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{{#Wiki_filter:RBS Remote Shutdown Room Heat-UpPage 1Evaluation of RBS Remote Shutdown Panel Rooms following a Loss ofControl Building HVACPurposeEvaluate the temperatures in the Remote Shutdown Panel rooms (Division 1 andDivision 2 RSS) following a loss of Control Building HVAC.BackgroundOn March 9, 2015, during a scheduled refueling outage, RBS experienced a temporaryloss of Control Building and Main Control Room (MCR) cooling due to trip of theassociated chilled water system (HVK). The NRC has raised concerns regarding thereliability of electrical equipment and the long-term habitability of the Main Control Room(MCR) following a loss of cooling. RBS has developed detailed GOTHIC thermal-hydraulic models of the RBS Main Control Room and Control Building and evaluatedthe MCR heat-up following a loss of all cooling assuming various mitigating actions(References 1, 2, and 6). The MCR heat-up evaluations include cases with designbasis normal operating MCR heat loads (Ref. 3) and with measured heat loadsdetermined from a steady-state MCR heat balance performed during normal operations(Ref. 4). The measured heat loads are 57% of the design normal operating heat load.The MCR heat-up evaluations show that the MCR average temperature reaches 116 | {{#Wiki_filter:RBS Remote Shutdown Room Heat-UpPage 1Evaluation of RBS Remote Shutdown Panel Rooms following a Loss ofControl Building HVACPurposeEvaluate the temperatures in the Remote Shutdown Panel rooms (Division 1 andDivision 2 RSS) following a loss of Control Building HVAC.BackgroundOn March 9, 2015, during a scheduled refueling outage, RBS experienced a temporaryloss of Control Building and Main Control Room (MCR) cooling due to trip of theassociated chilled water system (HVK). The NRC has raised concerns regarding thereliability of electrical equipment and the long-term habitability of the Main Control Room(MCR) following a loss of cooling. RBS has developed detailed GOTHIC thermal-hydraulic models of the RBS Main Control Room and Control Building and evaluatedthe MCR heat-up following a loss of all cooling assuming various mitigating actions(References 1, 2, and 6). The MCR heat-up evaluations include cases with designbasis normal operating MCR heat loads (Ref. 3) and with measured heat loadsdetermined from a steady-state MCR heat balance performed during normal operations(Ref. 4). The measured heat loads are 57% of the design normal operating heat load.The MCR heat-up evaluations show that the MCR average temperature reaches 116 o Fwithin two hours of a loss of HVAC with design heat loads. However, using the actual, measured heat loads, the MCR temperature remains below 113 oF for six hoursfollowing a loss of HVAC. Should mitigating actions to provide cooling to the MCR prove unsuccessful and the environmental conditions in the MCR worsen such thatoperator habitability is challenged, operators could evacuate to the Division 1 or Division2 Remote Shutdown (RSS) rooms and shutdown the plant from the remote shutdownpanels. This evaluation determines if the Division 1 and Division 2 RSS rooms willremain habitable and equipment remain available during a loss of control building HVAC event.ConclusionsBoth the Division 1 and Division 2 RSS rooms would remain habitable and equipmentwould remain available following a loss of HVAC in the control building. Should theMCR be abandoned due to a loss of control building HVAC, operators would open thedoors to the RSS rooms to allow access. Opening of these doors would provide mixingvia natural circulation with the air in the adjacent control building rooms. As shown inReference 6, the Control Building Switchgear Area heat loads under a LOCA-LOOPcondition is lower than the heat loads for a LOCA with offsite power, which wouldreduce the temperatures in the RSS rooms. Page 167 of Reference 7 shows that theheatup for these rooms is minimal under LOOP conditions. The MCR heat-upcalculations show that the MCR would remain habitable for at least 6 hours assumingmeasured heat loads and 2 hours assuming design heat loads. Without taking creditfor metal heat sinks in the RSS rooms, temperatures in the most limiting RSS room areexpected to remain below 108°F during the first 2 hours and below 114°F at 6 hours.Therefore, in the unlikely event of a rapid MCR heat-up requiring early MCR evacuation(within 2 hours), the temperature in the limiting RSS room after opening doors is RBS Remote Shutdown Room Heat-UpPage 2expected to be less than 108 oF. For the slower MCR heat up using measured heatloads, MCR evacuation is less likely due to the increased time (6 hours) available toimplement mitigating actions. However, if evacuation to the RSS rooms occurs at 6hours, the temperature in the limiting RSS room after opening doors is expected to beless than 114 oF. The temperatures predicted for the RSS rooms are lower than thevalues reported in G13.18.12.3*161 (Reference 7), due to the refined heat loads andmodeling techniques applied in ENTR-078-CALC-001 (Reference 6) and thisevaluation.EvaluationRSS Room DescriptionThe Division 1 (CB098-11) and Division 2 (CB098-13) RSS rooms are located on the 98foot elevation of the control building. The volume of the Division 1 RSS is approximately 971 ft 3 while the Division 2 RSS is approximately 1626 ft | ||
: 3. The control panels in theserooms as listed in the tables below provide a substantial amount of steel mass thatwould act as a heat sink during heat up of the rooms following a loss of HVAC. TheDivision 1 RSS room includes a single door that opens to the general area of the 98 footelevation (CB098-10). The Division 2 RSS room includes two doors that open to theStandby Switch Gear Room 1B (CB098-12).Division 1 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 1 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 1: Div. 1 RSS E-226 Heat LoadsDiv. 1EquipmentHeat LoadNormal(Watts)LOCA withOffsitePower(Watts)C61-PNLP001 200200RSS-PNL101540540Lighting (5)480480TOTAL12201220A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS101. The individualparts and components of the RSS-PNL101 were reviewed in ESK-4RSS101 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL101 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Div. 1 RSS room contained 4 light fixtures with each fixture containing two40W light bulbs. Based on the review, the revised heat loads are presented in Table 2. | : 3. The control panels in theserooms as listed in the tables below provide a substantial amount of steel mass thatwould act as a heat sink during heat up of the rooms following a loss of HVAC. TheDivision 1 RSS room includes a single door that opens to the general area of the 98 footelevation (CB098-10). The Division 2 RSS room includes two doors that open to theStandby Switch Gear Room 1B (CB098-12).Division 1 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 1 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 1: Div. 1 RSS E-226 Heat LoadsDiv. 1EquipmentHeat LoadNormal(Watts)LOCA withOffsitePower(Watts)C61-PNLP001 200200RSS-PNL101540540Lighting (5)480480TOTAL12201220A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS101. The individualparts and components of the RSS-PNL101 were reviewed in ESK-4RSS101 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL101 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Div. 1 RSS room contained 4 light fixtures with each fixture containing two40W light bulbs. Based on the review, the revised heat loads are presented in Table 2. | ||
RBS Remote Shutdown Room Heat-UpPage 3Table 2: Div. 1 RSS Revised Heat LoadsDiv. 1EquipmentHeat LoadLOCA withOffsitePower(Watts)Reduction | RBS Remote Shutdown Room Heat-UpPage 3Table 2: Div. 1 RSS Revised Heat LoadsDiv. 1EquipmentHeat LoadLOCA withOffsitePower(Watts)Reduction (%)C61-PNLP001200 0%RSS-PNL101180 67%Lighting (4)320 33%TOTAL70043%Division 2 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 2 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 3: Div. 2 RSS E-226 Heat LoadsDiv. 2EquipmentHeat LoadNormal(Watts)LOCA withOffsite Power(Watts)RSS-PNL102540540Lighting (2)192192TOTAL732732A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS102. The individualparts and components of the RSS-PNL102 were reviewed in ESK-4RSS102 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL102 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Division 2 RSS room contained 2 light fixtures with each fixture containingtwo 34W light bulbs. Based on the review, the revised heat loads are presented in Table 4.Table 4: Div. 2 RSS Revised Heat LoadsDiv. 2EquipmentHeat LoadLOCA withOffsite Power(Watts)Reduction (%)RSS-PNL102200 63%Lighting (2)136 29%TOTAL33654% | ||
(%)C61- | RBS Remote Shutdown Room Heat-UpPage 4RSS Room Temperatures Following Loss of HVACThe temperatures in the Division 1 and 2 RSS rooms following a loss of HVAC werecalculated using the Control Building (GOTHIC) model that opens the doors in theControl Building at 30 minutes developed in Reference 6. The temperatures of the RSSrooms did not change at 2 and 6 hours for the case with no doors opened fromReference 6. The control building heat loads for the LOCA with offsite power case wereused as they result in the bounding heat loads for LOCA and non-LOCA cases. Therevised heat loads from Table 2 and 4 are used in the RSS rooms. The model does notcredit metal heat sinks in the RSS rooms which would reduce the temperature in theserooms. The model also does not consider opening the doors to these rooms, whichwould allow mixing with the adjacent rooms. The case with inverters operating in theStandby Switchgear Rooms is selected to conservatively maximize the temperature inStandby Switchgear Room 1B located outside the Division 2 RSS room.Table 5 shows the temperatures in the RSS rooms and adjacent rooms outside theDivision 1 RSS room (98 foot General Area, CB098-10) and the Division 2 RSS room(Standby Switchgear room 1B, CB098-12) at 2 and 6 hours. The temperatures in theDivision 1 RSS rooms remain below 115 oF at 2 hours and below 119 o F at 6 hours.Temperatures in the Division 2 RSS room remain below 100 oF at 2 and 6 hours. Thetemperature outside the Division 1 RSS room is 97.2 oF at 2 hours and 101.8 o F at 6hours. The temperature in the Standby Switchgear Room outside the Division 2 RSSroom is 108.5 oF at 2 hours and 114.4 oF at 6 hours. Should the MCR be abandoned,operators would open the doors to the RSS rooms to allow access. Due to the smallsize of these rooms, opening the room doors would be a highly effective means ofproviding mixing of the room air with the larger adjacent rooms. The RSS rooms wouldbe expected to stabilize at a temperature within a few degrees of the temperature of thearea outside the room. Therefore, the temperature in the Division 1 RSS room willdecrease after the door is opened for operator access and is estimated to be no more than 100 oF at 2 hours and 110 oF at 6 hours. The temperature in the Division 2 RSSroom will increase after the door is opened for operator access. The temperature wouldbe no more than 108 oF at 2 hours and 114 o F at 6 hours.Table 5: RSS and Adjacent Room Temperatures RoomTemperature (o F)2 hours6 HoursDiv 1 RSS (CB098-11)114.2118.7General Area (CB098-10)97.2101.8Div 2 RSS (CB098-13)97.899.7Stby SG Room 1B (CB098-12)108.5114.4 RBS Remote Shutdown Room Heat-UpPage 5References1. Calculation ENTR-078-CALC-003, Rev. 4, "Main Control Room Heat-Up Under Lossof HVAC Conditions for 24 Hours."2. RBS-ME-16-00002, Rev. 0 (ENTR-078-CALC-004, Rev. 0), "Main Control RoomHeat-Up Analysis During Loss of HVAC Conditions for 24 Hours."3. EC61975, "References for E-226 Calculation Revision."4. RBS-ME-16-00003, Rev. 0, "Evaluation of Main Control Room Heat-up on Loss ofHVAC Based on Empirical Temperature and Flow Data."5. Calculation E-226, Rev. 5, "Control Building Electrical Equipment Heat ReleaseDuring LOCA Condition With Off Site Power Available and Also Control BuildingElectrical Heat Release During LOCA Condition Without Offsite Power (LOOP andwith EGS-EG1B Diesel Generator Not Responding."6. Calculation ENTR-078-CALC-001, Rev. 1, "Control Building Heatup AnalysisFollowing Loss of HVAC."7. Calculation G13.18.12.3*161, Rev. 2, "Standby Switchgear Room Temperaturesfollowing Loss of Offsite Power and Loss of HVAC". | ||
(%)RSS- | RBS Remote Shutdown Room Heat-UpPage 1Evaluation of RBS Remote Shutdown Panel Rooms following a Loss ofControl Building HVACPurposeEvaluate the temperatures in the Remote Shutdown Panel rooms (Division 1 andDivision 2 RSS) following a loss of Control Building HVAC.BackgroundOn March 9, 2015, during a scheduled refueling outage, RBS experienced a temporaryloss of Control Building and Main Control Room (MCR) cooling due to trip of theassociated chilled water system (HVK). The NRC has raised concerns regarding thereliability of electrical equipment and the long-term habitability of the Main Control Room(MCR) following a loss of cooling. RBS has developed detailed GOTHIC thermal-hydraulic models of the RBS Main Control Room and Control Building and evaluatedthe MCR heat-up following a loss of all cooling assuming various mitigating actions(References 1, 2, and 6). The MCR heat-up evaluations include cases with designbasis normal operating MCR heat loads (Ref. 3) and with measured heat loadsdetermined from a steady-state MCR heat balance performed during normal operations(Ref. 4). The measured heat loads are 57% of the design normal operating heat load.The MCR heat-up evaluations show that the MCR average temperature reaches 116 o Fwithin two hours of a loss of HVAC with design heat loads. However, using the actual, measured heat loads, the MCR temperature remains below 113 oF for six hoursfollowing a loss of HVAC. Should mitigating actions to provide cooling to the MCR prove unsuccessful and the environmental conditions in the MCR worsen such thatoperator habitability is challenged, operators could evacuate to the Division 1 or Division2 Remote Shutdown (RSS) rooms and shutdown the plant from the remote shutdownpanels. This evaluation determines if the Division 1 and Division 2 RSS rooms willremain habitable and equipment remain available during a loss of control building HVAC event.ConclusionsBoth the Division 1 and Division 2 RSS rooms would remain habitable and equipmentwould remain available following a loss of HVAC in the control building. Should theMCR be abandoned due to a loss of control building HVAC, operators would open thedoors to the RSS rooms to allow access. Opening of these doors would provide mixingvia natural circulation with the air in the adjacent control building rooms. As shown inReference 6, the Control Building Switchgear Area heat loads under a LOCA-LOOPcondition is lower than the heat loads for a LOCA with offsite power, which wouldreduce the temperatures in the RSS rooms. Page 167 of Reference 7 shows that theheatup for these rooms is minimal under LOOP conditions. The MCR heat-upcalculations show that the MCR would remain habitable for at least 6 hours assumingmeasured heat loads and 2 hours assuming design heat loads. Without taking creditfor metal heat sinks in the RSS rooms, temperatures in the most limiting RSS room areexpected to remain below 108°F during the first 2 hours and below 114°F at 6 hours.Therefore, in the unlikely event of a rapid MCR heat-up requiring early MCR evacuation(within 2 hours), the temperature in the limiting RSS room after opening doors is RBS Remote Shutdown Room Heat-UpPage 2expected to be less than 108 oF. For the slower MCR heat up using measured heatloads, MCR evacuation is less likely due to the increased time (6 hours) available toimplement mitigating actions. However, if evacuation to the RSS rooms occurs at 6hours, the temperature in the limiting RSS room after opening doors is expected to beless than 114 oF. The temperatures predicted for the RSS rooms are lower than thevalues reported in G13.18.12.3*161 (Reference 7), due to the refined heat loads andmodeling techniques applied in ENTR-078-CALC-001 (Reference 6) and thisevaluation.EvaluationRSS Room DescriptionThe Division 1 (CB098-11) and Division 2 (CB098-13) RSS rooms are located on the 98foot elevation of the control building. The volume of the Division 1 RSS is approximately 971 ft 3 while the Division 2 RSS is approximately 1626 ft | ||
RBS Remote Shutdown Room Heat-UpPage 4RSS Room Temperatures Following Loss of HVACThe temperatures in the Division 1 and 2 RSS rooms following a loss of HVAC werecalculated using the Control Building (GOTHIC) model that opens the doors in theControl Building at 30 minutes developed in Reference 6. The temperatures of the RSSrooms did not change at 2 and 6 hours for the case with no doors opened fromReference 6. The control building heat loads for the LOCA with offsite power case wereused as they result in the bounding heat loads for LOCA and non-LOCA cases. Therevised heat loads from Table 2 and 4 are used in the RSS rooms. The model does notcredit metal heat sinks in the RSS rooms which would reduce the temperature in theserooms. The model also does not consider opening the doors to these rooms, whichwould allow mixing with the adjacent rooms. The case with inverters operating in theStandby Switchgear Rooms is selected to conservatively maximize the temperature inStandby Switchgear Room 1B located outside the Division 2 RSS room.Table 5 shows the temperatures in the RSS rooms and adjacent rooms outside theDivision 1 RSS room (98 foot General Area, CB098-10) and the Division 2 RSS room(Standby Switchgear room 1B, CB098-12) at 2 and 6 hours. The temperatures in theDivision 1 RSS rooms remain below 115 oF at 2 hours and below 119 | |||
RBS Remote Shutdown Room Heat-UpPage 1Evaluation of RBS Remote Shutdown Panel Rooms following a Loss ofControl Building HVACPurposeEvaluate the temperatures in the Remote Shutdown Panel rooms (Division 1 andDivision 2 RSS) following a loss of Control Building HVAC.BackgroundOn March 9, 2015, during a scheduled refueling outage, RBS experienced a temporaryloss of Control Building and Main Control Room (MCR) cooling due to trip of theassociated chilled water system (HVK). The NRC has raised concerns regarding thereliability of electrical equipment and the long-term habitability of the Main Control Room(MCR) following a loss of cooling. RBS has developed detailed GOTHIC thermal-hydraulic models of the RBS Main Control Room and Control Building and evaluatedthe MCR heat-up following a loss of all cooling assuming various mitigating actions(References 1, 2, and 6). The MCR heat-up evaluations include cases with designbasis normal operating MCR heat loads (Ref. 3) and with measured heat loadsdetermined from a steady-state MCR heat balance performed during normal operations(Ref. 4). The measured heat loads are 57% of the design normal operating heat load.The MCR heat-up evaluations show that the MCR average temperature reaches 116 | |||
: 3. The control panels in theserooms as listed in the tables below provide a substantial amount of steel mass thatwould act as a heat sink during heat up of the rooms following a loss of HVAC. TheDivision 1 RSS room includes a single door that opens to the general area of the 98 footelevation (CB098-10). The Division 2 RSS room includes two doors that open to theStandby Switch Gear Room 1B (CB098-12).Division 1 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 1 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 1: Div. 1 RSS E-226 Heat LoadsDiv. 1EquipmentHeat LoadNormal(Watts)LOCA withOffsitePower(Watts)C61-PNLP001 200200RSS-PNL101540540Lighting (5)480480TOTAL12201220A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS101. The individualparts and components of the RSS-PNL101 were reviewed in ESK-4RSS101 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL101 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Div. 1 RSS room contained 4 light fixtures with each fixture containing two40W light bulbs. Based on the review, the revised heat loads are presented in Table 2. | : 3. The control panels in theserooms as listed in the tables below provide a substantial amount of steel mass thatwould act as a heat sink during heat up of the rooms following a loss of HVAC. TheDivision 1 RSS room includes a single door that opens to the general area of the 98 footelevation (CB098-10). The Division 2 RSS room includes two doors that open to theStandby Switch Gear Room 1B (CB098-12).Division 1 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 1 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 1: Div. 1 RSS E-226 Heat LoadsDiv. 1EquipmentHeat LoadNormal(Watts)LOCA withOffsitePower(Watts)C61-PNLP001 200200RSS-PNL101540540Lighting (5)480480TOTAL12201220A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS101. The individualparts and components of the RSS-PNL101 were reviewed in ESK-4RSS101 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL101 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Div. 1 RSS room contained 4 light fixtures with each fixture containing two40W light bulbs. Based on the review, the revised heat loads are presented in Table 2. | ||
RBS Remote Shutdown Room Heat-UpPage 3Table 2: Div. 1 RSS Revised Heat LoadsDiv. 1EquipmentHeat LoadLOCA withOffsitePower(Watts)Reduction | RBS Remote Shutdown Room Heat-UpPage 3Table 2: Div. 1 RSS Revised Heat LoadsDiv. 1EquipmentHeat LoadLOCA withOffsitePower(Watts)Reduction (%)C61-PNLP001200 0%RSS-PNL101180 67%Lighting (4)320 33%TOTAL70043%Division 2 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 2 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 3: Div. 2 RSS E-226 Heat LoadsDiv. 2EquipmentHeat LoadNormal(Watts)LOCA withOffsite Power(Watts)RSS-PNL102540540Lighting (2)192192TOTAL732732A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS102. The individualparts and components of the RSS-PNL102 were reviewed in ESK-4RSS102 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL102 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Division 2 RSS room contained 2 light fixtures with each fixture containingtwo 34W light bulbs. Based on the review, the revised heat loads are presented in Table 4.Table 4: Div. 2 RSS Revised Heat LoadsDiv. 2EquipmentHeat LoadLOCA withOffsite Power(Watts)Reduction (%)RSS-PNL102200 63%Lighting (2)136 29%TOTAL33654% | ||
(%)C61- | RBS Remote Shutdown Room Heat-UpPage 4RSS Room Temperatures Following Loss of HVACThe temperatures in the Division 1 and 2 RSS rooms following a loss of HVAC werecalculated using the Control Building (GOTHIC) model that opens the doors in theControl Building at 30 minutes developed in Reference 6. The temperatures of the RSSrooms did not change at 2 and 6 hours for the case with no doors opened fromReference 6. The control building heat loads for the LOCA with offsite power case wereused as they result in the bounding heat loads for LOCA and non-LOCA cases. Therevised heat loads from Table 2 and 4 are used in the RSS rooms. The model does notcredit metal heat sinks in the RSS rooms which would reduce the temperature in theserooms. The model also does not consider opening the doors to these rooms, whichwould allow mixing with the adjacent rooms. The case with inverters operating in theStandby Switchgear Rooms is selected to conservatively maximize the temperature inStandby Switchgear Room 1B located outside the Division 2 RSS room.Table 5 shows the temperatures in the RSS rooms and adjacent rooms outside theDivision 1 RSS room (98 foot General Area, CB098-10) and the Division 2 RSS room(Standby Switchgear room 1B, CB098-12) at 2 and 6 hours. The temperatures in theDivision 1 RSS rooms remain below 115 oF at 2 hours and below 119 o F at 6 hours.Temperatures in the Division 2 RSS room remain below 100 oF at 2 and 6 hours. Thetemperature outside the Division 1 RSS room is 97.2 oF at 2 hours and 101.8 o F at 6hours. The temperature in the Standby Switchgear Room outside the Division 2 RSSroom is 108.5 oF at 2 hours and 114.4 oF at 6 hours. Should the MCR be abandoned,operators would open the doors to the RSS rooms to allow access. Due to the smallsize of these rooms, opening the room doors would be a highly effective means ofproviding mixing of the room air with the larger adjacent rooms. The RSS rooms wouldbe expected to stabilize at a temperature within a few degrees of the temperature of thearea outside the room. Therefore, the temperature in the Division 1 RSS room willdecrease after the door is opened for operator access and is estimated to be no more than 100 oF at 2 hours and 110 oF at 6 hours. The temperature in the Division 2 RSSroom will increase after the door is opened for operator access. The temperature wouldbe no more than 108 oF at 2 hours and 114 o F at 6 hours.Table 5: RSS and Adjacent Room Temperatures RoomTemperature (o F)2 hours6 HoursDiv 1 RSS (CB098-11)114.2118.7General Area (CB098-10)97.2101.8Div 2 RSS (CB098-13)97.899.7Stby SG Room 1B (CB098-12)108.5114.4 RBS Remote Shutdown Room Heat-UpPage 5References1. Calculation ENTR-078-CALC-003, Rev. 4, "Main Control Room Heat-Up Under Lossof HVAC Conditions for 24 Hours."2. RBS-ME-16-00002, Rev. 0 (ENTR-078-CALC-004, Rev. 0), "Main Control RoomHeat-Up Analysis During Loss of HVAC Conditions for 24 Hours."3. EC61975, "References for E-226 Calculation Revision."4. RBS-ME-16-00003, Rev. 0, "Evaluation of Main Control Room Heat-up on Loss ofHVAC Based on Empirical Temperature and Flow Data."5. Calculation E-226, Rev. 5, "Control Building Electrical Equipment Heat ReleaseDuring LOCA Condition With Off Site Power Available and Also Control BuildingElectrical Heat Release During LOCA Condition Without Offsite Power (LOOP andwith EGS-EG1B Diesel Generator Not Responding."6. Calculation ENTR-078-CALC-001, Rev. 1, "Control Building Heatup AnalysisFollowing Loss of HVAC."7. Calculation G13.18.12.3*161, Rev. 2, "Standby Switchgear Room Temperaturesfollowing Loss of Offsite Power and Loss of HVAC".}} | ||
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RBS Remote Shutdown Room Heat-UpPage 4RSS Room Temperatures Following Loss of HVACThe temperatures in the Division 1 and 2 RSS rooms following a loss of HVAC werecalculated using the Control Building (GOTHIC) model that opens the doors in theControl Building at 30 minutes developed in Reference 6. The temperatures of the RSSrooms did not change at 2 and 6 hours for the case with no doors opened fromReference 6. The control building heat loads for the LOCA with offsite power case wereused as they result in the bounding heat loads for LOCA and non-LOCA cases. Therevised heat loads from Table 2 and 4 are used in the RSS rooms. The model does notcredit metal heat sinks in the RSS rooms which would reduce the temperature in theserooms. The model also does not consider opening the doors to these rooms, whichwould allow mixing with the adjacent rooms. The case with inverters operating in theStandby Switchgear Rooms is selected to conservatively maximize the temperature inStandby Switchgear Room 1B located outside the Division 2 RSS room.Table 5 shows the temperatures in the RSS rooms and adjacent rooms outside theDivision 1 RSS room (98 foot General Area, CB098-10) and the Division 2 RSS room(Standby Switchgear room 1B, CB098-12) at 2 and 6 hours. The temperatures in theDivision 1 RSS rooms remain below 115 oF at 2 hours and below 119 | |||
Revision as of 12:36, 8 July 2018
| ML16092A034 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 04/01/2016 |
| From: | Young C H NRC/RGN-IV/DRP/RPB-C |
| To: | |
| Young C H | |
| References | |
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RBS Remote Shutdown Room Heat-UpPage 1Evaluation of RBS Remote Shutdown Panel Rooms following a Loss ofControl Building HVACPurposeEvaluate the temperatures in the Remote Shutdown Panel rooms (Division 1 andDivision 2 RSS) following a loss of Control Building HVAC.BackgroundOn March 9, 2015, during a scheduled refueling outage, RBS experienced a temporaryloss of Control Building and Main Control Room (MCR) cooling due to trip of theassociated chilled water system (HVK). The NRC has raised concerns regarding thereliability of electrical equipment and the long-term habitability of the Main Control Room(MCR) following a loss of cooling. RBS has developed detailed GOTHIC thermal-hydraulic models of the RBS Main Control Room and Control Building and evaluatedthe MCR heat-up following a loss of all cooling assuming various mitigating actions(References 1, 2, and 6). The MCR heat-up evaluations include cases with designbasis normal operating MCR heat loads (Ref. 3) and with measured heat loadsdetermined from a steady-state MCR heat balance performed during normal operations(Ref. 4). The measured heat loads are 57% of the design normal operating heat load.The MCR heat-up evaluations show that the MCR average temperature reaches 116 o Fwithin two hours of a loss of HVAC with design heat loads. However, using the actual, measured heat loads, the MCR temperature remains below 113 oF for six hoursfollowing a loss of HVAC. Should mitigating actions to provide cooling to the MCR prove unsuccessful and the environmental conditions in the MCR worsen such thatoperator habitability is challenged, operators could evacuate to the Division 1 or Division2 Remote Shutdown (RSS) rooms and shutdown the plant from the remote shutdownpanels. This evaluation determines if the Division 1 and Division 2 RSS rooms willremain habitable and equipment remain available during a loss of control building HVAC event.ConclusionsBoth the Division 1 and Division 2 RSS rooms would remain habitable and equipmentwould remain available following a loss of HVAC in the control building. Should theMCR be abandoned due to a loss of control building HVAC, operators would open thedoors to the RSS rooms to allow access. Opening of these doors would provide mixingvia natural circulation with the air in the adjacent control building rooms. As shown inReference 6, the Control Building Switchgear Area heat loads under a LOCA-LOOPcondition is lower than the heat loads for a LOCA with offsite power, which wouldreduce the temperatures in the RSS rooms. Page 167 of Reference 7 shows that theheatup for these rooms is minimal under LOOP conditions. The MCR heat-upcalculations show that the MCR would remain habitable for at least 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> assumingmeasured heat loads and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> assuming design heat loads. Without taking creditfor metal heat sinks in the RSS rooms, temperatures in the most limiting RSS room areexpected to remain below 108°F during the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and below 114°F at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.Therefore, in the unlikely event of a rapid MCR heat-up requiring early MCR evacuation(within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />), the temperature in the limiting RSS room after opening doors is RBS Remote Shutdown Room Heat-UpPage 2expected to be less than 108 oF. For the slower MCR heat up using measured heatloads, MCR evacuation is less likely due to the increased time (6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) available toimplement mitigating actions. However, if evacuation to the RSS rooms occurs at 6hours, the temperature in the limiting RSS room after opening doors is expected to beless than 114 oF. The temperatures predicted for the RSS rooms are lower than thevalues reported in G13.18.12.3*161 (Reference 7), due to the refined heat loads andmodeling techniques applied in ENTR-078-CALC-001 (Reference 6) and thisevaluation.EvaluationRSS Room DescriptionThe Division 1 (CB098-11) and Division 2 (CB098-13) RSS rooms are located on the 98foot elevation of the control building. The volume of the Division 1 RSS is approximately 971 ft 3 while the Division 2 RSS is approximately 1626 ft
- 3. The control panels in theserooms as listed in the tables below provide a substantial amount of steel mass thatwould act as a heat sink during heat up of the rooms following a loss of HVAC. TheDivision 1 RSS room includes a single door that opens to the general area of the 98 footelevation (CB098-10). The Division 2 RSS room includes two doors that open to theStandby Switch Gear Room 1B (CB098-12).Division 1 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 1 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 1: Div. 1 RSS E-226 Heat LoadsDiv. 1EquipmentHeat LoadNormal(Watts)LOCA withOffsitePower(Watts)C61-PNLP001 200200RSS-PNL101540540Lighting (5)480480TOTAL12201220A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS101. The individualparts and components of the RSS-PNL101 were reviewed in ESK-4RSS101 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL101 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Div. 1 RSS room contained 4 light fixtures with each fixture containing two40W light bulbs. Based on the review, the revised heat loads are presented in Table 2.
RBS Remote Shutdown Room Heat-UpPage 3Table 2: Div. 1 RSS Revised Heat LoadsDiv. 1EquipmentHeat LoadLOCA withOffsitePower(Watts)Reduction (%)C61-PNLP001200 0%RSS-PNL101180 67%Lighting (4)320 33%TOTAL70043%Division 2 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 2 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 3: Div. 2 RSS E-226 Heat LoadsDiv. 2EquipmentHeat LoadNormal(Watts)LOCA withOffsite Power(Watts)RSS-PNL102540540Lighting (2)192192TOTAL732732A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS102. The individualparts and components of the RSS-PNL102 were reviewed in ESK-4RSS102 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL102 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Division 2 RSS room contained 2 light fixtures with each fixture containingtwo 34W light bulbs. Based on the review, the revised heat loads are presented in Table 4.Table 4: Div. 2 RSS Revised Heat LoadsDiv. 2EquipmentHeat LoadLOCA withOffsite Power(Watts)Reduction (%)RSS-PNL102200 63%Lighting (2)136 29%TOTAL33654%
RBS Remote Shutdown Room Heat-UpPage 4RSS Room Temperatures Following Loss of HVACThe temperatures in the Division 1 and 2 RSS rooms following a loss of HVAC werecalculated using the Control Building (GOTHIC) model that opens the doors in theControl Building at 30 minutes developed in Reference 6. The temperatures of the RSSrooms did not change at 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> for the case with no doors opened fromReference 6. The control building heat loads for the LOCA with offsite power case wereused as they result in the bounding heat loads for LOCA and non-LOCA cases. Therevised heat loads from Table 2 and 4 are used in the RSS rooms. The model does notcredit metal heat sinks in the RSS rooms which would reduce the temperature in theserooms. The model also does not consider opening the doors to these rooms, whichwould allow mixing with the adjacent rooms. The case with inverters operating in theStandby Switchgear Rooms is selected to conservatively maximize the temperature inStandby Switchgear Room 1B located outside the Division 2 RSS room.Table 5 shows the temperatures in the RSS rooms and adjacent rooms outside theDivision 1 RSS room (98 foot General Area, CB098-10) and the Division 2 RSS room(Standby Switchgear room 1B, CB098-12) at 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The temperatures in theDivision 1 RSS rooms remain below 115 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and below 119 o F at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.Temperatures in the Division 2 RSS room remain below 100 oF at 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Thetemperature outside the Division 1 RSS room is 97.2 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 101.8 o F at 6hours. The temperature in the Standby Switchgear Room outside the Division 2 RSSroom is 108.5 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 114.4 oF at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Should the MCR be abandoned,operators would open the doors to the RSS rooms to allow access. Due to the smallsize of these rooms, opening the room doors would be a highly effective means ofproviding mixing of the room air with the larger adjacent rooms. The RSS rooms wouldbe expected to stabilize at a temperature within a few degrees of the temperature of thearea outside the room. Therefore, the temperature in the Division 1 RSS room willdecrease after the door is opened for operator access and is estimated to be no more than 100 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 110 oF at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The temperature in the Division 2 RSSroom will increase after the door is opened for operator access. The temperature wouldbe no more than 108 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 114 o F at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.Table 5: RSS and Adjacent Room Temperatures RoomTemperature (o F)2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s6 HoursDiv 1 RSS (CB098-11)114.2118.7General Area (CB098-10)97.2101.8Div 2 RSS (CB098-13)97.899.7Stby SG Room 1B (CB098-12)108.5114.4 RBS Remote Shutdown Room Heat-UpPage 5References1. Calculation ENTR-078-CALC-003, Rev. 4, "Main Control Room Heat-Up Under Lossof HVAC Conditions for 24 Hours."2. RBS-ME-16-00002, Rev. 0 (ENTR-078-CALC-004, Rev. 0), "Main Control RoomHeat-Up Analysis During Loss of HVAC Conditions for 24 Hours."3. EC61975, "References for E-226 Calculation Revision."4. RBS-ME-16-00003, Rev. 0, "Evaluation of Main Control Room Heat-up on Loss ofHVAC Based on Empirical Temperature and Flow Data."5. Calculation E-226, Rev. 5, "Control Building Electrical Equipment Heat ReleaseDuring LOCA Condition With Off Site Power Available and Also Control BuildingElectrical Heat Release During LOCA Condition Without Offsite Power (LOOP andwith EGS-EG1B Diesel Generator Not Responding."6. Calculation ENTR-078-CALC-001, Rev. 1, "Control Building Heatup AnalysisFollowing Loss of HVAC."7. Calculation G13.18.12.3*161, Rev. 2, "Standby Switchgear Room Temperaturesfollowing Loss of Offsite Power and Loss of HVAC".
RBS Remote Shutdown Room Heat-UpPage 1Evaluation of RBS Remote Shutdown Panel Rooms following a Loss ofControl Building HVACPurposeEvaluate the temperatures in the Remote Shutdown Panel rooms (Division 1 andDivision 2 RSS) following a loss of Control Building HVAC.BackgroundOn March 9, 2015, during a scheduled refueling outage, RBS experienced a temporaryloss of Control Building and Main Control Room (MCR) cooling due to trip of theassociated chilled water system (HVK). The NRC has raised concerns regarding thereliability of electrical equipment and the long-term habitability of the Main Control Room(MCR) following a loss of cooling. RBS has developed detailed GOTHIC thermal-hydraulic models of the RBS Main Control Room and Control Building and evaluatedthe MCR heat-up following a loss of all cooling assuming various mitigating actions(References 1, 2, and 6). The MCR heat-up evaluations include cases with designbasis normal operating MCR heat loads (Ref. 3) and with measured heat loadsdetermined from a steady-state MCR heat balance performed during normal operations(Ref. 4). The measured heat loads are 57% of the design normal operating heat load.The MCR heat-up evaluations show that the MCR average temperature reaches 116 o Fwithin two hours of a loss of HVAC with design heat loads. However, using the actual, measured heat loads, the MCR temperature remains below 113 oF for six hoursfollowing a loss of HVAC. Should mitigating actions to provide cooling to the MCR prove unsuccessful and the environmental conditions in the MCR worsen such thatoperator habitability is challenged, operators could evacuate to the Division 1 or Division2 Remote Shutdown (RSS) rooms and shutdown the plant from the remote shutdownpanels. This evaluation determines if the Division 1 and Division 2 RSS rooms willremain habitable and equipment remain available during a loss of control building HVAC event.ConclusionsBoth the Division 1 and Division 2 RSS rooms would remain habitable and equipmentwould remain available following a loss of HVAC in the control building. Should theMCR be abandoned due to a loss of control building HVAC, operators would open thedoors to the RSS rooms to allow access. Opening of these doors would provide mixingvia natural circulation with the air in the adjacent control building rooms. As shown inReference 6, the Control Building Switchgear Area heat loads under a LOCA-LOOPcondition is lower than the heat loads for a LOCA with offsite power, which wouldreduce the temperatures in the RSS rooms. Page 167 of Reference 7 shows that theheatup for these rooms is minimal under LOOP conditions. The MCR heat-upcalculations show that the MCR would remain habitable for at least 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> assumingmeasured heat loads and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> assuming design heat loads. Without taking creditfor metal heat sinks in the RSS rooms, temperatures in the most limiting RSS room areexpected to remain below 108°F during the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and below 114°F at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.Therefore, in the unlikely event of a rapid MCR heat-up requiring early MCR evacuation(within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />), the temperature in the limiting RSS room after opening doors is RBS Remote Shutdown Room Heat-UpPage 2expected to be less than 108 oF. For the slower MCR heat up using measured heatloads, MCR evacuation is less likely due to the increased time (6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) available toimplement mitigating actions. However, if evacuation to the RSS rooms occurs at 6hours, the temperature in the limiting RSS room after opening doors is expected to beless than 114 oF. The temperatures predicted for the RSS rooms are lower than thevalues reported in G13.18.12.3*161 (Reference 7), due to the refined heat loads andmodeling techniques applied in ENTR-078-CALC-001 (Reference 6) and thisevaluation.EvaluationRSS Room DescriptionThe Division 1 (CB098-11) and Division 2 (CB098-13) RSS rooms are located on the 98foot elevation of the control building. The volume of the Division 1 RSS is approximately 971 ft 3 while the Division 2 RSS is approximately 1626 ft
- 3. The control panels in theserooms as listed in the tables below provide a substantial amount of steel mass thatwould act as a heat sink during heat up of the rooms following a loss of HVAC. TheDivision 1 RSS room includes a single door that opens to the general area of the 98 footelevation (CB098-10). The Division 2 RSS room includes two doors that open to theStandby Switch Gear Room 1B (CB098-12).Division 1 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 1 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 1: Div. 1 RSS E-226 Heat LoadsDiv. 1EquipmentHeat LoadNormal(Watts)LOCA withOffsitePower(Watts)C61-PNLP001 200200RSS-PNL101540540Lighting (5)480480TOTAL12201220A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS101. The individualparts and components of the RSS-PNL101 were reviewed in ESK-4RSS101 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL101 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Div. 1 RSS room contained 4 light fixtures with each fixture containing two40W light bulbs. Based on the review, the revised heat loads are presented in Table 2.
RBS Remote Shutdown Room Heat-UpPage 3Table 2: Div. 1 RSS Revised Heat LoadsDiv. 1EquipmentHeat LoadLOCA withOffsitePower(Watts)Reduction (%)C61-PNLP001200 0%RSS-PNL101180 67%Lighting (4)320 33%TOTAL70043%Division 2 RSS Heat LoadsThe E-226 R5 calculation (Ref. 5, pg. 44) provides the following heat loads for theDivision 2 RSS (note that normal heat loads and LOCA with offsite power are identical).Table 3: Div. 2 RSS E-226 Heat LoadsDiv. 2EquipmentHeat LoadNormal(Watts)LOCA withOffsite Power(Watts)RSS-PNL102540540Lighting (2)192192TOTAL732732A review of the panels and walk downs were performed to evaluate the panels andlighting to ensure that the heat loads documented in the E-226 R5 calculation wereaccurate. The panel review was performed by reviewing ESK-4RSS102. The individualparts and components of the RSS-PNL102 were reviewed in ESK-4RSS102 and theheat load of the heat generating components was determined based on the wattagerating of each item. The total heat load for RSS-PNL102 is found by summing up theheat loads of the individual components. The lighting review was performed by walkdowns. The Division 2 RSS room contained 2 light fixtures with each fixture containingtwo 34W light bulbs. Based on the review, the revised heat loads are presented in Table 4.Table 4: Div. 2 RSS Revised Heat LoadsDiv. 2EquipmentHeat LoadLOCA withOffsite Power(Watts)Reduction (%)RSS-PNL102200 63%Lighting (2)136 29%TOTAL33654%
RBS Remote Shutdown Room Heat-UpPage 4RSS Room Temperatures Following Loss of HVACThe temperatures in the Division 1 and 2 RSS rooms following a loss of HVAC werecalculated using the Control Building (GOTHIC) model that opens the doors in theControl Building at 30 minutes developed in Reference 6. The temperatures of the RSSrooms did not change at 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> for the case with no doors opened fromReference 6. The control building heat loads for the LOCA with offsite power case wereused as they result in the bounding heat loads for LOCA and non-LOCA cases. Therevised heat loads from Table 2 and 4 are used in the RSS rooms. The model does notcredit metal heat sinks in the RSS rooms which would reduce the temperature in theserooms. The model also does not consider opening the doors to these rooms, whichwould allow mixing with the adjacent rooms. The case with inverters operating in theStandby Switchgear Rooms is selected to conservatively maximize the temperature inStandby Switchgear Room 1B located outside the Division 2 RSS room.Table 5 shows the temperatures in the RSS rooms and adjacent rooms outside theDivision 1 RSS room (98 foot General Area, CB098-10) and the Division 2 RSS room(Standby Switchgear room 1B, CB098-12) at 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The temperatures in theDivision 1 RSS rooms remain below 115 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and below 119 o F at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.Temperatures in the Division 2 RSS room remain below 100 oF at 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Thetemperature outside the Division 1 RSS room is 97.2 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 101.8 o F at 6hours. The temperature in the Standby Switchgear Room outside the Division 2 RSSroom is 108.5 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 114.4 oF at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Should the MCR be abandoned,operators would open the doors to the RSS rooms to allow access. Due to the smallsize of these rooms, opening the room doors would be a highly effective means ofproviding mixing of the room air with the larger adjacent rooms. The RSS rooms wouldbe expected to stabilize at a temperature within a few degrees of the temperature of thearea outside the room. Therefore, the temperature in the Division 1 RSS room willdecrease after the door is opened for operator access and is estimated to be no more than 100 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 110 oF at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The temperature in the Division 2 RSSroom will increase after the door is opened for operator access. The temperature wouldbe no more than 108 oF at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 114 o F at 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.Table 5: RSS and Adjacent Room Temperatures RoomTemperature (o F)2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s6 HoursDiv 1 RSS (CB098-11)114.2118.7General Area (CB098-10)97.2101.8Div 2 RSS (CB098-13)97.899.7Stby SG Room 1B (CB098-12)108.5114.4 RBS Remote Shutdown Room Heat-UpPage 5References1. Calculation ENTR-078-CALC-003, Rev. 4, "Main Control Room Heat-Up Under Lossof HVAC Conditions for 24 Hours."2. RBS-ME-16-00002, Rev. 0 (ENTR-078-CALC-004, Rev. 0), "Main Control RoomHeat-Up Analysis During Loss of HVAC Conditions for 24 Hours."3. EC61975, "References for E-226 Calculation Revision."4. RBS-ME-16-00003, Rev. 0, "Evaluation of Main Control Room Heat-up on Loss ofHVAC Based on Empirical Temperature and Flow Data."5. Calculation E-226, Rev. 5, "Control Building Electrical Equipment Heat ReleaseDuring LOCA Condition With Off Site Power Available and Also Control BuildingElectrical Heat Release During LOCA Condition Without Offsite Power (LOOP andwith EGS-EG1B Diesel Generator Not Responding."6. Calculation ENTR-078-CALC-001, Rev. 1, "Control Building Heatup AnalysisFollowing Loss of HVAC."7. Calculation G13.18.12.3*161, Rev. 2, "Standby Switchgear Room Temperaturesfollowing Loss of Offsite Power and Loss of HVAC".