ML16120A420

Palisades - Final Safety Analysis Report Update, Revision 32, Chapter 6 - Engineered Safeguards Systems - Sections

ML16120A420
Person / Time
Site:	Palisades
Issue date:	04/18/2016
From:	Entergy Nuclear Operations
To:	Office of Nuclear Reactor Regulation
Shared Package
ML16120A302	List: ML16120A321 ML16120A325 ML16120A326 ML16120A327 ML16120A344 ML16120A345 ML16120A347 ML16120A359 ML16120A360 ML16120A361 ML16120A362 ML16120A379 ML16120A380 ML16120A381 ML16120A382 ML16120A415 ML16120A416 ML16120A417 ML16120A419 ML16120A420 ML16120A421 ML16120A571 ML16120A573 ML16120A574 ML16120A575 ML16120A588 ML16120A589 ML16120A590 ML16120A591 ML16120A596 ML16120A597 ML16120A598 ML16120A599 ML16120A602 ML16120A603 ML16120A604 ML16120A608 ML16120A609 ML16120A610 ML16123A314 ML16123A315 ML16123A316 ML16123A320 ML16123A321 ML16123A326 ML16123A328 ML16123A329 ML16126A109 PNP 2016-015, Final Safety Analysis Report Update, Revision 32, Table of Contents
References
PNP 2016-015
Download: ML16120A420 (52)

Text

FSAR CHAPTER 6 - ENGINEERED SAFEGUARDS SYSTEMSRevision 30SECTION 6.4Page 6.4-1 of 6.4-36.4CONTAINMENT SUMP PH CONTROL6.4.1DESIGN BASISPursuant to Amendments 158 and 165 to the Operating License DPR-20 andthe changes to the Technical Specifications, the existing Iodine RemovalSystem involving hydrazine and sodium hydroxide addition has been deleted.The Containment Spray System acts to reduce the post-accident level offission products in the containment atmosphere. In addition, baskets ofsodium tetraborate (NaTB) are installed in the containment to maintain aneutral containment sump solution by the onset of the recirculation phase, forpurposes of iodine retention.6.4.2.1 General DescriptionThe sodium tetraborate (NaTB) baskets consist of wire mesh basketscontaining between 8,186 and 10,553 lbs of granular NaTB decahydrate(Reference 25) and are placed inside the containment at the 590' elevation.The baskets have solid lids and are raised from the floor to avoid loss ofNaTB due to any spillage or leakage on the containment floor during normalplant operations. The NaTB baskets are sized and designed to ensure timelydissolution of NaTB by the onset of containment spray recirculation, and toensure contact with flooding. Theapproximate time for a RecirculationActuation Signal (RAS) is 20 minutes after a large break LOCA with bothtrains of engineered safeguards equipment operating.6.4.2.2 OperationPrior to Recirculation Actuation Signal (RAS), borated water from thecontainment spray and the postulated pipe break would be flowing towardsthe containment sump. In the case of a large break LOCA, the EmergencyCore Cooling System (ECCS) water is pumped into the containment and thuscreating a highly turbulent environment. The granular NaTB is submergedand dissolved in the flood, thus raising the pH of the containment sumpsolution by the onset of containment spray recirculation. In the case of amuch smaller break, the flow rate would not be as high as that after a largebreak LOCA. However, RAS would not occur as quickly as in the large breakscenario and consequently a longer period of time would be available for theNaTB to dissolve.The pH of the aqueous solution collected into the containment sump shouldbe maintained at a level sufficiently high to provide assurance that significantlong term iodine re-evolution does not occur. Long term iodine retention maybe achieved only when the equilibrium sump solution pH, after mixing anddilution with the primary coolant and ECCS injection, is above 7. This pHvalue is achieved by the onset of the spray recirculation mode. Containmentsump pH control with granular NaTB is completely passive, requiring noactive mechanical or operator action. Periodic samples of NaTB are taken toensure the NaTB 's dissolution and buffering capabilities.

FSAR CHAPTER 6 - ENGINEERED SAFEGUARDS SYSTEMSRevision 30SECTION 6.4Page 6.4-2 of 6.4-36.4.2.3 MaterialsThe material of the equipment and components of the Emergency CoreCooling Systems have been examined for compatibility with the sodiumtetraborate solution and are adequate for extended operation in contact withthis solution. The components and materials are listed in Table 6-10. TheNaTB baskets are fabricated from all stainless steel materials to bechemically compatible with the NaTB.Service Water Valves Body - Carbon Steel ASTM A 216 WCB Operator Enclosure - Cast IronContainment Spray NozzlesThe design of the spray nozzles was reviewed to confirm that the spraynozzles are not subject to clogging from debris entering the recirculationsystem through the containment sump screens. It was concluded that sodiumtetraborate solution will have no effect on containment spray systemoperation.Containment Air Cooler Fan Blades The fan blades are aluminum and would be affected by this solution ifexposure were credible. Exposure is not considered possible since the fansdraw suction from the steam generator compartments which are covered and,therefore, not exposed to the spray water. Any droplets carried into thesecompartments will first pass through an inlet filter and then are passed overthe coils. The filter will remove most of these droplets and the coils willremove the balance. Any droplets passing through the filter will beintercepted by the coils and diluted by the condensate on the coils. Anydroplets which might escape the coils will be considerably diluted; further, thelow velocity in the fan inlet plenum will allow any droplets which escape thecoils to fall into the condensate collection chamber and the physical locationof the fans in a vertical duct approximately six feet above the outlet of thecoolers precludes the transport of droplets to the fan blades. Additionally,when the containment air cooler fans were replaced under Facility ChangeFC-548, the new fan blades and fan wheel hubs were coated with stainlesssteel, which prevents the aluminum from being chemically affected.

FSAR CHAPTER 6 - ENGINEERED SAFEGUARDS SYSTEMSRevision 30SECTION 6.4Page 6.4-3 of 6.4-36.4.2.4 PaintThe paint systems used on the large surface area equipment insidecontainment were selected on the basis of withstanding the post-MHAenvironmental condition of 283°F, 55 psig, 100% relative humidity, boratedwater, an integrated dose of 2 x 107 rads, and suitable heat transfer to theheat sinks.To meet these requirements, the primary paint system selected was aCarboline Co inorganic zinc system, Carbo Zinc 11 primer and inorganic zincfinish No 3912. Inorganic zinc paint systems have been tested as follows:1.Irradiated at 2.6 x 106 R/h to a cumulative dose up to 1 x 1010 R ascovered by ORNL Report No 3916 and ORNL Report No 3589 (seeReferences 3 and 4). The conclusions based on the results of theirradiation tests are that the inorganic zinc paint systems will withstandthe post-MHA radiation.2.Subjected to 44 hours5.092593e-4 days <br />0.0122 hours <br />7.275132e-5 weeks <br />1.6742e-5 months <br />' test with samples submerged in a solution at212°F, 1.3% boric acid and 9.5 pH. Conclusions derived from theORNL test data are that the inorganic zinc systems will withstand thepost-MHA condition with negligible hydrogen production.3.Subjected to manufacturer's test with samples submerged in a solutionof 9.5 pH with the temperature varied as follows:150°F to 285°F in 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />s285°F held for 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />s285°F to 200°F in 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />sFrom the test results, the manufacturer has reported no significant physicalchange in the paint system and calculates a hydrogen production of5 x 10-6 grams/square foot/hour of surface.Decontaminable coatings of the generic epoxy and phenolic type have beenused in the Palisades containment. Both systems have also been subjectedto and satisfactorily passed tests of irradiation up to 1 x 1010 rads as reportedin ORNL-3589 and ORNL-3916 (see References 4 and 3, respectively).Certain small surface area equipment has been coated with systems such asred lead primer on structural steel and various manufacturers' standardcoatings on equipment. These systems have not been specifically subjectedto tests at post-MHA conditions. Past experience of removing these systemsindicates that, if the paint failed, it would become a granular residue andwould not fail by large sheets falling from the surface. The granular residuewould settle to the floors with minimum possibility of settlement entering thedrain piping and recirculation piping. Therefore, failure of these paint systemsto a granular residue would not result in plugging of any of the Palisadesrecirculation or spray equipment.

FSAR CHAPTER 6 - ENGINEERED SAFEGUARDS SYSTEMSRevision 30SECTION 6.4Page 6.4-1 of 6.4-36.4CONTAINMENT SUMP PH CONTROL6.4.1DESIGN BASISPursuant to Amendments 158 and 165 to the Operating License DPR-20 andthe changes to the Technical Specifications, the existing Iodine RemovalSystem involving hydrazine and sodium hydroxide addition has been deleted.The Containment Spray System acts to reduce the post-accident level offission products in the containment atmosphere. In addition, baskets ofsodium tetraborate (NaTB) are installed in the containment to maintain aneutral containment sump solution by the onset of the recirculation phase, forpurposes of iodine retention.6.4.2.1 General DescriptionThe sodium tetraborate (NaTB) baskets consist of wire mesh basketscontaining between 8,186 and 10,553 lbs of granular NaTB decahydrate(Reference 25) and are placed inside the containment at the 590' elevation.The baskets have solid lids and are raised from the floor to avoid loss ofNaTB due to any spillage or leakage on the containment floor during normalplant operations. The NaTB baskets are sized and designed to ensure timelydissolution of NaTB by the onset of containment spray recirculation, and toensure contact with flooding. Theapproximate time for a RecirculationActuation Signal (RAS) is 20 minutes after a large break LOCA with bothtrains of engineered safeguards equipment operating.6.4.2.2 OperationPrior to Recirculation Actuation Signal (RAS), borated water from thecontainment spray and the postulated pipe break would be flowing towardsthe containment sump. In the case of a large break LOCA, the EmergencyCore Cooling System (ECCS) water is pumped into the containment and thuscreating a highly turbulent environment. The granular NaTB is submergedand dissolved in the flood, thus raising the pH of the containment sumpsolution by the onset of containment spray recirculation. In the case of amuch smaller break, the flow rate would not be as high as that after a largebreak LOCA. However, RAS would not occur as quickly as in the large breakscenario and consequently a longer period of time would be available for theNaTB to dissolve.The pH of the aqueous solution collected into the containment sump shouldbe maintained at a level sufficiently high to provide assurance that significantlong term iodine re-evolution does not occur. Long term iodine retention maybe achieved only when the equilibrium sump solution pH, after mixing anddilution with the primary coolant and ECCS injection, is above 7. This pHvalue is achieved by the onset of the spray recirculation mode. Containmentsump pH control with granular NaTB is completely passive, requiring noactive mechanical or operator action. Periodic samples of NaTB are taken toensure the NaTB 's dissolution and buffering capabilities.

FSAR CHAPTER 6 - ENGINEERED SAFEGUARDS SYSTEMSRevision 30SECTION 6.4Page 6.4-2 of 6.4-36.4.2.3 MaterialsThe material of the equipment and components of the Emergency CoreCooling Systems have been examined for compatibility with the sodiumtetraborate solution and are adequate for extended operation in contact withthis solution. The components and materials are listed in Table 6-10. TheNaTB baskets are fabricated from all stainless steel materials to bechemically compatible with the NaTB.Service Water Valves Body - Carbon Steel ASTM A 216 WCB Operator Enclosure - Cast IronContainment Spray NozzlesThe design of the spray nozzles was reviewed to confirm that the spraynozzles are not subject to clogging from debris entering the recirculationsystem through the containment sump screens. It was concluded that sodiumtetraborate solution will have no effect on containment spray systemoperation.Containment Air Cooler Fan Blades The fan blades are aluminum and would be affected by this solution ifexposure were credible. Exposure is not considered possible since the fansdraw suction from the steam generator compartments which are covered and,therefore, not exposed to the spray water. Any droplets carried into thesecompartments will first pass through an inlet filter and then are passed overthe coils. The filter will remove most of these droplets and the coils willremove the balance. Any droplets passing through the filter will beintercepted by the coils and diluted by the condensate on the coils. Anydroplets which might escape the coils will be considerably diluted; further, thelow velocity in the fan inlet plenum will allow any droplets which escape thecoils to fall into the condensate collection chamber and the physical locationof the fans in a vertical duct approximately six feet above the outlet of thecoolers precludes the transport of droplets to the fan blades. Additionally,when the containment air cooler fans were replaced under Facility ChangeFC-548, the new fan blades and fan wheel hubs were coated with stainlesssteel, which prevents the aluminum from being chemically affected.

FSAR CHAPTER 6 - ENGINEERED SAFEGUARDS SYSTEMSRevision 30SECTION 6.4Page 6.4-3 of 6.4-36.4.2.4 PaintThe paint systems used on the large surface area equipment insidecontainment were selected on the basis of withstanding the post-MHAenvironmental condition of 283°F, 55 psig, 100% relative humidity, boratedwater, an integrated dose of 2 x 107 rads, and suitable heat transfer to theheat sinks.To meet these requirements, the primary paint system selected was aCarboline Co inorganic zinc system, Carbo Zinc 11 primer and inorganic zincfinish No 3912. Inorganic zinc paint systems have been tested as follows:1.Irradiated at 2.6 x 106 R/h to a cumulative dose up to 1 x 1010 R ascovered by ORNL Report No 3916 and ORNL Report No 3589 (seeReferences 3 and 4). The conclusions based on the results of theirradiation tests are that the inorganic zinc paint systems will withstandthe post-MHA radiation.2.Subjected to 44 hours5.092593e-4 days <br />0.0122 hours <br />7.275132e-5 weeks <br />1.6742e-5 months <br />' test with samples submerged in a solution at212°F, 1.3% boric acid and 9.5 pH. Conclusions derived from theORNL test data are that the inorganic zinc systems will withstand thepost-MHA condition with negligible hydrogen production.3.Subjected to manufacturer's test with samples submerged in a solutionof 9.5 pH with the temperature varied as follows:150°F to 285°F in 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />s285°F held for 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />s285°F to 200°F in 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />sFrom the test results, the manufacturer has reported no significant physicalchange in the paint system and calculates a hydrogen production of5 x 10-6 grams/square foot/hour of surface.Decontaminable coatings of the generic epoxy and phenolic type have beenused in the Palisades containment. Both systems have also been subjectedto and satisfactorily passed tests of irradiation up to 1 x 1010 rads as reportedin ORNL-3589 and ORNL-3916 (see References 4 and 3, respectively).Certain small surface area equipment has been coated with systems such asred lead primer on structural steel and various manufacturers' standardcoatings on equipment. These systems have not been specifically subjectedto tests at post-MHA conditions. Past experience of removing these systemsindicates that, if the paint failed, it would become a granular residue andwould not fail by large sheets falling from the surface. The granular residuewould settle to the floors with minimum possibility of settlement entering thedrain piping and recirculation piping. Therefore, failure of these paint systemsto a granular residue would not result in plugging of any of the Palisadesrecirculation or spray equipment.