Deficiency Rept:On 780928,during Routine Design Review, Undersizing of Refueling Water Storage Tank Was Discovered. Tank Storage Capacity Has Been Increased.Design Drawings for Tank Piping & Foundation Will Be ModifiedML18079A952 |
Person / Time |
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Site: |
Salem |
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Issue date: |
10/28/1978 |
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From: |
YANKEE ATOMIC ELECTRIC CO. |
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To: |
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Shared Package |
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ML18079A951 |
List: |
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References |
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NUDOCS 7909240038 |
Download: ML18079A952 (4) |
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Category:DEFICIENCY REPORTS (PER 10CFR50.55E & PART 21)
MONTHYEARML18107A3441999-06-0101 June 1999 Interim Part 21 Rept Re Premature Over Voltage Protection Actuation in Circuit Specific Application in Dc Power Supply.Testing & Evaluation Activities Will Be Completed on 990716 ML18106B0931999-02-25025 February 1999 Part 21 Rept Re Possible Defect in Swagelok Pipe Fitting Tee,Part Number SS-6-T.Caused by Crack Due to Improper Location of Heated Bar.Only One Part Out of 7396 Pieces in Forging Lot Was Found to Be Cracked.Affected Util,Notified ML18106B0551999-02-0101 February 1999 Part 21 Rept Re Possible Matl Defect in Swagelok Pipe Fitting Tee,Part Number SS-6-T.Defect Is Crack in Center of Forging.Analysis of Part Is Continuing & Further Details Will Be Provided IAW Ncr Timetables.Drawing of Part,Encl ML18106B0441999-01-29029 January 1999 Part 21 Rept Re Possible Defect in Swagelok Pipe Fitting Tee Part Number SS-6-T.Caused by Crack in Center of Forging. Continuing Analysis of Part & Will Provide Details in Acoordance with NRC Timetables ML17354B0971998-09-0909 September 1998 Part 21 Rept Re Possible Machining Defect in Certain One Inch Stainless Steel Swagelok Front Ferrules,Part Number SS-1613-1.Caused by Tubing Slipping Out of Fitting at Three Times Working Pressure of Tubing.Notified Affected Utils ML17264A9381997-07-10010 July 1997 Deficiency Rept Re Potential Safety Hazard Associated w/FM-Alco 251 Engin,High Pressure Fuel tube-catalog: 4401031-2 in Which Dual Failure Mode Exists.Caused by Incorrect Forming Process ML18102A3701996-09-0606 September 1996 Part 21 Rept Re Installation of NUS Model OCA 801 Signal Isolator Modules & Model Mth 801 Signal Summator Modules. Replacement Modules Including Spares for Plant,Unit 2 Have Been Inspected by Vendor & Repaired ML18102A3381996-08-21021 August 1996 Part 21 Rept Re Chipping of Latching Mechanism Props Installed in GE 4 Kv magne-blast Circuit Breakers,Type AM-4.16-350-2H.Two Affected Breakers Have Been Returned to Vendor ML18102A5591996-08-0808 August 1996 Part 21 Rept Re Defect in NUS Model OCA801 Signal Isolator Modules.Replacement Modules Installed in Reactor Control & Protection Sys ML18101A8771995-08-0404 August 1995 Interim Part 21 Rept Re Potentially Reportable Deficiency in Edward Valve Model 838YT Check Valves Due to Disk Exhibiting Excessive Leakage.Disk from Original Valve Cleaned, Inspected & Installed in Replacement Valve ML18101A8611995-08-0101 August 1995 Interim Part 21 Rept Re Velan Valve Corp Check Valve Failure to Close.Insp of Internals Showed Moderate Wear in Gap Between Valve Disc & Hanger Arm.New Disc Installed & Valve Tested Satisfactorily ML18038A8971994-09-0707 September 1994 Part 21 Rept Re Defect in Latching Mechanism of Potter & Brumfield Relay on C&D High Voltage Shut Down Alarm Assembly Printed Circuit Boards.Pull Test on Relay Reset Button Incorporated Into Receiving Insp Procedures ML18100B2391994-07-27027 July 1994 Part 21 Rept Re Signal Summators PM-505B & 506B Found to Saturate High When Summators Lose Power & Reenergized. Summators Powered from Independent Vital Instrument Buses & Inverters.Design Changes Implemented ML18100B2271994-07-25025 July 1994 Part 21 Rept Re Cracking in Valve Stem & Plug Connection Pinning Collar Area on PORVs 1PR1 & 1PR2.Caused Attributed to Either IGSCC or Hydrogen Assisted Cracking.Porv Internals Replaced W/Internals Mfg from SS 316 Matl W/Plug Stellited ML18100B2101994-07-14014 July 1994 Deficiency Rept Re PORV Plug & Stem Material Defects. Initially Reported 940714.PORV Internals Were Replaced W/Plug Stellited ML18100B1911994-06-30030 June 1994 Initial Part 21 Rept Re Deficiency in Signal Summators PM-505B & PM-506B Supplied by Westinghouse.Design Changes Implemented & Operators Made Aware of Affects of Power Supply Transient on Summator Operability ML18100A7681993-12-13013 December 1993 Interim Part 21 Rept Re Discovery That Ge/Alco EDGs High Pressure Injection Tube Studs Did Not Meet Correct Matl non- Std & Not Correct Geometry.All Nonconforming Studs Identified & Replaced ML18096B2421993-02-0101 February 1993 Part 21 Rept Re Possible Matl Defect in Stainless Steel Swagelock Tube Fittings.Initially Reported on 921218.List of Part Numbers,Heat Codes & Addl Affected Customers Encl ML20126J5961992-12-31031 December 1992 Part 21 Rept Re Potential Loss of RHR Cooling During Nozzle Dam Removal.Nozzle Dams May Create Trapped Air Column Behind Cold Leg Nozzle Dam.Mod to Nozzle Dams Currently Underway. Ltrs to Affected Utils Encl ML20118B4391992-09-11011 September 1992 Part 21 Rept Re Degradation in Abb Type 27N Undervoltage Relays Used in Electrical Switchgear.Recommends That Users Review Applications Requiring Exposures Greater than 1E03 Rads TID W/Time Delay Function Option ML18095A4031990-08-0202 August 1990 Part 21 Rept Re MSIV Design Deficiency at Plant.Design Spec Provided by Westinghouse Did Not Specify Requirement to Provide Seal in Capability & Util Design Process Failed to Recognize Deficiency ML18095A2321990-05-24024 May 1990 Part 21 Rept Re Discrepancies Identified in ECCS Flow Orifice K Factors Supplied by Westinghouse.Initially Reported on 900518.Util Fabricated New Orifice Plates to Original Specs ML18095A2251990-05-22022 May 1990 Part 21 Rept Re Insufficient Welds on Pedestal Support Alignment Lug & Slide Shoe for 11,12,21 & 22 Charging/Safety Injection Pumps.Initially Reported on 900516.Windows Cut in Support Pedestals to Gain Access to Affected Areas ML18094B4461990-04-27027 April 1990 Part 21 Rept Re shaft-to-pinion Key Failures in Limitorque Actuators.Initially Reported on 900424.Caused by Reduction of cross-sectional Area & Ultimate Propagation of Cracks. Util Intends to Replace Keys in Actuators W/Keys of Steel ML18094A4421989-05-16016 May 1989 Part 21 Rept Re Defect in Solid State Protection Sys. During Mods in Solid State Protection Sys Cabinets,Noted That Two Wires Became Dislodged from Circuit Board.Visual Insp & Complete Pull Test Performed ML18093A8281988-05-0606 May 1988 Part 21 & Deficiency Rept Re Asea Brown Boveri,Power Distribution,Inc Low Voltage K-Line Circuit Breakers. Efforts Underway to Define Quantity & Type of Component Parts That May Need to Be Replaced ML20153G0111988-05-0606 May 1988 Part 21 Rept Re Potential Defect in Bussman Buss KTK-R Fuse Blocks W/Part Numbers 2078,2079 & 2080.Purchasing Records Reviewed to Identify If Any Parts Were Actually Used or Shipped to Customers.Results Listed ML18093A4721987-10-23023 October 1987 Part 21 Rept Re Calibr Gas Leakage Problem in Exo-Sensors, Inc Containment Hydrogen Analyzer Sys.Caused by Design Deficiency Associated W/Calibr Gas Subassembly.Monitoring Program to Be Maintained for Period After Sys Mods ML20215G2441987-06-16016 June 1987 Part 21 Rept Re Failure of Load Sequencing Equipment Supplied in Aug 1977 During Scheduled Testing.Caused by Open Electrical Connection on One Crimp Lug.Since 1978,insulated Lugs Used on All Equipment FVY-86-105, Part 21 Rept Re Design Defect Relating to Limitorque Motor Operators Mfg Prior to 1975.Mfg Contacted & Retrofit Kits Installed on safety-related & nonsafety-related Operators. Addl Info Encl1986-11-10010 November 1986 Part 21 Rept Re Design Defect Relating to Limitorque Motor Operators Mfg Prior to 1975.Mfg Contacted & Retrofit Kits Installed on safety-related & nonsafety-related Operators. Addl Info Encl ML20215G5351986-10-10010 October 1986 Part 21 Rept Re Vendor Tests of air-operated Diaphragm Valves Revealing Natural Frequencies Less than Required Values of 33 Hz.Initially Reported on 841227.No Adverse Effects Noted During Testing ML20215G6801986-10-10010 October 1986 Part 21 Rept Re Vendor Tests of air-operated Diaphragm Valves Revealing Natural Frequencies Less than Required Values of 33 Hz.Initially Reported on 841227.No Adverse Effects Noted During Testing ML20206S0841986-06-30030 June 1986 Part 21 Rept Re Possible Cut Wires in Wire Harness of Bbc Brown Boveri K600/K800 Circuit Breakers.Initially Reported on 860509.Safety Implications Listed.Gear Guard Designed to Prevent Cut Wires ML20140J4261986-03-31031 March 1986 Part 21 Rept Re Nuclear Valves Shipped to Pse&G.Internal Parts Lapped Which Could Reduce or Eliminate Nickel Plating Resulting in Seat Leakage & Shifting Problems ML20210G9921985-08-13013 August 1985 Part 21 Rept Re Failure of Isolated Worm Shaft Gear When Certain Critical Speeds Combined W/Repetitive Transfer of Actuator Clutch Mechanism from Manual (Handwheel) to Motor Drive Mode.Two Possible Solutions Noted ML20116E8481985-04-23023 April 1985 Part 21 Rept Forwarding Rev 1 to Insp Procedure for Investigating Emergency Diesel Generators for Fractured Welds on Air Deflectors.Rev Will Be Forwarded to Each Facility ML20092D9711984-06-15015 June 1984 Part 21 Rept Re Thermal Nonrepeatability & Other Calibr Errors in Barton Lot 1 Transmitters.Initially Reported on 840615.Transmitter Defects Identified & Expected Error Deviations Calculated.Utils Notified ML20082F3621983-11-17017 November 1983 Part 21 Rept Responding to IE Bulletin 83-06, Nonconforming Matls Supplied by Tube-Line Corp. List of Matls & Sys in Which Installed Encl ML18082A1421980-02-15015 February 1980 Final Deficiency Rept:Check Valve 2DR-7 Failed to Meet Applicable Seismic Class I Loading.Caused by Design Defect. Addl Support Will Be Completed by 800228 ML18081B0481979-12-21021 December 1979 Final Deficiency Rept Re Undetectable Failure in Engineered Safety Features Actuation Sys.Testing Procedures Revised to Include Testing of Permissive Circuitry P4 on Periodic Basis.Unit Will Be Tested Prior to Operation ML18081B0601979-12-0303 December 1979 Initial Deficiency Rept Re Potential Dropped Rod Events Leading to Calculated DNB Ratios Lower than Reported to NRC for Certain Westinghouse Plants.Util Is Investigating Condition for Applicability to Facility ML18081A3751979-10-0505 October 1979 Significant Deficiency Rept Re Containment Purge & pressure- Vacuum Relief Valves.Actuator Torque Values Were Insufficient to Move Valves from Open to Closed Positions W/ Design Differential Pressure of 60 Psi.Design Reviewed ML18081A3781979-10-0505 October 1979 Significant Deficiency Rept 79-06 Re Steam Generator Water Level Instrumentation.Pipe Breaks in Containment Could Lead to Elevated Temp Readings Which Could Result in Delayed Protection Sys Actuation.Setpoints to Be Changed ML18081A7551979-10-0404 October 1979 Interim Deficiency Rept Re Max Flow of RHR Pump During post- LOCA Mode.Caused by Low Sys Resistance to Pump Runout Conditions.Sys Resistance Increased by Placement of Resized Orifices ML18079A9521978-10-28028 October 1978 Deficiency Rept:On 780928,during Routine Design Review, Undersizing of Refueling Water Storage Tank Was Discovered. Tank Storage Capacity Has Been Increased.Design Drawings for Tank Piping & Foundation Will Be Modified ML20086C0041976-07-0101 July 1976 Interim Deficiency Rept Re Fan Coil Unit Motor 15 Failure to Meet Test Requirements.Initially Reported on 760611.Fan Coil Unit Motor from Unit 1 Installed in Place of Motor 15.Faulty Motor Returned to Westinghouse for Repair ML20086C0201976-06-17017 June 1976 Interim Deficiency Rept Re Polar Gantry Crane Gear Misalignment.Initially Reported on 760611.Caused by Misalignment of Hoist Drum Gear & Pinion.Drum Assembly Realigned & Secured & Dressing Gears Initiated ML20086C0301976-06-10010 June 1976 Final Deficiency Rept Re Pressurizer Snubber Malfunction. Initially Reported on 760402.Caused by Heavy Corrosion Buildup.Nine Units Replaced W/Pacific Scientific Units & 54 Units Replaced W/Combination of Redesigned Units ML20086C0421976-06-0202 June 1976 Interim Deficiency Rept Re Automatic Transfer of 4-kV Outside Feed.Initially Reported on 760512.Caused by Design Error.Circuitry for Automatic Bus Transfer Redesigned to Eliminate Possibility of Transfer ML20086C0741976-05-28028 May 1976 Suppl to Deficiency Rept Re Steam Generator Head Cladding Indications.Initially Reported on 760408.Cause Still Under Investigation.Ultrasonic Exam Conducted 1999-06-01
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217A9931999-09-30030 September 1999 NRC Regulatory Assessment & Oversight Pilot Program, Performance Indicator Data ML18107A5581999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Salem,Unit 2.With 991014 Ltr ML18107A5571999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Salem,Unit 1.With 991014 Ltr ML18107A5301999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Salem,Unit 2.With 990913 Ltr ML18107A5311999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Salem,Unit 1.With 990913 ML18107A5031999-08-26026 August 1999 LER 99-006-00:on 990729,determined That SG Blowdown RMs Setpoint Was non-conservative.Caused by Inadequate ACs for Incorporating Original Plant Licensing Data Into Plant Procedures.Blowdown Will Be Restricted.With 990826 Ltr ML18107A5201999-08-12012 August 1999 Rev 0 to Sgs Unit 2 ISI RFO Exam Results (S2RFO#9) Second Interval,Second Period, First Outage (96RF). ML18107A4811999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Salem,Unit 1.With 990813 Ltr ML18107A4821999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Salem,Unit 2.With 990813 Ltr ML18107A4691999-07-28028 July 1999 LER 99-008-00:on 990714,determined That Limit Switch Cables Were Subject to Multiple Hot Shorts in Same Fire Area.Caused by Inadequate Original Post Fire Safe Shutdown Analysis.All Limit Switch Cables for MOVs Were Reviewed.With 990728 Ltr ML18107A4441999-07-0606 July 1999 LER 99-007-00:on 990605,surveillance for Quadrant Power Tilt Ratio (QPTR) Was Missed.Caused by Human Error.Qptr Calculation Was Performed & Personnel Involved Have Been Held Accountable IAW Pse&G Policies.With 990706 Ltr ML18107A4211999-07-0202 July 1999 LER 99-005-00:on 990605,11 Containment Declared Inoperable. 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ML18107A4351999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Salem,Unit 1.With 990713 Ltr ML18107A4341999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Salem,Unit 2.With 990713 Ltr ML20196H8621999-06-30030 June 1999 NRC Regulatory Assessment & Oversight Pilot Program, Performance Indicator Data, June 1999 Rept ML18107A3951999-06-17017 June 1999 LER 99-004-00:on 990520,reactor Tripped from 100% Power,Due to Negative Flux Trip Signal from Nuclear Instrumentation. Cause Has Not Been Determined.Discoloration Was Identified on One of Penetrations.With 990617 Ltr ML18107A3661999-06-0909 June 1999 LER 99-003-00:on 990513,unplanned Entry Into TS 3.0.3 Was Made.Caused by Human error.Re-positioned Creacs Supply Fan Selector Switches & Revised Procedures S1 & S2.OP-ST.SSP-0001(Q).With 990609 Ltr ML18107A3551999-06-0202 June 1999 LER 99-005-00:on 990504,failure to Meet TS Action Statement Requirements for High Oxygen Concentration in Waste Gas Holdup Sys Occurred.Caused by Inability of Operators. 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[Table view] |
Text
. .
ATTACHMENT Report* oo the Seabrook Statioo ....
- Refueling ~ater Storage Tank Design Deficiency
~*..,
Prepared by: Yan..~ee Atomic Electric CoEpaoy for Public Se:x:vice Cowpany of Ne~ Hanpshire October 28, 1978 790924 O<Y~'b
Introduct ~on I
On Septe!Lber 28, 1978 Mr. Seth Folsom of the Region l office of the ~RC vas inf or-;::ed by Mr. John Haseltine of Yankee Atomic Elec~ric Coc?3oy, Seabrook Station Project Hanager, of a design defic.ieoc.y assod. .ated 'Jith the refueling Yater storage tap~s (?.~ST) at Seabrook Station. - The deficiency
.. as reported under 10CFR50.5Sa(e) and ... as reported Yithin 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of con£ iri::a tion of the deficiency. !he deficiency 'l.iaS reported to Mr. Folsom as an undersizing of the RWST.
The undersizing ..,as discovered in a routine design revie',;o of the Net Positive
_Suction Read (NPSH) for the containment spray and residual heat reooval I
pm:ps. The design r~vie'l.I' verified proper ~iPS'H but it also sho.,.ed that there ~*
did not appear to be sufficient ..,ater inthe RWST to col!lplete the traI!Sfer ;
of purq> suctions from the tank to the cootainnent suop before it vas e;:;ptiedc
[_
This report ser-ves as a '.1ritten :report under the 30 cay req uire!t-cnts in 10CFR50.55a(e)(3) and is arranged t-0 provide the infor:::.ation requested ~
in the regulation. I Descrintion of Deficiencv I
r The vater stor-age capacity of the RWST serves dual purposes in the I station design. One is to flood the cavity and canal area above the reactor prior to refuelings and the other is to supply bor-ated ~ater to the containment spray and injection puw;:is during a less of coolant accident.
As reported to the IE Inspector on Septe::;ber 28, the deficiency concerns tl~e undersizing of the RWST's useable volume for a loss of coolant accident.
The tank ~as adequately sized for the flooding of the re.actor cavity and c.a.nal.
The tank capacity is dependent: upon a *nu~er of parameters. The major para~eter is the flooding of the containn:ent during a loss of coolant:
accident to a height *.Jhic.h Yill provide sufficient NPSH. for the contaim::ent spray and residual heat removal pumps and proper containment sucp screen submergence. The 375,000 gallon design submitted in the Preliminary Safety Analysis Report (?SJ...R) met thls requirement. Approxiwately 350,000 gallons r
I of the tank ~as assumed to be injected and this volume did alloY sufficient:
flooding of the contairu:;:;e.nt to meet pump NPSH requireoents and screen coverage. The deficiency arose in the ability of the rewaining 25,000 gallons in the tank to meet the other design parameters.
The other design paraoe.ters are instrument error, a vorking allo~ance, transfer alloYance, single failure, and unuseable voluoe. The f ollc*ing is an explanation of vhat these parameters are and ho~ they vere satisfied or not: satisfied in the original design of the R~ST.
- 1. Instrusent er~or - Increased volume is necessary to account for tbe accuracy of the instru~ntation reading the R~ST level. Initially a nominal 1% full scale instru~~nt accuracy error ~as assur..ed ~hich trar£lates into 3500 gallons. This error h2..S to be taken t~ice - once
. I"*-
.4 to 2s;;_ire that the tank does initially contain 350,0C'O ::;2llo::is anc a sec.ond time to assure that 350,000 gallons has b~cn ~.'.")jE:cte~. r:-:u s' 7 ,000 gallons of capacity ...*as necessary for i.::s ::.ru=e: n::. error.
Recently, ~e *ere infon;ied by ~estinghouse, ~~o is res?onsible [or the RWST level instrumentation, that they prefer a 3~ full scale ins trut:1ent error ...,hich causes an increase in the allo*-*ance for instruoent error to 21,000 gallons.
- 2. Yorking allovance - Some allo...,ance above the required capacity of 350,000 g2llons is necessary to prevent alar.::s ~1th only minor ~ater losses from the tank. It ...,ould not be practical to maintain a level at the e.y~ct setpoint and thus, a na.:::inal 3,000 gallons over and above the design capacity is desired for this ::iargin.
- 3. Trar.sfer allo*ance - Additional ~WS! capacity must be provided to accomr:Ddate a reasonable delay ti~e associated vith the trar.sfer of certai.n pump suctions from the RWS! to the contairu:;ent sump. As stated in RESAR-3, "w-hen the prop-er quantity of *.:ater has been trap.sferr-ed--* _,
to the contain=ent, the cootain:::ent suu:rp valves open. This au to~ tically sh i f ts RHR and contain~ent spray pu:::;p suet ions to the
- containment su'Op. Ho"'*eve r, the safety inject ion and charging pu:::ips continue to draw from the RWST.If you assuDed a 10 r:llnute realigo~eot time, the allo*ance would be 24,000 gallons since the flow rate of the pumps remaining on the RWS! is 2,400 gallons per ninute (gpm).
- 4. Single failure - Because of the autocatic trar£fer of R...~R and contail:lUent pucps to the Su::lp, sone allo~ance oust be included for a single failure. The most limiting single failure for tank capacity r_esults if the contain:;;ient suu;p valve for one of the trains failed .
~o open upon a low level signal from the RWST. Should this ...,.ors t singl~
failure occur, the associated R..~R and containment spray pumps in "that train 'IJill continue to dra~ from the RWS! at a rate of 7800 GPM. If you assume it takes 5 minutes to recognize and correct the condition, then an additional. 39,000 gallons ..... ould have to.be added to the tank to compensate for the single failure.
- 5. Unuseable volume - Once the i-:::J.ve rt of the tank pump suet ion pipes are reached the pumps lase suction and arry rewaining vater in the tank is unusable. This unusable volu~ ~ust be included in the design calculations and for a 375,000 gallon tank it is approximately 14,000 gallons.
The design parameters for instrm:ient error, transfer allow-ance and single failure have changed since the original sizing of the tank. The following tabl~ is a su!Iill'.ary of required capacities under the old and revise design parameters:
Design Para=eter
- Requi:-ed Old r:',...1S 1 Vo l'Jme
!~ e'wl
- 1. Injection C3pacity 350,000 gal 350, 000 gal
- 2. Instruoent error 7,000 gal 21, 000 gal
- 3. ~orking allo~ance 3,000 gal 3,000 gal
- 4. Transfer allo*.:ance 24, 000 gal
- 5. Sing],_~ failure. 39 000 gal I
- 6. Unusable voluce 14' 000 £al 14.000 ~al Total 374,000 gal 451,000 gal As sho~n by the table, the original 375,000 gallon tank "t.;Ould have met all the old des!gn parameters but is substantially undersized for the n~ or revised para;:;eters.
Analysis of Safetv IllrDlications If the tank size had rec.ained at 375,000 gallons, i t is possible that the puwps t.::king suction from i t "t.;Ould have nm out of 'l.:ater and lost suction. The safety injection and charging pun;ps are multistage pu<=?S and upon less of suc~ion may cease and beco~e i~operable. Thus,* the path from the discharge of the residual heat re:::ioval pumps -::hrot!gh these pumps r::.ay have been lost. Bo~ever, even 'wlith ~erst single :ailure for tank sizing, the containment spray and residual heat rei:;:ioval patbs into the reactor coolant system and containment respectively ~ould have re~ined operable and ~ater could have been supplied to the core and containwent at:;iosphere.
No accident analysis ~as made of a loss of coolant accident under these conditions since the design has been c~anged and these conditions are no lo~ger credible.
Corrective Action The R~ST storage capacity has been increased from 375,000 gallons to 475,000 gallons. This larger size is more than adequate for all the design considerations and leaves some raa.rgin for possible future cha~es.
No vork on the tank foundation, piping or erection has started and
- thus, no field uudification needs to be taken to enlarge the tan..~. P.o~ever, design drawings for the tank, piping and foundations ~ere COQplete and certified for construction and ~11 ba.ve to be codified. The spray cheoical addition tack ~ill also have to* increase in size proportional to the R~ST or the concentration of checicals in it will have to increase to co~per~ate for the RWST e~2a~~~went. A decision on ~hat ~111 be done to the spray c:iei:;iical addition tank ":oJill be r...ade in the near future and docm::en-::ed in the final Safety Analysis Report.
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