.25 and distributions assigned in 2178.
392 kW fire with a severity factor of 0.75 (where 392 represents the upper Also, consider including an example of 75 % of the upper half of the this into Appendix D for additional clarity distribution or the 87.5th percentile on the application.
fire)."
NUREG-2230 growth profiles should be mentioned as an option. The exposed 4.4.2 cabinet growth should begin 10 minutes after growth starts in the exposing cabinet Assume the peak fire intensity for the As written, this sentence states that the exposing enclosure corresponds to the peak fire HRR from the exposing 98th percentile of the peak HRR enclosure corresponds to the HRR of the 4.5 (pg 4-16) distribution applicable to the exposing exposing enclosure, which is redundant.
enclosure (i.e., based on size, function, Consider rephrasing to remove the and/or fuel loading conditions). redundancy.
The guidance and analysis presented and described in this section apply Suggest adding Bin 9 (air compressors) 5.1 only to the determination and analysis as part of the analysis for electric motor of electrical fires in electric motors heat release rate and fire growth.
(bins 2, 14, 21, 26, and 32).
If the intent of this sentence is to convey "extensive damage to the ignition Only a small fraction, 2 events, 5.1.5.1 (pg source" as grounds for assuming threat describe fires that caused extensive 104) of external damage to targets outside the damage to the ignition source.
ignition source, it should be clearly noted.
Include the "<" symbol within the figures 5.1.5.2 (pg to denote less than the stated HP values Figures 5-1, 5-2, and 5-3 105) on the axes. Include axis bars on figure 5-3.
The wiring used in the rotor and stator 5.1.6.1 (pg are insulated with a coating that is Typo - Remove second " that is 110) assumed to be flammable. that is assumed to be flammable."
assumed to be flammable.
Based on a review of pictures showing the internal components of electric 5.1.6.1 (pg motors, the cables within an electric Sentence is unclear.
110) motor do not run the entire length of the motor casing is assumed to contain the cables and conductors.
Similar to the HRRs presented in Similar to the HRRs presented in NUREG/CR-6850 [1] and NUREG-2178 5.1.6.1 (pg NUREG/CR-6850 [1] and NUREG-
[2], this method utilizes a gamma 113) 2178 [2] utilize a gamma distribution is distribution which is selected for two selected for two reasons:
reasons:
- 2. It produces a good fit to the data 5.1.6.1 (pg Suggest more technical wording to while maintaining a similar technical 113) replace "good fit" within this justification.
approach as previously used.
In some cases, these temperature ratings are greater than the steady state failure criteria for thermoplastic If the intent of this sentence is for the 5.1.6.1 (pg. electrical cables, therefore it is analyst to assume thermoset cable 111) considered appropriate to treat the criteria, it should be clearly noted.
insulation as having superior performance relative to a thermoplastic cable.
It is unclear as to the purpose of this The feeder cable to the adjacent motor sentence. If the intent is to provide 5.1.7 (pg.
is routed directly behind and adjacent evidence that no external damage 118) to the ignition source. occurred during the described event, it should be clearly stated.
5.1.7 (pg. Stray paragraph break between lines 12 This is confirmed by investigation of 119) and 13 of this page.
5.1.8: "Growth: 2 minutes, t-squared 5.1.8 (pg 5- Fire growth duration of electric motors in growth"
- 18) Section 9.3.1 does not match what is 9.3.1: "Growth: 3 minutes, t-squared 9.3.1 (pg 9-2) provided in Section 5.1.8 growth" The scope of this evaluation does not The scope of this evaluation does not impact the treatment of fires in oil filed impact the treatment of fires in oil filled 5.2 (pg 120) transformers which are expected to transformers which are expected to have have substantially different burning substantially different burning characteristics due to the liquid fuel. characteristics due to the liquid fuel.
- 2. It produces a good fit to the data 5.2.6.1 (pg Suggest more technical wording to while maintaining a similar technical 130) replace "good fit" within this justification.
approach as previously used.
Specifically with the increase from 69kW Any increase in the ZOI due to the to 130 kW peak HRR, the plume ZOI for increase in the HRR following the thermoplastic targets increases by ~1.8 guidance provided in Table 5-8 ft and the radiant ZOI increases by ~9 5.2.6.1 (pg compared to the peak HRR following inches. Likewise, the thermoset plume 132) the guidance provided in NUREG/CR- ZOI increases by ~ 1.4ft and the radiant 6850 of 69 kW will be on the order of ZOI increases by ~6 inches. Suggest inches. clarification, plume ZOI changes by more than a matter of inches..
Up until this point in the report, fire diameter has been calculated using the guidance found in Section 4.2 of NUREG-2178 Volume 1 (i.e., enclosure footprint or assigning the characteristic fire diameter). It is not clear how equation 6-3 of this report was derived 6
nor is it clear what the heat flux value represents. Suggest using the guidance found in Section 4.2 of NUREG-2178 Volume 1 OR provide reference for equation and define what the heat flux variable is meant to represent and if a radiative fraction needs to be included.
The location factor is typically not used for calculating the fire diameter. Remove 6 (pg. 6-2; location factor from fire diameter Equation 6-3) equation. If location factor is necessary, provide justification.
Define traditional image method fire location factor or just state "traditional
"...different bias using both the fire location factor". Update key in 6 (pgs. 6-5, traditional image method fire location Figures 6-3 and 6-4 to include location 6-6, and 6-7) factor and the modified fire location factor in the description of each data set factor.."
or figure titles to include mention of location factor.
There is a dip in the temperature profile "The temperature profile presented in 6 (pg. 6-4, in Figure 6-1 and it is not addressed in Figure 6-1 remains primarily steady at line 12) the text. Include statement from NIST various distances from a wall surface" test which addresses this dip.
The first step uses the MCR suppression rate in Table 8-6 for calculations of the Pns with a floor value of 1E-03. This results in fires that are suppressed prior to approximately 18 minutes using a suppression rate of 0.385. The second step captures all Specify that the two-step method is to be 7.4 remaining MCR fire durations up to the used for sources in the MCR besides the (7-3) proposed floor of 2.4E-07 by making main control board use of the ignition source bin specific suppression rate. For example, a fire in a cabinet located within the MCR will use the Interruptible and Growing suppression rates presented in NUREG-2230 [62] for fire durations in excess of 18 minutes.
In Table 8-15 there are values for in-cabinet detection is credited that are worse than values in Table 8-14 where 8.6 (pg 8-34) there is no in-cabinet detection credited for the same enclosure type, which seems counterintuitive.
The data in Tables 8-14 and 8-15 appears to suggest that the Fraction of Fires that Spread to an Adjacent Panel
() is more severe for Thermoset cabinets than Thermoplastic cabinets, (e.g., 0.114 (TS) vs 0.078 (TP) in Table 8.6 (pg 8-34) 8-14 for 4a-Closed MCBs). This seems counterintuitive given that NUREG/CR-6850 and NUREG-2178 Volume 1 Suggest Thermoplastic fire HRRs/Severity factors are more severe than those of thermoset fires.
8.9 The manual suppression rate is The manual suppression rate is (8-39) defined as 0.385 min-1 from Table 8-7. mentioned in Table 8-6 The following growth, steady burning, Update statement to match Section and decay durations should be used 5.1.6.2, which states the fire growth for 9.3.1 for motor fires. electric motors is:
(9-2) Growth: 3 minutes, t-squared growth Growth: 2 minutes, t-squared growth Steady burning: 20 minutes Steady burning: 13 minutes Decay: 3 minutes, linear decay Decay: 2 minutes, linear decay
Section 7 discusses the background on the NSP floor and provides a basis for lowering the floor to 2.4E-7 for fire Add statement discussing two-step 9.5 scenarios in single unit MCRs. A method for calculation manual non-(9-4) revised floor value for dual unit MCRs suppression for non-MCB fires over 18 of 3.5E-07 is also recommended minutes in the MCR based on a sensitivity analysis for multi-unit control rooms.
Tables A-3, A-4, and A-5 refer to All references to NUREG/CR-6805 Appendix A NUREG/CR-6805. should be changed to 6850.
Do these values apply to Groups 1, 2, and 3 as well as Groups 4a and 4b?
There does not appear to be enough information to determine which groups Appendix B these apply to. Please clarify which groups these apply to and if not Groups 1, 2, and 3 then include updated tables for those groups.
Enclosures 4, 5, and 6 are discussed in this section, each of which are said to be 2178, Group 4b enclosures with default loading and based on Figure D-1, these 6 "Ignition in the Exposing enclosure enclosures would represent closed (Enclosure 5) will be assumed to take door configurations. However, the D.2.2 (pdf pg places at time = 0. The peak HRR of HRR that is identified is 325kW, which is 242) 325 kW will be reached after 12 the HRR for Group 4b, default loading minutes following a t2 growth profile with open doors.
per NUREG/CR-6850."
Either fix this by updating the HRR used in the example to match closed door configuration, or update the cabinet to specify that the cabinet has open doors.
Given the new NSP floor described in It is unclear how this should be applied Section 7, the numerical results for the relative to the growing/interruptible fires Page 8-16 Control Room suppression curve are described in section 7.4. If this version is presented in Table 8-7. strictly for Bin 4, this should be noted.
It would seem more practical for Based on this ZOI, the recommended application of this guidance to allow for a process consists of identifying targets grid or square approach of the same size Page 8-22 within circles of approximately 0.09 to be used to ensure all area of the m2 (1.0 ft2) throughout the surface of board is covered and simplify the the panel.
process.
20 kW is never explicitly stated as the limit in the discussion of previous recall that small fires under 20 kW are branches. If this is an equivalent based Page 8-24 explicitly modeled in earlier branches on the 1.0 ft2 ZOI, the inputs for this of the scenario progression event tree should be given such as TP or TS cable assumed, radiatvie or plume target assumed, etc.
Calculation of fire ignition frequencies Does this include the location weighting for each panel within the MCB. The Page 8-3 factor from 6850? i.e. factor of 2 for a 2 ignition frequency for this screening unit plant with 1 MCR.
process is a multiplication of For this example, since the rear MCB panels are counted separately, it would Pages 8 8.3.2.2 Frequency Apportionment be useful to have an image of what the 8-14 Example 2 rear side looks like to illustrate the point.
The current images in Figure 8-6 and 8-7 are only front side images.
The ratio of the two is 2.1 (57.5/27.3).
Section The 2.2 value may have mistakenly been 2.2.3.1 (pg The ratio of these two is 2.2.
taken from the area of the cylinder.
38)
Update paragraph to use 2.1.
It is not clear how the ZOI is to be calculated once an adjusted emissivity is This results in horizontal ZOIs of 1.65 calculated. Clarify that when using m (5.4 ft) and 0.93 m (3.1 ft) from the method 2 of Section 2.2.3.1 (i.e., heat Section 2.3.1 edge of the fire respectively for the TP flux ratio), the analyst should use the (pg 44)
(6 kW/m2) and TS threshold damage Solid Flame 2 tab of FDT 05.1 and fluxes (11 kW/m2). assume the target is located at a height of 1/2 the flame height (i.e., bounding case).
The first step uses the MCR suppression rate in Table 8-6 for calculations of the Pns with a floor value of 1E-03. This results in fires that are suppressed prior to approximately Section 7.4, 18 minutes using a suppression rate of Figure 7-1, 0.385. The second step captures all Provide equations so the values in Table and Table 7- remaining MCR fire durations up to the 7-2 can be replicated. Statement is 2 proposed floor of 2.4E-07 by making unclear how to apply the two-step (7-3, 7-4, and use of the ignition source bin specific calculation 7-5) suppression rate. For example, a fire in a cabinet located within the MCR will use the Interruptible and Growing suppression rates presented in NUREG-2230 [62] for fire durations in excess of 18 minutes.
The number of significant figures shown varies within a column. For example, the flame height of the small cabinet reports Table 2-1 the measurement in meters to the (pg35) hundredths place and the 378.5 liter oil spill only reports to the ones place.
Make number of significant figures shown within a given column consistent.
The Distance for Heat Flux values presented do not take into account the fire diameter, D. Based on the equation presented in Figure 2-1 and FDT 05.1, the values calculated should have D/2 Table 2-1 subtracted. Update values OR add (pg35) assumption that the area is assumed 0.
If fire diameter is included, update Section 2.2.1 pertaining to Distance Ratio to discuss highest ratio of 1.93 following the update to Figure 2-1.
The Adjusted FDT ZOI values given for Table 2-5 (pg the 1000kW fire do not match with those
- 67) provided in Section 2.3.1. Make values consistent.
It is not clear which FDT (i.e., adjusted or unadjusted) was used to populate the Table 3-3 numbers in Table 3-3, Table 3-4 and and Table 3- Table 3-9. Provide documentation of 4 (pg 76) and which FDT was used.
Table 3-9 (pg
Since this an MCB specific analysis, reference to the radiative fraction of Table 8-10 0.3 lTypical fire radiant fraction typical cable materials should be made to ensure this radiant fraction is acceptable.
Table 8-17 Manual suppression rate constant from Update statement to reference Section and 8-18 Section 8.3.2 8.3.3