ML20080B365

Forwards Revised FSAR Pages Reflecting Mods to Reactor Bldg Standby Ventilation Sys Control Logic.Info Will Be Included in Forthcoming Rev 31 to FSAR

ML20080B365
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	08/03/1983
From:	James Smith LONG ISLAND LIGHTING CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
SNRC-946, NUDOCS 8308050442
Download: ML20080B365 (19)

Text

{{#Wiki_filter:_ 1-e _-.-nm ? ) LONG ISLAND LIGHTING COMPANY { dE%EP E SHOREHAM NUCLEAR POWER STATION g P.O. BOX 618, NORTH COUNTRY ROAD + WADING RIVER, N.Y.11792 Direct Dial Number August 3, 1983 SNRC-946 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Transmittal of the RBSVS Design Modifications Shoreham Nuclear Power Station - Unit 1 Docket No. 50-322

Dear Mr. Denton:

Primarily Ts a result of the Preoperational Testing Program, improvements to the design of the Reactor Building Standby Ventilation' System have been made. The system modifications include the following revisions to the RBSVS control logic: The differential pressure transmitters will initiate the system and provide monitoring in the control room. System response is now a function of the unit cooler return air temperature. The RBSVS system modifications are presented as Enclosure 1 to this letter; revisions to the present FSAR text are denoted by a bar in the right hand margin. This information will also be included in the forthcoming Revision 31 of the Shoreham FSAR. If any additional information is required, please contact this office. Very truly yours, '. 0 L. Smith Manager, Special Projects Shoreham Nuclear Power Station RT:bc B308050442 830803 Q) T Enclosure PDR ADOCK 05000322 A PDR I cc: J. Higgins FC-8935.1 g p

ATTACHMENT 1 Lawrence Brenner, Esq. Herbert H. Brown, Esq. Administrative Judge Lawrence Coe Lanpher, Esq. Atomic Safety and Licensing Karla J. Letsche, Esq. -Board Panel Kirkpatrick, Lockhart, Hill U.S. Nuclear Regulatory Commission Christoper & Phillips Washington, D.C.. 20555 8th Floor 1900 M Street, N.W. Washington, D.C. 20036 Dr. Peter A. Morris Administrative Judge Atomic Safety and Licensing Mr. Marc W. Goldsmith Board Panel Energy Research Group U.S. Nuclear Regulatory Commission 4001 Totten Pond Road Washington, D.C. 20555 Waltham, Massachusetts 02154 Dr. George A. Fergus6n MHB Technical Associates School of Engineering 1723 Hamilton Avenue Howard University Suite K 2300 Fifth Street San Jose, California 95125 Washington, D. C. 20059 i Stephen B. Latham, Esq. Twomey, Latham &.Shea Daniel F. Brown, Esq. 33 West Second Street Attorney P.O. Box 398 Atomic Safety and Licensing Riverhead, New York 11901 Board Panel U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Ralph Shapiro, Esq. Cammer and Shapiro, P.C. 9 East 40th Street Bernard M. Bordenick, Esq. New York, New York'10016 David A. Repka, Esq. U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Matthew J. Kelly, Esq. State of New York Department of Public Service James Dougherty Three Empire State Plaza 3045 Porter Street Albany, New York 12223 Washington, D.C. 20008

SNPS-1 FSAR 1. Automatically isolate the reactor building secondary containment upon receipt of LOCA or abnormal condition signal and maintain the bbilding at a subatmospheric pressure. 2. Provide positive means to ensure holdup,

mixing, and dilution of postulated airborne radioactive contaminants within the reactor building secondary containment free air volume.

3. Minimize release of radioactivity to the environs by continually decontaminating the reactor building air release required to maintain the design building vacuum. 6.2.3.2

System Design

The RBSVS (Fig. 6.2.3-1) has 100 percent redundancy and physical and electrical separation of active components. The RDSVS contains two subsystems: the recirculation and exhaust subsystem and the unit cooler subsystem. The recirculation and exhaust subsystem has three 100 percent capacity parallel 45,000 cfm reactor building recirculation fans, two 100 percent capacity parallel 1,585 cfm exhaust booster fans, two 100 percent capacity parallel RBSVS filter trains designed to handle 1,310 cfm, and two 100 percent capacity RBSVS cooling coils in series. The above equipment utilizes common ductwork. The unit cooler subsystem has two 100 percent capacity sets of four 40,000 cfm each unit coolers and one 100 percent capacity unit cooler for each of the notor generator (MG) rooms (111, 112, 113A, and ll3B), motor control center (MCC) rooms (East and West), and the 1R42*MCC-OBI enclosure. The chilled water cooling coils in the above subsystems are serviced by four 50 percent capacity 275 ton water chillers. These water chillers and associated piping comprise the RBSVS and control room air condi-tioning (CRAC) chilled water system, described in Section 9.2.9. ~As stated in Section 6.2.3.1, the design basis of the RBSVS is to exhaust filtered reactor building secondary containment air in a controlled manner in order to limit the release of radioactivity to i levels within zegulatory guideline values under DBA conditions. The RBSVS is designed to maintain the secondary containment build-ing pressure at least 0.25 in, of water gage lower than the average measured outside pressure at all times. At high wind speeds, some local exfiltration could occur. However, due to the extra dilution which accompanies the higher wind speeds, the site boundary doses j are well within the 10CFR 100 guidelines following a design basis accident, even if local exfiltration does occur. The leaktightness criteria for the secondary containment is 50 percent of the secondary containment free volume per day (700 cfm) at -0.25 in. of water gage. Two pressure probe rings are physically located inside the reactor building secondary containment, running along the metal siding wall at approximately the 210 ft elevation. The rings are l constructed of small diameter tubing, with four probes in each ring penetrating the concrete crane pedestal and ending open to the outside atmosphere. Restricting orifices in each probe help l 6.2-51 Revision 30 - June 1983 1

SNPS-1 FSAR prevent pressure transients and gradients from arising within.the ring. Four probes for each of the two rings are staggered by approximately 45 degrees. A tube from the rings leads to redun-dant, physically separated differential pressure transmitters, each with the other side of a diaphragm opcn to the reactor building secondary containment. These transmitters generate RBSVS initi-ation on increasing reactor building pressure and provide moni-toring in the control room. During RBSVS mode, the RBSVS exhaust fans are designed to maintain the secondary containment at least 0.25 in. of water gage below the measured outside pressure. The expected infiltration at -0.25 in. of water gage with respect to average external surface pressure, is 700 cfm. The reactor building secondary containment maximum pressure of -0.25 in. of water gage with respect to average external surface pressure, is maintained by the filtered exhaust of the secondary containment air via the BBSVS. The recirculation and exhaust system will exhaust 1,160 cfm through the RBSVS filter trains to the clevated release point. This will ensure that the infiltration mass flow rate is always matched or exceeded by the exhaust mass flow rate. The RBSVS cooling coils and unit coolers are designed to maintain reactor building temperature, thereby preventing increases in pressure due to heat gains. The unit

• cooler coils have motor operated valves which control chilled water flow to the coils during RBSVS mode.

The regulating signal for all unit cooler coils is based on the unit cooler return air temperature. 6.2.3.3 Design Evaluation 6.2.3.3.1 Normal Plant Operating Mode During normal or refueling operation of the plant, two of the three reactor building exhaust fans will be operating, delivering 900,000 cfm of reactor building secondary containment exhaust air to the atmosphere via the station ventilation booster exhaust fans. The reactor building exhaust booster fans, RBSVS filter trains, and RBSVS cooling coils will not operate at this time. The reactor building supply system will deliver approximately l 89,000 cfm of conditioned outside air to the reactor building secondary containment. An additional 1,000 cfm exhaust will result l from the assumed infiltration of outside air into the secondary containment due to the normal plant operation design pressure of between -1.5 and -2.0 in, of water gage with respect to average external surface pressure. During normal plant operation, the RBSVS unit coolers will not be used, however, provisions have been i made for utilizing them when required for temperature control, especially during refueling operations. The unit coolers for the MCC rooms (East and West), the IR42*MCC-OBI enclosure, and the MG rooms (111, 112, ll3A and ll3B) will be operating during normal and standby operating modes. These unit coolers will operate under i temperature control of the individual areas served. These unit l coolers are served by one 275 ton water chiller normally operational for the control building as described in Section 9.2.9. 6.2-52 Revision 30 - June 1983 w ~ . - ~ _ - _ _ ~,7..-.

SNPS-1 FSAR The secondary containment ventilation isolation valves, both supply and exhaust, will be open to permit the flow of air into and out of the building. A minimum pressure differential of -1.0 in, of watcr l gage with respect to average external surface pressure will be maintained by modC ating the supply fan. damper under the control of a differential pressure signal. The differential pressure will be measured in the same manner as that described in Section 6.2.3.2. 6.2.3.3.2 Standby Operating Mode The RBSVS will be actuated automatically in response to any of the following signals: 1. Iligh airborne activity in the refueling level normal ventilation exhaust. 2. A manual signal from the station main control room. 3. IIigh pressure in the drywell. 4. Low reactor water level. 5. The failing closed of a reactor building secondary containment supply or exhaust air isolation valve. 6. Loss of power to the normal 480 V buses. 7. Rise of secondary containment pressure toward atmospheric pressure. Note: A time delay will be provided for this signal to eliminate short term fluctuation of differen-tial pressure. Upon receipt of any of the above signals, the following events will take place automatically: 1. The reactor building secondary containment ventilation isolation valves will close. 2. If the primary containment ventilation isolation valves are open for purposes of purging, they will close. 3. The reactor building supply system and normal ventilation unit coolers will be shut down. 4. By suitable opening and closing of dampers, the reactor building normal exhaust system will be transformed into a recirculation system, with air diverted to the RBSVS cooling coils and RBSVS filter trains. 5. The two reactor rooms building exhaust fans and unit coolers for MCC and MG rooms which were operating immedi-ately prior to receipt of the accident signal (s) will continue to operate, or, in the case of coincident losa of offsite power, will be restarted. 6.2-53 Revision 30 - June 1983 1

SNPS-1 FSAR 6. The two RBSVS exhaust booster fans will start. 7. The two RBSVS filter trains will be actuated. 8. The f ans. on each of the twb sets of four RBSVS unit coolers will be started. 9. The chilled water control valves on all RBSVS unit coolers will modulate under the control of its respective return air temperature indicator controller. 10. The RBSVS cooling coil chilled water valves open fully. l 11. The chilled water circulating pump in each of the two redundant RBSVS and CRAC chilled water systems will start, with the water chillers set to start in response to the system load. The two redundant chilled water systems will be isolated from each other and from the domi neralized water makeup. Approximately 30 min. after actuation of the

RBSVS, the main control room operator has the following possible alternative actions:

1. If two reactor building exhaust fans are running, the control room operator may shut down one. If only one started or continued to run, no action is

required, although the third may be started.

2. If both reactor building exhaust booster fans are run-ning, the control room operator may shut down one. If only one started, no action is required. 3. If all RBSVS unit coolers, RBSVS cooling coils, RBSVS and CRAC water chillers, and associated controllers in both sets are functioning properly, the control room operator may shut down one entire set. If any one item in one set failed to operate properly, the control room operator may shut down that entire set or may elect to continue operation of any or all other items. If one entire set failed to actuate, no action is required. When the above actions have been completed, the. RBSVS will be in operation as designed, or if the control room operator so chooses, with 100 percent redundancy. Each reactor building exhaust fan will have a motor operated damper that will close to prevent backflow when it is not operating. The reactor building exhaust f an (s) in operation will take exhaust air from each floor level below the refueling level. Air will then discharge to a mixing chamber where baffles will cause turbulence and mix the air. The main duct leaving the missing chamber will deliver approximate-ly 43,400 cfm design to the RBSVS cooling coil, which removes heat as required and then to a ring header above the refueling level 6.2-54 Revision 30 - June 1983

i SNPS-1 FSAR floor. The air will be discharged through diffusers that provide a high degree of mixing with refueling level ambient air. This air will be drawn continually from the refueling level, through the equipment batch openings, and back into the exhaust inlets located at each of the lower levels. This air circulation system will involve essentially'the entire reactor building secondary contain-ment volume in the air flow path. An inlet take-off duct is provided to take the remaining 1,585 cfm l design from the mixing chamber and deliver it to the reactor build-ing exhaust booster fan (s) in operation. Each reactor building exhaust booster fan has a motor operated damper that will close to prevent backflow when it is not operating. Each reactor building exhaust booster fan will deliver 1,585 cfm design to the RBSVS filter train in operation. i The RBSVS filter trains may be aligned so that one filter train will be used'for filtering 1,310 cfm of contaminated air, and the other will have a backflow of 150 cfm of filtered air from the first filter train, flowing to the orifice upstream of the filter train for cooling purposes. The remaining 275 cfm of contaminated air will pass through the orifice upstream of the first RBSVS i filter train and back to the secondary containment. With this arrangement 1,160 cfm of filtered air will travel out the exhaust duct to the elevated release point and hence to the environment. 1 l An alternate RBSVS filter train alignment that may be selected by the control room operator involves the continuous use of both RBSVS filter trains in a once-through filtration alignment. Redundant motor operated dampers located in the duct to the elevated release point will modulate under the control of flow elements to control the. exhaust air flow rate to 1,160 cfm, regardless of the number of j fans or filter trains in operation. i Each - RBSVS filter train consists of the following principal com-ponents: 1. Filter cabinet assembly consisting of steel frame, filter mounting structures, access doors,

covering, and sup-(

ports.. 2. A 5.7 kW clectric heating coil and controls to maintain I the relative humidity of the air entering the filters at l a mrximum of 70 percent. 3. An extended media dry type profilter with a mean effi-ciency of 85 percent by N.B.S. Atmospheric Dust Spot Test. 4. A high efficiency particulate air (HEPA) filter with a l minimum officiency of 99.97 percent by DOP

testing, located downstream of the prefilter.

5. A charcoal filter bank for radioiodine adsorption, discussed below. 6.2-55 Revision 30 - June 1983 1 L.

SUPS-1 FSAR 6. A !! EPA filter located downstream of the charcoal filter bank with efficiency as stated above. 7. Filter instrumentation system consisting of flow and pressure switches, transmitters, and alarms to facilitate monitoring and testing filter operation. The effective f ace area of the charcoal filter is of such dimen-sions that the average air velocity through the charcoal bed is less than 40 ft/ min for the 2 in, bed depth when the filter train is operating at the design flow rate. Gas residence time in the bed is in excess of.25 sec. The carbon base material is virgin coconut shell, steam activated, MSA 85851 or BC 727 or their equivalent. The charcoal has as a minimum an elemental iodine adsorption efficiency at 25 C and 90 percent relative humidity of 99.99 percent, a methyl iodine removal efficiency at 25 C and 90 percent relative humidity of 95 percent, and an ignition. tempera-ture of not less than 340 C. A fixed orifice is provided for each filter train to remove decay heat by means of ventilation from the charcoal filter in the inactive filter train. The cooling air flow rate is 150 cfm. Filter train components are fully accessible by means of access doors built into the filter cabinets. Cabinets are designed with space between components to permit access for filter inspection, testing, maintenance, and removal. Provisions are not made to permit removing an RBSVS filter train as a single unit because of the problems and hazards involved in mani-pulating such a bulky item containing contaminated material. The contaminated charcoal will be transported in shielded containers. Following a postulated DBA, a waiting period would be required before the charcoal is replaced. The filter assembly is designed so that all types of filter components may be removed with minimum radiation exposure to operating personnel required to change such filter units and devices under possible radiation conditions. Seven-unit coolers are provided for the MCC and MG rooms. Each contains a cooling coil aad a fan. The unit coolers draw air from the area served and remove heat, as required by the temperature control, and return the air to the same area. There are four (two spare) RBSVS unit coolers that serve the 8 ft. level of the secondary containment, and four (two spare) RBSVS unit coolers that serve the refueling level. Each contains a cooling coil and a 40,000 cfm fan. With the exception of two of the RBSVS unit coolers which serve the 8 ft. levels, the unit coolers draw air from the secondary containment level which they serve, remove heat as required by the temperature controller, and return the air l to the same secondary containment level. Two unit coolers draw air from the 40 ft. level and discharge it to the 8 ft. level. The transient pressure response of the secondary containment is shown on Fig. 6.2.3-2 for a major LOCA. The transient is 6.2-56 Revision 30 - June 1983

~ I. SNPS-1 FSAR calculated considering inleakage from the primary containment and the environment, sensible heat gains, and heat and mass additions from the fuel pool. Due to the ' relatively free communication between areas within the reactor building (secondary containment) and the pressure equalizing effects of the redundant mixing fans and associated return and supply ductwork, no significant pressure variation exists within the secondary containment. A single node analysis is adequate to demonstrate the ability of the RBSVS to maintain a negative pressure within the secondary containment. In calculating the transient, primary-to-secondary containment leakage in treated as constant at the maximum technical specifica-l tion limit of 0.5 percent primary containment free volume per day with the primary containment atmosphere at 290* F. Atmospheric inleakage to the secondary containment is taken at the maximum technical specification value of 0.25 in. wg differential pressure l and is assumed to vary with the square root of the calculated pressure differential. Exhaust flow from the RBSVS is controlled by redundant modulating dampers at 1160 cfm. Mass transfer and latent heat loa.d from the fuel pool are calculated in accordance with Reference 10, while the fuel pool convective heat load is calculated in accordance with Reference 11 assuming natural con-vection with a pool temperature or 125 F and and a pool surfacp' area of 1300 fta. A constant building heat load of 4.16 x 10 ntu/hr (including the fuel pool sensible heat load) is employed. The load is greater than that existing immediately following the LOCA when certain F.onsafety related process equipment and lines are still considered part of the heat load, but heat transfer from the primary containment has not yet reached a maximum value. Heat gains are calculated using building ambient temperature of 85 F or less in order to maximize the calculated value. A 12 second delay i is. assumed before initiation of the RBSVS. During this time the secondary containment is considered isolated (except for inleakage) l with no means of heat removal. Once the RBSVS has been actuated and power is available on the i emergency buses, heat is removed by unit coolers and cooling coils as previously noted. No model is incorporated in this analysis to simulate modulation of the cooling water flow to these units. ] Therefore, the curve shown on Fig. 6.2.3-2 does not represent an actual post LOCA transient, but that which would result from one train operation at 100 percent cooling water

flow, a maximum cooling water temperature of 55 F and a constant filtered discharge rate of 1160 cfm.

Incorporation of a model to consider modulation l of cooling water flow would not affect the maximum absolute pres-sure attained in this analysis. It would serve only to decrease the rate of depressurization and the maximum depression during the j transient. Referring to Fig. 6.2.3-2, the pressure in the secon-l dary containment begins to rise at t=0 due to interruption of l normal ventilation with a simultaneous increase in the building I heat-load and continued atmospheric inleakage. At t=12 sec., the RBSVS starts and rapidly cools the secondary containment atmos- [

phere, thereby lowering the internal pressure.

Neglecting l modulation of the cooling water flow, the pressure continues to l t 6.2-57 Revision 30 - June 1983 i l L

SNPS-1 FSAR decrease until increasing atmospheric inleakage offsets the de-900 sec., permitting the pressure to creasing temperature at t = rise. As a steady state temperature is approached in the secondary containment, the pressure continues to, rise until the mass flow rate of air and water vapor into the secondary containment plus the rate of fuel pool evaporation equals the mass flow' rate of air and. water vapor out plus the rate of water vapor condensed by the unit coolers. Steady state is reached approximately 1.5 hours following the accident. This transient demonstrates the ability of the system to maintain a pressure in the secondary containment sufficiently below atmospher-ic to preclude airborno activity bypassing the RBSVS filter trains. Unit cooler and cooling coil paramaters used in this analysis are listed in Table 6.2.3-1. 6.2.3.4 Tests and Inspections The RBSVS will be tested and inspected prior to initial plant operations to ensure that the system functions in accordance with design requirements. The recirculation system air flow rates will be measured to verify that they are in accordance with design flow rates. Air delivery from RBSVS unit coolers will also be verified, as will chilled water flow rates from the RBSVS and CRAC water chillers to each RBSVS unit cooler and RBSVS cooling coil. RBSVS filter trains will be tested for compliance with the codes and requirements cited within Regulatory Guide 1.52. The RBSVS will also be tested as a system to ensure that the design negative pressure can be attained with the design exhaust air flow rate. All ductwork and piping will be tested and inspected to ensure structural integrity and leaktightness. After plant operation has begun, the RBSVS will be tested period-ically on a system and a component basis. The R3SVS filter train llEPA filters and charcoal adsorbers will be tested for compliance with the codes and requirements cited within Regulatory Guide 1.52. The system as a whole will be tested for its ability to maintain the design secondary containment negative pressure at the design exhaust flow rate. 6.2.3.5 Instrumentation Applications The instrumentation and controls for the RBSVS are described in Section 7.3. 6.2.3.6 Materials The RBSVS filter train frame is of all welded steel construction with steel sheet walls. The heater is of stainless steel. Pre-filters are extended media dry type. IIEPA filter media is dry type in accordance with MIL-F-51079A. Charcoal adsorber is steam activated, impregnated virgin coconut shell. Aluminum is not used. The reactor building exhaust fans have steel casing, vanes and shaft, and cast aluminum hub and blades. The fans for the RBSVS 6.2-58 Revision 30 - June 1983

SNPS-1 FSAR 3. Automatic controls as well as manual controls of redun-dant components, with these controls independent as well as electrically and physically separated. 4. Annunciation in the main cont'rol room upon failure cf an operating component and/or start of the redundant compo-nent. 5. Maintaining of the temperature in the control building rooms within the design limits. 6. Closing of the main control room exhaust line isolation valves following a LOCA. 7. Closing of the main control room emergency filter trains bypass line isolation valves and starting the booster fans following a LOCA. These actions will assure continuation of positive pressure in the main control room following an accident. Radiation monitoring of the two outdoor air intakes is to provide the operator with infor-mation about the conditions of these sources, and does not perform an automatic control function. For the logic diagrams that show the autoinatic start of the CRAC and chilled water control system components, see Figs. 7.3.1-16A through M, 7.3.1-17A through F, and 7.3.1-18. 7.3.1.3.4 Environmental Considerations The safety related instrumentation and controls of the CRAC system are designed to withstand and to remain functional in the environ-mental conditions discussed in Section 3.11. 7.3.1.3.5 Operational Considerations The CRAC system is in uso during normal plant operations, thus providing assurance of its operability. Automatic functions may be tested a.uring normal plant operation. The operability of redundant radiation monitoring channels in both outdoor air intakes can readily be observed and compared. In case of different indicator / recorder readings between the two channels, a test will be per-formed. The two channels will be periodically calibrated. 7.3.1.4 Reactor Building Standby Ventilation System Instrumentation and Controls 7.3.1.4.1 System Identification The instrumentation and controls of the RBSVS are used to maintain the reactor building at a negative pressure with respect to the outdoors to preclude leakage of radioactive particulates and gases directly to the outdoors, to maintain the reactor building at or below the maximum design temperature, and to reduce radioactive 7.3-40 Revision 22 - July 1981

SNPS-1 FSAR particulates and gaseous concentration in the exhaust air from the reactor building before exhausting to the outdoors. The control sche e logic diagrams for the RBSVS is shown on Figs. 7.3.1-19A through L. 7.3.1.4.2 Power Sources Power for the redundant motors and motor operated dampers is supplied from separate standby buses. Power for redundant instru-mentation is supplied from separate standby 120 V ac buses. 7.3.1.4.3 Equipment Design During normal operation, the reactor building will be maintained at a vacuum, about 1.5 to 2.0 in. w.g., by the reactor building normal l ventilation system (RBNVS). In the event of an accident or other similar condition, the RBSVS will automatically be actuated in response to any of the follosing: 1. liigh airborne activity in the exhaust at the refueling level 2. Iligh pressure in the drywell 3. Low reactor water level 4. A rise in building pressure toward atmosphere 5. Loss of power to the normal plant service buses i 6. Reactor building supply or exhaust isolation valves closed 7. A manual signal from the main control room Upon receipt of a signal for any of the above conditions, the normal ventilation system isolation valves will close automatically and the two operating exhaust fans will continue to run. The feas j will take suction from each floor level below the refuehng floor through the normal ventilation exhaust duct system. Dual isolation l dampers in series will automatically close, in the exhaust duct from the refueling level, to prevent air form teing drawn from that level during the RBSVS mode. Dual isolation dampers will also stop i exhaust air flow from the contaminated area exhaust system. The exhaust fans will discharge to a mixing plenum where baffles will cause turbulence and uniformly mix the air. A takeoff duct will be provided which is designed to take a proportional sample of the air flow leaving the mixing plenum. The flow rate of the sample will be equal to the building in leakage, plus filter train l circulation and cooling air requirements, and will maintain the secondary containment at a minimum vacuum of 0.25 in, w.g. The sample air 7.3-41 Revision 22 - July 1981

SNPS-1 PSAR 14. 10CFR50 Appendix B - Quality Assurance The CRAC system's control system meets these requirements in the manner set forth in Chapter 17. 7.3.2.4 Reactor Building Standby Ventilation System Instrumentation and Controls 7.3.2.4.1 General Functional Requirements Conformance Each filter train, the fans, and associated valving of the RBSVS are equipped with a control system of instrumentation, indicator lights, and control switches which are physically and electrically separate from their redundant system. Because of the need to maintain the reactor building at subatmospheric pressure and design temperature, the control system remains functional during all plant and design basis conditions. A high radioactivity signal or other initiating signals, automatically route the exhaust air to the RBSVS recirculating and filtration systems. The valve controls are available to the main control room operator to allow selective plant area filtration. The controls for cach redundant portion of the system are designed such that credible failures, like destruction of a section of the panel; clectrical cable tray or initiating tray or initiating sensors for the system; a fire within the control pancl; or the loss of a single emergency power source, will not remove both trains of the system from proper operation. 7.3.2.4.2 Specific Regulatory Requirements Conformance The conformance of the RBSVS instrumentation and controls to the industry standards, regulatory requirements, and criteria listed on Fig. 7.1.1-2 is shown below. 1. IEEE-279-1971 The control system of the RBSVS is designed for compli-ance with all portions of this industry standard. 2. IEEE-323-1971 Qualification of components of the RBSVS control system is discussed and documented in Section 3.11 in compliance to this industry standard. 3. IEEE-336-1971 The extent of conformance to this industry standard on the installation, inspection, and testing requirements of instrumentation and electric equipment during construc-tion is demonstrated in Chapter 17. 7.3-115 Revision 24 - December 1981

F I \\ t '300 ACE N0Illiot C0E0lTl0N CONTROL ACTIO LOSS OF SIGNAL, (NOTE 5) ORIVES VALVES OPEN [O F10. 7. 3.1-19 A (INITIATIONSIGNAL] iTN.. CRC (NOTE 3) [ RETURN AIR TEMPERATURE ,,,g, g,7, m O n-I [UNITC00tERFAN IT464UC-002A 42 RUMMING VALVE TC FULL CLOSED POSITION j 4 i PDR IT46 2 A TOR CUlWN3 g DIFFCRENTIAL PRESS Polc C.I NOTES: 1. IT43&TCv022A SHCWN - UMIT COOLER CCMTROL YALVE IT4CteTCV0228, 023A, 0238, 024A, 0245. 02EA. 0255, SINILAR. 2. IT*454TCV026A SHOWM - RBSYS COCn.INGCO'L CONTROL VADE VA EC I?.'TIAT ON,CLOSE CtJ Rf1SVS REET. 3 CRC - LOCATED IN PELAY ROOM ~ 4. STATION TO BE LEFT IN NANUAL IITH 20MA CONSTANT DUTPUT, DRIVING iT46*TCV02SA CLOSED.

5. LOSS OF SIGNAL ON BECK ACTUATCA IS FIELD CONNECTED TO OPEN IT46*TCV026 A.

[ \\ t

s \\ ~ N REnLTANT \\ l U U A IT46*TCV076A T N fi) NOT -.--{!) C DA (t m 2) H/A RCS)$ COOLING C0ll C0lCh0L VALVE D SETPOINT[CIC l 90 F (NOTE 3) I i U' O B '3 A A IT46 +TCV022A T v3-4DULATES --Ep NOT --Ep C >A ile l UFIT COOLER CONTROL VALVE (NOTE 11 l r. ). j k(NOTE 4 Q pe 3 H/A '\\ /Ca N i 3 b3 A3ERTai l CAlJ hiso kvailable On 4%perture Card t l NUCLEAR SAFETY RELATED l 1 i l 1 FIG. 7. 3.1 - 19D l REACTOR BUILDING STANDBY VENTIL ATION SYSTEM l SHCREHAM NUCLEAR PCV.ER STATION-UNIT I l FINAL SAFETY ANALYSIS REPORT f y m.- 8so8T5b42T2 - of

[ e SNPS-1 FSAR main control room. Further details of instrumentation and controls t for the CRAC system are discussed in Section 7.3. 9.4.2 Reactor Building Normal Vent'ilation System (RBNVS) 9.4.2.1 Design Bases The RBNVS is designed to: 1. Provide filtered outside air at a rate of approximately 2.5 air changes per hour. 2. Ensure air flow from areas of low potential radioactive contamination to areas of higher potential contamination. 3. Remove heat gain generated by piping and equipment. 4. Maintain the secondary containment at a negative pressure of between 1.5 and 2.0 in. during normal operation. l 5. Monitor for radioactive release through the exhaust air system. 6. Maintain the building at a maximum exhaust air tempera-ture of 110 F in the refueling level, 104 F in the remainder of the building, and 130 F in the reactor building portion of the steam pipe tunnel. The RBNVS, except for the portion shared with the reactor building standby ventilation system (RBSVS), is not a safety related syatem.

However, all ductwork and equipment is seismically analyzed to ens.ure that no damage is dono to safety related equipment and systems.

l 9.4-4a/b Revision 24 - December 1981 l

e SNPS-1 pSAR 9.4.2.2 System Descrio_t, ion The RBNVS consists of a supply system, an exhaust system, and supplements unit coolers located in high heat gain areas as shown in Fig. 9.4.2-1. The supply system comprises, in the direction of flow, outsian air intake duct, two isolation butterfly valves in series, two 100 percent supply fans (one spuare), glycol preheat coil, filters, two chilled water cooling coils, dampers, and distribution ductwork. Each floor level is provided with its own hot uater heating coil. Air quantities required for cooling, heating, or air changes are supplied to each floor lcycl. Air flows are from areas of lesser contamination potential to areas of higher contamination potential. The exhaust system, which in part is combincd with the reactor , building standby ventilation system (RBSVS Section 6.2.3), com-prises, in the direction of flow, return grilles, ductwork, three 50 percent exhaust fans, (one spare), and two isolation butterfly valves in series. Air is exhausted from all levels of the secon-dary containment, including shielded cubicles and the secondary containment portion of the steam pipe tunnel. The refueling level exhaust maintains a slight negative pressure compared to the remainder of the secondary containment, thus ensuring a positive flow of air from the lower levels. Exhaust air is delivered to the suction side of the station ventilation booster exhaust fans (Section 9.4.4). Unit coolers are provided in the vicinity of high heat gain equipment. Each unit cooler consists of a cabinet with a chilled water cooling coil and fan. Chilled water for the unit coolers and the supply system cooling coils is supplied by the plant main chilled water system (Section 9.2.8). During normal station operation, the RBNVS maintains the design temperature and pressure in the secondary containment. Pressure differential controllers modulate the supply system dampers down-stream to restrict the supply air flow rate if the secondary containment pressure rises above -1.0 in, w.g. Supply air for the refueling level is cooled by a separate cooling coil, with bypass. The chilled water flow control valve on this cooling coil is modulated by a temperature indicator controller in the refueling level exhaust, with a low temperature override by a temperature indicator controller on the discharge side of the cooling coil. Supply air for the lower levels is cooled by another cooling coil. The chilled water flow control valve on this cooling coil is modulated by the temperature indicator controller that reads the highest temperature exhaust in any one of the exhaust ducts for the several louer levels, with a low temperature override by a tempera-indicator controller on the discharge side of the cooling ture coil. 9.4-5

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