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e, PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 | e, PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 | ||
.215)841-4502 JOHN S. KEMPER vic ua rsio c"' | |||
June 25, 1986 E NGINEE RING AND RESE ARCH Mr. Daniel R. Muller, Director Docket Nos: | |||
50-277 BWR Project Directorate #2 50-278 Division of BWR Licensing U.S. Nuclear Regulatory Commission Washington, D.C. | |||
20555 | |||
==Subject:== | ==Subject:== | ||
| Line 28: | Line 31: | ||
==Dear Mr. Muller:== | ==Dear Mr. Muller:== | ||
Enclosed are responses to the Requests for Additional Information (RAIs) transmitted in the reference letter. | Enclosed are responses to the Requests for Additional Information (RAIs) transmitted in the reference letter. | ||
A site visit was held February 24, with the NRC staff and consultants, at which time several of these responses were discussed and field conditions were reviewed. | A site visit was held February 24, with the NRC staff and consultants, at which time several of these responses were discussed and field conditions were reviewed. | ||
| Line 34: | Line 36: | ||
Sincerely, | Sincerely, | ||
[f l - | [f l - | ||
/ | |||
GJR/dmm/04038601 J | GJR/dmm/04038601 J | ||
Enclosure (1) | Enclosure (1) | ||
Copy to: | Copy to: | ||
Dr. T. E. Murley Administrator, Region 1 T. P. Johnson, Resident Inspector h | |||
NRC Document Control Desk 0 | |||
i t | |||
8607090288 860625 PDR ADOCK 05000277 F | |||
PDR | |||
O PHILADELPHIA ELECTRIC COMPANY MECHANICAL ENGINEERING N2-1 2301 Market Street Request for InformatIon (RAI) | O PHILADELPHIA ELECTRIC COMPANY MECHANICAL ENGINEERING N2-1 2301 Market Street Request for InformatIon (RAI) | ||
Appendix R Exemption Requests Peach Bottcm Atmic Power Stations Units 2 and 3 Docket Nos. 50-277 and 50-278 Question 280.1: | Appendix R Exemption Requests Peach Bottcm Atmic Power Stations Units 2 and 3 Docket Nos. 50-277 and 50-278 Question 280.1: | ||
The statement is made on page 4 of the September 24 letter that "an exemption is requested from the requirement for a fixed suppression system in Fire Areas 8 and 50." Page 5 of the same exemption states " Essentially,..., this proposed exemption requests that the wall at el. 195' be considered equivalent to a three-hour barrier for purposes of separating two fire areas." | The statement is made on page 4 of the September 24 letter that "an exemption is requested from the requirement for a fixed suppression system in Fire Areas 8 and 50." | ||
Page 5 of the same exemption states " Essentially,..., this proposed exemption requests that the wall at el. 195' be considered equivalent to a three-hour barrier for purposes of separating two fire areas." | |||
Clarify the specific Intent of this exemption request. | Clarify the specific Intent of this exemption request. | ||
===Response=== | ===Response=== | ||
The exemption is requested from the requirement of Section III.G.2.b which allows an alternative of 20 feet with no intervening ccrrbustibles, and detection and suppression in lieu | The exemption is requested from the requirement of Section III.G.2.b which allows an alternative of 20 feet with no intervening ccrrbustibles, and detection and suppression in lieu of a three-hour fire barrier. The specific exerrption is from installing the sprinkler system. The vertical separation between redundant safe shutdown equipment approaches 85 feet, not to mention the non-rated barriers constricting propagation of a fire. A fire would have to start at the barrier in question, propagate down one elevation in the Reactor Building and three elevations on the Turbine Building side to affect redundant safe shutdown equipment. Fire detection is provided in all safety-related areas. Addition of a sprinkler system for each area would essentially mean sprinkling most of both the Reactor and Turbine Buildings. Application of local sprinklers at the barrier is not warranted due to the minimal conbustible loading. | ||
Question 280.2: | |||
On page 4 of the Structural Steel Survivability Analysis, it is stated that fixed ventilation systens are assumed not to contribute to the ventilation rate, since installed fire dampers will actuate. To facilitate the staff's review, provide the following: | On page 4 of the Structural Steel Survivability Analysis, it is stated that fixed ventilation systens are assumed not to contribute to the ventilation rate, since installed fire dampers will actuate. To facilitate the staff's review, provide the following: | ||
Confirm that all ventilation openings through boundaries a. | |||
used in the analysis are provided with fire dampers (Ex. | |||
Fire Area 50, el. 195'). | Fire Area 50, el. 195'). | ||
b. | |||
Response; | Discuss the impact on the analysis of fire dampers renalning open until they reach actuation tanperature. | ||
Response; There are many cases where fixed ventilation systens installed a. | |||
through barriers used in the analysis are not provided with fire dampers. The reference section of the methodology reflects how plant ventilation conditions are considered at rated fire barriers. The methodology does not address the following: | |||
1. | |||
Approved or pending exemption requests which justify the elimination of the requirement to Install fire dampers in specific ventilation openings. | |||
2. | |||
Conditions where the ceiling is a rated fire barrier but the compartment below where the exposure fire would originate is not surrounded by rated fire barriers. Ventilation openings in these non-rated barriers would not necessarily be provided with fire dampers. | |||
As detailed below, these ventilation openings are unimportant to the analysis and may be ignored. | As detailed below, these ventilation openings are unimportant to the analysis and may be ignored. | ||
b. | |||
The analysis assumes that ventilation is supplied through one or more fully open unobstructed doors, it further assumes that no heat is lost either by products of combustion leaving the compartment or by radiation through any opening. With these conservative assumptions, other smaller ventilation openings become unimportant and can be ignored. This is particularly so when ventilation openings are located at higher elevations in a compartnent. | |||
In this case, the openings would be above the neutral plane of a fire in the room, generally 1/3 the door height off the floor, and would act only as a vent and not as a supply of combustion air. Additionally, our experience has been that the plant fire protection personnel generally will trip the ventilation systen until a fire is controlled and smoke removal is started. | |||
_3_ | _3_ | ||
Question 280.3: | Question 280.3: | ||
The description of Fire Areas 8 and 50 in the Septenber 24, 1985, letter (page 6) describes the location of safe shutdown ccmponents, equipment, and circuits. They are located on the lower elevations of Fire Area 8 (el .135' and 165') and lower elevations of Fire Area 50 Cel. 116' and below). Provide the following: | The description of Fire Areas 8 and 50 in the Septenber 24, 1985, letter (page 6) describes the location of safe shutdown ccmponents, equipment, and circuits. They are located on the lower elevations of Fire Area 8 (el.135' and 165') and lower elevations of Fire Area 50 Cel. 116' and below). Provide the following: | ||
a. | |||
Describe the fire protection systens on the elevations containing these safe shutdown components, equipment, and circuits. | |||
b. | |||
Identify the closest spatial separation between redundant safe shutdown conponents or circuits. | |||
c. | |||
Describe any intervening carbustibles near the open penetrations on el. 195'. | |||
The description should address the open stair in Fire Area 8. | |||
===Response=== | ===Response=== | ||
a. | |||
The fire protection systens are as described in the Septenber 23, 1985, letter, Section D. | |||
" Fire Protection Syst sW'. | |||
b. | |||
The safe shutdown equipnent is shown on attached sketches (Attachnents A and B). | |||
The load centers that feed the notor control centers for the RHR valves are located on elevation 165' on the J-line wall. | The load centers that feed the notor control centers for the RHR valves are located on elevation 165' on the J-line wall. | ||
(See Attachment A.) This equipnent is approximately 50 feet from the open hatch. | (See Attachment A.) This equipnent is approximately 50 feet from the open hatch. | ||
The redundant shutdown equipment is shown on the attached sketch B and consists of power feeds in conduits that drop out of the bottan of the switchgear rooms (elevation 135') | The redundant shutdown equipment is shown on the attached sketch B and consists of power feeds in conduits that drop out of the bottan of the switchgear rooms (elevation 135') | ||
and run beloa elevation 116', The conduits are at least 25 feet from the open turbine building hatch, and this hatch is 150 feet fran the J-line wall . | and run beloa elevation 116', | ||
Taking credit for non-rated walls, there is 340 feet between the redundant shutdown equipnent. Not taking credit for non-rated walls, and performing calculations on the closest diagonals results in separation of 90 feet, | The conduits are at least 25 feet from the open turbine building hatch, and this hatch is 150 feet fran the J-line wall. | ||
Taking credit for non-rated walls, there is 340 feet between the redundant shutdown equipnent. Not taking credit for non-rated walls, and performing calculations on the closest diagonals results in separation of 90 feet, c. | |||
ventilation equipnent on a mezzanine level above. At this elevation, the connon wall is adjacent to the Turbine Building roof. | The extent of the conbustible loading is six cable trays on the Turbine Building side of the barrier in question. The open stalrway on the Reactor Building side leads to nore ventilation equipnent on a mezzanine level above. At this 4 | ||
elevation, the connon wall is adjacent to the Turbine Building roof. | |||
Question 280.4: | . Question 280.4: | ||
On page 4 of the {{letter dated|date=May 23, 1985|text=May 23, 1985, letter}}, the IIcensee requests exenption from the requirements of Section III.G.2 for two ventilation penetrations based on minimal combustible loading and radiological plant safety concerns. Sufficient information is not provided to evaluate this exemption. Describe the location of redundant safe shutdown equipment with respect to these openings. Provide additional information on the level of fire protection in this area to justify that the existing level of fire protection provides a level of safety equivalent to that required by Appendix R. | On page 4 of the {{letter dated|date=May 23, 1985|text=May 23, 1985, letter}}, the IIcensee requests exenption from the requirements of Section III.G.2 for two ventilation penetrations based on minimal combustible loading and radiological plant safety concerns. | ||
Sufficient information is not provided to evaluate this exemption. Describe the location of redundant safe shutdown equipment with respect to these openings. | |||
Provide additional information on the level of fire protection in this area to justify that the existing level of fire protection provides a level of safety equivalent to that required by Appendix R. | |||
===Response=== | ===Response=== | ||
| Line 87: | Line 109: | ||
d | d | ||
_5_ | |||
Question 280.5: | Question 280.5: | ||
On page 11 of the Structural Steel Survivability Analysis, the IIcensee states that the model conservatively asstanes that no heat is lost through the floor only. | On page 11 of the Structural Steel Survivability Analysis, the IIcensee states that the model conservatively asstanes that no heat is lost through the floor only. | ||
a. | |||
Provide the basis for including the total wall surface area for heat loss considering the depth of the hot gas layer and the doors asstrned open during the analysis, b. | |||
Response; | Describe the sensitivity of the analysis to varying heat sink surface areas. | ||
For extrnple, how do the results vary for concrete heat sink surface areas consisting of the area of the ceiling and the area of the walls above the opened doors. | |||
The worst case heat release rate used was based on this conbustion air flow rate. For the higher cellings fcund in the plant, the removal of the wall surface below the neutral plane would have little effect on the results based on the other conservatism built into the methodology, | Response; a. | ||
The basis for including total wall surface area and excluding floor surfaces for calculating the total heat loss surface was two fold. First, the primary heat transfer mechanism to the rocm surfaces is radiation, not convection. The " hot layer" need not be in direct contact with the walls to transfer heat to it. | |||
The floor was excluded because of the effect of convective cooling by the influx of combustion air. Although this cooling will be less than the heating, the conservative asstrnption of no heat loss through the floor was made. Secondly, the worst case ventilation controlled fire will create a neutral plane approximately one third of the door height above the floor. | |||
The worst case heat release rate used was based on this conbustion air flow rate. For the higher cellings fcund in the plant, the removal of the wall surface below the neutral plane would have little effect on the results based on the other conservatism built into the methodology, b. | |||
The sensitivity of the compartment temperature result to heat sink surface area is virtually linear (T is inversely 9 | |||
proportional to A ). | |||
The effects on specific results of removing the lower portions of the room from the heat loss surface as an additional conservatism would depend on room geometry. For exanple, in a compartment 40' wide by 60' long by 20' high, the change in heat loss area would be 7.3%. | |||
For the same compartment with a 10' ceiling height, the change in heat loss area would be 10.6%. To put this in proper perspective, however, compared to the methodology asstrnption of no convective heat loss, Harmathy reports convective losses to be between 50 to 90% of the tntal heat released. Addition or deletion of that percentage of the wall area below the hot layer has little or no effect on resultant room temperature. | |||
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Latest revision as of 04:07, 8 December 2024
| ML20199K986 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom |
| Issue date: | 06/25/1986 |
| From: | Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Muller D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8607090288 | |
| Download: ML20199K986 (8) | |
Text
{{#Wiki_filter:_ - - _ _ _ _ _ - _ e, PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 .215)841-4502 JOHN S. KEMPER vic ua rsio c"' June 25, 1986 E NGINEE RING AND RESE ARCH Mr. Daniel R. Muller, Director Docket Nos: 50-277 BWR Project Directorate #2 50-278 Division of BWR Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Request for Additional Information (RAI) Concerning Peach Bottom Appendix R, Structural Steel Issues
Reference:
Letter G. E. Gears to E. G. Bauer, Jr., dated March 13, 1986
Dear Mr. Muller:
Enclosed are responses to the Requests for Additional Information (RAIs) transmitted in the reference letter. A site visit was held February 24, with the NRC staff and consultants, at which time several of these responses were discussed and field conditions were reviewed. We trust that the informat an obtained during your visit and these responses to the RAIs will resolve any outstanding questions and/or concerns regarding Philadelphia Electric Company's Appendix R exemption requests and the structural steel survivability analysis. Sincerely, [f l - / GJR/dmm/04038601 J Enclosure (1) Copy to: Dr. T. E. Murley Administrator, Region 1 T. P. Johnson, Resident Inspector h NRC Document Control Desk 0 i t 8607090288 860625 PDR ADOCK 05000277 F PDR
O PHILADELPHIA ELECTRIC COMPANY MECHANICAL ENGINEERING N2-1 2301 Market Street Request for InformatIon (RAI) Appendix R Exemption Requests Peach Bottcm Atmic Power Stations Units 2 and 3 Docket Nos. 50-277 and 50-278 Question 280.1: The statement is made on page 4 of the September 24 letter that "an exemption is requested from the requirement for a fixed suppression system in Fire Areas 8 and 50." Page 5 of the same exemption states " Essentially,..., this proposed exemption requests that the wall at el. 195' be considered equivalent to a three-hour barrier for purposes of separating two fire areas." Clarify the specific Intent of this exemption request.
Response
The exemption is requested from the requirement of Section III.G.2.b which allows an alternative of 20 feet with no intervening ccrrbustibles, and detection and suppression in lieu of a three-hour fire barrier. The specific exerrption is from installing the sprinkler system. The vertical separation between redundant safe shutdown equipment approaches 85 feet, not to mention the non-rated barriers constricting propagation of a fire. A fire would have to start at the barrier in question, propagate down one elevation in the Reactor Building and three elevations on the Turbine Building side to affect redundant safe shutdown equipment. Fire detection is provided in all safety-related areas. Addition of a sprinkler system for each area would essentially mean sprinkling most of both the Reactor and Turbine Buildings. Application of local sprinklers at the barrier is not warranted due to the minimal conbustible loading.
Question 280.2: On page 4 of the Structural Steel Survivability Analysis, it is stated that fixed ventilation systens are assumed not to contribute to the ventilation rate, since installed fire dampers will actuate. To facilitate the staff's review, provide the following: Confirm that all ventilation openings through boundaries a. used in the analysis are provided with fire dampers (Ex. Fire Area 50, el. 195'). b. Discuss the impact on the analysis of fire dampers renalning open until they reach actuation tanperature. Response; There are many cases where fixed ventilation systens installed a. through barriers used in the analysis are not provided with fire dampers. The reference section of the methodology reflects how plant ventilation conditions are considered at rated fire barriers. The methodology does not address the following: 1. Approved or pending exemption requests which justify the elimination of the requirement to Install fire dampers in specific ventilation openings. 2. Conditions where the ceiling is a rated fire barrier but the compartment below where the exposure fire would originate is not surrounded by rated fire barriers. Ventilation openings in these non-rated barriers would not necessarily be provided with fire dampers. As detailed below, these ventilation openings are unimportant to the analysis and may be ignored. b. The analysis assumes that ventilation is supplied through one or more fully open unobstructed doors, it further assumes that no heat is lost either by products of combustion leaving the compartment or by radiation through any opening. With these conservative assumptions, other smaller ventilation openings become unimportant and can be ignored. This is particularly so when ventilation openings are located at higher elevations in a compartnent. In this case, the openings would be above the neutral plane of a fire in the room, generally 1/3 the door height off the floor, and would act only as a vent and not as a supply of combustion air. Additionally, our experience has been that the plant fire protection personnel generally will trip the ventilation systen until a fire is controlled and smoke removal is started.
_3_ Question 280.3: The description of Fire Areas 8 and 50 in the Septenber 24, 1985, letter (page 6) describes the location of safe shutdown ccmponents, equipment, and circuits. They are located on the lower elevations of Fire Area 8 (el.135' and 165') and lower elevations of Fire Area 50 Cel. 116' and below). Provide the following: a. Describe the fire protection systens on the elevations containing these safe shutdown components, equipment, and circuits. b. Identify the closest spatial separation between redundant safe shutdown conponents or circuits. c. Describe any intervening carbustibles near the open penetrations on el. 195'. The description should address the open stair in Fire Area 8.
Response
a. The fire protection systens are as described in the Septenber 23, 1985, letter, Section D. " Fire Protection Syst sW'. b. The safe shutdown equipnent is shown on attached sketches (Attachnents A and B). The load centers that feed the notor control centers for the RHR valves are located on elevation 165' on the J-line wall. (See Attachment A.) This equipnent is approximately 50 feet from the open hatch. The redundant shutdown equipment is shown on the attached sketch B and consists of power feeds in conduits that drop out of the bottan of the switchgear rooms (elevation 135') and run beloa elevation 116', The conduits are at least 25 feet from the open turbine building hatch, and this hatch is 150 feet fran the J-line wall. Taking credit for non-rated walls, there is 340 feet between the redundant shutdown equipnent. Not taking credit for non-rated walls, and performing calculations on the closest diagonals results in separation of 90 feet, c. The extent of the conbustible loading is six cable trays on the Turbine Building side of the barrier in question. The open stalrway on the Reactor Building side leads to nore ventilation equipnent on a mezzanine level above. At this 4 elevation, the connon wall is adjacent to the Turbine Building roof.
. Question 280.4: On page 4 of the May 23, 1985, letter, the IIcensee requests exenption from the requirements of Section III.G.2 for two ventilation penetrations based on minimal combustible loading and radiological plant safety concerns. Sufficient information is not provided to evaluate this exemption. Describe the location of redundant safe shutdown equipment with respect to these openings. Provide additional information on the level of fire protection in this area to justify that the existing level of fire protection provides a level of safety equivalent to that required by Appendix R.
Response
The ducts in question pass through a fire barrier between a duct chase located in the Remote Shutdown panel Area and the Radwaste Building HVAC Equipment Area. There are safety related cables within the duct chase on the remote shutdown panel side of the barrier. There are no safety related or safe shutdown components on the other side of the barrier, the 150' elevation of the Radwaste Building. Alternative Shutdown capability has been designed for a fire in the area of the duct chasa; and thereforc none of the cables or equipment are required for safe shutdown. The RW Building HVAC Equipment Area contains a minimal amount of fixed conbustibles. No fire detection is provided. Two dry chemical extinguishers are provided along with a hose reel in the area. The Remote Shutdown Panel Area is provided with four Ionization type smoke detectors. A modification is In progress to Install line type heat detection in the cable tray in the Remote Shutdown Panel Area. The room is provided with a hose reel, three CO extinguishers, and four dry chemical extinguishers.2 The ductwork at the penetration locations is 10 gauge welded construction, essentially the same thickness as one Inch schedule 40 steel pipe.
d _5_ Question 280.5: On page 11 of the Structural Steel Survivability Analysis, the IIcensee states that the model conservatively asstanes that no heat is lost through the floor only. a. Provide the basis for including the total wall surface area for heat loss considering the depth of the hot gas layer and the doors asstrned open during the analysis, b. Describe the sensitivity of the analysis to varying heat sink surface areas. For extrnple, how do the results vary for concrete heat sink surface areas consisting of the area of the ceiling and the area of the walls above the opened doors. Response; a. The basis for including total wall surface area and excluding floor surfaces for calculating the total heat loss surface was two fold. First, the primary heat transfer mechanism to the rocm surfaces is radiation, not convection. The " hot layer" need not be in direct contact with the walls to transfer heat to it. The floor was excluded because of the effect of convective cooling by the influx of combustion air. Although this cooling will be less than the heating, the conservative asstrnption of no heat loss through the floor was made. Secondly, the worst case ventilation controlled fire will create a neutral plane approximately one third of the door height above the floor. The worst case heat release rate used was based on this conbustion air flow rate. For the higher cellings fcund in the plant, the removal of the wall surface below the neutral plane would have little effect on the results based on the other conservatism built into the methodology, b. The sensitivity of the compartment temperature result to heat sink surface area is virtually linear (T is inversely 9 proportional to A ). The effects on specific results of removing the lower portions of the room from the heat loss surface as an additional conservatism would depend on room geometry. For exanple, in a compartment 40' wide by 60' long by 20' high, the change in heat loss area would be 7.3%. For the same compartment with a 10' ceiling height, the change in heat loss area would be 10.6%. To put this in proper perspective, however, compared to the methodology asstrnption of no convective heat loss, Harmathy reports convective losses to be between 50 to 90% of the tntal heat released. Addition or deletion of that percentage of the wall area below the hot layer has little or no effect on resultant room temperature. GJR/dnm/04298605
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