ML16299A381
| ML16299A381 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oconee, Rancho Seco, Midland, 05000000 |
| Issue date: | 06/15/1982 |
| From: | De Agazio A Office of Nuclear Reactor Regulation |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| TAC-48384, NUDOCS 8705280491 | |
| Download: ML16299A381 (29) | |
Text
0 REG4 UNITED STATES
? L NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 June 15, 1982 Dockets Nos. 50-312, 50-346, 50-287, 50-329 MEMORANDUM FOR:
John F. Stolz, Chief, Operating Reactors Branch #4, DL FROM:
Al De Agazio, Project Manager, Operating Reactors Branch #4, DL
SUBJECT:
FORTHCOMING MEETING WITH B&W OWNERS TASK GROUP FOR DAVIS-BESSE 1, MIDLAND, OCONEE 3 AND RANCHO SECO Time & Date:
1:00pm-3:00pm, Thursday, June 24, 1982 Location:
Phillips Building, P-422 Bethesda, Maryland
Purpose:
Owners Group discussion of generic repairs and design modifications related to damaged auxiliary feedwater header inside steam generators.
Requested
Participants:
NRC-DEisenhut, JKnight, TNovak, JStolz, EAdensam, OParr, JScin-to, ADe Agazio, MPadovan, PWAgner, DHood, JRajan, RLobel, Representatives from Regions II, III, & V.
Licensee-J. J. Mattimoe (SMUD); R. P. Crouse, (TECo);
R. L. Gi1l (DPC); Sullivan (CPCo), et al.
Other-Babcock & Wilcox Al De Agaziq6oject Manager Operating Reactors Branch #4, DL cc:
See next page 8705280491 820615 PDR ADOCK 05000287 P
MEETING NOTICE DISTRIBUTION OPERATING REACTORS, DIVISION OF LICENSING Docket File Regional Administrator NRC PDR U. S. N. R. C., Region II, III, V L PDR TERA NSIC ORB#4 Rdg JStolz Project Manager -ADe Agazio TNovak JHeltemes, AEOD OELD IE-3 OSD-3 SShowe, IE (PWR) or CThayer, IE (BWR)
Licensing Assistant Receptionist, Bethesda ACRS-10 Program Support Branch PTKuo (seismic reviews only)
HGaut, State Programs Rlattson ORAB, Rm.
542 Meeting Notice File BKGrimes, DEP SSchwartz, DEP FPagano, EPLB SRamos, EPDB MJambour NRC
Participants:
DEisenhut JKnight EAdensam OParr PWagner DHood JRajan RLobel
AUXILIARY FEEDWATER HEADER REPAIR PROGRAM PRESENTED BY THE BABCOCK &'WILCOX COMPANY, ON BEHALF OF:
TOLEDO EDISON COMPANY DUKE POWER COMPANY SACRAMENTO MUNICIPAL POWER DISTRICT JUNE 24, 1982
- BETHESDA, MARYLAND
S.
OUTLINE I. INTERNAL AFW HEADER DESIGN II. INSPECTION RESULTS UPDATE III.
PROBABLE CAUSE OF FAILURE IV. REPAIR APPROACH V. INTERNAL HEADER -REATTACHMENT VI.
EXTERNAL HEADER VII.
PRE-OPERATIONAL TESTS VIII. POST OPERATIONAL INSPECTIONS
Figure 1-1 ONCE-THROUGH STEAM GENERATOR WITH INTERNAL AUX. FEEDWATER HEADER Primary inlet nozzle.
Generating tubes Upper tube sheet Auxiliary feedwater header Upper shell Tube support.
Cylindrical plates baffle Steam outlet nozzles
INTERNAL AFW HEADER FUNCTIONAL REQUIREMENTS O DISTRIBUTE AFW TO TUBE BUNDLE 0 SHROUD EXTENSION 0
FILL AND DISTRIBUTION DURING WET LAYUP
Figure 1-2 LONGITUDINAL SECTION OF INTERNAL
.AFiN HEADER AT.DOWEL PIN P-ERI PH-ERAL TUBES 60 Z - IA.
HOLES ZEN, 7 DIA.
1tDIA. OUTER MOST TUSE$
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-Ais OLES
- 3/2, DQIA.I~~
TAB IYZ."WxZ Y"Lx K
-r K WELD VOWEL. PJIM.
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- 15.
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PLAN VIEW OF INTERNAL AUXILIARY FEEDWATER HEADER AL-AUXILIAY F5DAEFEbTe DE-I.
400 SQ A
At..T
. DOLL Plo
/
ASS E h1, 9L Y AF WMA RAMlCHo 0fCo Fig. 1-4
INSPECTIONS PERFORMED INTERNAL HEADER 8 3600 VISUAL INSPECTION - TOP, OUTSIDE FACE, BOTTOM, OUTBOARD BRACKETS, DOWEL PINS (WHERE PRESENT), INBOARD BRACKETS (VIA HOLES IN SHELL),
AFW NOZZLE PENETRATION
§ UT OF BOTTOM PLATE FOR THICKNESS AND CRACKING AT X AXIS MANWAY AND AT EACH INJECTION OPENING 0 UT OF OUTER WRAPPER PLATE (DEEPEST CONCAVITY)
FOR CRACKING AT X AXIS MANWAY 0 PT OF LOWER OUTER WRAPPER PLATE WELD AT X AXIS MANWAY (DAVIS-BESSE AND OCONEE 5 ONLY) 8 ESTIMATE OF CURVATURE OF OUTER AND INNER WRAPPER PLATE STEAM GENERATOR SHELL 0 UT FOR INTERNAL FLAWS PRIOR TO DRILLING INJECTION HOLES 8 UT OF EXISTING AFW NOZZLE SHELL/KNUCKLE/BORE AREA AND PT OF KNUCKLE RADIUS
INSPECTIONS.PERFORMED (CONTINUED)
INSIDE STEAM GENERATOR 0 STEAM/FEEDWATER BAFFLE INSPECTED-FOR DOWEL PINS AND BRACKETS 0 TUBE BUNDLE AT INJECTION HOLES INSPECTED FOR LOOSE PARTS
-PERIPHERAL TUBES 0 EDDY CURRENT OF ALL PERIPHERAL TUBES (DAVIS-BESSE ONLY) 0 SELECTED PROFILIMETERY INSPECTION OF PERIPHERAL TUBES WITH EDDY CURRENT INDICATIONS IN THE HEADER REGION (DAVIS-BESSE ONLY) 9 VISUAL INSPECTION AND MEASUREMENT OF INNER WRAPPER PLATE UPPER CORNER CLEARANCE TO PERIPHERAL TUBES 0 MEASUREMENT OF CLEARANCE OF INNER WRAPPER PLATE LOWER CORNER TO PERIPHERAL TUBES
INSPECTION RESULTS DAVIS BESSE 0 OUTER WRAPPER PLATE DISTORTED INWARD AS MUCH AS 4-1/2".
INNER WRAPPER PLATE DISTORTED INWARD BUT NOT AS MUCL(HOUR, GLASS CROSS SECTION).
CIRCMERNIlt 8 HEADER SUPPORT BRACKETS BENT, TWO OUTER BRACKETS BROKEN OFF, BOTTOM LIGAMENT TORNKOUT, DOWEL-PINS BENT AND/OR MISSING 0 #1 STEAM GENERATOR AF' THERMAL SLEEVE WAS DJSENGAGED FROM AND MISALIGNED WITH THE INLET HOLE.
0 BOTTOM AND TOP HEADER PLATES ARE.SOUND. -BOTTOM PLATE IS STILL 3/8" NOMINAL THICKNESS WITH NO REPORTABLE UT INDICATIONS (40% SAMPLING OF EXPOSED PLATE SURFACE) 0 HEADER WAS IN CONTACT WITH THE PERIPHERAL TUBES IN THE AREA BETWEEN THE X AXIS AND THE BRACKET BETWEEN THE X AND Y AXIS.
THIS IS TRUE MORE AT THE TOP OF THE HEADER THAN-BOTTOM 0 VERTICAL GAP BETWEEN HEADER AND SHROUD RANGES FROM 0 TO 3/4 INCHES 0 STEAM GENERATOR SHELL AND AFW NOZZLE REGION FREE OF UT INDICATIONS O ALL MISSING BRACKETS AND, ALL BUT ONE DOWELL PIN HAVE EEEN LOCATED AND RETRIEVEDWTODATE.NO DOWEL PINS-IN TUBE BUNDLE.
INSPECTION.RESULTS (CONTINUED)
RANCHO SECO 0 INWARD DISTORTION OF OUTER AND INNER WRAPPER PLATES 0 HEADER SUPPORT BRACKETS BENT, 5 DOWEL PINS MISSING, 11 DOWEL PINS LOOSE AND 1 INNER BRACKET WELD CRACKED (A OTSG) 0 BOTH-AFW THERMAL SLEEVES WERE DISENGAGED FROM THE INLET HOLE ALTHOUGH NO MISALIGNMENT WAS NOTED,
@ BOTTOM AND TOP HEADER PLATES ARE SOUND.
PLATES ARE NOMINAL THICKNESS WITH NO REPORTABLE INDICATIONS (ABOUT 30% SAMPLING OF EXPOSED PLATE SURFACE) 0 HEADERS FOUND WITH -GREATER THAN-THE MINIMUM 1/8" CLEARANCE WITH PERIPHERAL TUBES.
SOME INNER BRACKETS APPEAR TO HAVE LESS THAN 1/8" CLEARANCE TO ADJACENT TUBES 8 VERTICAL GAP BETWEEN HEADER AND SHROUD RANGES FROM 0 TO 1/4 INCHES 0 STEAM GENERATOR SHELL AND AFW NOZZLE REGION FREE OF UT INDICATIONS 0 ALL MISSING DOWEL PINS HAVE BEEN LOCATED AND RETRIEVED
7.
INSPECTION RESULTS (CONTINUED)
OCONEE 3 O OUTER WRAPPER PLATE DISTORTED INWARD 0 NINE DOWELL PINS AREI MSSING FROM BRACKET POSITIONS8 ALL BRACKETS ARE IN PLACE BUT SOME SHOW DISTORTION AND DAMAGE 0 AFW THERMAL SLEEVES WERE ENGAGED IN HEADER 0 BOTTOM HEADER PLATES IN AREAS OF ACCESS OPENINGS ARE SOUND WITH GREATER THAN NOMINAL THICKNESS INDICATED 0 A OTSG BOTTOM PLATE HAS A CIRCUMFERENTIALLY ORIENTED HOLE 4" X 1/4".
TOP PLATE HAS A RADIALLY ORIENTED
- CRACK 2" TO 3" LONG AND 1/8" TO 1/4" WIDE I B OTSG TOP PLATE HAS A 1/4" HOLE 0 SLIGHT VERTICAL GAP BETWEEN HEADER AND SHROUD NOTED AT SOME LOCATIONS 0 OTSG SHELL AND AFW NOZZLE FREE OF UT INDICATIONS 8 NO EVIDENCE OF ABNORMAL CORROSION ON INSIDE SURFACES OF OTSG A INTERNAL HEADER 0 FURTHER NDE INSPECTIONS ARE BEING CONDUCTED AND DE INSPECTIONS ARE PLANNED
DEFORMATION MECHANISM 0 CONDENSATION INDUCED HIGH PRESSURE DIFFERENTIAL DURING AFW INJECTION, CREATES BUCKLING OF THE INNER AND OUTER WRAPPER PLATES 1 THIS BUCKLING DEFORMS THE LOWER PLATE AND BINDS THE BRACKETS AND DOWEL PINS DEFEATING THE THERMAL SLIP MECHANISM 0 FORCES ARE SUFFICIENT TO BREAK BRACKET LIGAMENTS, BEND DOWEL PINS, BREAK INNER BRACKET DOWEL PIN WELDS AND DEFORM THE INNER BRACKETS TOWARD THE TUBE BUNDLE 0 SUCCESSIVE INITIATIONS INCREASE THE SEVERITY OF THE DAMAGE
e 0
REPAIR APPROACH REQUIREMENTS o GAIN ACCESS FOR FURTHER INSPECTION AND REPAIR o MAINTAIN FLEXIBILITY FOR INTERNAL HEADER REATTACHMENT OR REMOVAL o MINIMIZE THE NUMBER OF HOLES TO BE MACHINED IN THE OTSG SHELL G MEET FUNCTIONAL REQUIREMENTS
- RETRIEVE LOOSE PARTS APPROACH
@ USE PROVEN EXTERNAL RING HEADER DESIGN TO DISTRIBUTE AFW TO THE TUBE BUNDLE s MACHINE A MINIMUM OF SIX 5" DIAMETER HOLES INTO OTSG SHELL AND SHROUD, HOLES SERVE DUAL PURPOSE OF PROVIDING ACCESS TO INTERNAL HEADER/TUBE BUNDLE AND DISTRIBUTE AFW TO THE TUBE BUNDLE.
o WELD EXISTING HEADER TO SHROUD TO RETAIN SHROUD EXTENSION FUNCTION o REMOVE EXISTING AFW NOZZLE SLEEVE AND CAP NOZZLE e STABILIZE AND REMOVE TUBES FROM SERVICE NOT MEETING MINIMUM CLEARANCE CRITERIA
SPECIAL CONSIDERATIONS 0 INSPECTIONS AND REPAIRS DEFINED AND CONDUCTED TO MINIMIZE RADIATION EXPOSURE OF PERSONNEL O SECONDARY SIDE LAYUP CONDITIONS MONITORED AND MAINTAINED WITHIN ESTABLISHED LIMITS 8 MATERIAL CONTROL, CLEANLINESS AND TUBE PROTECTION MAINTAINED THROUGH REPAIR ACTIVITIES
INTERNAL HEADER REATTACHMENT DESIGN CRITERIA 0 CONTINUE TO SERVE AS AN EXTENSION OF THE UPPER SHROUD AS ORIGINALLY DESIGNED TO PRECLUDE TUBE INSTABILITY PROBLEMS 0 BE CONCENTRIC WITH THE TUBE BUNDLE SUCH THAT MINIMUM CLEARANCE BETWEEN HEADER AND TUBES OF 1/8" IS ACHIEVED CLEARANCE IS BASED ON MAXIMUM OPERATING TUBE VIBRATION AMPLITUDES, MAXIMUM DIFFERENTIAL THERMAL MOTIONS, MAXIMUM MOVEMENT DURING HEATUP AND MARGIN 0 REATTACHED HEADER MUST WITHSTAND EXPECTED STATIC AND DYNAMIC LOADS RESULTING FROM:
- NORMAL AND UPSET OPERATING TRANSIENTS
- SEISMIC CONDITIONS (OBE)
FLOW INDUCED VIBRATION 0 RESTRAINED HEADER MUST NOT CAUSE LEAKAGE OF STEAM GENERATOR TUBES WHEN SUBJECTED TO FAULTED CONDITIONS FROM THE MOST SEVERE ACCIDENT (STEAM LINE BREAK) AND SEISMIC (SSE) CONDITIONS 0 HEADER RESTRAINT DESIGN SHALL MEET ASME III CLASS 1 ALLOWABLES
INTERNAL HEADER REATTACHMENT DESIGN CRITERIA (CONTINUED) 0 RISK OF CREATING LOOSE PARTS MUST BE MINIMIZED
.6 PROCESS MUST BE APPLIED VIA EXISTING ACCESS MANWAY AND/OR AFW INJECTION NOZZLE OPENINGS 8 DESIGN MUST BE COMPATIBLE WITH NON-UNIFORM VERTICAL GAP BETWEEN SHROUD AND HEADER 0 PROCESS MUST NOT DAMAGE TUBES, CREATE LOOSE PARTS INSIDE THE OTSG OR INTRODUCE CONTAMINANTS WHICH CANNOT BE REMOVED
7ELD INTERNAL HEADER TYPICAL GUSSET CONFIGURATION OF HDR SHROUD ORIGINAL CONFIG URATION I. NEW MACHINED AFW INLET VIEW OF WELD AND GUSSET FROM INSIDE OF SHELL-TYPICAL OF 8
.GUS.SET PLATE SUGE PERIPHERAL TUBE
-SECURING INTERNAL AFIN HEADER
INTERNAL HEADER REATTACHMENT DESIGN 6 BOTTOM OF HEADER SECURED TO SHROUD IN 8 LOCATIONS AROUND CIRCUMFERENCE 6 7" CONTINUOUS FILLET WELD WITH.530" MINIMUM THROAT TO CARRY SHEAR AND THERMAL LOADS
' SHIM OR FILLERBAR WILL BE USED TO FILL VERTICAL GAP IF NECESSARY 0 GUSSET 5" X 3" X 1/2' FILLET WELDED TO THE HEADER AND SHROUD TO PROVIDE ADDITIONAL STABILITY TO RESIST MOMENTS 0 VISUAL INSPECTION OF WELDS AFTER ROOT PASS AND FINAL PASS
EXTERNAL HEADER DESIGN REQUIREMENTS 8 DISTRIBUTE AFW FLO4 DIRECTLY TO TUBE BUNDLE I CONCEPTUALLY IDENTICAL TO DESIGN IN CRYSTAL RIVER 3, OCONEE 1 & 2., ARKANSAS NUCLEAR 1, AND THREE MILE ISLAND 1 O PROTECT STEAM GENERATOR SHELL FROM THERMAL TRANSIENT DURING AFW INJECTION e PRECLUDE FIV OF OTSG TUBES 0 DESIGNED AND ANALYZED TO MEET CODES APPLICABLE TO THE LICENSING BASIS FOR THE INDIVIDUAL PLANTS
TUBESHEET Figure 3 REATTACHED INTERNAL HEADER 3" SCH 80 PIPE 32 1/2 TYPICAL OF 13 5/8 PENETRATIONS THROUG:
EACH STEAM GENERATO 6 AT OCONEE 3 AND 15 TSP RANCHO SECO 8 AT DAVIS BESSE 1 PERIPHERAL OCONEE 3 53 5/8 REF TUBES RANCHO SECO & DAVIS BESSE 1 50 REF SHELL
)L O;4j 010 SHROUD u
6" SCH 80 PIPE Figure 4-2 ARRANGEMENT OF REPLACEMENT EXTERNAL AFW HEADER-VERTICAL CROSS-SECTION
EXTERNAL HEADER DESIGN 0 CIRCULAR RING MADE OF 6" SCHEDULE 80 CARBON STEEL PIPE CAPPED AT BOTH ENDS P CONNECTED TO EXISTING AFW FEEDWATER PIPING APPROXIMATELY 450 FROM MIDPOINT OF HEADER CIRCUMFERENCE 0 SIX OR EIGHT FLANGED 3" SCH 80 VERTICAL RISERS APPROXIMATELY 50" HIGH DELIVER AFW TO THE OTSG O NOZZLE THERMAL SLEEVE PROTECTS SHELL AND PENETRATES SHROUD TO DELIVER FLOW TO TUBE BUNDLE 9 CENTERLINE OF NOZZLE SLEEVE IS 13-5/3" ABOVE 15TH TUBE SUPPORT PLATE 0 RISERS CONTAIN ORIFICES TO PROVIDE UNIFORM FLOW DISTRIBUTION TO TUBE BUNDLE
MANHOLE X
AH AFW BOTTOM INLET NOZZLE STEAM DISCHARGE BLIND FLANGED TERNAL HDR FEED NOZZLE 600 '43 TYP wy AFW RISER 450 TYP SHROUD NOZZLE
& THERMAL SLEEVE 29017'.
TYP RING HEADER S. G.- SHELL 6 NOZZLE CONFIGURATION.
SMUD 0-3 Figure 4-3B ARRANGEMENT OF 6 NOZZLE REPLACEMENT EXTERNAL AFW HEADER.
-PLAN VIEVW-
EXTERNAL HEADER DESIGN COMPARISON TO EXISTING DESIGNS S EXISTING DESIGN2IN 5 OPERATIG--PLANTS HAS-P-ROVEN HISTORY, NO EVIDENCE OF WATER RAMME-R-PROBLEMS>
DESIGN FEATURES TOP DISCHA RGENOZZLES TO PRECLUDE HEADER RING DRAINING DURING OPERATION AND SHORT HORIZONTAL RUNS FROM STEAM GENERATOR SHELL TO LIMIT VOID FORMATION AND SLUG ACCELERATION 0
AFW INJECTION POINT IN NEW DESIGN WAS RAISED 3" OVER PREVIOUS DESIGN TO PROVIDE BETTER ACCESS FOR HEADER REATTACHMENT. THERMAL SLEEVE HAS MORE GRADUAL TAPER TO PROVIDE OFFSETTING LOWER EXIT VELOCITY 8 NOZZLE THERMAL SLEEVE IS INCONEL IN LIEU 'OF CARBON STEEL FOR IMPROVED FATIGUE LIFE 0 RISER LENGTH VARIES IN OLD DESIGN (44" ON 0-I AND 74" FOR OTHER PLANTS).
NEW DESIGN LENGTH IS 50" FOR DB-1 AND RANCHO SECO AND 54" FOR OCONEE 3. LENGTH DIFFERENCES ARE NECESSARY TO ACCOMMODATE SPACE ENVELOPES AND HAVE INSIGNIFICANT EFFECT ON PERFORMANCE 0 NEW DESIGN HEADER HAS ORIFICE PLATES IN RISERS SIZED TO PROVIDE ABOUT 3 PSI RESISTANCE TO ACHIEVE MORE UNIFORM FLOW DISTRIBUTION 0 NOZZLE AZIMUTHAL ORIENTATION IN NEW DESIGN IS ESTABLISHED TO FACILITATE ACCESS TO INTERNAL HEADER SUPPORT LOCATIONS. AFW SUPPLY CONNECTION LOCATION SELECTED TO MINIMIZE PIPING CHANGES AND IMPROVE FLOW DISTRIBUTION.
POST INSTALLATION TUBE INSPECTION 0 EDDY CURRENT INSPECTION OF ALL PERIPHERAL TUBES BOTH FOR TUBE WALL INDICATIONS AND HEADER PROXIMITY WILL BE PERFORMED
§ TUBES WILL BE STABILIZED AND REMOVED FROM SERVICE FOR WALL INDICATIONS > 40% AND FOR HEADER PROXIMITY < 1/8".
PRE-OPERATIONAL TESTS 8 SHOP AND FIELD HYDROSTATIC TESTS OF PIPING, FEED RING, RISER ASSEMBLY AND AFW NOZZLE CAP 0 LEAK TEST OF SECONDARY SIDE AFTER SHELL FLANGE/
NOZZLE INSTALLATION O COLD FLO'A TEST TO ENSURE ALL LINES ARE CLEAR AND FREE OF OBSTRUCTIONS
POST OPERATION INSPECTIONS 0 EDDY CURRENT INSPECT AS SPECIAL INTEREST PER TECH SPECS, PERIMETER TUBES WITH CLOSE CLEARANCE TO THE INTERNAL HEADER AND AT AFW INJECTION POINTS A
6 VISUALLY INSPECT INTERNAL HEADER, ATTACHMENT WELDS AND THERMAL SLEEVE THROUGH SELECTED OPENINGS DURING THE NEXT TWO REFUELING OUTAGES AND 10 YEAR ISI 0 INCLUDE EXTERNAL AFW HEADER IN ISI PROGRAM