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{{#Wiki_filter:DUKE Steven D. Capps~ Vice President ENERGY° McGuire Nuclear | {{#Wiki_filter:DUKE Steven D. Capps~ Vice President ENERGY° McGuire Nuclear Station Duke Energy MG01VP I112700 Hagers Ferry Road Huntersville, NC 27078 o: 980.875.4805 f: 980.875.4809 Steven.Capps@duke-energy.com Serial No. MNS-16-023 March 16, 2016 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 | ||
==SUBJECT:== | ==SUBJECT:== | ||
Duke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station (MNS), Units 1 and 2 Docket Numbers 50-369 and 50-370, Renewed Facility Operating License NPF-9 and NPF-17 Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 Renewed Facility Operating License NPF-35 and NPF-52 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications | |||
Duke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station (MNS), Units 1 and | |||
==REFERENCES:== | ==REFERENCES:== | ||
: 1. Letter from Steven D. Capps (Duke Energy) to NRC (Serial: | : 1. Letter from Steven D. Capps (Duke Energy) to NRC (Serial: MNS-16-002), dated January 7, 2016 (ADAMS Accession Number ML16029A077), Proposed Technical Specifications (TS) Amendment TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3. 7.11, "Control Room Area Chilled Water System" (CNS)2. NRC letter from G. Edward Miller to Steven D. Capps (Duke Energy), dated March 1, 2016 (ADAMS Accession Number ML1 6055A333), McGuire Nuclear Station, Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 -Supplemental Information Needed For Acceptance of Requested Licensing Action RE: License Amendment Request for Control Room Chilled Water System Technical Specifications (TAC Nos.MF7224, MF7225, MF7226, and MF7227) | ||
MNS-16-002), | U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 2 By letter dated January 7, 2016 (Reference 1), Duke Energy submitted a License Amendment Request (LAR) for Technical Specifications (TS) TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3.7.11, "Control Room Area Chilled Water System" (CNS).The NRC staff reviewed the LAR and determined that supplemental information is needed regarding the acceptability of the proposed LAR in terms of regulatory requirements and the protection of public health and safety and the environment. | ||
By letter dated March 1, 2016 (Reference 2), the supplemental information was requested. | |||
Proposed Technical Specifications (TS) Amendment TS 3. 7.10, "Con trol Room Area Chilled Water System"(MNS), and TS 3. 7.11, "Control Room Area Chilled Water System" (CNS)2. NRC letter from G. Edward Miller to Steven D. Capps (Duke Energy), | |||
McGuire Nuclear Station,Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 -Supplemental Information Needed For Acceptance of Requested Licensing Action RE: License Amendment Request for Control Room Chilled Water System Technical Specifications (TAC Nos.MF7224, MF7225, MF7226, and MF7227) | |||
U.S. Nuclear Regulatory Commission MNS-1 6- | |||
By letter dated March 1, 2016(Reference 2), the supplemental information was requested. | |||
The supplemental information requires submission by March 17, 2016. The Duke Energy responses to the supplemental information are provided in the Enclosure to this letter.The conclusions of the original Significant Hazards Consideration and Environmental Considerations contained in the January 7, 2016, LAR (Reference | The supplemental information requires submission by March 17, 2016. The Duke Energy responses to the supplemental information are provided in the Enclosure to this letter.The conclusions of the original Significant Hazards Consideration and Environmental Considerations contained in the January 7, 2016, LAR (Reference | ||
: 1) are unaffected as a | : 1) are unaffected as a result of this supplemental response.Pursuant to 10 CER 50.91, a copy of this LAR supplement is being provided to the appropriate States of North and South Carolina officials. | ||
Pursuant to 10 CER 50.91, a copy of this LAR supplement is being provided to the appropriate States of North and South Carolina officials. | |||
There are no regulatory commitments contained in this letter or its enclosure. | There are no regulatory commitments contained in this letter or its enclosure. | ||
If you have any questions or need additional information on this matter, please | If you have any questions or need additional information on this matter, please contact Lee A. Hentz at (980) 875-4187.I declare under penalty of perjury that the foregoing is true and correct. Executed on March 16, 2016.Sincerely, Steven D. | ||
I declare under penalty of perjury that the foregoing is true and correct. | |||
Executed | |||
==Enclosure:== | ==Enclosure:== | ||
Response to Supplemental Information U.S. Nuclear Regulatory Commission MNS-1 6- | Response to Supplemental Information U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 3 cc: (with enclosure) | ||
Catherine | Catherine Haney Regional Administrator U.S. Nuclear Regulatory Commission | ||
-Region | -Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1 257 G.A. Hutto Ill (Catawba)Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear Station J. Zeiler Senior Resident Inspector (McGuire)U.S. Nuclear Regulatory Commission McGuire Nuclear Station G.E. Miller NRC Project Manager (McGuire)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8-G9A 111555 Rockville Pike Rockville, MD 20852-2738 J.A. Whited Project Manager (Catawba)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 B1A 11555 Rockville Pike Rockville, MD 20852-2738 S.E. Jenkins Manager Radioactive | ||
Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear | & infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.Columbia, SC 29201 W.L. Cox, IlI Section Chief, Division of Environmental Health Radiation Protection Section North Carolina Department of Environment and Natural Resources 1645 Mail Service Center Raleigh, NC 27699 U.S. Nuclear Regulatory Commission M NS-1 6-023 Enclosure 1 Page 1 of 3 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications By letter dated January 7, 2016 (Agencywide Documents Access and Management System Accession No. ML 16029A077), Duke Energy Carolinas, LLC (Duke Energy or the licensee), submitted a license amendment request for McGuire Nuclear Station, Units 1 and 2 (MNS 1 and 2) and Catawba Nuclear Station, Units 1 and 2 (CNS 1 and 2). The proposed amendment would modify the Control Room Area Chilled Water System Technical Specifications to allow a finite time to address a loss of both trains provided Control Room temperature remains below 90°F.The NRC staff has reviewed your application and concluded that the information delineated below is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed amendment in terms of regulatory requirements and the protection of public health and safety and the environment. | ||
U.S. Nuclear Regulatory Commission McGuire Nuclear | For MNS and CNS NRC Question 1 With both trains of the Control Room Area Chilled Water System inoperable, the effects of heat stress due to the rising temperature, under some circumstances, may impede the operators' ability to take actions required to safely operate the nuclear power unit. From a human factors perspective, please describe any effects that the proposed change may have on the control room operators. | ||
U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8- | In this description, include a justification that any impacted persons will still be able to successfully perform their job role.Duke Energy Response to Question 1 This question was further clarified during the March 1, 2016, conference call between the NRC Staff and Duke Energy: "What would be the impact on the Control Room Operators if the Control Room remained at or near 90°F for the duration of the proposed Condition B Completion Time of 24 hours." Duke Energy has in place an Administrative Procedure, "Heat and Cold Stress," based on an industry standard, that evaluates activities which expose workers to adverse environmental conditions and provides means and methods to avoid heat stress related health incidents. | ||
U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 | Control Room activities can be considered "Light work: sitting or standing with moderate arm or trunk movement, monitoring equipment, minimal walking." Per the Procedure's "Stay Time Chart," there are no stay time limits for light work up to a wet bulb globe temperature (WBGT) of 90°F. Stay time is defined as the recommended amount of time that a worker is expected to safely work in a moderate to high heat environment. | ||
& infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental | Control Room temperature is measured as a dry bulb temperature, meaning the impacts from humidity are not accounted for as they are with WBGT. Low humidity impacts dry bulb temperatures positively, thus the WBGT will equate to a lower temperature than the measured U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 2 of 3 dry bulb. Conversely, very high humidity (90-100%) | ||
Duke Energy Carolinas, LLC (Duke Energy or the licensee), | impacts dry bulb temperatures negatively, thus the WBGT will equate to a higher temperature than the measured dry bulb.During a loss of cooling event in the Control Room, there would not be an appreciable increase in humidity as temperature rises since mnost of the Control Room heat load is in the form of sensible heat. Latent heat, which drives humidity, accounts for only a fraction of the total room heat load. Thus, high humidity levels in the Control Room are not a concern for MNS or CNS.This means that the currently measured dry bulb temperature would be comparable to the WBGT, and there are no mandated stay time restrictions as long as the Control Room temperature remains 90°F or less.From a human factors perspective, based on the above considerations, the proposed change will have no adverse impact on Control Room Operators. | ||
submitted a license amendment request for McGuire Nuclear Station, Units 1 and 2 (MNS 1 | The effects of rising temperature in the Control Room should not impede the Operators' ability to take actions required to safely operate the nuclear power unit.Duke Energy also has readily available instruments that easily measure WBGT. These are available close to the Control Room and do not require any specific qualifications. | ||
For MNS and | Their set-up and use are described in the "Heat and Cold Stress" procedure. | ||
In this description, include a justification that any impacted persons will still | As such, an exact determination of Control Room WBGT can easily be determined. | ||
based on | In addition, Operator shifts are limited to 12 hours. Supplemental staffing can be provided to allow Operators to periodically rotate during shifts if the need arises.NRC Question 2 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less, verified every 12 hours. This value was determined assuming that at least one train of the Control Room Area Chilled Water System was available for active removal of heat. When in the proposed Condition B, the ability to remove heat from the Control Room would be significantly reduced. Although it appears that the increased frequency of verification of Control Room temperature (i.e., every 4 hours) is meant to account for this, the submittal does not address why it is adequate. | ||
Please provide a quantitative justification for the 4 hour surveillance interval and how the 90°F limit remains valid given potentially increased Control Room heat-up rates.Duke Energy Response to Question 2 The four hour monitoring frequency of Control Room temperature when in the proposed Condition B was predominately based on remaining consistent with NRC approved TSTF-477 Rev.3 and draft TSTF-553. | |||
Control Room activities can be considered "Light work: sitting or standing with moderate arm | As the Control Room is continuously occupied, any temperature changes would be immediately recognized by the Operators. | ||
Per the Procedure's "Stay | MNS and CNS have in place "Abnormal Procedures" (AP) to take mitigating actions when Control Room temperature reaches 80°F and take actions to shutdown the affected Units if temperature rises above 90°F. | ||
Control Room temperature is measured as a dry bulb temperature, meaning the impacts | U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 3 of 3 The MNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, chill water supply temperature increasing (alarms at 55°F), or Control Room supply air temperature increasing (alarms at 75°F). Once the AP is entered, MNS Control Room temperature is monitored continuously. | ||
impacts dry bulb temperatures negatively, thus the WBGT will equate to a higher temperature than the measured dry bulb.During a loss of cooling event in the Control Room, there would not be an appreciable | The CNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, Control Room Air Handling Unit (AHU) low flow alarm, Control Room Chiller "off'alarm or "critical trouble" alarm. If the CNS Control Room reaches 80°F, temperature is monitored continuously until one train of Control Room Area Chilled Water System (CRACWS)is restored.In summary, MNS and CNS enter the applicable AP for "Control Room High Temperature" prior to any significant increase in Control Room temperature or early symptoms of CRACWS equipment malfunctions. | ||
The effects of rising temperature | Once the APs are entered, Control Room temperature is continuously monitored with specific actions to be taken at 80°F and 90°F. These AP actions satisfy the intent of proposed Action B.1 and the associated Completion Time of four hours.As stated in Section 3.6 of the LAR, the most likely application of proposed Condition B and the associated Required Actions is when both CRACWS trains are inoperable but one train is functional with the ability to cool the Control Room. In this case, the Control Room temperature would remain constant at a normal value, and the 90°F limit is not challenged. | ||
Their set- | For CNS NRC Question 3 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less. The submittal also indicates that, while the temperature control band for MNS is 75°F to 900°F, the band for CNS is 72°F to 850°F. Please clarify the apparent discrepancy between the CNS licensing basis and system design.Duke Energy Response to Question 3 The current licensed design temperature for the CNS Control Room is 90°F. This is the Technical Specification (TS) limit as defined in CNS TS 3.7.11. This represents the temperature at which CNS will take action to shut down both Units. The 90°F limit does not represent the maximum temperature at which equipment in the Control Room will operate, nor does it represent the temperature at which CNS operates the Control Room. The CRACWS "design set point" (temperature at which the Control Room is maintained) is 74°F. In a large system, however, there is always a range of temperatures over which a system will operate. The submittal addresses this potential range by using the values stated in the Technical Specification Bases for CNS TS 3.7.11 which is 72 0 F -85°F.Although the operating range of 72°F- 85°F is the administrative limit, 90°F remains the TS limit as defined in CNS TS 3.7.11. It should be noted that CNS maintains the Control Room at 740°F.Actions will be taken anytime the Control Room temperature reaches 80 0 F or above. This provides margin to the LCO limit of 900°F. | ||
As such, an | DUKE Steven D. Capps~ Vice President ENERGY° McGuire Nuclear Station Duke Energy MG01VP I112700 Hagers Ferry Road Huntersville, NC 27078 o: 980.875.4805 f: 980.875.4809 Steven.Capps@duke-energy.com Serial No. MNS-16-023 March 16, 2016 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 | ||
In addition, Operator shifts are limited to 12 hours. Supplemental staffing can be provided | |||
Although it appears that the increased frequency of verification of Control Room temperature (i.e., every 4 hours) is meant to account for this, the submittal does not address why it is adequate. | |||
Please provide a quantitative justification for the 4 | |||
As the Control Room is continuously | |||
MNS and CNS have in place "Abnormal Procedures" (AP) to take mitigating actions | |||
U.S. Nuclear Regulatory Commission MNS-1 6- | |||
The CNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, Control Room Air Handling Unit (AHU) low flow alarm, Control Room Chiller "off'alarm or "critical trouble" alarm. If the CNS Control Room reaches 80°F, temperature | |||
In summary, MNS and CNS enter the applicable AP for "Control Room High Temperature" | |||
Once the APs are entered, Control Room temperature is continuously monitored with specific actions to be taken at 80°F and 90°F. These AP actions satisfy | |||
For | |||
DUKE Steven D. Capps~ Vice President ENERGY° McGuire Nuclear | |||
==SUBJECT:== | ==SUBJECT:== | ||
Duke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station (MNS), Units 1 and 2 Docket Numbers 50-369 and 50-370, Renewed Facility Operating License NPF-9 and NPF-17 Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 Renewed Facility Operating License NPF-35 and NPF-52 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications | |||
Duke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station (MNS), Units 1 and | |||
==REFERENCES:== | ==REFERENCES:== | ||
: 1. Letter from Steven D. Capps (Duke Energy) to NRC (Serial: | : 1. Letter from Steven D. Capps (Duke Energy) to NRC (Serial: MNS-16-002), dated January 7, 2016 (ADAMS Accession Number ML16029A077), Proposed Technical Specifications (TS) Amendment TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3. 7.11, "Control Room Area Chilled Water System" (CNS)2. NRC letter from G. Edward Miller to Steven D. Capps (Duke Energy), dated March 1, 2016 (ADAMS Accession Number ML1 6055A333), McGuire Nuclear Station, Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 -Supplemental Information Needed For Acceptance of Requested Licensing Action RE: License Amendment Request for Control Room Chilled Water System Technical Specifications (TAC Nos.MF7224, MF7225, MF7226, and MF7227) | ||
MNS-16-002), | U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 2 By letter dated January 7, 2016 (Reference 1), Duke Energy submitted a License Amendment Request (LAR) for Technical Specifications (TS) TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3.7.11, "Control Room Area Chilled Water System" (CNS).The NRC staff reviewed the LAR and determined that supplemental information is needed regarding the acceptability of the proposed LAR in terms of regulatory requirements and the protection of public health and safety and the environment. | ||
By letter dated March 1, 2016 (Reference 2), the supplemental information was requested. | |||
Proposed Technical Specifications (TS) Amendment TS 3. 7.10, "Con trol Room Area Chilled Water System"(MNS), and TS 3. 7.11, "Control Room Area Chilled Water System" (CNS)2. NRC letter from G. Edward Miller to Steven D. Capps (Duke Energy), | |||
McGuire Nuclear Station,Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 -Supplemental Information Needed For Acceptance of Requested Licensing Action RE: License Amendment Request for Control Room Chilled Water System Technical Specifications (TAC Nos.MF7224, MF7225, MF7226, and MF7227) | |||
U.S. Nuclear Regulatory Commission MNS-1 6- | |||
By letter dated March 1, 2016(Reference 2), the supplemental information was requested. | |||
The supplemental information requires submission by March 17, 2016. The Duke Energy responses to the supplemental information are provided in the Enclosure to this letter.The conclusions of the original Significant Hazards Consideration and Environmental Considerations contained in the January 7, 2016, LAR (Reference | The supplemental information requires submission by March 17, 2016. The Duke Energy responses to the supplemental information are provided in the Enclosure to this letter.The conclusions of the original Significant Hazards Consideration and Environmental Considerations contained in the January 7, 2016, LAR (Reference | ||
: 1) are unaffected as a | : 1) are unaffected as a result of this supplemental response.Pursuant to 10 CER 50.91, a copy of this LAR supplement is being provided to the appropriate States of North and South Carolina officials. | ||
Pursuant to 10 CER 50.91, a copy of this LAR supplement is being provided to the appropriate States of North and South Carolina officials. | |||
There are no regulatory commitments contained in this letter or its enclosure. | There are no regulatory commitments contained in this letter or its enclosure. | ||
If you have any questions or need additional information on this matter, please | If you have any questions or need additional information on this matter, please contact Lee A. Hentz at (980) 875-4187.I declare under penalty of perjury that the foregoing is true and correct. Executed on March 16, 2016.Sincerely, Steven D. | ||
I declare under penalty of perjury that the foregoing is true and correct. | |||
Executed | |||
==Enclosure:== | ==Enclosure:== | ||
Response to Supplemental Information U.S. Nuclear Regulatory Commission MNS-1 6- | Response to Supplemental Information U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 3 cc: (with enclosure) | ||
Catherine | Catherine Haney Regional Administrator U.S. Nuclear Regulatory Commission | ||
-Region | -Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1 257 G.A. Hutto Ill (Catawba)Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear Station J. Zeiler Senior Resident Inspector (McGuire)U.S. Nuclear Regulatory Commission McGuire Nuclear Station G.E. Miller NRC Project Manager (McGuire)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8-G9A 111555 Rockville Pike Rockville, MD 20852-2738 J.A. Whited Project Manager (Catawba)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 B1A 11555 Rockville Pike Rockville, MD 20852-2738 S.E. Jenkins Manager Radioactive | ||
Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear | & infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.Columbia, SC 29201 W.L. Cox, IlI Section Chief, Division of Environmental Health Radiation Protection Section North Carolina Department of Environment and Natural Resources 1645 Mail Service Center Raleigh, NC 27699 U.S. Nuclear Regulatory Commission M NS-1 6-023 Enclosure 1 Page 1 of 3 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications By letter dated January 7, 2016 (Agencywide Documents Access and Management System Accession No. ML 16029A077), Duke Energy Carolinas, LLC (Duke Energy or the licensee), submitted a license amendment request for McGuire Nuclear Station, Units 1 and 2 (MNS 1 and 2) and Catawba Nuclear Station, Units 1 and 2 (CNS 1 and 2). The proposed amendment would modify the Control Room Area Chilled Water System Technical Specifications to allow a finite time to address a loss of both trains provided Control Room temperature remains below 90°F.The NRC staff has reviewed your application and concluded that the information delineated below is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed amendment in terms of regulatory requirements and the protection of public health and safety and the environment. | ||
U.S. Nuclear Regulatory Commission McGuire Nuclear | For MNS and CNS NRC Question 1 With both trains of the Control Room Area Chilled Water System inoperable, the effects of heat stress due to the rising temperature, under some circumstances, may impede the operators' ability to take actions required to safely operate the nuclear power unit. From a human factors perspective, please describe any effects that the proposed change may have on the control room operators. | ||
U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8- | In this description, include a justification that any impacted persons will still be able to successfully perform their job role.Duke Energy Response to Question 1 This question was further clarified during the March 1, 2016, conference call between the NRC Staff and Duke Energy: "What would be the impact on the Control Room Operators if the Control Room remained at or near 90°F for the duration of the proposed Condition B Completion Time of 24 hours." Duke Energy has in place an Administrative Procedure, "Heat and Cold Stress," based on an industry standard, that evaluates activities which expose workers to adverse environmental conditions and provides means and methods to avoid heat stress related health incidents. | ||
U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 | Control Room activities can be considered "Light work: sitting or standing with moderate arm or trunk movement, monitoring equipment, minimal walking." Per the Procedure's "Stay Time Chart," there are no stay time limits for light work up to a wet bulb globe temperature (WBGT) of 90°F. Stay time is defined as the recommended amount of time that a worker is expected to safely work in a moderate to high heat environment. | ||
& infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental | Control Room temperature is measured as a dry bulb temperature, meaning the impacts from humidity are not accounted for as they are with WBGT. Low humidity impacts dry bulb temperatures positively, thus the WBGT will equate to a lower temperature than the measured U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 2 of 3 dry bulb. Conversely, very high humidity (90-100%) | ||
Duke Energy Carolinas, LLC (Duke Energy or the licensee), | impacts dry bulb temperatures negatively, thus the WBGT will equate to a higher temperature than the measured dry bulb.During a loss of cooling event in the Control Room, there would not be an appreciable increase in humidity as temperature rises since mnost of the Control Room heat load is in the form of sensible heat. Latent heat, which drives humidity, accounts for only a fraction of the total room heat load. Thus, high humidity levels in the Control Room are not a concern for MNS or CNS.This means that the currently measured dry bulb temperature would be comparable to the WBGT, and there are no mandated stay time restrictions as long as the Control Room temperature remains 90°F or less.From a human factors perspective, based on the above considerations, the proposed change will have no adverse impact on Control Room Operators. | ||
submitted a license amendment request for McGuire Nuclear Station, Units 1 and 2 (MNS 1 | The effects of rising temperature in the Control Room should not impede the Operators' ability to take actions required to safely operate the nuclear power unit.Duke Energy also has readily available instruments that easily measure WBGT. These are available close to the Control Room and do not require any specific qualifications. | ||
For MNS and | Their set-up and use are described in the "Heat and Cold Stress" procedure. | ||
In this description, include a justification that any impacted persons will still | As such, an exact determination of Control Room WBGT can easily be determined. | ||
based on | In addition, Operator shifts are limited to 12 hours. Supplemental staffing can be provided to allow Operators to periodically rotate during shifts if the need arises.NRC Question 2 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less, verified every 12 hours. This value was determined assuming that at least one train of the Control Room Area Chilled Water System was available for active removal of heat. When in the proposed Condition B, the ability to remove heat from the Control Room would be significantly reduced. Although it appears that the increased frequency of verification of Control Room temperature (i.e., every 4 hours) is meant to account for this, the submittal does not address why it is adequate. | ||
Please provide a quantitative justification for the 4 hour surveillance interval and how the 90°F limit remains valid given potentially increased Control Room heat-up rates.Duke Energy Response to Question 2 The four hour monitoring frequency of Control Room temperature when in the proposed Condition B was predominately based on remaining consistent with NRC approved TSTF-477 Rev.3 and draft TSTF-553. | |||
Control Room activities can be considered "Light work: sitting or standing with moderate arm | As the Control Room is continuously occupied, any temperature changes would be immediately recognized by the Operators. | ||
Per the Procedure's "Stay | MNS and CNS have in place "Abnormal Procedures" (AP) to take mitigating actions when Control Room temperature reaches 80°F and take actions to shutdown the affected Units if temperature rises above 90°F. | ||
Control Room temperature is measured as a dry bulb temperature, meaning the impacts | U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 3 of 3 The MNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, chill water supply temperature increasing (alarms at 55°F), or Control Room supply air temperature increasing (alarms at 75°F). Once the AP is entered, MNS Control Room temperature is monitored continuously. | ||
impacts dry bulb temperatures negatively, thus the WBGT will equate to a higher temperature than the measured dry bulb.During a loss of cooling event in the Control Room, there would not be an appreciable | The CNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, Control Room Air Handling Unit (AHU) low flow alarm, Control Room Chiller "off'alarm or "critical trouble" alarm. If the CNS Control Room reaches 80°F, temperature is monitored continuously until one train of Control Room Area Chilled Water System (CRACWS)is restored.In summary, MNS and CNS enter the applicable AP for "Control Room High Temperature" prior to any significant increase in Control Room temperature or early symptoms of CRACWS equipment malfunctions. | ||
The effects of rising temperature | Once the APs are entered, Control Room temperature is continuously monitored with specific actions to be taken at 80°F and 90°F. These AP actions satisfy the intent of proposed Action B.1 and the associated Completion Time of four hours.As stated in Section 3.6 of the LAR, the most likely application of proposed Condition B and the associated Required Actions is when both CRACWS trains are inoperable but one train is functional with the ability to cool the Control Room. In this case, the Control Room temperature would remain constant at a normal value, and the 90°F limit is not challenged. | ||
Their set- | For CNS NRC Question 3 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less. The submittal also indicates that, while the temperature control band for MNS is 75°F to 900°F, the band for CNS is 72°F to 850°F. Please clarify the apparent discrepancy between the CNS licensing basis and system design.Duke Energy Response to Question 3 The current licensed design temperature for the CNS Control Room is 90°F. This is the Technical Specification (TS) limit as defined in CNS TS 3.7.11. This represents the temperature at which CNS will take action to shut down both Units. The 90°F limit does not represent the maximum temperature at which equipment in the Control Room will operate, nor does it represent the temperature at which CNS operates the Control Room. The CRACWS "design set point" (temperature at which the Control Room is maintained) is 74°F. In a large system, however, there is always a range of temperatures over which a system will operate. The submittal addresses this potential range by using the values stated in the Technical Specification Bases for CNS TS 3.7.11 which is 72 0 F -85°F.Although the operating range of 72°F- 85°F is the administrative limit, 90°F remains the TS limit as defined in CNS TS 3.7.11. It should be noted that CNS maintains the Control Room at 740°F.Actions will be taken anytime the Control Room temperature reaches 80 0 F or above. This provides margin to the LCO limit of 900°F.}} | ||
As such, an | |||
In addition, Operator shifts are limited to 12 hours. Supplemental staffing can be provided | |||
Although it appears that the increased frequency of verification of Control Room temperature (i.e., every 4 hours) is meant to account for this, the submittal does not address why it is adequate. | |||
Please provide a quantitative justification for the 4 | |||
As the Control Room is continuously | |||
MNS and CNS have in place "Abnormal Procedures" (AP) to take mitigating actions | |||
U.S. Nuclear Regulatory Commission MNS-1 6- | |||
The CNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, Control Room Air Handling Unit (AHU) low flow alarm, Control Room Chiller "off'alarm or "critical trouble" alarm. If the CNS Control Room reaches 80°F, temperature | |||
In summary, MNS and CNS enter the applicable AP for "Control Room High Temperature" | |||
Once the APs are entered, Control Room temperature is continuously monitored with specific actions to be taken at 80°F and 90°F. These AP actions satisfy | |||
For | |||
Revision as of 14:15, 8 July 2018
| ML16081A135 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 03/16/2016 |
| From: | Capps S D Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| MNS-16-023 | |
| Download: ML16081A135 (6) | |
Text
DUKE Steven D. Capps~ Vice President ENERGY° McGuire Nuclear Station Duke Energy MG01VP I112700 Hagers Ferry Road Huntersville, NC 27078 o: 980.875.4805 f: 980.875.4809 Steven.Capps@duke-energy.com Serial No. MNS-16-023 March 16, 2016 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Duke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station (MNS), Units 1 and 2 Docket Numbers 50-369 and 50-370, Renewed Facility Operating License NPF-9 and NPF-17 Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 Renewed Facility Operating License NPF-35 and NPF-52 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications
REFERENCES:
- 1. Letter from Steven D. Capps (Duke Energy) to NRC (Serial: MNS-16-002), dated January 7, 2016 (ADAMS Accession Number ML16029A077), Proposed Technical Specifications (TS) Amendment TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3. 7.11, "Control Room Area Chilled Water System" (CNS)2. NRC letter from G. Edward Miller to Steven D. Capps (Duke Energy), dated March 1, 2016 (ADAMS Accession Number ML1 6055A333), McGuire Nuclear Station, Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 -Supplemental Information Needed For Acceptance of Requested Licensing Action RE: License Amendment Request for Control Room Chilled Water System Technical Specifications (TAC Nos.MF7224, MF7225, MF7226, and MF7227)
U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 2 By letter dated January 7, 2016 (Reference 1), Duke Energy submitted a License Amendment Request (LAR) for Technical Specifications (TS) TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3.7.11, "Control Room Area Chilled Water System" (CNS).The NRC staff reviewed the LAR and determined that supplemental information is needed regarding the acceptability of the proposed LAR in terms of regulatory requirements and the protection of public health and safety and the environment.
By letter dated March 1, 2016 (Reference 2), the supplemental information was requested.
The supplemental information requires submission by March 17, 2016. The Duke Energy responses to the supplemental information are provided in the Enclosure to this letter.The conclusions of the original Significant Hazards Consideration and Environmental Considerations contained in the January 7, 2016, LAR (Reference
- 1) are unaffected as a result of this supplemental response.Pursuant to 10 CER 50.91, a copy of this LAR supplement is being provided to the appropriate States of North and South Carolina officials.
There are no regulatory commitments contained in this letter or its enclosure.
If you have any questions or need additional information on this matter, please contact Lee A. Hentz at (980) 875-4187.I declare under penalty of perjury that the foregoing is true and correct. Executed on March 16, 2016.Sincerely, Steven D.
Enclosure:
Response to Supplemental Information U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 3 cc: (with enclosure)
Catherine Haney Regional Administrator U.S. Nuclear Regulatory Commission
-Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1 257 G.A. Hutto Ill (Catawba)Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear Station J. Zeiler Senior Resident Inspector (McGuire)U.S. Nuclear Regulatory Commission McGuire Nuclear Station G.E. Miller NRC Project Manager (McGuire)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8-G9A 111555 Rockville Pike Rockville, MD 20852-2738 J.A. Whited Project Manager (Catawba)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 B1A 11555 Rockville Pike Rockville, MD 20852-2738 S.E. Jenkins Manager Radioactive
& infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.Columbia, SC 29201 W.L. Cox, IlI Section Chief, Division of Environmental Health Radiation Protection Section North Carolina Department of Environment and Natural Resources 1645 Mail Service Center Raleigh, NC 27699 U.S. Nuclear Regulatory Commission M NS-1 6-023 Enclosure 1 Page 1 of 3 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications By letter dated January 7, 2016 (Agencywide Documents Access and Management System Accession No. ML 16029A077), Duke Energy Carolinas, LLC (Duke Energy or the licensee), submitted a license amendment request for McGuire Nuclear Station, Units 1 and 2 (MNS 1 and 2) and Catawba Nuclear Station, Units 1 and 2 (CNS 1 and 2). The proposed amendment would modify the Control Room Area Chilled Water System Technical Specifications to allow a finite time to address a loss of both trains provided Control Room temperature remains below 90°F.The NRC staff has reviewed your application and concluded that the information delineated below is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed amendment in terms of regulatory requirements and the protection of public health and safety and the environment.
For MNS and CNS NRC Question 1 With both trains of the Control Room Area Chilled Water System inoperable, the effects of heat stress due to the rising temperature, under some circumstances, may impede the operators' ability to take actions required to safely operate the nuclear power unit. From a human factors perspective, please describe any effects that the proposed change may have on the control room operators.
In this description, include a justification that any impacted persons will still be able to successfully perform their job role.Duke Energy Response to Question 1 This question was further clarified during the March 1, 2016, conference call between the NRC Staff and Duke Energy: "What would be the impact on the Control Room Operators if the Control Room remained at or near 90°F for the duration of the proposed Condition B Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." Duke Energy has in place an Administrative Procedure, "Heat and Cold Stress," based on an industry standard, that evaluates activities which expose workers to adverse environmental conditions and provides means and methods to avoid heat stress related health incidents.
Control Room activities can be considered "Light work: sitting or standing with moderate arm or trunk movement, monitoring equipment, minimal walking." Per the Procedure's "Stay Time Chart," there are no stay time limits for light work up to a wet bulb globe temperature (WBGT) of 90°F. Stay time is defined as the recommended amount of time that a worker is expected to safely work in a moderate to high heat environment.
Control Room temperature is measured as a dry bulb temperature, meaning the impacts from humidity are not accounted for as they are with WBGT. Low humidity impacts dry bulb temperatures positively, thus the WBGT will equate to a lower temperature than the measured U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 2 of 3 dry bulb. Conversely, very high humidity (90-100%)
impacts dry bulb temperatures negatively, thus the WBGT will equate to a higher temperature than the measured dry bulb.During a loss of cooling event in the Control Room, there would not be an appreciable increase in humidity as temperature rises since mnost of the Control Room heat load is in the form of sensible heat. Latent heat, which drives humidity, accounts for only a fraction of the total room heat load. Thus, high humidity levels in the Control Room are not a concern for MNS or CNS.This means that the currently measured dry bulb temperature would be comparable to the WBGT, and there are no mandated stay time restrictions as long as the Control Room temperature remains 90°F or less.From a human factors perspective, based on the above considerations, the proposed change will have no adverse impact on Control Room Operators.
The effects of rising temperature in the Control Room should not impede the Operators' ability to take actions required to safely operate the nuclear power unit.Duke Energy also has readily available instruments that easily measure WBGT. These are available close to the Control Room and do not require any specific qualifications.
Their set-up and use are described in the "Heat and Cold Stress" procedure.
As such, an exact determination of Control Room WBGT can easily be determined.
In addition, Operator shifts are limited to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Supplemental staffing can be provided to allow Operators to periodically rotate during shifts if the need arises.NRC Question 2 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less, verified every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. This value was determined assuming that at least one train of the Control Room Area Chilled Water System was available for active removal of heat. When in the proposed Condition B, the ability to remove heat from the Control Room would be significantly reduced. Although it appears that the increased frequency of verification of Control Room temperature (i.e., every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) is meant to account for this, the submittal does not address why it is adequate.
Please provide a quantitative justification for the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> surveillance interval and how the 90°F limit remains valid given potentially increased Control Room heat-up rates.Duke Energy Response to Question 2 The four hour monitoring frequency of Control Room temperature when in the proposed Condition B was predominately based on remaining consistent with NRC approved TSTF-477 Rev.3 and draft TSTF-553.
As the Control Room is continuously occupied, any temperature changes would be immediately recognized by the Operators.
MNS and CNS have in place "Abnormal Procedures" (AP) to take mitigating actions when Control Room temperature reaches 80°F and take actions to shutdown the affected Units if temperature rises above 90°F.
U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 3 of 3 The MNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, chill water supply temperature increasing (alarms at 55°F), or Control Room supply air temperature increasing (alarms at 75°F). Once the AP is entered, MNS Control Room temperature is monitored continuously.
The CNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, Control Room Air Handling Unit (AHU) low flow alarm, Control Room Chiller "off'alarm or "critical trouble" alarm. If the CNS Control Room reaches 80°F, temperature is monitored continuously until one train of Control Room Area Chilled Water System (CRACWS)is restored.In summary, MNS and CNS enter the applicable AP for "Control Room High Temperature" prior to any significant increase in Control Room temperature or early symptoms of CRACWS equipment malfunctions.
Once the APs are entered, Control Room temperature is continuously monitored with specific actions to be taken at 80°F and 90°F. These AP actions satisfy the intent of proposed Action B.1 and the associated Completion Time of four hours.As stated in Section 3.6 of the LAR, the most likely application of proposed Condition B and the associated Required Actions is when both CRACWS trains are inoperable but one train is functional with the ability to cool the Control Room. In this case, the Control Room temperature would remain constant at a normal value, and the 90°F limit is not challenged.
For CNS NRC Question 3 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less. The submittal also indicates that, while the temperature control band for MNS is 75°F to 900°F, the band for CNS is 72°F to 850°F. Please clarify the apparent discrepancy between the CNS licensing basis and system design.Duke Energy Response to Question 3 The current licensed design temperature for the CNS Control Room is 90°F. This is the Technical Specification (TS) limit as defined in CNS TS 3.7.11. This represents the temperature at which CNS will take action to shut down both Units. The 90°F limit does not represent the maximum temperature at which equipment in the Control Room will operate, nor does it represent the temperature at which CNS operates the Control Room. The CRACWS "design set point" (temperature at which the Control Room is maintained) is 74°F. In a large system, however, there is always a range of temperatures over which a system will operate. The submittal addresses this potential range by using the values stated in the Technical Specification Bases for CNS TS 3.7.11 which is 72 0 F -85°F.Although the operating range of 72°F- 85°F is the administrative limit, 90°F remains the TS limit as defined in CNS TS 3.7.11. It should be noted that CNS maintains the Control Room at 740°F.Actions will be taken anytime the Control Room temperature reaches 80 0 F or above. This provides margin to the LCO limit of 900°F.
DUKE Steven D. Capps~ Vice President ENERGY° McGuire Nuclear Station Duke Energy MG01VP I112700 Hagers Ferry Road Huntersville, NC 27078 o: 980.875.4805 f: 980.875.4809 Steven.Capps@duke-energy.com Serial No. MNS-16-023 March 16, 2016 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Duke Energy Carolinas, LLC (Duke Energy)McGuire Nuclear Station (MNS), Units 1 and 2 Docket Numbers 50-369 and 50-370, Renewed Facility Operating License NPF-9 and NPF-17 Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 Renewed Facility Operating License NPF-35 and NPF-52 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications
REFERENCES:
- 1. Letter from Steven D. Capps (Duke Energy) to NRC (Serial: MNS-16-002), dated January 7, 2016 (ADAMS Accession Number ML16029A077), Proposed Technical Specifications (TS) Amendment TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3. 7.11, "Control Room Area Chilled Water System" (CNS)2. NRC letter from G. Edward Miller to Steven D. Capps (Duke Energy), dated March 1, 2016 (ADAMS Accession Number ML1 6055A333), McGuire Nuclear Station, Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 -Supplemental Information Needed For Acceptance of Requested Licensing Action RE: License Amendment Request for Control Room Chilled Water System Technical Specifications (TAC Nos.MF7224, MF7225, MF7226, and MF7227)
U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 2 By letter dated January 7, 2016 (Reference 1), Duke Energy submitted a License Amendment Request (LAR) for Technical Specifications (TS) TS 3. 7.10, "Con trol Room Area Chilled Water System" (MNS), and TS 3.7.11, "Control Room Area Chilled Water System" (CNS).The NRC staff reviewed the LAR and determined that supplemental information is needed regarding the acceptability of the proposed LAR in terms of regulatory requirements and the protection of public health and safety and the environment.
By letter dated March 1, 2016 (Reference 2), the supplemental information was requested.
The supplemental information requires submission by March 17, 2016. The Duke Energy responses to the supplemental information are provided in the Enclosure to this letter.The conclusions of the original Significant Hazards Consideration and Environmental Considerations contained in the January 7, 2016, LAR (Reference
- 1) are unaffected as a result of this supplemental response.Pursuant to 10 CER 50.91, a copy of this LAR supplement is being provided to the appropriate States of North and South Carolina officials.
There are no regulatory commitments contained in this letter or its enclosure.
If you have any questions or need additional information on this matter, please contact Lee A. Hentz at (980) 875-4187.I declare under penalty of perjury that the foregoing is true and correct. Executed on March 16, 2016.Sincerely, Steven D.
Enclosure:
Response to Supplemental Information U.S. Nuclear Regulatory Commission MNS-1 6-023 Page 3 cc: (with enclosure)
Catherine Haney Regional Administrator U.S. Nuclear Regulatory Commission
-Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1 257 G.A. Hutto Ill (Catawba)Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear Station J. Zeiler Senior Resident Inspector (McGuire)U.S. Nuclear Regulatory Commission McGuire Nuclear Station G.E. Miller NRC Project Manager (McGuire)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8-G9A 111555 Rockville Pike Rockville, MD 20852-2738 J.A. Whited Project Manager (Catawba)U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 B1A 11555 Rockville Pike Rockville, MD 20852-2738 S.E. Jenkins Manager Radioactive
& infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.Columbia, SC 29201 W.L. Cox, IlI Section Chief, Division of Environmental Health Radiation Protection Section North Carolina Department of Environment and Natural Resources 1645 Mail Service Center Raleigh, NC 27699 U.S. Nuclear Regulatory Commission M NS-1 6-023 Enclosure 1 Page 1 of 3 Response to Request for Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding License Amendment Request for Control Room Chilled Water System Technical Specifications By letter dated January 7, 2016 (Agencywide Documents Access and Management System Accession No. ML 16029A077), Duke Energy Carolinas, LLC (Duke Energy or the licensee), submitted a license amendment request for McGuire Nuclear Station, Units 1 and 2 (MNS 1 and 2) and Catawba Nuclear Station, Units 1 and 2 (CNS 1 and 2). The proposed amendment would modify the Control Room Area Chilled Water System Technical Specifications to allow a finite time to address a loss of both trains provided Control Room temperature remains below 90°F.The NRC staff has reviewed your application and concluded that the information delineated below is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed amendment in terms of regulatory requirements and the protection of public health and safety and the environment.
For MNS and CNS NRC Question 1 With both trains of the Control Room Area Chilled Water System inoperable, the effects of heat stress due to the rising temperature, under some circumstances, may impede the operators' ability to take actions required to safely operate the nuclear power unit. From a human factors perspective, please describe any effects that the proposed change may have on the control room operators.
In this description, include a justification that any impacted persons will still be able to successfully perform their job role.Duke Energy Response to Question 1 This question was further clarified during the March 1, 2016, conference call between the NRC Staff and Duke Energy: "What would be the impact on the Control Room Operators if the Control Room remained at or near 90°F for the duration of the proposed Condition B Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." Duke Energy has in place an Administrative Procedure, "Heat and Cold Stress," based on an industry standard, that evaluates activities which expose workers to adverse environmental conditions and provides means and methods to avoid heat stress related health incidents.
Control Room activities can be considered "Light work: sitting or standing with moderate arm or trunk movement, monitoring equipment, minimal walking." Per the Procedure's "Stay Time Chart," there are no stay time limits for light work up to a wet bulb globe temperature (WBGT) of 90°F. Stay time is defined as the recommended amount of time that a worker is expected to safely work in a moderate to high heat environment.
Control Room temperature is measured as a dry bulb temperature, meaning the impacts from humidity are not accounted for as they are with WBGT. Low humidity impacts dry bulb temperatures positively, thus the WBGT will equate to a lower temperature than the measured U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 2 of 3 dry bulb. Conversely, very high humidity (90-100%)
impacts dry bulb temperatures negatively, thus the WBGT will equate to a higher temperature than the measured dry bulb.During a loss of cooling event in the Control Room, there would not be an appreciable increase in humidity as temperature rises since mnost of the Control Room heat load is in the form of sensible heat. Latent heat, which drives humidity, accounts for only a fraction of the total room heat load. Thus, high humidity levels in the Control Room are not a concern for MNS or CNS.This means that the currently measured dry bulb temperature would be comparable to the WBGT, and there are no mandated stay time restrictions as long as the Control Room temperature remains 90°F or less.From a human factors perspective, based on the above considerations, the proposed change will have no adverse impact on Control Room Operators.
The effects of rising temperature in the Control Room should not impede the Operators' ability to take actions required to safely operate the nuclear power unit.Duke Energy also has readily available instruments that easily measure WBGT. These are available close to the Control Room and do not require any specific qualifications.
Their set-up and use are described in the "Heat and Cold Stress" procedure.
As such, an exact determination of Control Room WBGT can easily be determined.
In addition, Operator shifts are limited to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Supplemental staffing can be provided to allow Operators to periodically rotate during shifts if the need arises.NRC Question 2 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less, verified every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. This value was determined assuming that at least one train of the Control Room Area Chilled Water System was available for active removal of heat. When in the proposed Condition B, the ability to remove heat from the Control Room would be significantly reduced. Although it appears that the increased frequency of verification of Control Room temperature (i.e., every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) is meant to account for this, the submittal does not address why it is adequate.
Please provide a quantitative justification for the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> surveillance interval and how the 90°F limit remains valid given potentially increased Control Room heat-up rates.Duke Energy Response to Question 2 The four hour monitoring frequency of Control Room temperature when in the proposed Condition B was predominately based on remaining consistent with NRC approved TSTF-477 Rev.3 and draft TSTF-553.
As the Control Room is continuously occupied, any temperature changes would be immediately recognized by the Operators.
MNS and CNS have in place "Abnormal Procedures" (AP) to take mitigating actions when Control Room temperature reaches 80°F and take actions to shutdown the affected Units if temperature rises above 90°F.
U.S. Nuclear Regulatory Commission MNS-1 6-023 Enclosure 1 Page 3 of 3 The MNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, chill water supply temperature increasing (alarms at 55°F), or Control Room supply air temperature increasing (alarms at 75°F). Once the AP is entered, MNS Control Room temperature is monitored continuously.
The CNS AP is entered by Operators on symptoms such as: Control Room temperature increasing, Control Room Air Handling Unit (AHU) low flow alarm, Control Room Chiller "off'alarm or "critical trouble" alarm. If the CNS Control Room reaches 80°F, temperature is monitored continuously until one train of Control Room Area Chilled Water System (CRACWS)is restored.In summary, MNS and CNS enter the applicable AP for "Control Room High Temperature" prior to any significant increase in Control Room temperature or early symptoms of CRACWS equipment malfunctions.
Once the APs are entered, Control Room temperature is continuously monitored with specific actions to be taken at 80°F and 90°F. These AP actions satisfy the intent of proposed Action B.1 and the associated Completion Time of four hours.As stated in Section 3.6 of the LAR, the most likely application of proposed Condition B and the associated Required Actions is when both CRACWS trains are inoperable but one train is functional with the ability to cool the Control Room. In this case, the Control Room temperature would remain constant at a normal value, and the 90°F limit is not challenged.
For CNS NRC Question 3 The submittal indicates that the current licensed design temperature of the Control Room equipment is 90°F or less. The submittal also indicates that, while the temperature control band for MNS is 75°F to 900°F, the band for CNS is 72°F to 850°F. Please clarify the apparent discrepancy between the CNS licensing basis and system design.Duke Energy Response to Question 3 The current licensed design temperature for the CNS Control Room is 90°F. This is the Technical Specification (TS) limit as defined in CNS TS 3.7.11. This represents the temperature at which CNS will take action to shut down both Units. The 90°F limit does not represent the maximum temperature at which equipment in the Control Room will operate, nor does it represent the temperature at which CNS operates the Control Room. The CRACWS "design set point" (temperature at which the Control Room is maintained) is 74°F. In a large system, however, there is always a range of temperatures over which a system will operate. The submittal addresses this potential range by using the values stated in the Technical Specification Bases for CNS TS 3.7.11 which is 72 0 F -85°F.Although the operating range of 72°F- 85°F is the administrative limit, 90°F remains the TS limit as defined in CNS TS 3.7.11. It should be noted that CNS maintains the Control Room at 740°F.Actions will be taken anytime the Control Room temperature reaches 80 0 F or above. This provides margin to the LCO limit of 900°F.