ML13004A060

Units 1 and 2, Updated Final Safety Analysis Report, Revision 14, Chapter 6.0 - Engineered Safety Features

ML13004A060
Person / Time
Site:	Byron, Braidwood
Issue date:	12/14/2012
From:	Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Office of Nuclear Material Safety and Safeguards
References
RS-12-221
Download: ML13004A060 (642)

Text

B/B-UFSAR 6.1-1 CHAPTER 6.0 - ENGINEER ED SAFETY FEATURES

6.0 ENGINEERED

SAFETY FEATURES The engineered safety features of the By ron and Braidwood Stations are those systems who se actions are essential to a safety action requir ed to mitigate the c onsequences of postulated accidents. The features can be divided into five general groups as follows: containment systems, emergency core cooling systems (ECCS), habitability systems, fission pr oduct removal, and control systems and other systems. The engineered safety features, listed above, are disc ussed in detail thro ughout this chapter. 6.1 ENGINEERED SAFETY FEATURES MATERIALS

6.1.1 Metallic

Materials 6.1.1.1 Materials Sele ction and Fabrication Material specifications used for the princip al pressure retaining applications in the co mponents of the engine ered safety features (ESF) are listed in Table 6.1-1.

In some cases, Table 6.1-1 may not be totally inclusive of the material speci fications used in the listed applications; however, the listed spe cifications are representative of those materials utilized.

All of the materials used conform to the requirements of the ASME Boiler and Pressure Vessel Code,Section III, plus applicable and appropriate addenda and code cases.

The welding materials used for joining t he ferritic base materials of the ESF conform to or are equivalent to ASME Material Specifications SFA 5.1, 5.5, 5.13, 5.17, 5.18, 5.20, 5.23, and 5.28. The welding materials used for joining nickel-chromium-iron alloy in s imilar base material c ombination and in dissimilar ferritic or austenitic base material combination conform to ASME Material Specifications SFA 5.11 and 5.14. The welding materials used f or joining the austenitic stainless steel base materials c onform to ASME M aterial Specificatio ns SFA 5.4, 5.9, and 5.30. These materials are tested a nd qualified to the requirements of the AS ME Code,Section III a nd Section IX rules, and are used in proced ures which have been qualified to these same rules.

Parts of components in c ontact with borated wa ter are fabricated of, or clad with austenitic st ainless steel or equivalent corrosion resistant ma terial. The integ rity of the safety-related components of the ESF is maintained during all stages of component manufacture.

Austenitic stainless s teel is used in the final heat treated con dition as required by the respective ASME Code Section II material specification for t he particular type or grade of alloy. Fur thermore, austenitic stainless steel materials used in the ESF comp onents are handled, protected, stored, and cleaned ac cording to recognized

B/B-UFSAR 6.1-2 REVISION 1 - DECEMBER 1989 and accepted methods w hich are designed to minimize contamination which could lead to stress corrosion cracking; these controls are stipulated in Westinghouse proce ss specifications, which are discussed in Subsection

5.2.3. Additional

i nformation concerning austenitic stainless steel, including the avoidance of sensitization and the prevention of intergranular attack, can be found in Subsection 5.2.

3. No cold worked a ustenitic stainless steels having yield stre ngths greater than 90, 000 psi are used for components of the ESF supplied by Westinghouse.

Components within the containment that would be exposed to core cooling water and co ntainment sprays in the event of a loss-of-coolant accident utilize materials listed in Table 6.1-1. These components are manufactured pr imarily of stainless steel or other corrosion resistant material.

The integrity of the materials of constru ction for ESF equipment when exposed to post design-basis accident (DBA) conditions has been evaluated.

Post DBA conditions were conse rvatively repres ented by test conditions. The test progra m (Reference 1) performed by Westinghouse considered spray and core cooli ng solutions of the design chemical compos itions, as well as the design chemical compositions contamina ted with corrosion and deterioration products which may be transferred to the solution during recirculation. The effects of s odium (free caus tic), chlorine (chloride), and fluorine (fluori de) on austenitic stainless steels were considered.

Based on this inves tigation, as well as testing by ORNL and ot hers, the behavior of austenitic stainless steels in the post D BA environment will be acceptable. No cracking is anticipated on any equipment even in the presence of postulated levels of contaminant s, provided the core cooling and spray solution pH is maintained at an ad equate level. The inhibitive properties of alkal inity (hydroxyl ion) against chloride cracking and the inhibitive characteristic of boric acid on fluoride cracking h ave been demonstrated.

Coatings on exposed surfaces within the co ntainment are not subj ect to breakdown under exposure to the spray solution and can withstand the temperature and pressure expec ted in the event of a loss-of-coolant accident.

The majority of the co ating work inside contai nment complies with the guidelines of Regu latory Guide 1.54, "Quality Assurance Requirements for Protective Coat ings Applied to Water-Cooled Nuclear Power Plants."

The majority of the ma terial manufactured and applied conforms to requirements of ANSI N101.2, "Protective Coatings (Paints) for Light Water Nuclear Reactor Containment Facilities," ANSI N5.12, "Protec tive Coatings (P aints) for the Nuclear Industry," a nd ANSI N101.4, "Qua lity Assurance for Protective Coatings Applied to Nuclear F acilities" (see Subsection 6.1.2).

Information concerning t he degree to whi ch the materials used comply with requiremen ts for control of ferrite content in stainless steel weld metal, cleaning of fluid systems and

B/B-UFSAR 6.1-3 REVISION 11 - DECEMBER 2006 associated components, and control of the use of sensitized stainless steels can be found in Appendix A.

6.1.1.2 Composition, Compatibility, and Stability of Containment and Core Spray Coolants The containment spray sy stem is designed to provide a sufficient quantity of 30% to 36%

sodium hydroxide to t he containment to form a minimum of 8.0 pH solution when c ombined with the spilled reactor coolant water, the safety inje ction accumulator inventory, and the refue ling water storage t ank inventory. Refer to Subsection 6.5.2 for information on pH ch anges during system operation. The proba bility of stress-c orrosion cracking of austenitic stainless s teel components is there fore minimized by maintaining the long-t erm sump pH between 8.0 and 10.5.

Most components in the containment are fabricated of austenitic stainless steel. These materials are compatible with the NaOH solution, with the exc eption of galvanized s teel and aluminum.

To prevent degradation of the sodium hydroxi de, an inert gas is maintained within the spray additive tank.

A relief valve is provided to prevent overpres surization of the tank.

The vessels used for storing ESF coolants include the accumulators, the cont ainment spray additive (sodium hydroxide) tank, and the refueling water storage tank.

The ESF coolant is sto red in a stainless-steel-lined concrete refueling water storage tank. The chlor ide ion concentration of borated water coolant stored in this tank no rmally is less than 0.15 ppm, therefore stress corrosion c racking of the lined stainless steel or E SF components through which the coolant circulates is very unlikely.

The accumulators are carbon steel clad with aust enitic stainless steel. Because of the corrosion resistance of these materials, significant corrosive attack on the stor age vessels is not expected.

The accumulators are vessels filled with borated water and pressurized with nitrogen gas.

The nominal boron concentration is 2200 to 2400 ppm. Samples of the sol ution in the accumulators are taken periodically f or checks of boron concentration.

Principal design parameters of t he accumulators are listed in Table 6.3-1.

B/B-UFSAR 6.1-3a REVISION 7 - DECEMBER 1998 The refueling water stor age tank is a source of borated cooling water for injection. The no minal boron concentration is 2300-2500 ppm, which is below the solubility limit at freezing.

The temperature of the refueling water is maintained above freezing. Further infor mation on the refueling water

B/B-UFSAR 6.1-4 REVISION 1 - DECEMBER 1989 storage tanks is given in Subsection 3.8.4.1

.3, Sections 6.3 and 6.5, and the Tec hnical Specifications.

6.1.2 Organic

Materials

Criteria have been developed for selection and a pplication of protective coatings for structures and components inside containment. The coatings on most of the structure and components conform to this crite ria and, as a result, will remain intact and protect e xposed surfaces duri ng and after any postulated event. The l imited amount of undocumented/

unqualified coatings h ave been identified and an evaluation of the potential effect of coatings failure on co ntainment ECCS sump functionality has been c ompleted. This eval uation demonstrates that coating failure will no t result in unac ceptable sump performance.

The following coating sy stems, which apply to the containment building, have been used, and each of these sy stems provides corrosion protection for the exp osed metal and concrete surfaces and facilitates the de contamination process:

a. Steel Containment

1. System Descripti on - A prime coat of inorganic zinc-rich coating and a finish coat of phenolic organic coating with the exception that the finish coat at Braidwood is lim ited to a height of 8 feet 0 inch above the operati ng floor (elevation 426 feet 0 inch).

2. System Thickness - Min imum dry film thicknesses are as follows:

a) Prime Coat - 3 mils minimum, 6 mils maximum; b) Finish Coat -

4 mils minimum, 6 mils maximum; and c) Total System Thickne ss - 7 mils minimum, 12 mils maximum.

3. Manufacturers and coatings a) Inorganic zinc - ric h primer carbo zinc 11SG inorganic zinc - Carboline Company or equivalent.

b) Phenolic organic fin ish coat - Phenoline 305 finish - Car boline Company or equivalent.

B/B-UFSAR 6.1-5 REVISION 1 - DECEMBER 1989 b. Concrete walls and ste el embedded in walls

1. System description -

one epoxy surface coat applied over formed conc rete wall and ceiling surfaces and over concrete masonry wall surfaces, and one phenolic finish coat applied over the surfacer coat.

2. Uses - indoor surfaces of conc rete walls and ceilings, concrete mason ry walls and metalwork that require protect ion from a corrosive atmosphere, chemical att ack and wear, irradiation, radioactive materials and the decontamination processes involved, and whic h provides f or general maintenance service and moderate impact and abrasion service.

3. System thickness - min imum dry film thicknesses are as follows:

a) Surfacer coat - appl ied to a reasonably smooth, sealed surface - about 20 to 30 mils.

b) Finish coat -

4 to 6 mils.

c) Total system thi ckness - 24 to 36 mils.

4. Manufacturers and coatings a) Typical surfacer coa t - Surfacer 195 -

Carboline Company or equivalent.

b) Typical finish coat -

Phenoline 305 finish -

Carboline Company or equivalent.

c. Concrete floors and st eel embedded in floors

1. System description - o ne epoxy prime coat and one phenolic finish co at applied over finished concrete floors and the miscellaneous steel embedded in the floor.

2. Uses - indoor surfaces or concre te floors that require protection from a corros ive atmosphere, chemical attack and wear, irradiation, radioactive materials and the deco ntamination processes involved, and which pr ovides for general maintenance service and heavy impact and abrasion service.

3. System thickness - min imum dry film thicknesses shall be as follows:

B/B-UFSAR 6.1-6 a) Prime Coat -

20 to 30 mils.

b) Finish Coat -

6 to 8 mils.

c) Total system thi ckness - 26 to 38 mils.

4. Manufacturers and coatings - same as specified for prime coats and fini sh coats for concrete walls.

d. Curing Procedures fo r All Coating Systems Ambient, but not less than 60 o F. Properties of the coating systems are as follows:

1. Dry Density:

a) Coating system for steel conta inment - 0.148 psf. b) Coating system for concrete walls - 0.265 psf. c) Coating system for concrete floors - 0.265 psf. 2. Heat transfer through the various materials comprising the prima ry containment s tructure will be essentially in di rect proportion to the resistance indicated in the following tabulation:

Part of Structure Thickness (in) Resistance (R) Percentage of Total R Value (%) Coating System 0.007 0.00280 0.44 Steel Liner Plate 0.250 0.00074 0.06 Concrete Walls 42.000 5.60000 88.00 Air (Both Sides) 0.78000 11.50 Totals 42.257 6.38354 100.00

3. Approximate surface ar ea covered by each coating system: a) Steel Containm ent - 104,000 ft 2 , b) Concrete Walls and E mbedded Steel - 86,200 ft 2 , and c) Concrete Floors and Em bedded Steel - 31,100 ft 2.

The coating systems that are used on components in the NSSS vendor's scope of supply are given in Table 6.1-3.

B/B-UFSAR 6.1-7 REVISION 1 - DECEMBER 1989 Quantification of sign ificant amounts of prote ctive coatings on Westinghouse supplied components located ins ide the containment building is given in Table 6

.1-2; the painte d surfaces of Westinghouse supplied equipment comprise a small percentage of the total painted surfac es inside containment.

For large equipment requiring pr otective coatings (specifically itemized in Table 6.1-2), Westin ghouse specifies or approves the type of coating systems utilized; requir ements with which the coating system must comply are stipulated in W estinghouse process specifications, which supplement the equ ipment specifications.

For these components, the generic types of coa tings used are zinc, rich silicate, or epoxy based primer with or without chemically-cured epoxy or epoxy modified phenolic top coat.

The remaining equipment requires protective coatings on much smaller surface areas and is procured from n umerous vendors; for this equipment W estinghouse specifications require that high quality coatings be applied using good commercial practices and in accordance with c onventional industry standards. Table 6.1-2 includes i dentification of this equipment and total quantities of protective coati ngs on such equipment.

Protective coatings for use in the reactor containment have been evaluated as to thei r suitability in p ost-DBA conditions.

Tests have shown that certain epoxy and modified phenolic systems are satisfactory for in-containment use. This evaluation (Reference 2) con sidered resistance to high temperature and chemical conditi ons anticipated during a LOCA, as well as high radi ation resistance.

Information regarding quality assurance requirements for protective coatings is discussed in Appe ndix A. Further compliance information h as been submitted to the NRC for review (via letter NS-CE-1352 dated February 1, 1977, to C. J.

Heltemes, Jr., Quali ty Assurance Branch, NRC, from C.

Eicheldinger, Westinghou se PWRSD, Nuclear Safety Dept.) and accepted (via letter dated April 27, 1977, to C. Eicheldinger from C. J. Hel temes, Jr.).

The majority of coat ings inside containm ent comply with the guidelines of Regulatory Guide 1.54, "Qualit y Assurance Requirements for Protective Coat ings Applied to Water-Cooled Nuclear Power Plants." The coating mate rial conforms to requirements of ANSI N101.2, "Protective Coatings (Paints) for Light Water Nuclear Reactor Cont ainment Facilities," ANSI N5.12, "Protective Coati ngs (Paints) for the Nuclear Industry," and ANSI N101.4, "Quality Assu rance for Protec tive Coatings Applied to Nucle ar Facilities."

A review has been comp leted of the coatings qu alification in each containment. Braidw ood 1 was found to have the largest

B/B-UFSAR 6.1-8 REVISION 11 - DECEMBER 2006 amount of undocumented or unqualified coatin gs and was used for all subsequent evaluatio

n. The quantity of unqualified coatings was then assumed to fail and b ecome detached.

Conservative assumptions were utilized for the fragment size and specific gravity in calculating t he transport of fragments to the sump.

The results demonstrated that a rela tively small portion of the failed coatings would re ach the sump screens.

The resulting blockage was evaluated with respect to pump NP SH requirements and found to cause only an i nsignificant change in the NPSH margin.

The Category 1 equipment coat ing, as described in letter NS-CE-1352 dated February 1, 197 7, meets ANSI N101.2, and meets the alternate QA program on control of paint as described in WCAP-8370. The range of coating thicknesses for this equipment is 5.5 mils to 8.0 mils.

6.1.2.1 Formation of Combustible Gas Mix tures from Organic Materials and Protective Coating The protective coating systems inside the containment are described in detail in Subsection 6.1.

2. Based on the information given in that subs ection, the resu ltant amounts of gas evolved are listed in Table 6.1-4. Temp erature and chemical effects on the generation of hydrogen and me thane gas from these coatings are expected to be minimal.

With a containment volume of 2.81 x 10 6 ft 3 , the concentration of generated gas is less than 0.024% of the containment volume. Therefore, the coating systems used inside containment, which are quali fied to ANSI N101.2, will not create solid debris or significant amoun ts of hydrogen or methane gas due to rad iolytic and chemical decomposition at DBA conditions. Hydrogen generation from zinc based coatings is discussed in S ubsection 6.2.5.

Charcoal and oil present inside the containment are located within filter housin gs and mechanica l components, re spectively.

Thus, charcoal and oil are not e xposed to the co ntainment spray and will not create debr is nor generate hydrogen and methane gas.

Other organic materials within the primary c ontainment are the insulation and jacke t materials of pow er, control and instrumentation cables.

Ethylene propylene rubber (EPR)/hypalon (chlorosulfonated poly ethylene) are used for the construction of insulation/jackets for t he Okonite power and control cables.

Ethylene propylene diene monomer (EPDM)/hypalon are used for the construction of the in sulation/jacket for the Samuel Moore instrumentation cables.

Power, control, and instrumentation cables purchased under N uclear Electrical Ma terial Standard N-EM-0035 (representing cables procured and installed after the initial fuel load) may be constructe d of other approved insulation and j acket materials. The qu antity of hydrogen and methane from this sour ce is a small fraction of that from other sources.

B/B-UFSAR 6.1-9 REVISION 7 - DECEMBER 1998 The quantity (weight and volume) of uncovere d cable and cable in conduit or closed cable trays are as follows:

a. Uncovered

Weight (W) = 1 1,359.31 pounds Volume (V) = 81.96 cubic feet

b. Covered W = 75,061.53 pounds V = 586.49 cubic feet.

A breakdown of cable diameters and assoc iated conductor cross sections is shown on Table 6.1-5.

The insulation and jacket materials are also indicated on Table 6.1-5. There is no wood or asphalt inside the containment.

6.1.3 Postaccident

Chemistry In the event of an a ccident, sodium hydr oxide and boric acid solutions will be present in t he containment sum p; the presence of sodium hydroxide in the sump soluti on will reduce the probability of stress corrosion cracking of austenitic stainless steels by maintaining the long-term sump sol ution pH at 8.0 or greater.

There are two independent safety grade sumps in the containment which are used to recycle ESF fluids. The o nly significant source of low pH fluids is a p ossible leak of borated reactor coolant. The boric acid content of this water is very low, and as a result, the pH of the coolant will be only slightly less than 7.0. In the event of a L OCA, the reactor c oolant pH will be increased by the addition of NaOH in the contain ment spray. A sufficient quantity of NaOH is added to maintain the pH of liquids in the containme nt at 8.0 or greater. This pH level can be maintained even in the event of a maximum break size LOCA, and the concurrent failure of one of the two saf ety grade containment spray systems. The cont ainment spray systems are designed so that each division fully covers the containment, thereby ensuring that all reactor coolant spillage, when combined with the spray, has a minimum pH of 8.0.

6.1.3.1 Steamline Break Inside Containment

In the event of a main steamline break i nside the containment concurrent with failure of the i solation valve to close in the

B/B-UFSAR 6.1-9a REVISION 7 - DECEMBER 1998 faulted steamline, there would be backflow f rom piping w hich is external to the containm ent. Low steamline pressure setpoints would be reached within approxim ately 5 seconds after the break occurs, and the three re maining main steamli ne isolation valves and the main feedwat er isolation valves would require an additional 5 seconds for closure.

In addition, steam would be released from the steam generator via a 1.1-ft 2 flow restrictor for Unit 1 and a 1.4-ft 2 flow restrictor for Unit 2 located within the vessel di scharge nozzle. Peak containment pressure resulting from this break is high enough to cause actuation of containment spray and ca ustic eduction.

After the t ype of break has been ascertained, the caustic addition can be secured by operator action. Once the con tainment pressure has decreased below 15 psig, the CS pu mps may also be secured.

B/B-UFSAR 6.1-10 REVISION 7 - DECEMBER 1998 Although there may be up to 1.50 ppm of ammonia in the steam resulting from decomposi tion of morpholine or from direct feed of ammonia, this has no significant effect upon pH of condensed steam containment spray mixture as it ac cumulates in the containment sump.

6.1.3.2 Main Fee dwater Line Break Inside Containment In the event of a main feedwater line failure inside the containment concurrent w ith failure of the iso lation valve to close in the faulted l ine, but with the feedwater regulator valve located in the turbi ne building assumed to close within 10 seconds after the break occurs, the resultin g peak containment pressure will differ between Unit 1 and Unit 2 d ue to feedwater design differences. U nit 1 has a larger break size due to the feedring/J-tube arra ngement in the f eedwater system. Unit 2 has a preheater design with a flow restricting o rifice. For Unit 1, the containment spray system may actuate on high containment pressure; however, the integrated energy int o containment for a Unit 1 main feed line break is less than the energy associated with a main steamline br eak. Accordingly, t he containment spray would run for less time following a main feedl ine break, and the quantity of liquid and t he impact on the max imum value of pH is bounded by the main st eamline break evaluation for Unit 1. For Unit 2, the peak conta inment pressure respon se will be less than the pressure at which co ntainment spray is a ctuated. Therefore, for Unit 2 the accumul ation of liquid in the containment basement will be the amount of liquid discharged from the feedwater line, plus water and steam released from the feedwater nozzle via a restricting orifice loca ted in the nozzle.

It is assumed that all four reactor containment f an coolers will condense flashed steam at their total des ign rate of 6,840 lb/m in. The following chemical composition of the liquid is expected:

Free hydroxide, ppm as CaCO 3 less than 0.15 Ammonia, ppm less than 0.25 In addition, there w ill be trace quantities of other substances such as silica, sodi um and chlorides.

B/B-UFSAR 6.1-11 REVISION 7 - DECEMBER 1998 6.1.3.3 Loss-of-Coolant Accident In the event of a pipe break of a reactor coolant loop, both safety injection and con tainment spray will be i nitiated. The pH of the final sump solu tion is independent of the number of trains of ECCS and CS pumps in operation. The final sump pH is determined by the quantity of water and concentr ation of boron in the RWST, the RCS, and the SI accumulators and the quantity of water and concentration of NaOH educted from the containment spray additive tank. The pH of the spray so lution is determined by the CS pump sucti on source and the qu antity of NaOH educted from the spray additive tank. The systems function in the same manner regardless of whether one or two ECCS/containment spray trains are in operation. The re sidual heat removal pumps will be semiautomatically transferred to the recirculation mode when the refueling water storage tank reaches the Lo-2 level setpoint.

The charging and safety injection pumps are th en manually aligned for the recirculation mo de. The containment spray pumps will continue to operate with suction fro m the RWST until the RWST reaches the Lo-3 level s etpoint. The operator will then manually align the containment spray pump suction from the RWST to the recirculation sump. C austic addition will continue until the spray additive tank reac hes the Lo-2 level r egardless of CS pump suction source. This ens ures that the final su mp solution pH will always be between 8.0 and 10.5. The spray pH may exceed the upper EQ limit of 10.5 depending on the spray additive tank NaOH concentration. Refer to Subsection 6.5.2 for further information on spray pH.

6.1.4 References

1. WCAP-7803, "Behavior of Aust enitic Stainless Steel in Post Hypothetical Loss of Coolant Environment." 2. Picone, L. F., "Ev aluation of Protective Coatings for Use in Reactor Containment," WCAP 7825, December 1971.

3. Bolt, R., and Carroll, J., "Radiation Effects on Organic Materials," Academic Press, 1963.

4. Zhiklarer, V., et al., "Study of Radiolysis of Epichloryhydrin by an Electrical Conducting Me thod," (Institute of Physical Chemistry, K ier, 1973), abstract only in Nuclear Science Abstracts , 28, No. 12, I tem 29672, 1973.

B/B-UFSAR 6.1-12 REVISION 7 - DECEMBER 1998 TABLE 6.1-1

ENGINEERED SAFETY FEATURES MATERIALS

Valves Bodies SA182 Type F 316 or SA351 Gr CF8 or CF8M

Bonnets SA182 Type F 316 or SA351 Gr CF8 or CF8M

Discs SA182 Type F 316 or SA564 Gr 630 or SA351 Gr CF8 or CF8M

Pressure retaining bolting SA453 Gr 660

Pressure retaining nuts SA45 3 Gr 660 or SA194 Gr 6

Ball Valves (1" Nominal Pipe Size a nd Approved for Specific Application

Bodies A-479 Type 316

Flanges A-479 Type 316

Ball A-276 Type 316

Pressure retaining bolting SA-453 Gr 660 Pressure retaining nuts SA-194 Gr 6

Auxiliary Heat Exchangers

Heads SA240 Type 304

Nozzle necks SA24 0 Type 304

Tubes SA249 Type 304 Tube sheets SA515 Gr 70 with Stainless Steel Cladding A-8 Analysis

Shells SA240 Type 304

Flange SA182 Gr F304

B/B-UFSAR 6.1-12a REVISION 12 - DECEMBER 2008 TABLE 6.1-1 Cont'd Auxiliary Pressure Vesse ls, Tanks, Filters, etc.

Shells and heads SA351 Gr CF8A, SA240 Type 304, SA264 Clad Plate of SA537 Gr B with SA240 Type 304 Clad and Stainless Steel Weld Overlay A-8 Analysis

Flanges and nozzles SA182 Gr F304, SA350 Gr LF2 with SA240 T ype 304 and Stainless Steel Weld Overlay A-8 Analysis

Piping SA 312 Type 30 4, Type 316 or SA 376 Type 304, Type 316

Containment Recirculation Sump Screen SA-240 TP 304

B/B-UFSAR 6.1-13 TABLE 6.1-1 (Cont'd)

Pipe fittings SA40 3 WP304 Seamless

Closure bolting and nuts SA19 3 Gr B7 and SA194 Gr 2H

Auxiliary Pumps

Pump casing and heads SA351 Gr CF8 or CF8M, SA182 Gr F304 or F316

Flanges and nozzles SA182 Gr F304 or F316k SA403 Gr WP316L Seamless

Stuffing or packing box cover SA35 1 Gr CF8 or CF8M, SA240 Gr 304 or 316

Closure bolting SA193 Gr B7, Br B8 or SA453 Gr 660

Closure nuts SA194 Gr 8

Tubing SA213 Type 304, 304L, 316 or 316L Pipe SA312 Type 304, 304L, 316 or 316L

Piping Pipe SA312, Type 304 SA358, Type 304 SA376, Type 304

Fittings SA182, GR F304 SA403, GR WP304

Flanges SA182, GR F304 SA182, GR F304

Bolting SA193, GR B7

B/B-UFSAR 6.1-14 TABLE 6.1-2

PROTECTIVE COATINGS ON WESTINGHOUSE-SU PPLIED EQUIPMENT INSIDE CONTAINMENT COMPONENT PAINTED SURFACE AREA (ft 2) Reactor coolant pump motors 1600 Accumulator tanks 5400

Manipulator crane 3100

Other refueling equipment 1100

Remaining equipment <1300

(such as valves, auxiliary tanks and heat exch anger supports, transmitters, alarm horns, and small instruments)

B/B-UFSAR 6.1-15 TABLE 6.1-3 NSSS CONTAINME NT PAINT

SUMMARY

PAINT TYPE MANUFACTURER'S DESIGNATION SURFACE AREA COVERED (ft

2) DRY DENSITY (mil/ft 2) CURING PROCEDURE Polyamide Amercote No. 66 5,000 0.009* Finish coat dry for 7 days at 70

°F with air circulation 18,300 0.007* Air dry in 2-4 hours hours at 75

°F coating cures in-service Carboline 4674* (black) Organic modified silicone base

with low chloride content

• Coatings are generally covered by insulation.

B/B-UFSAR 6.1-16 TABLE 6.1-4 GAS EVOLUTION FROM P ROTECTIVE COATINGS PROTECTIVE COATING QUANTITY (lb) ORGANIC: VEHICLES (%) G-VALUE*

GAS EVOLVED (ft 3)** Modified Phenolic finish coat -

Phenoline 305 1.54 x 10 4 66 0.08 61 Surfacer coat -

Epoxy Polyamide Surfacer 195 3.29 x 10 4 34 0.8 670

• G-Value = Molecules of gas evolved upon radiolytic decompos ition per 100 ev. For phenolics, the G-val ue for gas evolution is given in Table 6.3 of Reference 1. For epoxy coatings, a va lue 10 times that for phenolics was used, based on the radiolysis of its constituent epichlorhydrin (Reference

2) and for conservatism.

• • Gas Evolved = Total gas generated for 2 x 10 8 rads dose. Not all gases evolved are hydrogen or methane. No exper imental data or qu alified procedures r egarding hydrogen or methane generation from these coating systems under the subject conditions currently exist.

B/B-UFSAR 6.1-17 TABLE 6.1-5 CABLES IN CONTAINMENT OUTSIDE DIAMETER WEIGHT (lbs) VOLUME (ft

3) CABLE SIZE (in.) UNCOVERED COVERED UNCOVERED COVERED INSULATION MATERIAL*

JACKET MATERIAL*

3-1/c 3.229 1754.5 5270.72 13.7 41.17 EPR Hypalon 500 KCMIL

3/c 500 2.587 - 9912 - 51.1 EPR Hypalon KCMIL 1/c 500 1.072 1126.08 4760.1 3.83 8.71 EPR Hypalon KCMIL

4/c 4/0 2.038 284.24 953.04 1.54 5.16 EPR Hypalon

3/c 4/0 1.848 179.85 542.82 1.02 3.09 EPR Hypalon

1/c 4/0 0.73 - 36.8 - 0.13 EPR Hypalon

4/c 4/0 1.608 - 380.7 - 2.28 EPR Hypalon 3/c 1/0 1.458 362 1086 2.32 6.96 EPR Hypalon

3/c #2 1.15 569.91 2928.2 3.39 17.46 EPR Hypalon

2/c #2 1.008 1341.34 4024.69 11.09 33.29 EPR Hypalon 1/c #2 0.447 27 81 0.11 0.33 EPR Hypalon

3/c #6 0.953 355.35 2735.85 2.55 19.64 EPR Hypalon 3/c #10 0.636 314.4 2080.8 2.31 15.3 EPR Hypalon 3/c #14 0.512 - 12.92 - 0.11 EPR Hypalon

B/B-UFSAR 6.1-18 TABLE 6.1-5 (Cont'd)

OUTSIDE DIAMETER WEIGHT (lbs) VOLUME (ft

3) CABLE SIZE (in.) UNCOVEREDCOVERED UNCOVERED COVERED INSULATION MATERIAL*

JACKET MATERIAL* 7/c #14 0.688 - 28.8 - 0.23 EPR Hypalon 6/c (2 #2, 1.371 1635.4 4903.24 11.33 33.96 EPR Hypalon 4 #6) 37/c #16 0.8 - No. Infor. - 0.55 EPR Hypalon 19/c #16 0.5 - No. Infor. 0.15 EPR Hypalon 12/c #16 0.5 - No. Infor. - 0.07 EPR Hypalon 12/c #14 0.945 1268.85 7264.95 11.24 64.34 EPR Hypalon 0.6 - No. Infor. - 0.09 EPR Hypalon 14/c (2 #14, 12 #18) 9/c #14 0.793 258 2143.98 2.06 17.1 EPR Hypalon 7/c #14 0.688 536.32 2682.24 4.33 21.64 EPR Hypalon 4/c #14 0.588 988.77 4537.21 8.1 37.2 EPR Hypalon 2/c #14 0.484 357.3 2054.25 3.04 17.5 EPR Hypalon 1/c #14 0.204 - 709.73 - 5.03 EPR Hypalon 27/c #16 0.8 - No. Infor. - 0.19 EPDM Hypalon 1.0 - 7209.55 - 80.74 EPDM Hypalon 24/c (22 #20, 2 #12) 12 TW PR #16 1.08 - 963.11 - 11.65 EPDM Hypalon

B/B-UFSAR 6.1-19 TABLE 6.1-5 (Cont'd)

OUTSIDE DIAMETER WEIGHT (lbs) VOLUME (ft

3) CABLE SIZE (in.) UNCOVEREDCOVERED UNCOVERED COVERED INSULATION MATERIAL*

JACKET MATERIAL* 8 TW PR #16 0.93 - 231.07 - 2.8 EPDM Hypalon 8 TW PR #20 0.755 - 167.53 - 2.38 EPDM Hypalon 5 TW PR #16 1.0 - 299.92 - 3.56 EPDM Hypalon 4 TW PR #16 0.73 - 135.04 - 1.83 EPDM Hypalon 4 TW PR #20 0.615 - 27.74 - 0.41 EPDM Hypalon 3 TW PR #16 0.9 - 56.1 - 0.73 EPDM Hypalon 4/c #2 0.5 - 32.94 - 0.5 EPDM Hypalon 3/c #14 0.6 - No. Infor.- 0.62 EPDM Hypalon 3/c #16 0.395 - 1868.66 - 19.16 EPDM Hypalon 2 TW PR #16 0.62 - 1196.65 - 18.05 EPDM Hypalon 1 TW PR #16 0.365 - 2554.6 - 28.13 EPDM Hypalon 1 TW PR #20 0.325 374.21 - 4.69 EPDM Hypalon RG - 11/U 0.4 - 814.37 - 8.46 EPDM Hypalon TRIAX TOTAL 11,359.3175,061.53 81.96 586.49

• EPR - Ethylene - Propylene Rubber EPDM - Ethylene - Pro pylene Diene Monomer Hypalon - Chlorosul fonated Polyethylene

BYRON-UFSAR 6.4-1 REVISION 12 - DECEMBER 2008 6.4 HABITABILITY SYSTEMS The Control Room Habitability Sy stems (CRHS) a re plant systems that help ensure control room en velope (CRE) hab itability. CRE habitability must be maintained during n ormal operations as well as during radiologic al, hazardous chemic al, or smoke event emergencies. The CRHS includes the co ntrol room emergency ventilation/filtration system and the co ntrol room heating, ventilating and air-conditioning (HVAC) systems. The CRE boundary is considered an integral part of the CRHS, since it is critical to maintaining CRE habitability. T he CRE is the area within the confines of t he CRE boundary that contains the spaces that control room occupants inhabit to c ontrol the u nit during normal and accident co nditions. This ar ea encompasses the control room and other non-critical areas to which frequent personnel access, or c ontinuous occupancy is not necessary in the event of an accident.

The CRE is protec ted during normal operation, natural e vents, and accident conditions. The CRE boundary is the combination of w alls, floor, r oof, ducting, doors, penetrations and equi pment that physically form the CRE.

The CRE boundary must be maintained to ensure that the inleakage of unfiltered air in to the CRE will not exceed the inleakage assumed in the l icensing basis analysis of design basis accident consequences to CRE occupants.

Adequate food, water s torage, sanitary facil ities, and medical supplies are provided to meet the requirements of operating personnel during and after an incident. In addition, the environments in all spac es served by the control room HVAC system (control room envelope) are controlled withi n specified limits which are conducive to prolonged service lif e of Safety Class 1 components during al l station conditions.

6.4.1 Design

Basis The design bases of the habitabi lity systems u pon which the functional design is establish ed are summarized as follows:

a. Redundant strings of H VAC equipment are provided to maintain habitable envir onmental conditions in the control room envelope.

b. The habitability systems are designed to support a maximum of seven peo ple during normal and 30 days of abnormal station operating conditions. During an emergency, action will be ta ken as needed to deliver food to the control room ope rating personnel. An unlimited water supply a nd onsite first aid is available.

c. Sanitary facilities are provid ed for control room operating personnel.

BYRON-UFSAR 6.4-1a REVISION 12 - DECEMBER 2008

d. The radiological effects on the control room envelope resulting from any incid ent described in Chapter 15.0 are considered in the de sign of the habitability system. e. The design inclu des provisions to pr eclude the effects of toxic gases (carb on dioxide and smo ke) from inside or outside the plant.

f. Seven SCBA units are ava ilable inside the control room envelope with dedicated air bottles.

Two additional units are provided to comply with the single failure criteria described in Re gulatory Guide 1.95.

Additional reserve air s upplies are main tained onsite to provide a total of six hours of breat hing air for each of the seven emer gency staff personnel.

g. The habitability systems are designed to operate effectively during a nd after a DBA s uch as a LOCA with the simultaneous loss of offsite power, safe shutdown earthquake, or fail ure of any one of the control room HVAC system equ ipment string components.

h. Radiation monitors a nd ionization detectors continuously monitor the control room HVAC system outside makeup air i ntakes. Also, i onization detectors continuously monitor the control room HVAC system turbine building makeup air intakes.

Area radiation monitors are provided in the control room. Detection of high radiation or pro ducts of combust ion is alarmed in the control room and related protec tion functions are simultaneously i nitiated. Press ure differential indicators are p rovided in the c ontrol room which monitor the pressure differential between strategic areas within the control roo m envelope and surrounding areas. Low pressure differential is alarmed in the control room.

Outdoor air and indi vidual room temp erature indicators in the control room are provided for the control room envelope.

i. The CRE Boundary is ma intained to ensure that unfiltered inleakage into th e CRE will not exceed the inleakage assumed in the lic ensing basis analysis of Design Basis Acciden t consequences to CRE occupants.

The assumed amount of un filtered inleakage is provided in Table 6.4-1a.

BYRON-UFSAR 6.4-2 REVISION 12 - DECEMBER 2008

6.4.2 System

Design 6.4.2.1.1 Definition of Control Room The control room consists of the main control room (Units 1 and 2), Shift Manager's office/records room, main control room toilet, and storage room.

6.4.2.1.2 Definition of Co ntrol Room Envelope The control room envelope consis ts of control ro om, auxiliary electric equipment rooms, upper cable spreading rooms, control room HVAC equipment ro oms, security control ce nter, locker rooms, toilet, janitor's closet, electr onic shop, and corridors.

6.4.2.2 Ventilation System Design Detailed control room HVAC system description is presented in Subsection 9.4.1. T he control room emergenc y makeup unit is described in S ubsection 6.5.1.

All the system equipment components are design ed to perform their function during and after the safe shutdown earthquake except for the electric space h eating, humidificati on equipment, the security computer A/C unit, and toilet and locker room recirculation filter uni ts, which are supported to remain intact, but may not function.

All system components are pr otected from internally and externally generated missiles. A layout of the control room envelope, showing doors, corri dors, stairways, and boundary walls/floors/ceilings gi ven in Drawing M-1033-13.

Shield walls are shown on Figure 6.4-2.

The description of con trols, instruments, and ionization and radiation monitors for the control room HVAC system is included

BYRON-UFSAR 6.4-3 REVISION 12 - DECEMBER 2008 in Subsections 7

.1.2.1 and 7.3.1

.1. The locations of makeup air intakes and potential sources of radioactive and toxic gas releases are indicated in Drawings M-132 3-1 and M-1323-8 and Figures 6.4-3 and 6.4-4.

6.4.2.3 Leaktightness The entire control r oom envelope is designed as a low-leakage construction. A ll cable pans and duct p enetrations are sealed.

Approximately 6,000 cfm of outside air is introduced in the control room envelope except during the 100%

outdoor air purge mode and (Braidwood only) chlorine isolation mode. This quantity of air is sufficient to maintain the control room envelope at a positive pressure with respect to areas adjacent to the CRE to minimize unfiltered inle akage. The positive p ressure inside the control room envelop e minimizes infiltra tion of potentially contaminated air fro m adjacent areas.

During emergency operati on (radiation accide nt) of the control room ventilation system, the normall y open minimum outside air makeup dampers are c losed. Infiltrati on through damper and personnel ingress/egress is the only expecte d source of unfiltered air into the system. Analyzed unfiltered inleakage values are provided in Table 6.4-1a.

Technical Specification 5.5.

18, "Control Room Envelope Habitability," requires determining the amount of unfiltered air inleakage in accordance with the testing methods and frequencies specified in Sections C.1 and C.2 of Regulat ory Guide 1.197, "Demonstrating Control R oom Envelope Integrity at Nuclear Power Reactors," Revis ion 0, May 2003.

6.4.2.4 Interaction Wi th Other Zones and Pressure-Containing Equipment The control room HVAC system ser ves only rooms in the control room envelope. Areas surrounding the contro l room envelope are served by various systems.

The control room offices HVAC system (a separate system, not a part of the control room envelop e) is shut down by a high radiation signal detected in the control room HVAC system outside air intakes.

The auxiliary building areas adjacent to the control room envelope are at neg ative pressure with respect to ambient and contr ol room pressures at all times. The naturally vented turbine building pressure is a function of elevation and will v ary seasonally depen ding on outside air temperatures. The b uilding pressure at the main floor is approximately atmosphe ric at all times.

BYRON-UFSAR 6.4-4 REVISION 12 DECEMBER 2008 All penetrations between the cab le spreading r ooms and the control room are sealed airtight. Any relea se of carbon dioxide within the cable sprea ding room would not enter the control room. Actuation of any of the carbon di oxide zone systems isolates that zone from airflow by simultane ously closing the airflow dampers surround ing the affected zone.

Normal access paths be tween plant areas and the control room envelope are double-door (two do ors in series) v estibules to minimize system interact ion. Single doors are not normally used and are under administrati ve control of the operator.

There are no high-energy lines in the proximity or within the control room envelope.

Small fire extinguis hers are provided in areas within the co ntrol room envelope.

BRAIDWOOD-UFSAR 6.4-5 REVISION 12 - DECEMBER 2008 6.4 HABITABILITY SYSTEMS The Control Room Habitability Sy stems (CRHS) a re plant systems that help ensure control room en velope (CRE) hab itability. CRE habitability must be maintained during n ormal operations as well as during radiologic al, hazardous chemic al, or smoke event emergencies. The CRHS includes the co ntrol room emergency ventilation/filtration system and the co ntrol room heating, ventilating and air-conditioning (HVAC) systems. The CRE boundary is considered an integral part of the CRHS, since it is critical to maintaining CRE habitability. T he CRE is the area within the confines of t he CRE boundary that contains the spaces that control room occupants inhabit to c ontrol the u nit during normal and accident co nditions. This ar ea encompasses the control room and other non-critical areas to which frequent personnel access, or c ontinuous occupancy is not necessary in the event of an accident.

The CRE is protec ted during normal operation, natural e vents, and accident conditions. The CRE boundary is the combination of w alls, floor, r oof, ducting, doors, penetrations and equi pment that physically form the CRE.

The CRE boundary must be maintained to ensure that the inleakage of unfiltered air in to the CRE will not exceed the inleakage assumed in the l icensing basis analysis of design basis accident consequences to CRE occupants.

Adequate food, water s torage, sanitary facil ities, and medical supplies are provided to meet the requirements of operating personnel during and after an incident. In addition, the environments in all spac es served by the control room HVAC system (control room envelope) are controlled withi n specified limits which are conducive to prolonged service lif e of Safety Class 1 components during al l station conditions.

6.4.1 Design

Basis The design bases of the habitabi lity systems u pon which the functional design is establish ed are summarized as follows:

a. Redundant strings of H VAC equipment are provided to maintain habitable envir onmental conditions in the control room envelope.

b. The habitability systems are designed to support a maximum of seven peo ple during normal and 30 days of abnormal station operating conditions. During an emergency, action will be ta ken as needed to deliver food to the control room ope rating personnel. An unlimited water supply a nd onsite first aid is available.

c. Kitchen and sani tary facilities are provided for control room ope rating personnel.

BRAIDWOOD-UFSAR 6.4-5a REVISION 12 - DECEMBER 2008 d. The radiological effects on the control room envelope resulting from any incid ent described in Chapter 15.0 are considered in the de sign of the habitability system.

e. The design inclu des provisions to pr eclude the effects of toxic gases (carb on dioxide and smo ke) from inside or outside the plant.

f. Seven SCBA units are ava ilable inside the control room envelope with dedicated air bottles.

Two additional units are provided to co mply with single failure criteria from Regulatory Gui de 1.95. Additional bottled air supplies are mai ntained onsite to provide a total of 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> of br eathing air for each of the seven emergency staf f personnel. Proceduralized methods are availabl e to refill SCBAs if required for long term use.

g. The habitability systems are designed to operate effectively during a nd after a DBA s uch as a LOCA

BRAIDWOOD-UFSAR 6.4-6 REVISION 12 - DECEMBER 2008 with the simultaneous loss of offsite power, safe shutdown earthquake, or fail ure of any one of the control room HVAC system equ ipment string components.

h. Radiation monitors a nd ionization detectors continuously monitor the control room HVAC System outside makeup air intak es. Also, ionization detectors contin uously monitor the control room HVAC system turbine building makeup air intakes.

Area radiation m onitors are provided in the control room. Detection of high rad iation or products of combustion is alarmed in the control room and related protection funct ions are simultaneously initiated. Pressure dif ferential indicators are provided in the control room which monitor the pressure differential betwee n strategic areas within the control room envelope and surrounding areas. Low pressure differential is ala rmed in the control room.

Outdoor air and indi vidual room temp erature indicators in the control room are provided for the control room envelope.

i. The CRE Boundary is ma intained to ensure that unfiltered inleakage into th e CRE will not exceed the inleakage assumed in the lic ensing basis analysis of Design Basis Acciden t consequences to CRE occupants.

The assumed amount of unfilt ered inleakage is provided in Table 6.4-1a.

6.4.2 System

Design 6.4.2.1.1 Definition of Control Room

The control room consists of the mai n control room (Units 1 and 2), Shift Manager's office/recor ds room, main control room toilet, and storage room.

6.4.2.1.2 Definition of Co ntrol Room Envelope The control room envelope consis ts of control ro om, auxiliary electric equipment rooms, upper cable spreading rooms, control room HVAC equipment ro oms, security control ce nter, locker room, toilet, kitchen, janit or's closet, ele ctronic shop, and corridors.

6.4.2.2 Ventilation System Design Detailed control room HVAC system description is presented in Subsection 9.4.1. T he control room emergenc y makeup unit is described in S ubsection 6.5.1.

BRAIDWOOD-UFSAR 6.4-7 REVISION 12 - DECEMBER 2008 All the system equipme nt components are designed to perform their function during and after the safe shu tdown earthquake except for the e lectric space heating, h umidification equipment, the security computer A/C unit, and kitchen, toilet, locker room exhaust fans and filters, and st orage room toilet recirculation filter unit which are su pported to remain in tact, but may not function.

All system components are pr otected from internally and externally generated missiles. A layout of the control room envelope, showing doors, corri dors, stairways, and boundary walls/floors/ceilings is given in Drawing M-1033-13. Shield walls are shown on Figure 6.4-2.

The description of con trols, instruments, and ionization and radiation monitors for the control room HVAC system is included in Subsections 7

.1.2.1 and 7.3.1

.1. The locations of makeup air intakes and potential sources of radioactive and toxic gas releases are indicated in Drawings M-132 3-1 and M-1323-8 and Figures 6.4-3, a nd 6.4-4.

6.4.2.3 Leaktightness The entire control r oom envelope is designed as a low-leakage construction. A ll cable pans and duct p enetrations are sealed.

Approximately 6,000 cfm of outside air is introduced in the control room envelope except during the 100%

outdoor air purge mode and (Braidwood only) chlorine isolation mode. This quantity of air is sufficient to maintain the control room envelope at a positive pressure with respect to areas adjacent to the CRE to minimize unfiltered inle akage. The positive p ressure inside the control room envelop e minimizes infiltra tion of potentially contaminated air fro m adjacent areas.

During emergency operati on (radiation accide nt) of the control room ventilation system, the nor mally open minim um outside air makeup dampers are c losed. Infiltrati on through damper and personnel ingress/egress is the only expecte d source of unfiltered air into the system. Analyzed unfiltered inleakage valves are provided in Table 6.4-1.

Technical Specification 5.5.

18, "Control Room Envelope Habitability," requires determining the amount of unfiltered air inleakage in accordance with the testing methods and frequencies specified in Sections C.1 and C.2 of Regulat ory Guide 1.197, "Demonstrating Control R oom Envelope Integrity at Nuclear Power Reactors," Revis ion 0, May 2003.

6.4.2.4 Interaction Wi th Other Zones and Pressure-Containing Equipment The control room HVAC system ser ves only rooms in the control room envelope. Areas surrounding the contro l room envelope are served by various systems.

BRAIDWOOD-UFSAR 6.4-8 REVISION 12 - DECEMBER 2008 The control room offices HVAC system (a separate system, not a part of the control room envelop e) and the l aboratory HVAC system and the r adwaste HVAC system are shut down by a high radiation signal detected in the control room HVAC system outside makeup air intakes. The auxil iary building areas adjacent to the control room envelope are at negative pressure with respect to ambi ent and control room pressures at all times. The naturally ve nted turbine bui lding pressure is a function of elevation and will vary seasonally depending on outside air temperatures.

The building pressure at the main floor is approximate ly atmospheric at all times.

All penetrations between the cab le spreading r ooms and the control room are sealed airtight. Any release of carbon dioxide within the cable spreading room would not enter the control room. Actua tion of any of the carbon dioxide zone systems isolates that zone from airflow by simultaneously closing the airflow dampers surr ounding the affe cted zone.

Normal access paths be tween plant areas and the control room envelope are double-door (two do ors in series) v estibules to minimize system interact ion. Single doors are not normally used and are under administrat ive control of the operator.

There are no high-energy lines in the proximity or within the control room envelope.

Small fire extinguis hers are provided in areas within the co ntrol room envelope.

B/B-UFSAR 6.4-9 REVISION 12 - DECEMBER 2008 The carbon dioxide fire protection system design is discussed in Subsection 2.3.3 and A ppendix A5.4 of the Fi re Protection Report.

6.4.2.5 Shielding Design The design-basis accident for the control room a rea shielding is the loss-of-coolant acci dent (LOCA). The shielding is designed so that the doses to the contr ol room personnel over the course of the accident are we ll below the limit spe cified in General Design Criteria 19 of 10 CFR 50, Appendix A.

The design of the control room envelope shielding is based on the sources given in Table 6

.4-1. The distr ibution of the LOCA sources outside the cont rol room are shown in Figures 6.4-3 and 6.4-4. All of the nob le gases and iodin es are presumed to remainairborne and event ually escape into the plume. Radioactive decay in the plume is ignored.

Shielding thicknesses for the co ntrol room are s hown in Figure 6.4-2 and enumerated in Table 6.4-1. The so urces for the LOCA shielding model are shown in Figures 6.4

-3 and 6.4-4.

6.4.3 System

Operati onal Procedures The control room is a common fac ility which serves both Units 1 and 2. The facility is served by two completely red undant HVAC equipment trains. T he systems are shown in simplified schematic in Figures 6.4-5, 6.4-6, 6.4-7; and 6.4-8 (Byr on only). Note that only one of the redunda nt trains is detailed in the sketches; the other train contains equivale nt equipment. The control room envelop e is supplied with filtered, cooled and reheated (as necessary) air to maintain a su itable environment.

Under normal conditions the system operates as shown in Figure 6.4-5. The supply air consists of a ir that is recirculated from the control room envelope and outsid e air that is induced into the system to provide for cont rol room envelope pressurization and to makeup for air that is exhausted.

This mixture of recirculated and outside air is mixed and then passed through high-efficiency filters and then bypasses th e charcoal adsorbers prior to being discharged in to the control room.

Upon detection of high radiation in the minimum outside air intake, or upon a sa fety injection signa l, the norma lly open outside air dampers clos

e. The normally clo sed dampers of the turbine building emerg ency air intake are opened and the emergency makeup air filter unit is started. In addition, air that is normally bypassi ng the recircu lation charcoa l adsorber is routed through this char coal adsorber. All of these actuations

B/B-UFSAR 6.4-10 REVISION 12 - DECEMBER 2008 are automatic and the new system line-up is shown diagrammatically in Figure 6.4-6.

In addition, a r adiation monitor located on each of the emergency makeup air filter tr ains monitors the radiological quality of the air d elivered to the co ntrol room envelope.

Should high moisture d ue to a steam line bre ak in the turbine building occur, a humidi ty sensor located in the turbine building emergency makeup air intake will annunciate this condition in the main control room. This will alert the operator of this condition. The operator may then draw the m akeup air from the minimum outside air inta ke by opening the normally closed bypass damper and clos ing the turbine buildi ng emergency makeup air intake damper. This is shown diagrammatically in Figure 6.4-7. In this minimum outside air intake c onfiguration, the control room HVAC system will not automatically realign to the turbine building makeup air intake on a high radiation or ESF-SI actuation.

To remove any toxic gase s, odors, and smoke fr om the control room environs, a charcoal adsorber is provided with each control room HVAC equipment strin

g. These adsorbers, located downstream of high-efficiency filters, are normally bypassed.

At Braidwood, if the station is notified of a tox ic gas release in the near vicinity, the control ro om HVAC system is manu ally isolated via a control switch on the local panel. Actuatio n of the control switch places the system in 100%

recirculation mode and routes the air through the char coal adsorbers.

On detection of ionization produ cts in the return air duct or mixed air plenum, the mixed air (return air and makeup air) is automatically routed thr ough the charcoal adso rber and annunciated on the main control boar

d. The operator may continue to route the system supply air through the charcoal adsorber for sm oke removal, or depending on the co ndition of the outside air, may manually bypass the charcoal ad sorber and purge the entire system with outside air. On ion ization detection in outdoor makeup air intake, annunciation in the control room alerts the operator to transfer operation to a redundant equipment string utilizing a remote intake.

In the event of high radiation detec tion in the makeup air intake of the control room HVAC system, the radiation monitoring system automatically shu ts off normal outside makeup air supply to the system. The minimum outside air requirement is obtained from the turbine building mak eup air intake and is routed through the emergency makeup air filter unit and fan (for removal of radioactive particulates and iodine) before being supplied to the system. The makeup air is then mixed with r eturn air and is routed through the r ecirculation charcoal adso rber for the removal of radioactive iodine be fore being supplied to the vital areas of the control room envelope.

Two emergency makeup air filter units and fans a re provided, each capable of handling mi nimum requirements of ma keup air for the system. In the event of high radiation levels, each train is B/B-UFSAR 6.4-11 REVISION 12 - DECEMBER 2008 sized to process 6,000 cfm of makeup air.

The emergency makeup air filter units are described in detail in Subsection 6.5.1.

At Byron, to preclud e injecting a HE PA filter challe nging agent into the control room envelope d uring emergency make up air unit filter testing, the makeup air filter un it may be op erated with the system in purge mode. This configuration is illustrated in Figure 6.4-8. T he filter challenging ag ent is injected into the makeup air filter hous ing, mixes with the ai r being purged from the control room envelope and is exp elled to the outside air.

The makeup air filter unit air inlet is aligned to t he outside air intake to protect the cont rol room envelope from a high radiation condition in the intake air.

A high radiation condition in the outside air wou ld result in a high radiation signal being gen erated that would realign the purge dampers such that all air entering the cont rol room envelope would be treated by the makeup air filt er unit. In this makeup outside air intake configuration, the c ontrol room HVAC system will not automatically realign to the turbine buildin g makeup air intake on a high radiation or ESF-SI actuation.

6.4.4 Design

Evaluation The control room HVAC sy stem is designed to ma intain a habitable environment compatible with pr olonged service life of safety-related compone nts in the contr ol room under all the station operating conditions. The system is only provided with redundant equipment st rings to meet the single-failure criterion.

The equipment strings are powered from redun dant Unit 1 ESF buses and are operable during loss of offsite powe

r. All the control room HVAC system equipment exc ept heating and humidification equipment is designed for Seismic Category I loads.

6.4.4.1 Radiolog ical Protection Two radiation monitors are provided in e ach control room HVAC system makeup air intake to dete ct high radiation. These monitors cause annunciation in the control room upon detection of high radiation or moni tor failure condit ions. Area radiation monitors are provided in the c ontrol room.

The respective emergency makeup air filter un it connected to the operating equipment string (designed to re move radioactive particulates and adsorb radioactive iodine from the min imum quant ity of makeup air) is automatically started upon high radi ation signals in makeup air. The radia tion monitors are desc ribed in detail in Subsections 11.5

.2 and 12.3.4.

The control room ventilation sys tem along with the CRE and control room shielding are designed to limit the occupational dose below levels required by Ge neral Design Criteri on 19 of 10 CFR 50 Appendix A.

The introduction of the minimum quantity of outside air to maintain the control room and other areas serv ed by the control room HVAC system at a positive pressure with respect to B/B-UFSAR 6.4-11a REVISION 12 - DECEMBER 2008 external areas adjacent to the CRE boundary, at all the station operating conditions (except at Braidwood, w hen the system is in recirculation mode) mini mizes the possibilit y of infiltration of unfiltered air into the control room (see Subsection 6.4.2.3).

The physical location of makeup air intakes (s ee Drawings M-1323-1 and M-1323-8) provides the option of drawing makeup air for the control room HVAC system from the less contaminated intake during and after an event i nvolving the release of airborne activity.

It is possible one of the ma keup intakes may not have any contaminants, while the other intake may have contaminants.

An assessment of the radiological dose to control room occupants has been made for the loss-of-co olant accident (LOCA) postulated in Subsection 15.6.5, as well as other design ba ses accidents.

Control room AST dose re sults are given in Tab les 15.0-11 and 15.0-12.

B/B-UFSAR 6.4-12 REVISION 12 - DECEMBER 2008 For the DBA LOCA case, core inve ntory radionuclide release fractions are per Regulatory G uide 1.183 Table 2, and are available for release to the environment during the phased release period.

Leakage from ESF equipm ent handling post-LOCA fluids is taken from T able 15.6-13. Credit for reduction of the amount of iodine avail able for release by engineered safety features (ESF) containment sprays is taken.

Similarly credit is taken for the ESF control room makeup air filters (Subsection 6.5.1), the recirculation charcoal adsorbers , and ESF auxiliary building filters (Subsection 6.5.1).

The total dose as depicted in Fi gure 6.4-4 is co mprised of four components, three of which are dependent on site meteorology.

The effective atmospheric dispersion values, /Q, used were calculated using the latest vers ion of the "Atmo spheric Relative CONcentrations in Bu ilding Wakes" (A RCON96) methodology (Reference 1), as shown in Section 2.3.6. A RCON96 calculates the highest 5 th percentile /Q values for the entire accident period (i.e., 0-2 hours, 2-8 ho urs, 8-24 hours, 1-4 days, and 4-30 days) using the on-site meteorolog ical data. The values of /Q used in this analysis are gi ven in Table 6.4-la.

Control room occupancy factors were taken fr om Table 1 of Reference 2.

When in accident mode, t he control room HVAC system design has all incoming air passing through HEP A and charcoal filters. In addition, the makeup air mixes with the recircul ation air flow and the mixture passes t hrough the rec irculation charcoal filter and medium efficiency filter. The fil tration of intake and recirculation air flows limit the buildup of airborne iodine in the control room.

The resulting parametric factors and associated dose s are given in Table 6.4-1. The doses are below Gen eral Design Criterion 19 to 10 CFR 50, Appendix A guideli nes as interpreted by NUREG-0800, Section 6.4.

BYRON-UFSAR 6.4-13 REVISION 12 - DECEMBER 2008 6.4.5 Testing and Inspection The control room HVAC system and its components are thoroughly tested in a program cons isting of the following:

a. factory and componen t qualification tests, b. onsite preoperat ional testing, and

c. onsite subsequent periodic testing.

Periodic inleakage testing of the CRE is performed in general conformance to Regulatory Guide 1.197 Revision 0 Sections C.1 and C.2. Written test pro cedures establish minimum acceptable values for all tests. Test results are recorde d as a matter of performance record, thus enablin g early detection of faulty performance.

All equipment is factory inspect ed and tested in accordance with the applicable equipment specifications, codes, and quality assurance requ irements. System duct work and erection of equipment is insp ected during various construction stages for quality assurance. Construction tests are p erformed on all mechanical components, and the system is balanced for the design airflows and syst em operating pre ssures. Controls, interlocks, and safety d evices on each system are cold checked, adjusted, and tested to ensure the proper se quence of operation.

The equipment manufact urers' recommendations and station practices are considered in de termining requir ed maintenance.

6.4.6 Instrumentation

Requirements All the instruments and controls for the control room HVAC system are electric or electronic. Fu rther details are provided in the following:

a. Each redundant control room HVAC system has a local control panel, and e ach is independent ly controlled.

Important operating function s are controlled and monitored from the main control room.

Local control panels containing the lo cal control switches are located inside equip ment rooms that are under the administrative contr ol of operators.

b. Instrumentation is pro vided to monitor important variables associated with normal operation and to alarm abnormal condi tions on the main control board.

c. A radiation detection sy stem is provided to monitor the radiation levels at the system outside air intakes. A high radiation s ignal is alarmed on the main control board.

BYRON-UFSAR 6.4-14 REVISION 12 - DECEMBER 2008 d. The ionization d etection is provided both in rooms and in the return ai r path from main c ontrol boards.

Ionization detection is annunciated in the main control room.

e. The control room HVAC system is designed for automatic environmental cont rol with manual starting of fans. f. A fire protection system water connection is provided to each charcoal adsorber bed.

g. The various instruments of the control system are described in det ail in Chapter 7.0.

h. The emergency makeup air filter unit u pstream HEPA filter high differenti al pressure is annunciated.

The emergency makeup air fil ter unit high and low airflow rates are an nunciated in the main control room. This airflow rate is indicated on the local control panel.

i. The control room supply fan high and low differential pressures are annunciated in the main control room.

Supply fan trip is also annuncia ted in the main control room. S upply fan differ ential pressure is indicated on the local control panel.

BRAIDWOOD-UFSAR 6.4-15 REVISION 12 - DECEMBER 2008 6.4.4.2 Chlorine Gas Protection The control room HVAC system is provided with control switches on the local control panels which can manually isolate the system upon notification of an accidental rele ase of chlorine gas from sources external to the station. Upon isolation of the system from outd oor makeup air, the control room HVAC system operates in 1 00% recirculation mo de, thus routing the recirculated air throu gh recirculation filters.

6.4.5 Testing

and Inspection The control room HVAC system and its components are thoroughly tested in a program cons isting of the following:

a. factory and componen t qualification tests, b. onsite preoperat ional testing, and

c. onsite subsequent periodic testing.

Periodic inleakage testing of the CRE is performed in general conformance to Regulatory Guide 1.197 Revision 0 Sections C.1 and C.2. Written test pro cedures establish minimum acceptable values for all tests. Test results are recorde d as a matter of performance record, thus enablin g early detection of faulty performance.

All equipment is factory inspect ed and tested in accordance with the applicable equipment specifications, codes, and quality assurance requ irements. System duct work and erection of equipment is insp ected during various construction stages for quality assurance. Construction tests are p erformed on all mechanical components, and the system is balanced for the design airflows and syst em operating pre ssures. Controls, interlocks, and safety d evices on each system are cold checked, adjusted, and tested to ensure the proper se quence of operation.

The equipment manufact urers' recommendations and station practices are considered in de termining requir ed maintenance.

6.4.6 Instrumentation

Requirements All the instruments and controls for the control room HVAC system are electric or electronic. Fu rther details are provided in the following:

a. Each redundant control room HVAC system has a local control panel, and e ach is independent ly controlled.

Important operating function s are controlled and monitored from the main control room.

Local control panels containing the lo cal control switches are located inside equip ment rooms that are under the administrative contr ol of operators.

BRAIDWOOD-UFSAR 6.4-16 REVISION 12 - DECEMBER 2008 b. Instrumentation is pro vided to monitor important variables associated with normal operation and to alarm abnormal condi tions on the main control board.

c. A radiation detection sy stem is provided to monitor the radiation levels at the system outside air intakes. A high radiation s ignal is alarmed on the main control board.

d. The ionization d etection is provided both in rooms and in the return ai r path from main c ontrol boards.

Ionization detection is annunciated in the main control room.

e. The control room HVAC system is designed for automatic environmental cont rol with manual starting of fans. f. A fire protection system water connection is provided to each charcoal adsorber bed.

g. The various instruments of the control system are described in det ail in Chapter 7.0.

h. The emergency makeup air filter unit u pstream HEPA filter high differen tial pressure is annunciated.

The emergency makeup air fil ter unit high and low airflow rates are an nunciated in the main control room. This airflow rate is also indicated and the low airflow is annunciated on the local control panel. i. The control room supply fan high and low differential pressures are annunciated in the main control room.

Supply fan trip is also annuncia ted in the main control room. S upply fan differ ential pressure is indicated on the local control panel.

B/B-UFSAR 6.4-16a REVISION 12 - DECEMBER 2008

6.4.7 References

1. Ramsdell, J. V.

Jr. and C. A. Simonen, "Atmospheric Relative Concentrations in Buil ding Wakes". Pr epared by Pacific Northwest Laboratory for the U.S. Nuclear Regulatory Commission, PNL-10521, NUREG/CR-6331, Rev. 1, May 1997.

2. Murphy, K.G., and Campe, K.H

., "Nuclear Powe r Plant Control Room Ventilation System Design for Meeting General Design Criterion 19, " Proceedings of the Thirteenth AEC Air Cleaning Conference, August 1974.

3. NEI 99-03, "Control Room Hab itability Assessment Guidance,"

June 2001.

BYRON-UFSAR 6.4-17 REVISION 13 - DECEMBER 2010 TABLE 6.4-1 EXPECTED DOSE TO CONTROL ROOM PERSONNEL AT B YRON STATION FOLLOWING A LOSS-OF-CO OLANT ACCIDENT (LOCA)

CONCRETE SHIELD ACCUMULA TED 30 DAY DOSE, REM THICKNESS BETWEEN SOURCE AND CONTROL ROOM, INCHES TEDE Direct Dose From Airborne Radio-activity in the Containment Sidewall - 102 0.023 Ceiling - 68

Dose From Post-LOCA Plume Surrounding Control Room 24 0.015 Dose From Radioa ctivity Accumulated on Control R oom Makeup Air Filters 8 0.013 Dose From Air Drawn into the Control Room From Containment Leakage N/A 3.343 From ESF Equipment Leakage N/A 1.389 10 CFR 50.67 limits 5 ____________________ Note: Principal assu mptions are li sted in Ta ble 6.4-1a.

BYRON-UFSAR 6.4-18 REVISION 13 - DECEMBER 2010 TABLE 6.4-1a PRINCIPAL ASSUMPTIONS USED IN CONTROL ROOM HABITABILITY CALCULATIONS Loss-of-Coolant Accident Modeling Subsection 15.6.5 Control room atm ospheric dispersion factor (/Q) for Containment leakage 0-0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 1.73E-3 sec/m 3 0.5-2 hour 1.01E-3 sec/m 3 2-8 hour 7.

25E-4 sec/m 3 8-24 hour 3.07E-4 sec/m 3 24-96 hour 2.

07E-4 sec/m 3 96-720 hour

1.46E-4 sec/m 3 Control room atm ospheric dispersion factor (/Q) for ESF leakage 0-0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />

0.5-1.8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />

1.8-3.3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />

3.3-8 hour

8-24 hour

24-96 hour 96-720 hour

Control room HVAC envelope volume

2.22E-3 sec/m 3 1.92E-3 sec/m 3 2.46E-3 sec/m 3 1.92E-3 sec/m 3 8.14E-4 sec/m 3 5.52E-4 sec/m 3 4.40E-4 sec/m 3 200,000 ft 3 (Note 1) Control room volume used for finite cloud correction 70,275 ft 3 Control room air intake flow 6000 cfm +

10%

Control room air filt ered recirculation flow 39,150 cfm Control room a ir intake filter efficiency (all forms of iodine) 0.99 (particulate) 0.95 (element al/organic)

Control room recircul ation flow filter efficiency Elemental iodine 0.9 Organic iodine 0.9

ESF Equipment leak rate UFSAR Table 15.6-13

Unfiltered inleakag e into the control room 500 cfm BYRON-UFSAR 6.4-18a REVISION 12 - DECEMBER 2008 TABLE 6.4-1a (continued)

PRINCIPAL ASSUMPTIONS USED IN CONTROL ROOM HABITABILITY CALCULATIONS

Occupancy factor 0-24 hour 1.0 24-96 hour 0.6 96-720 hour 0.4

Breathing rate 3.50E-4 m 3/sec ____________

_________

NOTE 1: Based on a calculated volume of 230,830 ft 3

BRAIDWOOD-UFSAR

6.4-19 REVISION 13 - DECEMBER 2010 TABLE 6.4-1 EXPECTED DOSE TO CONTROL ROOM PE RSONNEL AT BRA IDWOOD STATION FOLLOWING A LOSS-OF-CO OLANT ACCIDENT (LOCA)

CONCRETE SHIELD ACCUMULA TED 30 DAY DOSE, REM THICKNESS BETWEEN SOURCE AND CONTROL ROOM, INCHES TEDE Direct Dose From Airborne Radio-activity in the Containment Sidewall - 102 0.023 Ceiling - 68 Dose From Post-LOCA Plume Sur-rounding Control Room 24 0.015 Dose From Radioactivity Accumu-lated on Control Room Makeup Air Filters 8 0.013 Dose From Air Drawn into the Control Room From Containment Leakage N/A 3.343 From ESF Equipment Leakage N/A 1.389 10 CFR 50.67 Limits 5 Note: Principal as sumptions are listed in Ta ble 6.4-1a.

BRAIDWOOD-UFSAR

6.4-20 REVISION 13 - DECEMBER 2010 TABLE 6.4-1a PRINCIPAL ASSUMPTIONS USED IN CONTROL ROOM HABITABILITY CALCULATIONS

Loss-of-Coolant Accident Modeling Subsection 15.6.5

Control room atm ospheric dispersion factor (/Q) for Containment Leakage 0-0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 1.73E-3 sec/m 3 0.5-2 hour 1.01E-3 sec/m 3 2-8 hour 7.25E-4 sec/m 3 8-24 hour 3.07E-4 sec/m 3 24-96 hour 96-720 hour 2.07E-4 sec/m 3 1.46E-4 sec/m 3

Control room atm ospheric dispersion factor (/Q) for ESF leakage 0-0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 0.5-1.8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 1.8-3.3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />

3.3-8 hour

8-24 hour

24-96 hour 96-720 hour

2.22E-3 sec/m 3 1.92E-3 sec/m 3 2.46E-3 sec/m 3 1.92E-3 sec/m 3 8.14E-4 sec/m 3 5.52E-4 sec/m 3 4.40E-4 sec/m 3 Control room HVAC envelope volume 200,000 ft 3 (Note 1) Control room volume used for finite cloud correction 70,275 ft 3 Control room air intake flow 6000 cfm +

10%

Control room air filte red recirculation flow 39,150 cfm Control room a ir intake filter efficiency (all forms of iodine) 0.99 (particulate) 0.95 (elemental/organic)

Control room recircu lation flow filter efficiency Elemental iodine 0.9 Organic iodine 0.9

ESF Equipment leak rate UFSAR Table 15.6-13

Unfiltered inleakage into the control room 500 cfm BRAIDWOOD-UFSAR

6.4-20a REVISION 12 - DECEMBER 2008 TABLE 6.4-1a (continued)

PRINCIPAL ASSUMPTIONS USED IN CONTROL ROOM HABITABILITY CALCULATIONS

Occupancy factor 0-24 hour 1.0 24-96 hour 0.6 96-720 hour 0.4

Breathing rate 3.50E-4 m 3/sec ____________________

NOTE 1: Based on a calculated volume of 232,872 ft 3

B/B-UFSAR 6.5-1 REVISION 12 - DECEMBER 2008 6.5 FISSION PRODUCT REMO VAL AND CONTROL SYSTEMS

6.5.1 Engineered

Safety Fe ature (ESF)

Filter Systems The following filtration systems, which are required to perform the safety-related fun ctions subsequent to a design-basis accident (DBA), are provided:

a. control room HVAC make up air filter units: this system is utilized to cl ean the incoming air of gaseous iodine and p articulates which are potentially present in incoming air following an accident.

b. auxiliary building exhau st system: this system can be utilized to reduc e gaseous iodine and particulate concentrations in gases leaking from primary containment and which are potentially present in nonaccessible cubicles (see Subsection 9.4.5) following the accident.

c. fuel handling building exhaust syste m: this system is utilized to reduc e gaseous iodine and particulate concentrations in the exhaust air from the fuel handling building w hich are potentially present following a fuel drop accident, involving recently irradiated fuel (i.e., fuel that has occupied part of a critic al core within the previous 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />).

6.5.1.1 Design Bases 6.5.1.1.1 Control Room Makeup Air Filter Units

a. The makeup air filter units are designed to start automatically and provide ou tside air to the control room HVAC system in resp onse to any one of the following signals:

1. high radiation signal from the r adiation monitors provided to monitor the radi ation levels at the control room HVAC ou tside air intakes;

2. manual activation from the main control room; and

3. ESF signal.

b. The alternative source term model de scribed in NUREG-1465 and Regulatory Guide 1.

183 is used in conjunction with approved methods to cal culate the quantity of activity released as a r esult of an accident and to determine inlet concentratio ns to the makeup air filter train.

c. The capacity of the ma keup air f ilter units is based on the air quantity required to maintain the control room served by the control r oom HVAC system at

B/B-UFSAR 6.5-2 REVISION 12 - DECEMBER 2008 0.125 in. of H 2 O positive pressu re with respect to adjacent areas.

d. Two full-capacity emerge ncy makeup air filter units and associated dampers, duct s, and controls are provided.

e. Each makeup air filter unit utilizes air heaters, demister, and prefilters needed to assure the optimum air conditions entering the high-efficiency particulate air (HEP A) filters and c harcoal adsorbers.

f. The emergency ma keup air filter unit exhibits a removal efficiency of no les s than 95% on gaseous forms of radioiodine and no less than 99% on all particulate matter

0.3 micron

and larger in size.

g. The makeup air filter unit is de signed to meet the single-failure criterion.

h. The power supplies meet IEEE 308-197 4 criteria and ensure uninterrupted operation in th e event of loss of normal ac power. The co ntrols meet IEEE 279-1971.

i. The makeup air filter units are designed to Safety Category 1 requirements.

j. The makeup air filter units are designed to permit periodic testing and inspect ion of principal system components as described in Subsection 6.5.1.4.

k. The electrical components are qualified in accordance with IEEE 344-1971 and IEEE 323-1974.

6.5.1.1.2 Auxiliary Buil ding Exhaust Systems

a. The auxiliary bu ilding exhaust system is designed to run continuously during all normal plant operations and exhaust auxiliary buildi ng air after filtering through prefilter and HEPA f ilter banks. Provisions are also made to route t he effluents from nonaccessible cubicl es in the auxili ary building (see Subsection 9.4.5) through ch arcoal adsorbers and HEPA filters on the f ollowing signals:

1. Automatically on a safety injection si gnal from Unit 1 or 2.

2. Manually through a contr ol switch in the main control room.

BYRON-UFSAR 6.5-3 REVISION 13 - DECEMBER 2010 b. On loss-of-coolant acc ident concurrent with loss of offsite power, the auxiliary building supply and exhaust fans pow ered by the unit having a LOCA coincident with a LOOP are tripped.

Two out of six charcoal booster fans are st arted, performing the following functions:

1. Maintain negative pres sure in the auxiliary building.

2. Route the exhaust ai r from nonaccessible cubicles through the c harcoal adsorber and downstream HEPA filter b efore exhausting to the outdoor atmosphere.

The auxiliary buildi ng supply and exhaust fans associated with the unit exp eriencing the LOCA/LOOP can be restarted manually by the control switch located on the main control panel af ter approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (based on expe cted ESF b us loading).

c. The radioactive gases leaking from the primary containment after a LOCA or during normal operation are treated in order to remove particulates and radioactive and nonradioacti ve forms of iodine to limit the offsite dose.

d. The auxiliary building exhaust syste m exhibits a removal efficiency of no less than 90% on radioactive and nonradioacti ve forms of iodine and no less than 99% on all particulate matter 0.3 micron and larger in siz

e. The particulate removal efficiency is predicated on the use of HEPA filters having a 99% particulate rem oval efficiency. The charcoal is tested to not less than (a) 99.8%

removal efficiency on methyl iodine, and (b) 99.9%

on elemental iodine in air of 70% rela tive humidity.

The charcoal is contained in leak-tight, all-welded construction adsorbe rs to preclude bypass of the charcoal and to ensure t he highest removal efficiencies on methyl iodine.

e. The exhaust air from the auxiliary building exhaust system is released at an elevation of 599 feet 2 inches. The d ischarge air vel ocity from each auxiliary building exhaust system vent stack is approximately 60 fps maximum.

f. The auxiliary building exhaust s ystem is designed with redundancy to meet the single-f ailure criteria.

g. The power supplies meet IEEE 308-197 4 criteria and ensure uninterrupted operation in the event of loss

BRAIDWOOD-UFSAR 6.5-3a REVISION 13 - DECEMBER 2010 b. On loss-of-coolant acc ident the auxiliary building supply and exhaust fans powered by t he unit having a LOCA are tripped. Two out of six charcoal booster fans are started, performing the following functions:

1. Maintain negative pres sure in the auxiliary building.

2. Route the exhaust ai r from nonaccessible cubicles through the c harcoal adsorber and downstream HEPA filter b efore exhausting to the outdoor atmosphere.

c. The radioactive gases leaking from the primary containment after a LOCA or during normal operation are treated in order to remove particulates and radioactive and nonradioacti ve forms of iodine to limit the offsite dose.

d. The auxiliary building exhaust syste m exhibits a removal efficiency of no less than 90% on radioactive and nonradioacti ve forms of iodine and no less than 99% on all particulate matter 0.3 micron and larger in siz

e. The particulate removal efficiency is predicated on the use of HEPA filters having a 99% particulate rem oval efficiency. The charcoal is tested to not less than (a) 99.8%

removal efficiency on methyl iodine, and (b) 99.9%

on elemental iodine in air of 70% rela tive humidity.

The charcoal is contained in leak-tight, all-welded construction adsorbe rs to preclude bypass of the charcoal and to ensure t he highest removal efficiencies on methyl iodine.

e. The exhaust air from the auxiliary building exhaust system is released at an elevation of 599 feet 2 inches. The d ischarge air vel ocity from each auxiliary building exhaust system vent stack is approximately 60 fps maximum.

f. The auxiliary building exhaust s ystem is designed with redundancy to meet the single-f ailure criteria.

g. The power supplies meet IEEE 308-197 4 criteria and ensure uninterrupted operation in the event of loss

B/B-UFSAR 6.5-4 REVISION 12 - DECEMBER 2008 of normal ac power. The controls meet IEEE 279-1971.

h. The auxiliary bu ilding exhaust system is designed to Safety Category I requirements.

i. The auxiliary bu ilding exhaust system is designed to permit periodic testing and inspection of the principal system components as described in Subsection 6.5.1.4. 6.5.1.1.3 Fuel Handling Building Exhau st System a. The fuel handling building exhaust system, which is part of the auxiliary bu ilding HVAC sy stem (see Subsection 9.4.5.1), is designed to run continuously during all normal plant operating conditions and while filtering the exhaust air through prefilter HEPA filter banks. Prov isions are also made to route the effluent from the fuel handling building through charcoal adsorbers and downstream HEPA filters on the f ollowing signals:

1. Automatically on hig h radiation signal from redundant safety-related area monitors from fuel handling building,

2. Automatically on a saf ety injection (SI) signal from Units 1 or 2, and

3. Manually through a contr ol switch in the main control room.

b. The radioactive gases rising from the fuel pool following a fuel drop accide nt are treated in order to remove particulates and radioactive and nonradioactive forms of iodine to limit the offsite dose to the guidelines of 10 CFR 50.67.

c. The fuel handling building exhaust system exhibits a removal efficiency of no les s than 90% on elemental iodine, 30% on organ ic iodide, and no less than a 99% on all particula te matter 0.3 mi cron and larger in size. The particulate removal efficiency is predicated on the use of HEPA filters having 99%

particulate removal efficien cy. The charcoal is tested to less than 10%

methyl iodide penetration when tested at a tem perature of 30

° C and 95%

relative humidity.

The charcoal is contained in leak-tight, all-welded c onstruction adsorbers to preclude bypass of the c harcoal and to ensure the highest removal efficien cies on meth yl iodine.

B/B-UFSAR 6.5-5 REVISION 11 - DECEMBER 2006 d. The fuel handling buildi ng exhaust system is designed with redundancy to meet the single-failure criterion.

e. The power supplies meet IEEE 308-197 4 criteria and ensure uninterrupted operation in the event of loss of normal ac power. T he controls meet IEEE 279-1971.

f. The fuel handling buildi ng exhaust system is designed to Safety Category I and Seismic Category I requirements.

g. The fuel handling buildi ng exhaust system is designed to permit perio dic testing and inspection of the principal system components as described in Subsection 6.5.1.4.

h. The fuel handling buildi ng exhaust system is designed to maintain the fuel handling building at a negative pressure of 1

/4 inch water gauge with respect to atmosphere.

6.5.1.2 System Design 6.5.1.2.1 Emergency Makeup Air Filter Units

a. The makeup a ir filter units wo rk in conjunction with the control room HVAC system. Refer to Subsection 9.4.1 for further discussion.

b. In the event of high radiation detection in the outside air intakes of the control room HVAC system, the radiatio n monitoring system automatically shuts off normal outsi de air supply to the system and routes air fr om the turbi ne building through the makeup air f ilter train and fan (for removal of radioactive p articulates and iodine) before it is supplied to the control room HVAC system. c. Two redundant makeup air filter trains a nd fans are provided, each capable of handling 6000 cfm.

d. Each makeup air filter unit is comprised of the following components in sequence:

1. A demister which rem oves any entrained water droplets and moisture to minimize water droplets and water loadi ng of the prefilter.

The demister meets qua lification requirements similar to those in Mi ne Safety Appliance Research (MSAR) Report 7 1-45 and will be UL Class I.

B/B-UFSAR 6.5-6 REVISION 10 - DECEMBER 2004 2. A single-sta ge electric heater, sized to reduce the humidity of the airs tream to at least 70%

relative humidity fo r the worst inlet conditions. A heater ca pacity of 23.8 kW was calculated using 110% of the filter design flow rate and entering air conditions of 95

°F and 100% relative humidi ty. A 27.2-kW heater is provided.

3. A prefilter, UL listed, all glass media, exhibiting no less than 80% efficiency based on ASHRAE 52.

4. A high-efficiency part iculate air (HEPA) filter, water resistant, capable of removing 99% minimum of particulate matter wh ich is 0.3 micron or larger in size.

The filter is designed to be fire resistant. Six 1000 cfm elements are provided. All eleme nts are fabricated in accordance with NRC Heal th and Safet y Bulletin 306, dated March 31, 1 971, covering Military Specification MIL-F-51068 latest revision in effect at time of purc hase, MIL-F-51079 latest revision in effect at ti me of purchase, UL-586, and after January 1995, AG-1 latest re vision in effect at time of purchase.

5. A charcoal adsorber capable of removing not less than 99% of radioactive forms of iodine is provided. The charc oal adsorber is an all-welded airtight type , filled with impregnated coconut shell charco al. The c harcoal adsorber beds hold charco al with 30 lb/ft 3 density, having an ignition t emperature of 340

°C. Total bed depth is 4 inches.

The bed dimensions are so designed that the air has at least 0.25 seco nds of residence time through the charcoal.

The charcoal shall be of the best grade availab le at the time of installation and meets the requirements of ANSI N509-1976. Charcoal r eceived after September 23, 1988 shall meet the requirements of ANSI N509-1980.

Ten test canisters a re provided for each charcoal adsorber. These canisters contain the same depth of the sa me charcoal as in the charcoal adsorber. The canisters are so mounted that a p arallel flow path is created between

B/B-UFSAR 6.5-6a REVISION 7 - DECEMBER 1998 each canister and the ch arcoal adsorber. Thus, the charcoal in the cani sters is subjected to the same contaminants as the charcoal in the bed. Periodically, one of the canisters is removed and laboratory t ested to reverify the adsorbent efficiency.

One deluge valve connected to the station fire protection system is m ounted adjacent to each

B/B-UFSAR 6.5-7 REVISION 11 - DECEMBER 2006 charcoal adsorber bank.

For each charcoal adsorber, a two-stage temperature switch is provided. When the first-stage setpoint (200°F) is exceeded, it is alarmed on the main control panel and indi cated on the local control panel. When t he second-stage setpoint (310°F) is exceeded, it is annunciated on the local control panel.

After the second-stage setpoint is reached, the deluge valve can be actuated manually. Ac tuation of the deluge valves is indicated in t he main cont rol room.

6. A high-efficiency pa rticulate filter identical to the upstream HEPA filter is p rovided to trap charcoal fines which a re entrained by the airstream.

7. A fan induces the ai r from the i ntake louvers and the makeup air filter train and discharges it to the suction si de of the control room air-handling equipment train. The fan performance is based on the maximum density and worst pressure condition, when it is inducing

-10 o F air from the outdo ors and the makeup air filter train, contai ning filters which operate at no less than twice t heir clean pressure drop.

8. Full-size access doors adjacent to each filter are provided in the eq uipment train housing.

Access doors are provi ded with transparent portholes to allow ins pection and maintenance of components without violating the train integrity. Spacing betw een filter sections is based on ease of mainten ance considerations.

9. The housing is an al l-welded construction, heavily reinforced, and built to low leakage requirements.

10. Interior lights with external light switches are provided between a ll train components to facilitate inspection, t esting, and replacement of components.

6.5.1.2.2 Auxiliary Buil ding Exhaust System

a. The auxiliary building exhaust syste m works in conjunction with the aux iliary building ventilation system as described in Subsection 9.4.5.

B/B-UFSAR 6.5-8 b. In the event of high radiation detection in the auxiliary building exhaust air duct, the auxiliary building charcoal booster fans are started manually. The charcoal filter bypass dampers are closed automatically and the effluents are routed through the charcoal a dsorbers (for removal of radioactive particulates and iodine) before being exhausted to the outdoors.

c. The auxiliary building exhaust syste m, common to both Units 1 and 2, cons ists of the following in sequence:

1. The following filter plenums operate in parallel:

a) Nonaccessible area exh aust filter plenums A, B, and C treating exhaust air from nonaccessible areas of the auxil iary building and discharging into auxiliary building exhaust plenum.

b) Fuel handling bu ilding exhaust plenum, treating exhaust air f rom fuel handling building and dischar ging into auxiliary building exhaust plenum.

c) Accessible area exha usts filter plenums, A, B, C, and D, treating exhaust air from accessible areas of the Auxiliary Building and discharging into auxiliary building exhaust plenum.

2. Auxiliary buildi ng exhaust plenum.

3. Four 50% capacity ex haust air fans drawing suction from the auxil iary building exhaust plenum. Two of the fans discharge into ductwork which direc ts air to the Unit 1 vent stack, and the o ther two fans discharge into ductwork which direc ts air to the Unit 2 vent stack. 4. Unit 1 and U nit 2 vent stacks.

d. Nonaccessible area exh aust filter plenums Each of the three nonaccessi ble area exhaust filter plenums, A, B, and C, are identical, and each has 50% of the capacity required to treat exhaust air from nonaccessible areas, i.e., each p lenum has an installed filter capacity of 62,000 cfm (for Byron) and 63,000 cfm (for Braidwood).

B/B-UFSAR 6.5-9 REVISION 2 - DECEMBER 1990 The exhaust air is routed from the potentially nonaccessible areas list ed in Table 6.5-5.

Each nonaccessible area exhaust filter p lenum consists of the following com ponents in sequence:

1. An isolation damper.

2. Three 20,910 cfm capac ity each, HEPA filter subplenums connected to operate in parallel, each consisting of t he following components:

a) A high-effic iency prefilter.

b) A HEPA filter.

3. A bypass damper is p rovided downstream of the HEPA filters which pro vides direct connection to the auxiliary build ing exhaust filter plenum, bypassing th e charcoal adsorber.

4. Three, 20,910 cfm ca pacity each, charcoal adsorber plenums connected to operate in parallel, and each con sisting of the following components:

a) A charcoal adsor ber with fire protection provisions.

b) A downstream HEPA filter.

5. Two charcoal adsorbe r booster fans with a design flow rate of 62,7 30 cfm each. (Each booster fan has a flow m easuring element and a flow control d amper downstream.)

e. Fuel handling bu ilding exhaust plenum This is described in det ail in Subsection 6.5.1.2.3.

f. Accessible a rea exhaust filter plenums (Non-ESF)

B/B-UFSAR 6.5-10 REVISION 10 - DECEMBER 2004 Each of the four accessi ble area exhaust filter plenums A, B, C, and D, are identical, a nd each has 33% of the capacity required to treat exhaust air from nonaccessible are a, i.e., each plenum is designed to handle a nom inal 41,830 cfm. Each accessible area exhaust filter plenu m consists of the following compon ents in sequence:

1. An upstream isolation damper.

2. Three, 13,943-cfm capa city each, HEPA filter subplenums each consisti ng of the following components:

a) A high-effic iency prefilter.

b) A HEPA filter.

3. A downstream isolati on damper and a backdraft damper before discharging into the auxiliary building exhaust plenum.

g. The high-efficiency pr efilters provi ded in the auxiliary building exhau st system are UL listed, all-glass media, exhibit ing no less than 80-85%

efficiency based on ASHRAE 52.

h. The high-efficiency part iculate air (HEPA) filter provided in the auxiliary buil ding exhaust system is water resistant and capable of removing 99% minimum of particulate matte r which is 0.3 mic ron or larger in size. The filter is designed to be fire resistant. Each element provi ded is rated for 1000 cfm capacity. All ele ments are fabricated in accordance with NRC Health and S afety Bulletin 306, dated March 31, 1971, covering Military Specification MIL-F-51068 la test revision in effect at time of purch ase, MIL-F-51079 latest revision in effect at time of purc hase, UL-586, and after January 1995, AG-1 l atest revision in effect at time of purchase.

i. The charcoal adsorbers provided in t he auxiliary building exhaust system are capable of removing not less than 90% of radioactive forms of iodine. The charcoal adsorbers are the t ray type and are filled with impregnated coconut shell charcoal. The charcoal adsorber beds hold charcoal of 30 lb/ft 3 density with an ignition temperature of 340

°C. Total bed depth is 2 inches.

B/B-UFSAR 6.5-10a REVISION 1 - DECEMBER 1989 The bed dimensions are so designed that the air has at least 0.25 seconds of res idence time through the charcoal. The charcoal shall be of the best grade available at the time of purchase and shall meet the requirements of ANSI N509-1976. Charcoal received after September 23, 1988 shall meet the requirements of ANSI N509-1980.

Ten test canisters are p rovided for each charcoal bank in each adsorber ba nk in each subplenum.

These canisters cont ain the same depth of the same charcoal as in the cha rcoal adsorber. The canisters are so mounted that a parallel flow path

B/B-UFSAR 6.5-11 REVISION 11 - DECEMBER 2006 is created between each canister and the charcoal adsorber. The charcoal in the canister is thus subjected to the same contam inants as the charcoal in the bed. Per iodically, one of the canisters is removed and laboratory t ested to reverify the absorbent efficiency.

One deluge valve connected to the station fire protection system is mou nted adjacent to each charcoal adsorber bank. For each charcoal adsorber, a two-stage temperature switch is provided. When the first-stage setpoint (200

°F) is exceeded, it is alarmed on the m ain control panel and indicated on the local control panel.

When the s econd-stage setpoint (310

°F) is exceeded, it is annunciated on the local control panel.

After the second-stage setpoint is reached, the deluge valve can be actuated manually. Actuatio n of the deluge valve is indicated in the main control room.

j. Full-size access doors a djacent to each filter bank are provided in the eq uipment plenum

s. Access doors are provided with transparent portholes to allow inspection and m aintenance of components without violating the tr ain integrity. Spacing between filter sections is based on ease of maintenance considerations. The ple nums are all-welded steel plate construction with intermediate concrete floors, heavily reinforc ed, and built to low leakage requirements.

6.5.1.2.3 Fuel Handling Building Exhau st System a. The fuel handling building exhaust system works in conjunction with the aux iliary building ventilation system as described in Subsection 9.4.5.

b. In the event of high radiation detection in the fuel handling building, the radiation monitoring system automatically routes the effluents through the charcoal adsorbers a nd booster fans (for removal of radioactive p articulates and iodine) before they are exha usted outdoors.

c. The fuel handling exha ust system as indicated in Drawing M-95 is comm on to both Units 1 and 2 and consists of the follow ing in sequence:

B/B-UFSAR 6.5-12 REVISION 10 - DECEMBER 2004 1. Area radiation monit ors located at the fuel pool in the fuel han dling building.

2. Two fuel handling buil ding exhaust filter plenums connected in parallel.

3. Auxiliary building e xhaust plenum, four 50%

capacity exhaust fans, and Unit 1 and 2 vent stacks are common with t he auxiliary building exhaust plenum, as described in Subsection 6.5.1.2.2.

d. Fuel handling buildi ng exhaust f ilter plenum Each of the two fuel handling building exhaust filter plenums (FHBE FP) is identical and each has 100% of the capacity req uired to treat exhaust air from the fuel handling b uilding, i.e., each plenum is designed to h andle a nominal 21,0 00 cfm. Each FHBEFP consists of the followi ng components:

1. An isolation damper.

2. A high-effic iency prefilter.

3. A HEPA filter.

4. A bypass damper downst ream of the HEPA filters which provides direct connection to the auxiliary building exh aust filter plenum, bypassing the ch arcoal adsorbers.

5. Two 100% capacity ch arcoal adsorber plenums connected in parallel, each consisting of the following components:

a) A charcoal adsor ber with fire protection provisions.

b) A HEPA filter.

c) An isolation damper.

6. A nominal 21,000 cfm capacity ch arcoal booster fan. Each fan has a f low measuring element and a flow control d amper downstream.

e. The high-efficiency pr efilters provi ded in the auxiliary building exhau st system are UL listed, all glass media, exhib iting no less than 85%

efficiency based on ASHRAE 52.

f. The high-efficiency part iculate air (HEPA) filter provided in the auxiliary bu ilding exhaust system

B/B-UFSAR 6.5-13 REVISION 8 - DECEMBER 2000 is water resistant, capa ble of removing 99% minimum of particulate matte r which is 0.3 mic ron or larger in size. The filter is designed to be fire resistant. Each element provi ded is rated for 1000 cfm. All elements are fabricated in accordance with NRC Health and S afety Bulletin 306, dated March 31, 1971, covering Milit ary Specificatio n MIL-F-51068 latest revision in e ffect at time of purchase, MIL-F-51079 latest revis ion in effect at time of purchase, UL-586, and after January 1995, AG-1 latest revision in e ffect at time of purchase.

g. The charcoal a dsorbers provided in the fuel handling building exhaust system are capable of removing not less than 90% of elemental i odine and 30% of organic iodide. The charcoal ad sorbers are tray type and are filled with impr egnated coconut shell charcoal.

The charcoal adsorber be ds hold charcoal of 30 lb/ft 3 density with an i gnition temperature of 340°C. Total bed de pth is 2 inches.

The bed dimensions are so designed that the air has at least 0.25 second of residence time through the charcoal. The charcoal shall be of the best grade available at the time of ins tallation and shall meet the requirements of ANSI N509-1976. Charcoal received after September 23, 1988 shall meet the requirements of ANSI N509-1980.

Ten test canisters are p rovided for each charcoal adsorber bank. These ca nisters contain the same depth of the same charco al as in the charcoal adsorber. The canisters are so moun ted that a parallel flow path is create d between each canister and the charcoal adsorber.

The charcoal in the canisters is thus subjec ted to the same contaminants as the charcoal in the bed. Periodi cally, one of the canisters is removed and laboratory tested to reverify the ads orbent efficiency.

h. The fuel handling buildi ng charcoal filter bypass line is closed a utomatically on a high radiation signal from safety-related area monitors located in the fuel handling building.

The bypass isolation dampers are also interlocked as follows: damper OVA051Y is inter locked with fan OVA0 4CA such that the damper will clos e when the fan is started, and similarly for damper OVA435Y and fan OVA04CB. The control and instrumentat ion for the interlock is shown on the same drawing as the charcoal booster fans.

B/B-UFSAR 6.5-13a REVISION 8 - DECEMBER 2000 i. The fuel handling building exhaust system does not include a means for humidity control of the exhaust air prior to entering the charcoal filters. Exhaust air relative humidit y will vary with the outside air conditions (temp erature and relative humidity), the evaporation rate of the spent fuel pool water (water temperature), and the area heat generation. The relative humidity of the inlet air to the fuel handling building exhaust filter system may be greater than 70%. Therefore, la boratory testing is conducted at 30°C and 95% relative humidity and the removal efficiencies for the element al and organic forms of radioiodine are 90% and 30% relatively.

B/B-UFSAR 6.5-14 REVISION 11 - DECEMBER 2006

THIS PAGE DELETED INTENTIONALLY.

B/B-UFSAR 6.5-15 REVISION 11 - DECEMBER 2006 j. One deluge valve connect ed to the station fire protection system is m ounted adjacent to each charcoal adsorber bank. For each charcoal adsorber, a two-stage temperat ure switch is provided. When the first-stage setpoint (200

°) is exceeded, it is alarmed on the m ain control panel and indicated on the local control panel.

When the second stage setpoint (310

°) is exceeded, it is annunciated on the local control panel.

After the second stage setpoint is reached, the deluge valve can be actuated manually. Actuatio n of the deluge valves is indicated in the main control room.

k. Full-size access doors a djacent to each filter bank are provided in the equipmen t plenums.

Access doors are provided with transp arent portholes to allow inspection and maintenan ce of components without violating the train inte grity. Spacing between filter sections is based on ease of maintenance considerations.

The plenums are all-welded steel plate construction with intermediate conc rete floors, heavily reinforced, and buil t to low leakage requirements.

B/B-UFSAR 6.5-16 REVISION 12 - DECEMBER 2008 6.5.1.3 Design Evaluation 6.5.1.3.1 Emergency Makeup Air Filter Units The emergency makeup air filter system w orks in conjunction with the control room HVAC system to maintain habitability in the control room. The design evaluation is gi ven in Subsection 6.4.4.

6.5.1.3.2 Auxiliary Buil ding Exhaust System The auxiliary building e xhaust system is desig ned to preclude direct exfiltration of contaminated air from the auxiliary building following an accident or abnormal occurrence which could result in abnormally high airbor ne radiation in the auxiliary building. E quipment is powered from essential buses, and all power circuits m eet the requirements of IEEE 279-1971 and IEEE 308-1974. Redundant components are provided where necessary to ensure that a single failure will n ot impair or preclude system operatio

n. A system failure analysis is given in Table 9.4-10.

6.5.1.3.3 Fuel Handling Building Exhau st System The fuel handling buildi ng exhaust system is designed to preclude direct exfiltration of contaminated air from the fuel handling building, when required following an accident or abnormal occurrence which cou ld result in abnorma lly high airborne radiation in the fue l handling building.

The fuel handling buildi ng will be mai ntained at a pressure of 0.25 inches (water) below atmosp heric pressure.

The basis for this requirement is the nega tive pressure differential indicated in SRP 6.2

.3 Section II. The fuel handling building exhaust system will be u nder negative pressure at all times.

The necessary airflow ra tes are as follows:

exhaust air - 21,000 cfm at 0.066 lb/ft 3 density; infiltration air - 4,0 70 cfm at 0.067 lb/ft 3 density; and supply air - 16,135 cfm at 0.067 lb/ft 3 density.

The control system has been modi fied to provide for a pressure differential controller sensing fuel han dling building/outdoor differential pressure and cont rolling a modula ting control damper in the air supply duct serving the fu el handling building.

Equipment is powered from es sential buses, a nd all power circuits meet requirements of IEEE 279-1971 and IEEE 308-1974.

Redundant components are provided where necessary to ensure

B/B-UFSAR 6.5-17 REVISION 12 - DECEMBER 2008 that a single fa ilure does not impair or preclude the system operation. A system failure analysis is given in Table 9.4-10.

6.5.1.3.3.1 Fuel Handling Ac cident Inside Sp ent Fuel Storage Building The accident is defined as the dropping of a s pent fuel assembly in the spent fuel pool resu lting in the rupture of the cladding of 264 fuel rods. The cause of the event can be identified as any mechanical failure or operating error which re sults in the dropping of a fuel assembly into the refu eling pool during its transfer from one position in the pool to another. The fr equency classification, as defined in Regulato ry Guide 1.70, can be categorized as one of limiting faults. This means that it is an o ccurrence that is not expected to occur but is postulated because its conseq uences would include the potential for the release of signi ficant amounts of radioactive material.

The step-by-step sequ ence of events from initiation to the final stabilized condition is described in Table 6.5-2. For the purpose of this accident, the time sequence will be referenced from the mome nt radioactivity is rele ased from the surface of the pool water.

As originally designed, least 12 seconds would be required for radioactivity to travel from the exhaust inlet to the first isolation damper. Thus, all acti vity released from the accident could be filtered through HEPA and charcoal filters prior to release to the stack. However, design basis analyses p erformed utilizing alternative source term methodology do not c redit filtration.

During handling of recently irradiated fuel (i.e. fuel that has occupied part of a critical core wit hin the previous 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />), the fuel handling buildi ng ventilation sys tem is required to be operable.

The normal supply system is designed to provide 19,050 cfm of outside air to the fuel hand ling building general area.

The exhaust inlets are located at the pool edge. The shortest di stance between the exhaust inlets and t he inboard isolation valve is 222 feet.

Redundant GM-type gamma detectors are mounted on the walls near the edge of the pool to provide re liable and rapid detection of radioactivity released f rom the pool surface.

If predetermined levels are excee ded, the monitors alarm locally and in the main control room and initiate control action to route the released activity through the e mergency exhaust system. Howeve r, design basis analyses performed utilizing alt ernative source term methodology do not credit filtration.

The monitors have an operating range which extends from 0.1 to 10 4 mR/hr. The lower range level is chosen to assure that normal operating levels are on scale (provides indication that the instrument is operationa l). Operating levels below 0.1 or greater than 50 mR/hr are unlike ly. Initial setpoints a re listed in Table 12.3-3.

The worst case fuel hand ling accident (as orig inally analyzed) has the potential of exceedi ng the 10 R/hr maxim um range of the fuel handling accident monito rs, but this environment will not prevent the monitor from com pleting its design function. Ge neral Atomics (GA) has tested this moni tor to 500 R/hr, and based on this

B/B-UFSAR 6.5-18 REVISION 12 - DECEMBER 2008 test, they have determin ed that this monitor will perform its function up to 1000 R/hr.

The monitor was origin ally selected to a ssure initiation of control action within 6 seconds or less. Co mmercially available area monitors are suitab le for this application.

Two separate and indep endent (nuclear sa fety-related) monitors are provided for the s pent fuel pool. T wo nuclear safety-related recorders are pr ovided in the control room for the spent fuel pool.

6.5.1.4 Tests and Inspections The engineered safety feature filter s ystems and their components are t horoughly tested in a pr ogram consisting of the following:

a. factory and componen t qualification tests,

b. onsite preoperat ional and filter acc eptance testing, and c. onsite periodic testing.

Written test pro cedures establish minimum acceptable values for all tests. Test results are recorde d as a matter of performance record, thus enablin g early detection of reduced performance.

The factory and component qual ification tests consist of the following:

a. equipment train housing - a leak test and magnetic particle or liquid penetrant testing per Section III of ASME Boiler and Pressure Vessel C ode of all welds which could cause bypass lea kage around HEPA filters or adsorber beds;

b. demister - qualification test or objective evidence to demonstrate compliance with specified design criteria;

c. HEPA filters - elements tested i ndividually by the manufacturer in accordance with the requirements of Regulatory Guide 1.52.

B/B-UFSAR 6.5-19 REVISION 8 - DECEMBER 2000 d. HEPA filter and char coal adsorber mounting frames-leak test across filt erless, covered bank;

e. adsorbent beds - model test of bed or objective evidence to demonstrate flow pressure characteristics and channeling effects;

f. adsorbent - qualification tests per ANSI N509-1976, after September 23, 1988 qua lification tests per ANSI N509-1980;

g. fans - tested in accorda nce with the latest revision of AMCA 210, "Air Mo ving and Conditioning Association Test Code for Ai r Moving Devices," to establish characteristic curves, etc.;

h. heater - uniform temperature test, high-temperature cutout test, and enter ing and leaving air temperature test;

i. prefilter - objective ev idence or cert ification that American Society of Heating, Refrigeration and Air Conditioning Enginee rs (ASHRAE) effici ency specified is attained; and

j. dampers - shop tests demonstrati ng leak-tightness and closure times.

The onsite preoperatio nal and filter a cceptance tests are discussed in Section 14.2.

Operating personnel are trai ned and required to make surveillance checks.

These checks s hall include visual inspection and p eriodically running the equipment trains for performance testing as o utlined in the Techn ical Specifications.

6.5.1.5 Instrumentat ion Requirements High differential pressure acr oss the upstream and downstream HEPA filter is alarmed on the local control panel. One high filter differential pres sure alarm for each plenum is provided on the main control panel.

For each charcoal adsorber, a two stage temperat ure switch is provided. When the fi rst stage setpoint (200

°) is exceeded, it is alarmed on the ma in control panel and ind icated on the local control panel. When the second-stage setpoint (310

°F) is exceeded, it is annu nciated on the local control panel. One deluge valve for eac h charcoal adsorber bed is provided which can be opened manually when the second-stage setpoint is reached.

Flow signals are transmitted to the local control panel for indication and for modulation of the control damper.

B/B-UFSAR 6.5-20 REVISION 7 - DECEMBER 1998 Remote manual operat ion is provided on t he main cont rol board for each fan.

Design details and logic of the instrume ntation are discussed in Subsections 7.3.1.1.

8 and 7.3.1.1.9.

6.5.1.6 Materials All component material is capable of a servi ce life of 40 years normal operation plu s 6 months post-LO CA at the maximum cumulative radiation e xposure without any ad verse effects on service, performance, or opera tion. All materials of construction are compatible wi th the radiati on exposure set forth. This include s but is not limited to all metal components, seals, gas kets, lubricants, and finishes, such as paints, etc.

Care is taken to avoid the use of any compounds or other chemicals during fabrication or production that contain chlorides or other constitue nts capable of i nducing stress corrosion in stainle ss steels which are used in the adsorber bed.

All components, including the housings, shal l be designed in accordance with the applicable pressure and temperature conditions.

All gaskets and seal p ads are closed-cel l, ozone-resistant, oil-resistant neoprene or silicone-rubber sp onge, Grade SCE-43 or current designation at time of purcha se in accordance with ASTM D1056.

Only adhesives as li sted and approved under AEC Health and Safety Bulletin 306, dated March 31, 1 971, covering Military Specification MIL-F-51 068C, dated June 8, 1970, and all the latest amendments and modifications are used.

The organic compounds in cluded in the filter train are as follows:

a. charcoal;

b. the binder in the HEPA filter media;

c. adhesive used in HEPA filters - approximately 1 liquid quart of fire-retardant neoprene or polyurethane foam adhesive is used to manufacture each HEPA filter;

d. neoprene gaskets used on HEPA filters and charcoal filter tray flanges;

e. the binder in the glass pads used in the demister section (this is a phe nolic compound); and

B/B-UFSAR 6.5-21 REVISION 12 - DECEMBER 2008 f. phenolic compounds and e lastomers associated with electrical components.

6.5.2 Containment

Spray Systems The containment spray sy stems are designed to remove fission products, primarily iodine, from the containment atmosphere for the purpose of minimizing the offsite radiolog ical consequences following the design-bas is loss-of-coolant acc ident. At the same time, the spray water serves to nominally reduce containment temperature and pressure dur ing the injection phase.

The containment spray systems may be used to mix the contents of the RWST prior to chemistry samp ling. This is accomplished by lining up the containm ent spray system for recirculation to the RWST. This lineup is identical to the o ne used to test the containment spray pumps and may be perfo rmed in any mode.

The containment spray sy stems may also be used to transfer borated water from the refueling cavity and transfer canal to the RWST. This is a ccomplished by taking suction from an RCS hot leg via RHR piping a nd discharging to the RWST via the containment spray system recircu lation piping.

This evolution can only be performed when t he reactor core is defueled.

6.5.2.1 Design Bases The containment spray sy stem is designed to re duce the pressure in the containme nt atmosphere at a rate which will ensure that the design leakage is not exce eded and to remove sufficient iodine from the containm ent atmosphere to li mit, in the unlikely event of a LOCA, the offsite a nd site boundary d oses to values below those set by 10 CFR 50.67.

The spray system is designed to provide a suffic ient quantity of 30% to 36% NaOH soluti on to the containment to form an 8.0-10.5 pH solution when combined with t he spilled reactor coolant water, the safety in jection accumulator inventory, and the refueling water storage tank inventory . Th e containment spray system consists of two entirely independ ent subsystems such that the aforementioned req uirements can be met in the event of a single active failur e in either of t he subsystems.

All components of th e containment spray system except the test/recirculating line are Safety Category I and Quality Group B and are protected from missiles which could re sult from a loss-of-coolant accident.

All risers and ring headers are supported to withsta nd loads resulting f rom the safe shutdown earthquake as well as operating loads. A seismic dynamic analysis has been perf ormed on the system.

B/B-UFSAR 6.5-21a REVISION 7 - DECEMBER 1998 The following criter ia apply to the spray nozzles:

a. The Sauter (surface to v olume ratio) mean diameter of the spray dro ps produced by the nozzle at the design pressure drop across the nozzle must be approximately 1000 m icrons or less.

b. The pressure nozzle used is of a swirl chamber design, without any internal parts, such as swirl vanes, etc., whi ch would be subject to clogging.

c. Flow through the nozzle at the desig n operating point is at least 15 gpm.

B/B-UFSAR 6.5-22 REVISION 12 - DECEMBER 2008 6.5.2.2 System Design (for Fission P roduct Removal)

The containment spray system has been divided into two independent 100% capacity pumping systems with no common headers. A single active failure in either of the two pumping systems will therefore not affect the op eration of t he other subsystem. A single-f ailure analysis is presented in Table 6.5-1. The system dia gram (Drawing M-46) illustrates equipment redundancy, flowpaths, a nd system operation.

The containment spray system includes six ring-type spray headers each having the following radii, pipe diameter, number of nozzles, and served by the pump indicated:

Ring Number Mean Radius Nominal Pipe Diameter in. Number of Nozzles Destination of Pump Delivering Fluid to the Ring 1 13 feet 0 inch 4 39 "A" Pump 2 23 feet 6 inches 6 51 "B" Pump 3 34 feet 1/2 inch 6 60 "A" Pump 4 45 feet 9 inches 6 90 "B" Pump 5 56 feet 7-1/2 inches 8 120 "A" Pump 6 64 feet 9 inches 8 112 "B" Pump

There are no cross c onnections between the "A" and " B" spray headers. Rings 1, 3, and 5 are supplied via a single 10-inch riser pipe with restricting orifices in laterals supplying rings 3 and 5 to assure th at the flow to each ring is proportionate to the number of nozzles supplied. Similarly, rings 2, 4, and 6 are supplied via a single 10-inch riser pipe w ith restricting flow orifices in laterals supply ing rings 4 and 6. The plan view of the spray headers sh owing nozzle location and orientation is given in Drawing M-53 5, Sheets 3-5.

The "A" pump is designed to deliver 15 gpm to each of 219 spray nozzles, plus approxim ately 130 gpm of m otive fluid to the eductor considering post-accident containment pressure versus RWST level time prof iles and pump degr adation. The "B" pump under like conditions is designed to deliver 15 gpm to each of 253 spray nozzles plus approximately 130 gpm of motive fluid to the eductor. The nomi nal pump ratings are t herefore 3415 and 3925 gpm for the "A" and "B" pumps respectiv ely, at 450 feet total developed head.

In the event of a high-high-high (Hi-3) containment pressure signal (corresponding to approximately 20 psig

), the CS007, the

CS019, B/B-UFSAR 6.5-23 REVISION 7 - DECEMBER 1998 and the CS010 valves w ill open immediately if they are not previously in the op en position; the CS pumps will start immediately once the CS019 valve is open, provid ed that offsite power to the ESF buses has not been lost.

Otherwise, upon receipt of a safety in jection signal and restoration of bus voltage, the containment spray pumps will be sequenced to start by the diesel en gine generator load se quencer, providing the Hi-3 signal is present a nd the CS019 valve is open. The valve motor operators will start immediately u pon receipt of an Hi-3 signal if power is available.

The refueling water stor age tank (RWST) (conta ining 2300 to 2500 ppm of boron) for each unit has a capaci ty of approximately 458,000 gallons. Lo w-level switches are provided to automatically open the c ontainment sump isolat ion valves, SI8811 A and B, on two out-of-four logic sensing a Lo-2 level with the presence of a safety i njection signal. It sh ould be noted that manual reset of safety injection does not defeat the automatic opening of the S I8811 A and B valves. The RHR p umps are thereby transferred to the r ecirculation mode au tomatically without stopping them. The charging pum ps and safety injection pumps are then manually changed to the recirculating mode (see Subsection 6.3.2.8). The cont ainment spray pump continues to take suction from the RWST until the Lo-3 level is reached. The CS pump suction is then manually tra nsferred to the recirculation sump. N aOH addition conti nues, regardless of pump suction source, until the spray additive tank Lo-2 level is reached. The spray additive tank is then manually isolated from the CS eductor.

Heat tracing the spray additive tanks and piping is not necessary to prevent crystalli zation of the 30%

to 36% sodium hydroxide solution. The spray a dditive tank also has a nominal 1 psig nitrogen cover blanket applied to eli minate ambient air contact with the solution.

B/B-UFSAR 6.5-24 REVISION 12 - DECEMBER 2008 The worst-case condition for maximum spray pH postulates the failure of one CS019 valve to open concu rrently with two trains of ECCS and CS pump in o peration. Since the spray additive tank is supplying only on e eductor, the t ime to deple te the spray additive tank is greater than the time to deplete the RWST.

This will result in transferring the suction of the CS pump to the containment recircul ation sump and continuing eduction of NaOH from the spray additive tank until the spray additive tank Lo-2 level is reached.

This will result in NaOH being added to sump water that alre ady contains NaOH.

At this time, the resulting pH may exceed 10.5. However, this is acceptable with regard to the equipm ent qualification limit of 10.5 (see Subsection 3.11.5) and for hydrogen generation purposes.

The worst-case condition for minimum spray pH postulates a containment spray flow rate approaching CS p ump runout (4600 gpm for B train) with minimum expect ed NaOH flow r ate. A spray pH of greater than 8.0 is still obtained.

Under both cases, the spray solution pH will be above 8.0 during the injection phase (NaOH additi on) and will pro vide a spray removal coefficient of 20hr

-1. Sufficient Na OH is delivered to the containment to form a minimum 8.0 pH sump solution when ECCS injection fluid (from the refueling water storage tanks and accumulators) is combined with s pilled reactor c oolant. This final sump pH will pro vide for long-term iod ine retention. This will result in a deconta mination factor of 200 in the containment atmosphere for sump te mperatures between 150

°F and 212

°F.

Regulatory Guide 1.1 addresses the recirculation mode in which temperatures of the pu mped fluid are at a maximum. The recirculation mode dic tates the design for r esidual heat removal and containment spray pu mp suction piping because during the injection phase there is 50 to 90 feet of positive head available from the ref ueling water storage tank acting on the suction of these pumps.

B/B-UFSAR 6.5-25 REVISION 12 - DECEMBER 2008 The residual heat removal pumps require approxim ately 12 feet of NPSH at 3000 gal/min design capacity and approximately 19 feet of NPSH at runout ca pacity of 5000 gal/m in. The containment spray "B" pump requi res approximately 19 feet of NPSH at 3925 gal/min design capac ity and approximately 22 feet of NPSH at 4600 gal/min runout ca pacity. Since the "B" train containment spray pump is of higher capacity than the "A" train pump, and the line size and equivalent feet of pipe are ab out the same for both the trains, for containment spray, the NPSH required versus available is most crit ical for the " B" train pump. Values of NPSH required are in dicated as approximate because there are slight variations between pu mps of dupli cate design.

Allowing no credit for t he water standing in the basement of the containment but assuming that the recirculat ion sump is full, the static head available is in excess of 30 feet for the containment spray pumps (contain ment basement elevation minus elevation of the centerline of t he containment s pray pumps) and in excess of 29 feet for the RHR pumps (cont ainment basement elevation minus elevation of the centerline of RHR pumps).

Based upon both the RHR and containment spray "B" Pump operating under runout conditions, friction losses between the sump and pump inlet are conservatively calculated to be less than 3.5 feet for containment spray and for RHR. The mini mum resultant NPSH available is approximately 29 fe et for the conta inment spray "B" pump and approximately 28 fe et for the RHR pumps.

For high temperature conditions, this analysis a ssumes that the liquid in the recirculat ion sump is at its vap or pressure at all times, thus there is no need to delibera tely continue a high containment pressure con dition to satisfy pump NPSH requirements.

As part of the chemical effects evaluati ons related to head loss through the containment recirculation sump str ainers (in support of Generic Letter 20 04-02), the NPSH analysi s for the RHR pumps has been performed at low temperatures.

In accordance with t he requirements specifie d in Regulatory Guide 1.1, the NPSH analysis at lo w temperatures assumes the containment atmospheric pressure is equal to the minimum containment atmospheric pressure that would be p resent inside containment before the Loss of Coolant Accid ent (LOCA) event.

This analysis does not credit calculated incre ases in containment pressure as a result of the LOCA.

Adequate net positive su ction head is available to the RHR pumps.

The sump solution satisfies NPSH req uirements of the pumps with adequate margin to assure sati sfactory pump oper ation concurrent with RHR pump runout at the rate of 5000 gpm and CS pump maximum flow of 4800 gpm.

B/B-UFSAR 6.5-25a REVISION 12 - DECEMBER 2008 Containment sump water temperatu re is not monitored for postaccident analysis.

Although identified in Regulatory Guide 1.97 as an important par ameter, containm ent sump water temperature indication w ould only be u seful to determine if adequate NPSH is available to the CS or RHR pumps during the recirculation mode. By design, cavitation of these pumps will not occur even at containment sa turation peak water temperature.

The B/B design complies with Regulatory Guid e 1.1 which states that, "Emergency core cooling and containment heat removal systems should be desi gned so that adequ ate net positive suction head (NPSH) is provi ded to system pu mps assuming maximum expected temperatures of pumped fluids and no increase in containment pressure from that present prior to post ulated loss of coolant accidents

." Containment sump wat er temperature is therefore not a parameter requir ed to indicate p roper operation of the CS or RHR systems whe n in the recirculation mode.

B/B-UFSAR 6.5-26 REVISION 12 - DECEMBER 2008 Containment spray operation will continue for a minimum of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following a LOCA. After 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of operation, containment spray may be terminated if containment pressure is l ess than 15 psig and the spray additive tank has r eached the Lo-2 level.

Following a MSLB, containment sp ray operation may be terminated after containment pressure is less than 15 psig.

NaOH addition may be secured prior to 15 psig.

Suction lines to each pu mp are provided with guard pipes and suction valve protection chambers up to and including the first valve outside the containment for passive failure protection.

Both pumps and all m otor-operated valves are supplied with power from the emergency diesel genera tors in the event of a loss of offsite power. Failure of a single dies el generator or emergency bus will aff ect one subsystem only.

Spray Engineering Company of Burlington, Massa chusetts, 1713A nozzles meet the require ments stated in the de sign basis. The following listed figures illustr ate the characterist ics of this nozzle when spraying i nto a chamber at atmos pheric pressure and normal ambient tempera ture and humidity:

a. Figure 6.5-5, Diameter of spray envelope versus height when spraying v ertically downward.

b. Figure 6.5-6, Diameter of spray envelope versus height when spraying horizontally.

c. Figure 6.5-7, Diameter of spray envelope versus height when spraying downward at a 45

° angle. The above figures are predicated upon a 40 psi d rop across each nozzle with a result ing flow of 15.2 gpm per nozzle. Pressure versus flow characterist ics of this nozzle a re illustrated in Figure 6.5-8.

In determining the number of spray noz zles required and their configuration, the e ffects of density of the containment atmosphere must be considered. The re duction factors to be applied to spray envelope diamet er as a function of containment saturation temperatu re are shown in Figure 6.5-9.

To prevent degradati on of the sodium h ydroxide, an inert atmosphere is maintained within the spray addi tive tank by means of a nominal 1 psig nitrogen blanket.

A relief valve is provided to prevent overpres surization of the tank.

B/B-UFSAR 6.5-26a REVISION 7 - DECEMBER 1998 The components for this system a re as follows:

a. Containment Spray Pumps Number - two per unit Type - Vertical centrifugal Material - Stainless steel

Capacity "A" pump - 3415 gpm Capacity "B" pump - 3925 gpm Net developed head - 450 feet

B/B-UFSAR 6.5-27 REVISION 10 - DECEMBER 2004 b. Spray Additive Tank Number - one per unit Material - Stainless steel Volume - 5000 gallons

Fluid - 30% to 36%

NaOH in water Cover gas - Nitrogen Design pressure - 1.3 psig Design temperature - 100

°F c. Eductors Number - two per unit Design Pressure - ap proximately 300 psig Design Temperature - 300

°F Design flow - 130 gpm at pressure connection (actual flow rate was determined during preoper ational testing)

Design educted flow -

25-60 gpm 30% NaOH at suction connec tion (for pH control)

Material - Stainless steel

d. Spray Nozzles Material - Stainless steel Type - Sprayco 6.5.2.3 Design Evaluation An extensive research and deve lopment program has been conducted as part of the NRC's Reactor Safety Program to determine the iodine removal effective ness of the chemical spray systems.

Containment spray experiments we re performed in the 1350 ft 3 vessel of the Nuclear Sa fety Pilot Plant (NS PP) at ORNL and were supported by additio nal containment spray experiments in the large 25-foot-diameter by 66.7-foot-high (26,500 ft

3) vessel (approximately one-fifth the scale of a typi cal 1000 MWe nuclear reactor) of the Containm ent Systems Experiment (CSE) at BNWL.

Since the contai nment spray tests

B/B-UFSAR 6.5-28 were begun, the iodine-r emoval capability of spray systems has been well established by over 80 spray tests in the NSPP and 28 spray tests in t he eight CSE experiments.

The verification of the containment spray sy stem spray coverage within the conta inment and system desi gn parameters has been completed at the Zion Station.

The experimental verification of the acceptabi lity of the containment spray system as a viable means of rapidly removing iodine from the containment has been completed by Westingh ouse Electric Corporation and reported in WCAP-7742 and other publications. T he adequacy of sodium hydroxide spray additive has been doc umented in various ORNL and BNWL reports.

The extensive research on the behavior of iodine in accident environments and the dose re duction factors provided by containment spray systems has be en completed, and the conclusion is that the containment spray system is an effective safety system which has been proven by experimental studies and large scale model tests.

One of the advantages of the sodium hydroxid e spray system is that it responds rapid ly by starting to clea n all the gas in the containment after an accident by abs orbing and reacting with the airborne iodine.

Other types of iodine-removal systems respond much more slowly and thus permit the iodine to remain airborne for a lo nger time. In compa rison to other systems, the spray system is m uch simpler in design. It utilizes system components which are reliable and well understood through extensive use. The fiss ion product removal capability is discussed in detail in Attachment A6.5.

The following sections of the containment wi ll not be directly covered during postaccid ent spray operation:

a. containment fan cool er discharge structures, b. missile barr ier passageways, c. chamber beneath upper internals storage area, d. chamber beneath lower internals storage area,

e. chamber beneath exchan ge fixture storage area, f. chamber beneath transfer tube, g. passageways above transfer tube, h. entrance to seal table,

i. volume beneath main steamline penetrations, B/B-UFSAR 6.5-29 REVISION 7 - DECEMBER 1998 j. volumes beneath floor slabs at elevati on 426 outside the missile barriers.

k. volume operating floor,

l. chamber bene ath pressurizer, m. chambers beneath steam generators

n. sheltered volumes bene ath seal table and heat exchanger compartments, o. net free volume within seal table an d heat exchanger compartments, and

p. net free volume with in the reactor v essel cavity and in-core instrument shaft.

The maximum net containment volume is 2,848,387 ft 3; the minimum net containment volume is 2,758,850 ft

3. The minimum net volume of the containment w hich is sprayed directly is 2,349,944 ft 3 , or 82.50% of the maximum net volume and 85.18%

of the minimum net volume. The regions not d irectly sprayed but having good communication with spr ayed regions have a maximum volume of 438,914 ft 3 and a minimum of 349,377 ft 3 , or 15.41% of maximum and 12.66% of minimum net containment volume.

The minimum net volume that is s prayed directly includes the volume above the operati ng floor minus: the polar crane; steam generator; pressuriz er; and reactor cool ant pump compartments; and plus: the refueling cavity; main steam vertical pipe chase; regenerative and exc ess letdown heat e xchanger compartments.

There are no regions within the containm ent that are unsprayed and not in communica tion with sprayed volumes within the containment. The seal table compartment, with a net volume of 3146 ft 3 , and the reactor coolant dr ain tank compart ment, with a net volume of 341 ft 3 , have poor communicati on with the sprayed regions of the conta inment, for a to tal of 3487 ft

3. This is 0.122% of the maximum net containment volume and 0.126% minimum net containment volume.

Under post-LOCA cond itions, there is 56,042 ft 3 of water in the containment basement.

This plus the dir ectly sprayed regions plus the seal table and reactor coolant drai n tank compartment totals are equal to 2,409,473 ft

3. The regions not directly sprayed but having good communication with s prayed volumes are by difference a maximum 438,914 ft 3 and a minimum of 349,377 ft 3 , or 15.41% and 12.66%

of maximum and mi nimum net containment volume. The 56,042 ft 3 of water in the containment basement corresponds to a water l evel of 5 feet 2 inc hes. The maximum evaluated flood level of 6 feet 3 inches has minimal effect on

B/B-UFSAR 6.5-29a REVISION 12 - DECEMBER 2008 these containment region volum es. The change to the maximum/minimum volumes is less than 0.1% fo r the regions not directly sprayed but having go od communication with sprayed volumes.

The containment spray pumps will be run for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following a LOCA. During this time, switchover of pump suction

B/B-UFSAR 6.5-30 REVISION 10 - DECEMBER 2004 from the injection to the reci rculation mode of operation will be manually initiate d and completed.

The containment spray pumps do not have to be stopped when transferring from th e injection mode to the recirculation mode of operation, provided that the RWST has not reached the empty level. A summary of the sequence of events le ading up to and during switchover follows.

The RWST level is initially one volume inaccuracy below the low alarm setpoint.

ECCS switchover is initiate d when the RWST Lo-2 alarm annunciates. This is discussed in Section 6.3.

Spray switchover is initiated when the RWST Lo-3 alarm annunciates. Upon r ecognition of the RW ST Lo-3 alarm, the operator opens the CS0 09 valve and closes the CS001 valve. At this time all ECCS a nd containment spray pumps have a long-term suction supply of water.

Upon initiation of containment s pray, the operat or monitors the spray additive tank le vel; on a LO-2 l evel, the containment spray eductor spray addi tive valve for e ach operating train is closed. In the event of a single failure of the containment spray eductor spray addi tive valve to op en, the pump in the train with the f ailed valve will not autosta rt. While the ECCS pumps are operating from the r ecirculation sump, the one operating spray pump continues to take s uction from the RWST until the RWST reaches the Lo-3 level. At this time the spray pump suction is switched to the recirc ulation sump.

Addition of required volume betw een Lo to Lo-2 l evel setpoints of 30-36% NaOH from the spray additi ve tank to the containment ensures the long-term required minimum s ump pH of 8.0 is maintained. This is accomplished by continuing caustic addition while the spray pump is taking suction from the sump.

At the initiation of containment spray, the CS pumps take suction from the RWST. The resu lting pH of the RWST and NaOH mixture will be greater than 8.0, as required for iodine absorption; however, it may exceed the upper EQ limit of 10.5 depending on the CSAT NaOH conce ntration. When the CS pumps are aligned to take suction from the containment sump, t he eductors may still be in operat ion, adding NaOH to the pump flow. This will result in a maximum spray pH. When NaOH addition is secured and the CS pump suction is from the recirculation sump, the spray pH will be the same as the sump pH (8.0-10.5). The effects of these pH values on e quipment qualifica tion and hydrogen generation have been evaluated and found acceptable. Below is a detailed description of the effects on pH caused by the CS system operation.

B/B-UFSAR 6.5-30a REVISION 10 - DECEMBER 2004 At the initiation of containment spray, water from t he RWST is mixed with NaOH from the spray additive tank. The pH of the mixture is determined pr imarily by the concentration of NaOH in the spray additive tank.

If the CSAT is at the upper concentration limit and the NaOH flow is at the upper limit, the resulting pH may be greater than the EQ limit of 10.5. When the source of containment spray water is swi tched from t he RWST to the recirculation sump (LOCA only), the eductor may be adding NaOH to sump water that has already been treated with NaOH.

This will cause the pH to increase. The inc rease is determined by the actual flow r ates before and pres ent at the time of switchover. However, this value is boun ded by the pH that occurs in the final minu te of NaOH addition, when it is assumed that all the NaOH previously added had mixed uniformly and flowed to the recirculat ion sump. The duration of increased pH is determined by the n umber of trains of ECCS and CS pumps in operation.

The NaOH injection flow rate to achieve a mi nimum spray pH of 8.0 (minimum allowable pH per SRP 6.5.2, revision 2 is 7.0) is approximately 25 gpm.

The examples above b ound the worst-case, calculated pH. The actual pH profile cannot be easi ly calculated.

Therefore, these worst case values have been reviewed. Both cases are acceptable regarding iodine removal and fin al sump pH. H owever, regarding the pH of the spray, the equipment quali fication of components in containment was p erformed assuming a maximum spray pH of 10.5 at 77°F. The pH described above has been reviewed concerning hydrogen generation and equipment qualification and has been found acceptable.

Operator Actions

The parameter used by the operat or to determine when to initiate containment spray suction transfer to the re circulation sump is the RWST level.

B/B-UFSAR 6.5-31 REVISION 7 - DECEMBER 1998 Eductor flows are stop ped when the spray additive tank level indicates that the req uired amount of NaOH has been added to achieve the required f inal pH in the con tainment sump. This ensures the required vol ume of 30% to 36% NaOH is added. There is a status lamp indicator to sh ow when the low-low level has been reached. There is also an annunc iator alarm. This quantity ensures that the requir ed pH is achieved under worst case conditions of maximum reactor coola nt and RWST boration.

In the case where the spray additive Lo-2 level alarm does not initiate before the RWST Lo-3 alarm initiates, spray switchover is initiated when the RWST L o-3 alarm initiates, and NaOH addition continues until the s pray additive ta nk Lo-2 level is reached.

Two series of operations are r equired to be acco mplished by the operator to complete spray s witchover: openi ng of the containment spray pump suction valve to the recirculation sump; and, closing of the co ntainment spray pump s uction valve to the RWST.

6.5.2.4 Tests and Inspections 6.5.2.4.1 Preopera tional Test Program The preoperational test program has been con ducted. The pump discharge was routed through t he test recirculating line back to the refueling water stor age tank (RWST) or rou ted directly into the refueling cavity i nside containment.

The valve operating and pump starting times, the p ump and eductor delivery rates, and valves adjusted to e nsure proper flows t hrough the eductors, were recorded. The ed uctors were test ed with demineralized water instead of sodium hydroxide, and t he test values were adjusted for the appropriate sod ium hydroxide flow rates. The actual eductor motive fluid flow rates were determined at this time. 6.5.2.4.2 Reliability Te sts and Inspections Routine periodic testing of the containment spray components and support systems are perf ormed per ASME Section XI requirements.

Remote operated valves a re cycled to v erify operability and inspected for leakag

e. The pumps are tested using the recirculation line to the RWST.

To implement the periodic co mponent testing requirements, Technical Specifications hav e been established.

These tests verify valve pos ition and actuation, pump performance and actuat ion, spray additive tank level and concentration, spray nozzle flow path, a nd NaOH addition rate.

B/B-UFSAR 6.5-31a REVISION 10 - DECEMBER 2004 The NaOH addition rate is veri fied by using the primary water system to simulate the spray additive tank level at the eductor suction. The tank level is simu lated at the high level alarm setpoint. In addition, the ed uctor motive flu id flow rate, as determined in the full-flow pr eoperational tests, is established. Under these conditions, the eq uivalent containment spray additive flow rate is verified to be adequate to ensure containment spray pH of greater than 8.0.

B/B-UFSAR 6.5-32 REVISION 10 - DECEMBER 2004 During periodic system testing, a visual inspection of pump seals, valve pac kings, flanged conne ctions and relie f valves is made to detect leaka ge and confirm t hat no significant deterioration is occurring in the containment spray system.

All testing of the con tainment spray system components may be done while the u nit is in operation except for air testing of the nozzles, which sho uld be accomplished when the reactor is shut down.

6.5.2.5 Instrumentat ion Requirements The containment spra y system is provided with the instrumentation and co ntrols to permit t he monitoring and actuation of the system from outside the containment.

The containment spray pumps and motor-operat ed valves can be actuated either automati cally or manually.

Automatic actuation signals are generated in the solid-state protection system cabinets. Both spra y subsystems will be act uated by a Hi-3 containment spray signal. A ctuation include s starting both pumps, and openi ng all valves re quired for system operation.

Manual actuation is from control swi tches on the main control board. Indicating lights are provided on the main c ontrol board and on the ESF status panels to show the status of the pumps and the position of the valves.

Main control board monitor lights are provided to show the status of t he pumps and valves as an operator aid in evalua ting system resp onse subsequent to automatic safeguard actu ation. Alarms on the main control board are provided for pump automatic trip, pump a utomatic start, pump fail to start and valves fail to open.

Refueling water storage tank level is in dicated on the main control board, and alarms are provided f or high, low, low-low, and low-low-low tank levels.

Spray additive tank level is indicated local ly and on the main control board. Alarms a re provided for high , low, and low-low tank levels. There is also a status l amp indicator and annunciator for low-low tank level located on the main control board.

During testing, either a djustable manual valves CS018A or CS021A and CS018B or CS021B in the caustic line are set (utilizing water and correcting for spe cific gravity) and loc ked in position at the desired 30% NaOH rate of flow to the eductor. In addition, the actual motive fluid flow rate to the eductor for each spray system was determined du ring preoperational te sting. These flow rates are used d uring periodic syste m testing. Main control board flow indicators are provid ed for pump discharge, pump to eductor recircul ation, and eductor N aOH suction, and an alarm is provided for NaOH i njection flow failure.

B/B-UFSAR 6.5-33 REVISION 10 - DECEMBER 2004 The temperature of the pump motor bearings is monitored.

Ammeters are provided on the main control board to monitor motor current.

Design details of th e containment sp ray controls and instrumentation are pres ented in Section 7.3.

6.5.2.6 Materials All components in the containment spray syst em which come into contact with spray s olution during either the injection or recirculation phase are fabricated of st ainless steel. All containment materials are compatible with th e NaOH solution with the exception of galvanized steel and aluminum.

These materials are discussed in Sub section 6.2.5.

6.5.3 Fission

Product Control Systems The primary containment fission product cont rol systems during normal plant ope rating conditions consist of the containment charcoal filter units and the containment miniflow purge system.

For further discussion of these systems, ref er to Subsections 9.4.8 and 9.4.9.

The system which operates foll owing a design-bas is accident to remove fission produ cts is the conta inment spray system. For further discussion of this system, refer to Subsection 6.5.2.

B/B-UFSAR

6.5-34 TABLE 6.5-1 SINGLE ACTIVE FA ILURE ANALYSIS - CONTAIN MENT SPRAY SYSTEM COMPONENT MALFUNCTION COMMENTS Refueling water storage tank None Passive componen t, active failure not credible. Spray additive tank None Passive component, a ctive failure not credible.

Containment spray pumps Failure to start Two provided, each with a separate power supply. Evaluation

based on one operating.

Eductors None Passive componen t, active failure not credible. Automatically operated valves

1. Spray additive tank outlet Failure to open Sepa rate lines to each train

2. Spray pump discharge Failure to open Redundant trains (RECIRCULATION P HASE ONLY)

INDICATION OF LOSS FLOW PATH OF FLOW PATH ALTERNATE FLOW PATH Containment spray subsystem Indication not required. Alte rnate spray subsystem. Pump suction from sump up Indication not required. --

to and including isolation Guard pipe or valve chamber valve. will assure pump suction.

B/B-UFSAR

6.5-35 TABLE 6.5-2 FUEL HANDLING ACCIDE NT INSIDE SPENT FU EL STORAGE BUILDING EVENT TIME

1. A fuel assem bly is being han dled by refueling equipment. The assemb ly drops onto the top of the spent fuel storage r acks or pool floor during fuel transfer. Some of the fuel rods in both the dropped assembly and/or the spent

storage racks are damage d, resulting in the release of radioacti ve noble gas and gaseous iodine to the spent fuel pool water.

0 second The gaseous activity ris es as a bubble(s) and reaches the pool surface partially depleted in iodine. 2. The nuclear safety-rel ated monitors near the pool begin to detect the gamma radiation as the gas reaches and emer ges from the pool surface. 0 second 3. The radioactive bubble (s) disperses and mixes with the air above t he pool surface and begins to move towards the exha ust inlets located at the pool edge. There are 31 exhaust inlets around the pool located 5 inches above the pool surface. 4. The monitor sends a si gnal to close the normal HVAC system isolation dampers and open the dampers on the emergency exhau st filter train.

6 seconds

5. The isolation dampers are closed and the dampers on the emergency exhaust filter train are opened routing air through HEPA and charcoal filters (5 seconds or less total).

11 seconds

B/B-UFSAR

6.5-36 and 6.5-37 REVI SION 7 - DECEMBER 1998

Tables 6.5-3 and 6.

5-4 have been dele ted intent ionally.

B/B-UFSAR

6.5-38 REVISION 6 - DECEMBER 1996 TABLE 6.5-5 NONACCESSIBLE AREAS OF THE AUXIL IARY BUILDING

PLANT AREA FLOOR ELEVATION Units 1 and 2 Floor Drain Sump Rooms 330 feet-0 inch Units 1 and 2 Equipment Drain Pump Rooms 330 feet-0 inch Units 1 and 2 Residual Heat Removal Pumps A and B Rooms 343 feet-0 inch Units 1 and 2 Containment Spray Pumps A and B Rooms 343 feet-0 inch Recycle Evaporators OA, OB Rooms 344 feet-6 inches Recycle Evaporator Feed Pumps OA, OB Rooms, and Recycle Evaporator Feed Pumps Valve Aisles 346 feet-0 inch Units 1 and 2 Collecti on Drain Sump Room 346 feet-0 inch (Byron)

Unit 1 Collection Drain Sump Room 346 feet-0 inch (Braidwood)

Unit 2 Collection Drain Sump Room/ 346 feet-0 inch Hot Machine Shop (Braidwood)

Gas Decay Tank Rooms 346 feet-0 inch Gas Decay Tank Valve Aisle 346 feet-0 inch Recycle Holdup Tank Pipe Tunnel and 346 feet-0 inch, Tank OA Room 374 feet-0 inch

Gas Decay Tank and R ecycle Evaporator Pipe 355 feet-4 inches,Tunnel 358 feet-2 inches Units 1 and 2 Residual Heat Exchanger 357 feet-0 inch Rooms A and B

Units 1 and 2 CASP Areas 364 feet-0 inch Units 1 and 2 Safety Injection Pumps A 364 feet-0 inch and B Rooms Units 1 and 2 Positive Displacement 364 feet-0 inch Charging Pump Room

Units 1 and 2 Centrifugal Charging Pumps 364 feet-0 inch A and B Rooms

B/B-UFSAR

6.5-39 REVISION 9 - DECEMBER 2002 TABLE 6.5-5 (Cont'd)

PLANT AREA FLOOR ELEVATION Units 1 and 2 Spray Additive Tank Room and 364 feet-0 inch, Pipe Penetration Area 383 feet-0 inch, 401 feet-0 inch

Units 1 and 2 Pipe Tunnels 375 feet-0 inch HRSS Lab Area, HRSS Tank and Pump Room 383 feet-0 inch, 401 feet-0 inch Units 1 and 2 Heat E xchanger Valve Aisles 383 feet-0 inch Radwaste and Blowdown Mixed Bed 383 feet-0 inch Demineralizer Valve Aisle

Radwaste Mixed Bed D emineralizer OA, OB and 383 feet-0 inch OC Cubicles Units 1 and 2 Filter V alve Aisle, Operating 383 feet-0 inch Area, Pipe Tunnel and 391 feet-6 inch Associated Filter Cubicles Blowdown Mixed Bed D emineralizer OA, OB, and 383 feet-0 inch OC and OD Cubicles

Radwaste and Blowdown Mixed Bed 391 feet-6 inch Demineralizer Valve Aisle and Operating Area

Units 1 and 2 Heat Exchanger Valve 392 feet-6 inch Operating Area Aux. Steam Pipe Tunnels 394 feet-0 inch Units 1 and 2 Pipe Tunnels 394 feet-6 inch

Spent Resin and Concentrate Pump Rooms 401 feet-0 inch, Radwaste Distillate Condensers R ooms A, B, C 401 feet-0 inch Units 1 and 2 Demin.

Valve Aisle, Pipe 401 feet-0 inch Tunnel and Associated Filter Cubicles

Surface Condenser Rooms A, B and C 401 feet-0 inch

Radwaste Evaporator Rooms A, B and C 414 feet-0 inch Radwaste Gas Compressors OA, OB Rooms 426 feet-0 inch B/B-UFSAR

6.5-40 TABLE 6.5-5 (Cont'd)

PLANT AREA FLOOR ELEVATION Clothes Change and S hower Room (Byron only) 426 feet-0 inch Mask Cleaning Room (Braidwood only) 426 feet-0 inch Gas Analyzer Cabinet Aisle 426 feet-0 inch Units 1 and 2 Volume C ontrol Tank Rooms and Valve Aisle 426 feet-0 inch Waste Gas Analyzer Rack Area 426 feet-0 inch

B/B-UFSAR A6.5-1 REVISION 12 - DECEMBER 2008 ATTACHMENT A6.5 IODINE REMOVAL EFFECTI VENESS EVALUATION OF CONTAINMENT SPRAY SYSTEM Following a postulated Loss-of-Coolant Accident, the containment spray system functions to remove airborne iodine (in both the elemental and particulate forms) thus reducing the amount of activity available to le ak from the containment.

The iodine removal constants of (e and p) are dependent on spray flow rate, droplet size, dropl et fall time, and sprayed volume.

The models from NUREG-0800, Section 6.5.2 (R eference 1) are used to calculate the removal constants.

Retention of iodine in solution depends on maintaining a sump solution pH of >

7.0 in accordance with R egulatory Guide 1.183.

B/B-UFSAR A6.5-1a REVISION 12 - DECEMBER 2008 ATTACHMENT A6.5 IODINE REMOVAL EFFECTI VENESS EVALUATION OF CONTAINMENT SPRAY SYSTEM A6.5.1 CONTAINMENT SP RAY DROPLET MODEL A6.5.1.1 Method of Calculation

In order to eliminate the need to scale-up factors from experimental results to full-sized reactor c ontainments, the size dependent calculations in this model were programmed for discrete size parameters, i.e., the calculations are repeated for incremental height s teps, and for 30 dif ferent drop-size groups to represent the effects of the drop-size distribution.

No significant e ffect on results was obs erved by increasing the number of groups.

The resulting model w ith discrete size dependent parameters has been pr ogrammed for a d igital computer.

The CIRCUS computer code is used to analyze the containment spray to determine average droplet size and fa ll time. A detailed description of the mat hematical models used in the code has been presented in many WC AP reports such as WCAP-83 76, "Iodine Removal by Spray in the Joseph M.

Farley Station Containment." In the computer code, the sprayed volu me of the containment is divided into layers of i ncremental height an d area equal to the total sprayed area at any heig ht z. The height-dependent calculations such as drop trajec tories and the chang e in the drop size distribution due to coale scence, are perf ormed for each height step, using t he parameters calcul ated in the previous step as input for the next step.

A6.5.1.2 Drop-Size Distribution

The drop-size distributi on used in t he model is based on data obtained from measurements of the actual size distri bution from the Sprayco 1713A nozzle for the design pressure drop of 40 psi.

Discussion of this d istribution and how it was obtained is presented in Ref erences 5 and 6.

A6.5.1.3 Condensation As the spray solutio n enters the high te mperature containment atmosphere, steam will c ondense on the spray drops. The amount of condensation is easily calculated by a mass balan ce of the drop: mh + m c h g = m'h f (A6.5-1)where: m and m' = the mass of the drop before and after condensation, lb, B/B-UFSAR A6.5-2 m c = the mass of condensate, lb, h = the initial enthalpy of the drop, Btu/lb, and h g and h f = saturation enthalpy of water vapor and liquid, Btu/lb.

The increase in each drop diameter in the distribution, therefore, is given by:

))h h)/(-h (( /v)v ( = )/d'(d fg g f 3 (A6.5-2) where: v f = the specific volume of liquid at saturation, ft 3/lb, v = the specific vol ume of the drop before condensation, ft 3/lb, h fg = the latent heat of evaporation, Btu/lb, d = the drop diameter, cm before condensation, and d' = the drop diameter, cm after condensation.

The drop-size distribu tion used in eva luating spray iodine removal effectiveness is a temporal distribu tion based on an average spatial distri bution which is in turn determined by integrating the spatial distribution over the entire fall height, for discrete height steps incl uding the effects of coalescence. In determining t he spatial distribution for each height step, the spati al distribution from t he previous step is used as input and no account is taken for the fact that the higher velocities of larger drops will r esult in these larger drops being further through their fall height at the end of the given height step.

The only place whe re drop velocity enters into the calculation of spatial distribution is in evaluating the number of collisions due to differences in drop velocities within a given height st ep. The only change s in the spatial drop-size distributi on throughout the spray fall height accounted for are th ose due to coalescence.

Since the larger drops are available to coalesce for the same length of time as the smaller drops, the number of collisions between drops will be overpredicted.

This will result in a relatively greater number of large drops, hence a lower ava ilable mass transfer surface area and larger terminal velocities.

This last effect results in shorter d rop residence times once the average spatial distribution is converted to a t emporal distribution.

These effects result in a conservative evalu ation of spray iodine removal e ffectiveness.

B/B-UFSAR A6.5-3 An average temporal distribution can also be determined by converting the s patial distribution at e ach height step to a temporal distribution and then taking the average of these. When compared to this, the temporal d istribution used in CIRCUS is more conservative in terms of both available mass transfer surface area and drop residence times. The di stribution shown in Figure 4 of Reference 5, and Fig ure 2-3 of Ref erence 6, is based on over 30,000 data points.

Analysis of these drop-size measurements shows that the drop-size distribution from this nozzle may he repre sented by a continuous distribution function, which is used as the input to the computer code.

This increase in drop si ze due to condensati on is expected to be complete in a few f eet of fall for the majority of drop sizes in the distribution. Mo re detailed calculations by Parsley (see Reference

2) show that even for the largest drops in the distribut ion, thermal equilib rium is reached in less than half of the available drop fall height. The change in the drop-size distribution due to condensation was conservatively modeled by a step increase to the equilibrium size immediately after the drops emer ge from the nozzle.

A6.5.1.4 Drop Trajectories A description of the actual drop trajectorie s is required to obtain accurate drop residence times a nd to obtain the trajectory angle required for the coalescence calculations described below. These traj ectories are obtained by integrating the equati ons of motion for each drop size.

The equations of motion were integrated numerically with the drag coefficient being determined iterat ively from Reynolds number and ter minal velocity.

These calculations yield the followi ng results.

A6.5.1.4.1 Spread and N ozzle Interference Trajectory results f or a range of drop s izes show that the horizontal velocities of the dro ps are quickly a ttenuated. For the smaller drop sizes (<400µ), the trajectory e ssentially is a straight fall. Even for 1000

µ drops, the hori zontal velocity component diminishes to less than 10% of the total velocity in less than 10 feet.

The effect of temper ature and pressure on drop trajectories has also b een calculated.

The resulting spray envelope is of smaller diameter at higher temperatures and pressure.

B/B-UFSAR A6.5-4 REVISION 9 - DECEMBER 2002 For downward-directed spray nozzles, the initial vertical velocity is higher than the term inal velocity, resulting in a slightly shorter residence time.

Correction factors a re calculated for ea ch drop size in the spectrum, so that the drop f all-times used f or the iodine removal calculations a re the actual drop residence times.

A measure of conservatism is added to the drop residence calculations by the use of the drop diameters after condensation.

Actually, the drop velocities would have been attenuated to a fraction of the initial nozz le velocity by the time condensation is complete.

A6.5.1.5 Drop Coalescence

This effect will tend to decrease the overall su rface-to-volume ratio of the spray, thereby affe cting the fission product removal capability of the system.

Concern h as been centered particularly on the ef fect of coalescence on scale-up factors applied to data obta ined from small-scale experiments. The effects of this phenomenon are accounted for by a mathematical model which is indep endent of the containment size.

The mathematical model u sed to account for d rop coalescence due to the effects of ov erlapping spray patterns and due to larger drops overtaking smaller ones sh ows the number of coalescences to be functions of t he collision and coa lescence efficiencies, as well as the trajectory angle, drop velocities, drop size, and drop density.

The coalescence efficien cy is the probability that a collision will result in the formation of a single larger drop.

The collision efficiency describ es the probabi lity that two drops on a geometric c ollision course, i.e., their centers of motion are separ ated by a dist ance less than the sum of the radii of the two drops, will actually collide.

The results calculated with this model show that the smaller drops with diameters near the mode of the di stribution are affected most. This is expected, since these sizes have the highest density of drop population. D ue to the considerably larger volumes of the larger diameter dr ops, however, the increase in the larger d rop population is no t very pronounced.

A6.5.1.6 Results Using the plant parame ters from Table A6.5-1 and taking into account the effects of c ondensation, drop tr ajectories, and drop coalescence, the average dropl et size calculated to be 1240 microns and the average fall time is 12.44 seconds.

B/B-UFSAR A6.5-5 REVISION 9 - DECEMBER 2002 A6.5.2 Elemental Iodine Spray Removal Coefficient The NRC's Standard Review Plan (Reference 1) identifies a methodology for the determin ation of spray r emoval of elemental iodine independent of the use of spray addit ive. The removal rate constant is determined by:

e = 6K g TF / VD Where e = Removal rate constant due to spray removal, hr-1 K g = Gas phase mass trans fer coefficent, 9.84 ft/min T = Time of fall of the spray drops, min F = Volume flow rate of sprays, ft 3/hr V = Containment sprayed volume, ft 3 D = Mass-mean diameter of the spray drops, ft The upper limit specified for this model is 20 hr

-1. Using the drop size and fall time from Subse ction A6.5.1.6 and the plant parameters from Ta ble A6.5-1, the el emental iodine removal coefficient is c alculated to be greater than 20 hr

-1. Since Reference 1 sp ecifies an upper limit of 20 hr

-1 , this value is to be used in the loss-of-c oolant accident (LOCA) dose analysis.

Removal of elemental iodine from the con tainment atmosphere is assumed to be terminated when the spray inject ion phase is terminated or, per Reference 1, when the airborne inventory drops to 0.5 percent of th e total elemental iodine released to the containment (this is a DF of 200).

A6.5.3 Particulate Iodine Removal Coefficient The particulate spray removal is determined using the model described in Reference 1:

p = 3hFE / 2VD Where p = Removal rate constant due to spray removal, hr-1 h = Drop Fall Height, ft F = Spray Flow Rate, ft 3/hr V = Volume Sprayed, ft 3 E = Single Drop Coll ection Efficiency D = Average Spra y Drop Diameter The E/D term depends upon the particle s ize distribution and spray drop size. From Reference 1, it is co nservative to use 10 m-1 for E/D until the point is reached when the inventory in the atmosphere is reduced to 2% of its original (DF of 50) at which time the value for E/D is reduced by a facto r of ten. The other parameters are taken from Table A6.5-1.

Using these inputs, the value for p is 6 hr-1. When a DG of 50 is reached, the removal coefficient is reduc ed to 0.6 hr

-1.

B/B-UFSAR A6.5-6 REVISION 9 - DECEMBER 2002 A6.5.4 Spray Perfor mance Evaluation A6.5.4.1 Injection Phase Operation The spray iodine removal analysis is based on the assumption that: a. Only one-out-of-two sp ray pumps are operating.

B/B-UFSAR A6.5-7 REVISION 12 - DECEMBER 2008 b. The emergency core cooling system (ECCS) is operating at its maxim um capacity.

The performance of the spray system was cons ervatively evaluated at the peak containm ent temperature and pressure following a postulated LOCA.

The spray flowrate of 2950 g pm per pump was used in the calculation of the spr ay removal coefficients.

Since this peak pressure condition is expected to exist, at most, for a few minutes, and since both mass t ransfer parameters and spray flowrate i mprove with decreasing p ressure, an appreciable margin is added to this evaluation by this assumption.

A6.5.4.2 Recirculation Phase Although elemental iodine removal by the sprays would be expected to continue during the spray recirculation p hase, no credit is taken for removal of elemental iodine after the spray injection phase is terminated.

Spray removal of particu late iodine would continue during the spray reci rculation phase.

Although the spray recirculation could contin ue indefinitel y, it is assumed that sprays are term inated eight hours into the accident.

A.6.5.4.3 Re-evoluation of Iodine Due to the addition of sodium hydroxide from the spray additive, the water in the containment sump is adjusted to a pH of greater than 7.0 and re-evolution of iodine need not be considered (Reference 1).

B/B-UFSAR A6.5-8 REVISION 9 - DECEMBER 2002 A6.5.5 References

1. NUREG-0800, NRC Standard Review Plan, Section 6.5.2 "Containment Spray as a Fiss ion Product Cleanup System,"

Revision 2, December 1988.

B/B-UFSAR A6.5-9 REVISION 9 - DECEMBER 2002 2. L. F. Parsley, Jr., "Des ign Consideratio ns of Reactor Containment Spray Systems - Part VI," ORNL-TM-2412 , Part 6, 1969. 3. Deleted.

4. Deleted.

5. M. O. Sanford, " Sprayco Model 1713A Nozz le Spray Drop-Size Distribution," WCAP 8258, Revision 1, May 1975.

6. E. V. Somers a nd M. O. Sanford, "Iodine Removal by Spray in the Joseph M. Farley Station Containment

," WCAP 8376, July 1974.

B/B-UFSAR A6.5-10 REVISION 9 - DECEMBER 2002 TABLE A6.5-1 INPUT PARAMETERS FOR SPRAY I ODINE REMOVAL ANALYSIS

Containment temperature 260 °F* Total containment free volume 2.85 x 10 6 ft 3 Fraction of containm ent volume sprayed 0.825 Spray fall height 141 ft

Net spray flowrate per pump 2950 gpm Number of spray pumps operation 1 of 2

• The effect of higher pe ak LOCA containment te mperatures has been evaluated up to 300

°F and has been det ermined to be negligible (Reference Westinghouse letter MSE-TPM-059, da ted September 1, 1995).

B/B-UFSAR 6.6-1 REVISION 6 - DECEMBER 1996 6.6 INSERVICE INSPECTION OF CLASS 2 AND 3 COMPONENTS This section describ es the inservice i nspection program for Class 2 and 3 components.

6.6.1 Components

Subject to Examination Class 2 and 3 components are exa mined and tested in accordance with the requirements of ASME Se ction XI, Subsections IWC and IWD, respectively.

The applicable Editi on and Addenda of Section XI are specified in 10 CFR 50.55a an d the Station ISI Program Plan. In cases where the Section XI requirements are determined to be impractical, a relief request is developed to detail why the e xamination(s) are imprac tical and also include proposed alternative examination (s). Relief requests are included in the station ISI program plan and submitted to the NRC for approval.

6.6.2 Accessibility

The design arrangements of Class 2 and 3 system components provides, to the extent possible, adequate clearances to conduct code required examinat ions. When specif ic exceptions to the above are identified, alternate examinations are described and justified in the inser vice inspection program.

6.6.3 Examination

Techniqu es and Procedures The examination techniqu es and procedures described in Section XI of the code are u sed to the extent po ssible. Whe n specific exceptions to the above are iden tified, alternate techniques and procedures will be d escribed and justified in the inservice inspection program.

6.6.4 Inspection

Inter vals and Scheduling An inspection interval, as defined in ASME S ection XI Subarticle IWA-2400, is a 10-year interval of service.

The schedule for inspection of Class 2 compon ents is in accordance with Subarticles IWA-2400 a nd IWC-2400. The sche dule for inspection of Class 3 components is in ac cordance with Suba rticles IWA-2400 and IWD-2400.

B/B-UFSAR 6.6-2 REVISION 6 - DECEMBER 1996 6.6.5 Examination and Testing Requirements Inservice inspection of Class 2 and 3 compon ents is in agreement with the specific examination and testing requ irements detailed in ASME Section XI, Tables IWC-2500-1 and IWD-2500-1, respectively. When th ese requirements c annot be met, a relief request is developed to detail why the e xamination(s) or test(s) are impractical and also inclu de proposed alternative examination(s).

Relief requests are include d in the Station ISI Program Plan and submitted to the NRC for approval.

6.6.6 Evaluation

of Examination Results/Repair Procedures Evaluation of the examination results for Class 2 and 3 components complies with the req uirements of A rticles IWC-3000 and IWD-3000, respective ly. Repair procedures for Class 2 and 3 components comply with the requirements of A rticles IWC-4000 and IWD-4000, respectively.

6.6.7 System

Pressure Testing System pressure testing of Class 2 and 3 com ponents is performed in accordance with A SME Section XI, Articles IWC-5000 and IWD-5000, respectively.

B/B-UFSAR REVISION 9 - DECEMBER 2002 Figure 6.2-15 has been deleted intentionally.

B/B-UFSAR REVISION 14 - DECEMBER 2012 Figure 6.2-24 has been deleted intentionally.

REVISION 14 DECEMBER 2012 Unit 1 ASTRUM COCO Confirmation --"Nf N 40T'""""'"-----------------, 35 25 20 15 , , 104---'----'-.,...-'---'----,-----.,.---'-.!-"'---,-..;....,;.--,----\ o 100 200 300 400 500 600 Time (s) 92fVj2j':556235/ j 7-Apr-OJ BYRON/BRAIDWOOD STATIONS UPDATED FINAL SAFETY ANALYSIS REPORT FIGURE 6.2-240 CONTAINMENT PRESSURE FOR ECCS LB LOCA (UNIT 1)

Unit 2 ASTRUM COCO Confirmation REVISION 14 DECEMBER 2012 40,.-------------------, 35 20 15 IO+--"-'--r----,,----"-'--r-:..-......... .........,..--".......,....------l o 100 200 300 400 500 600 Time (s) BYRON/BRAIDWOOD STATIONS UPDATED FINAL SAFETY ANALYSIS REPORT FIGURE 6.2-24b CONTAINMENT PRESSURE FOR ECCS LB LOCA (UNIT 2)

REVISION 14 DECEMBER 2012 Heat Transfer Coefficient to Steel Exposure I ' if 800,--.,.-----------------, 600 400 200 \ \ o 100 200 300 400 500 Time t 1446'2097 BYRON/BRAIDWOOD STATIONS UPDATED FINAL SAFETY ANALYSIS REPORT FIGURE 6.2-26 HEAT TRANSFER COEFFICIENT VERSUS TIME FOR ECCS LB LOCA REFERENCE TRANSIENT REVISION 14 DECEMBER 2012 220-r--------------------. 180 160 140 120 100 80 60 -!----'--'---'--r-'-----,----'---'--,.-----,----I o 100 200 300 400 500 Time (s) 1144612097 BYRON/BRAIDWOOD STATIONS UPDATED FINAL SAFETY ANALYSIS REPORT FIGURE 6.2-27 CONTAINMENT AIR TEMPERATURE VERSUS TIME FOR ECCS LB LOCA REFERENCE TRANSIENT

B/B - UFSAR 1 REVISION 7 - DECEMBER 1998