ML20101B260
| ML20101B260 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/15/1992 |
| From: | PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | |
| Shared Package | |
| ML20101B259 | List: |
| References | |
| PROC-920515, NUDOCS 9206010096 | |
| Download: ML20101B260 (163) | |
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{ TURBINE OVERSPEED PROTECTION MAINTENANCE AND TESTING PROGRAM - REVISION 0 SEABRO'OK UNIT I NUCLEAR POWER STATION Prepared by: ./ #A'17#M Date: S'U' E-V Reviewed by: M'[ 6cI Date: 5'042
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Approved by: !//8b l Date: M((Z-St 6n Mdnag)(r,'
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Approved by: dv Date: 6 7 (Difdct6r~ of Nuclear, Production // 9206010096 920525 PDR ADOCK 05000443 P PDR
l TURBINE OVERSPEED PROTECTION MAINTENANCE AND TESTING PROGRAM - REVISION 00 SEABROOK STATION UNIT I NUCLEAR POWER STATION l ABSTRACT This document describes the basis for the Turbine Maintenance and Testing Program for Seabrook Station Unit 1. This program addresses the requirement of the Seabrook Station Unit i Safety Evaluation Report Section 3.5.1.3. Included are descriptions identifying all items subject to examination and testing, tile type of examination or test, the periodicity of the examinations and tests, and the source (s) of the requirement (s). l L i 1
TABLE OF CONTENTS Cover Sheet / Approvals > Abstract Table of Contents 1 INTRODUCTION 1.1 General 1.2 Refereness 1.3 F.evisions and Chary,s 2 DESCRIPTION OF INSPECTION PROGRAM 2.1 Main Valves 2.1.1 Main Control Valves 2.1.2 Main Stop Valves 2.1.3 Combined Intercept Valves - 2.2 Low Pressure Turbines 2.2.1 Rotors 2-.3 High Pressure Turbine 2.3.1 Rotor Inspection Outages 05, 13, 21 2.3.2 Rotor inspection Outages 09,17,25 2.4 Other Turbine / Generator Components 3 INSPECTION EVALUATION CRITERIA 3.1 General l 3.2 Main Stop_ Valves l 3.3 Main Control Va!ves 3.4 Combined Intercept Valves i 3.5 Low Pressure Turbine Major inspections 11
3 INSPECTION EVALUATION CRITERIA ~ continued . . . . 3.6 Low Pressure Turbine Routine ~lnspections: 3.7 High Pressure Turbine Major inspections
=
3.8 EHC and Front Standard :
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- 4. INSPECTION
SUMMARY
- 5. DESCRIPTION OF PERIODIC TESTING AND CALIBRATION PRQQRAM 5.1 Overspeed Protection System Control System Calibration and Testing 5.1.1 Weekly Tests 5.1.2 Refueling Outage Tests 5.1.3 Refueling Outage Calibrations 5.2 Overspeed Protection System Valve Testing 5.2.1 Weekl!r Testing
-5.2.2 Month y -Testing .
5.2.3 Refueling Outage Testing
- 6. ATTACHMENTS Attachment-1, Maintenance MatrixE Attachment 2, General Electric GEK-379378, " Valve Studs Tightening, inspection and Replacement Recommendations",- May -
1982 (Reference 1.2.1) Attachment 3, Seabrook Station Maintenance-Manual-(SSMA) and Management Manual-(SSMM). (Reference.1.2.2): Attachment 4, General Electric GEK-46527B, " Periodic Operational. Test Summary" (Reference 1.2.3); Attachment 5,-- General Electric TIL 969, " Periodic Turbine Steam-Valve s Test -- Nuclear Units", . May 22,1984 - (Reference .14.41 Attachment 6, General Electric TILL1008 3, in-Service' Inspection of 1500 and 1800 RPM Nuclear Turbine Rotors (Reference. 1.2.5) Attachment 7, General Electric' TIL 922, Moisture Separator / Reheater. Drain Control System Maintenance (Reference 1.2.6) lll
G ATTACHMENTS continued . . . . Attachment 8, General Electric TIL 891, Valve Studs - Tightening, inspection and Re
~(Reference 1.2.7) placement Recommendations.
Attachment 9, General Electric TIL-- 930, improving the Reliability of Journal Bearings (Reference 1.2.8) AQchment 10, General Electric TIL 883, Hydraullc Thrust Bearing' Wear Detector Adjustment and Maintenance (Reference 1.2.9) Attachment 11, General Electric TIL 877,- EHC Hydraulic Power Unit' - (Reference 1.2.10) Attachment 12, General Electric-TIL, 914, Back Up Lube Oil System Reliability (Reference 1.2.11) Attachment 13, General Electric GEK-46354, Maintenance and inspection of Turbine Rotors and Buckets i IV
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1 1 1 INTRODUCTION 1.1 General This document descr!bes the ba#s for the Turbine Maintenance and Testing Program for Seabrook Station Unit 1. This program encompasses periodic tests und insped.ons to proctude generation of turbine missiles as a result of material defects or turbine overspeed. Inspection and testing intervals are based on Seabrook Station Unit i Updated Final Sr'ety Analysis Report, it.e Saabrook Station Unit i Safety Evaluation Report (SER), an.1 the maaut teturer's recommendations contained in references. The station's approach to tt:rbine!:;enerator mtintenance is based upon a four refueling cycle, i.e., pop.oximately six year intervals. The maintenance matrix, Adachment 1, conta rcfueling cycles one through twenty-six. The turbine genciabr has been divided in'o its major comporr'ts and the matrix shows slien n.ajcr or routine maintenances will take place. By laying cut such 1. maintenance v.hedule, all major components will be overhauled every four refueling cycles. This enables the station to plan, lay out the work, and ensure adequate resources are available. By implementing such a plan, Technic.:1 Specifications and commitments made In the UFSAR and SER are compl!sd wl;h for missile probability. As the station gains more operating experience combined with industry experience and technological changes, this maintenance program may change. All changes to the program will be reviewed and approved by the Station Manager and the Executive Director of Nuclear Production. A sumrnary report of inspections performed in accordance with this program will be written following each refueling outage and will be available for review. 1 . 1 l l l -
1.2 References 1.2.1 General Electric GEK 379378, Valve Studs Tightening, inspection and Replacement Recommendations, May 1982 1.2.2 Seabrook Statfor. Maintenanca Manual (SSMA) and Management Manual (SSMM) 1.2.3 General Electric GEK-465278, Periodic Operational Test Summary 1.2.4 General Electric TIL 969, Periodic Turbine Stearr Valve Test - Nuclear Units, May 22,1984 1.2.5 General Elect ic TIL 1008-3, in-Service inspection of 1500 and 1800 RPM Nuclear Turb!ne Rotors 1.2.6 General Electric TIL 922, Molsture Separator / Reheater Drain Control System Maintenance 1.2.7 General Electric TIL 891, Valve Studs - Tightening, inspection and
.eplacement Recommendations 1.2.8 General Electric TIL 930, improving the Reliability of Journal Bearings 1.2.9 General Electric TIL 883, Hydraulic Thrust Bearing Wear Detector Adjustment and Maintenance 1.2.10 General Electric TIL 877, EHC Hydraulic Power Unit 1.2.11 General Electric TIL, 914, Back-Up Lube Oil System Rollability l
1.2.12 General Electric GEK-46354, Maintenance and Inspection of Turbine Rotors and Buckets 1.3 Revisiotis and Changes Revisions to this program will be performed in accordance with routine compilance to station programs and procedures. l e
2 DESCRIPTION OF INSPECTION PROGRAM The following is a detailed description of the inspecCon Psogram for each component to be examined. 2.1 Main Valves The main valve inspection Intervals are based on meeting the requirements of the Seabrook Station Unit i SER and UFSAR and on recommendations contained in General Electric GEK 379378. 2.1.1 Main Control Valves Each of the Main Control Valves,1 MS-CV-1, CV2, CV3 and CV4 will be inspected per the atta:Aed matrix, corresponding to once overy fourth refueling outage, inspections will consist of visual and surfaco inspections of valve seats, discs and stems. Valve stand to body studs will be ultraeonically tes'ed. Valve bushings will be inspected and cleaned and bore diameters will be checked for proper c!earance. 2.1.2 Main Stop Valves Each of the Main Stop Valves,1-MS V135, V136, V137 and V138 will be inspected per the attached matrix, corresponding to once every i fourth refueling outage. Inspections will consist of visual and surface I Inspections of valve seats, discs and stems. Upper head to body J studs will be ultrasonically tested. Valve bushings will be inspected and cleaned and bore diameters will be checked for proper clearance. 2.1.3 Combined Intercept Valves Each of the Combined Intercept Valves,1-MS-V-159 through 170 will be inspected per the attached matrix, correspcnding to once every fourth refueling outage, inspections will consist of visual and surface inspections of valve seat 3, discs and stems. Upper head to booy studs will be ultrasonically tested. Valve bushings will be inspected and cleaned and bore diameters will be checked for proper clearance. 3
I _ 2.2 Low Pressure Turbines The Low Pressure Turbines A, B and C Inspection intervals are based upon the-~ maintenance matrix, which shows both major and minor _ inspections.- A major - Inspection is one whers the rotor is removed from the machine, where a minor-- Inspection is one where the rotor is left installed and visual examinations take place from inside the machines. This maintenance matrix fully meets technical specifications and commitments in the UFSAR and SER < Also, this program fully meets the requirements of _the missile generation prnbabilitics and recommendations contained in General Electric TIL 1006-3.- 2.2.1 - Rotors + Each Low Pressure Turbine Rotor will be inspected per the attached matrix, corresponding to every fourth refueling outage. . The results of the_ Inspection will be reviewed for the.next rotor inspection. . in no case will the inspection interval cxceed every fourth refueling optage. The inspection will consist of the following: A. An ultrasonic inspection of the'hore and keyway region of each shrunk on wheel and of the tangential entry buckat attachments and pins of the finger Lucket attachments and of the _last stage bucket attachment downstream finger in the area of the upper pin hole. B. A visual and magnetic particle inspection of all accessible surfaces of wheels, shaft, buckets, covers, packings, journals, couplings and bull gear. C. -A visual and ultrasonic inspection of adjacent coupling bolts. _ 4-
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2.3 High Pressure Turbine The High Pressure Turbine inspection intervals are based upon the maintenance matrix, which shows the major inspections. A major inspection is one where the rotor is removed from the machine. This maintenance matrix fully meets - technical spec!lications and commitments in the UFSAR and SER. Also, this program fully meets the requirements of the missile generation probabilities and recommendailons contained in General Electric TIL 1008 3. 2.3.1 Rotor inspection Outages 05,13,21 The High Pressure Turbine rotor will be inspected at approximately six year intervals, corresponding to every fourth refueling outage. Tnc inspection will consist of the following. A. A visual and magnetic particle inspection of all accessible surfaces of rotor body, shaft, buckets, covers, packings, journals and couplings. B. A visual find uhrasonic inspection of adjacent coupling bolts. j C. An ultrasonic inspection of the rotor from the periphery and bore. 2.3.2 Rotor Inspection Outages 09,17,25 The High Pressure Turbine rotor will be Inspected at approximately twelve year intervals, corresponding to every eight refueling outage, starting with the fifth refueling outage. The inspection will consist of the following. A. The inspections described in 2.3.1, ' Rotor inspection", items A i and B. B. An ultrasonic inspection of the tangential entry dovetails. 5 l
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- 2.4 Other Turbine / Generator Components-Other. Turbine / Generator component inspections recommended by the .
manufacturer or as a result of operating experience; These inspections are not governed by this maintenance and testing program. e 1 6 l l l v -, w v. , ,
l 3 INSPECTION EVALUATION CRITERIA 3.1 General Evaluation criteria for nondestructive examinations performed by Seabrook Station Unit I personnel or contractors under the direction of station personnel are controlled by station procedures. Unacceptable examination results will be documented per station programs. Ultrasonic inspections will be performed in accordance with the station procedures and standards. Indications will be evaluated and recommendations will be documented in an inspection repert. 3.2 Main Stop Valves,1-MS-V135,136,137 and 138 (Til 891) The main stop valves will be inspected as per the maintenance matrix. Scope of the inspection will cover but not be limited to the following: A. Visual examination of the steam side of the valve body, main seat and disc contact areas including welds. B. Establ!shing correct stem to bushing clearance, stem straightness and stem teal conditions. C. Check for full travel of the valve and its control function. D. Any unacceptable flaw, improper clearance or excessive corrosion that would cause a valve malfunction will be corrected. 7 l 5
3.3 Main Control Valves,1-MS-CV-1, CV2, CV3 and CV4 (Til 891) The main control valves will be inspected as per the maintenance matrix. Scope of the inspection will cover, but not be limited to, the following. A. Visual examination for evidence of leaking, sticking cracks and corrosive products. Visual examination of seat, disc contact area and seat welds. B. Establishing correct stem to bushing clearance and stem straightness. C. Check for valve travel, cracking points and control function. D. Any unacceptable flaw, improper clearance or excessive corroslen that would cause a valve malfunction will be corrected. 3.4 Combined Intercept Valves (Til 891) 1-MS-V-159 and 160, 1 MS-V-161 and 162,1-MS-V-163 and 164,1-MS V-165 and 1-MS-V-166,1-MS V-167 and 1-MS-V-168,1-MS-V-169 and 1-MS-V-170 The combined Intercept valves will be inspected as por the maintenance matrix. The scope of Inspection will cover, but not be limited to, the following: A. Visual examination of the steam path areas for evidence of leaking, sticking, cracks and corrosive products. Visual examination of the seat and disc areas for contact and integilty of welds. B. Establish correct stem run out and bushing clearances. Stroke and visually inspect operating mechanisms and cylinder assemblies. Full stroke the valve. I C. Perform complete operational check of the valve including interlocks and system control signals. D. Any unacceptable flaw, improper clearance, or excessive corrosion that l would cause a valve malfunction will be corrected. l l 8
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3.5 Low Pressure Turbine (A, B and C) Major inspecticns (flL- 1008) -
'Yhe low pressure turbines will be inspected as per_ the Jnalntenance matrix.
Scope of the inspections will cover, but not be !!mited to, the following. A. Routine maintenance and visual inspection of. exhaust hoods and casing
- diaphragms and packings, shaft packingo and springs.
B. Visually inspect rotor, magneflux, red oye or other station approved NDE techniques complete rotor. Visually inspect for erosion / corrosion buckets, wheels, tenons, and sleeves.
- C. Ultrasonic test last stage bucket dovetail pins. Visually inspect last stage buckets, i
D. Visually examine and check couplings, coupling bolts and coupling - alignment. E. Any unacceptabic flaw, improper clearance or excessive erosion or corrosion that would adversely affect the missile generation probabilities-will be evaluated. > 9
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3.6 Low Pressure Turbine Routine Inspection A visual inspection of the following components: roter last stage buckets tie wires erosion shields dovetails inner casina water spray piping and nonjes erosion plates pressure sensing lines outer hood struts rupture diaphragm gibs and keys pressure sensing lines and basket strainers 3.7 High Pressure Turbine Major inspections (Til 1008) The high pressure turbine will be insp 9ted as per the maintenance matrix. Scope of the inspection will cover, but not be limited to, the f% wing. A. Routine maintenance and visual inspections of diaphragms, packings, and springs. B. High pressure shell, exhaust hood and casing examine steam joints for steam cutt:ng or distortion. Magnaflux, red dye or other approved NDE techniques, high stress areas of the shells and hoods. C. Magnaflux, red dye or other approved NDE techniques complete rotor. D. Visually examine and check coupling, coupling bolts and coupling alignment. l E. Ultrasonic inspection of the high pressure rotor will be carried out at ilefuelings 05,13, and 21. l F. Any unacceptable flaw, improper clearance or excessive otosion or corrosion that would advert ely affect the missile generater probabilities will be evaluated. 10
4 3.8 EHC and Front Standard The EHC and front standard will be inspected as per the maintenance matrix. The scope of the inspection will cover, but not be limited to, the following: A. Visually inspect oil for containment build up. Flush and clean, if required, tank, hydraulic lines, and SOV. B. Verify integrity of all speed cables and speed probes, check gap of all speed probes. C. Verify correct operation of EHC:
. master trip push button . mechanical trip piston test
. electrical trip test - air relay dump valve
. manual trip handle D. Verify setpoints of all front standard mounted l essure switches.
1 EHC-S101 PS1 1 EHC-S101-PS2
, 1 EHC-S101-PS3 1 EHC-S101 PS4 -
1-EHC-S101 PSS 1 EHC-S101 PS12 E. Verify correct operation of all front standard limit switches. 1-EHC-ZS-S101 S1 1 EHC-ZS-S101 S2 1-EHC-ZS-S101 S3 1-EHC-ZS-S101-S5 1-EHC ZS-S101 S6 1-EHC-ZS-S101 S7 1-EHC-ZS-S101 S9 1-EHC-ZS-S101-S10 1 EHC-ZS-S101-S11 1-EHC-ZS-S101 S12 1 EHC-ZS-S101 S13 1-EHC-ZS-S101 S15 1 EHC-ZS-S101-S16 F. Verify correct clearance and condition of the trip latch assembly trip finger and wear hutton. 11
4 INSPECTION
SUMMARY
A full description of the turbine generator work by each refueling will be covered by the station's outage report plus the vendor's report. I 12
5 DESCRIPTION OF PERIODIC TESTING AND CALIBRATIOE. 5.1 Overspeed Protection System Control System Calibration and Testing The periodic testing and calibration per station procedures for the overspeed protection control system are based upon meeting all the requirements in UFSAR 3.5.1.3, Technical Specification 3/4.3.4 and GEK 49986, 46527B, and G080-1. 5.1.1 Weekly Tests i A. Mechanical Trip Piston Test B. Maintenance Weekly Electrical Trip Test j C. Turbine Generator Backup Overspeed Trip Circuit Test D. Mechanical Overspeed Trip Test 5.1.2 Refueling Outage Tests A. Main Turbine Overspeed Test i B. Actual 105% Lackup Overspeed Turbine Trip Test C. Main Turbine Minimum Oil Trip Test l
.[
13
5.1.3 Refueling Outage Calibration: fulfills technical specifications surveillance requirements 4.3.4.2c " Channel Calibration", Amendment No. 4 A. 1 EHC-S S104 MP4 Turbine Overspeed Protection Calibration B. 1.EHC-SY S104 MAN 1 Backup Overspeed C. 1 EHC-X E001 FUNC-1 Overspeed Relays D. 1-EHC-X MTP-CAL 1, Mechanical Arming Overspeed E. 1 EHC-S101 PS4-CAL-1, Turbine Generator Pressure Trip F. 1-TSI-X 5801-CAL-1, Vibration Eccentricity 5.2 Overspeed Protection System lhe overspeed protection system valve testing program is based upon meeting all requirements in UFSAR 3.5.1.3, Technical Specification 3.3.4, 4.3.4.2 and GE l Turbine Manual G080-1. l I 5.2.1 Weekly Testing A. OX1431.02, Main Turbine Stop Valve Operability Test,1-MS-V-135, 136,137 and 138 S. OX1431.04, Combined intermediate Valve Cyc!!ng Test,1-f 4S-V159 through 170 C. Extraction System Check Valves 1-EX V-2, 5, 8,11,14,17, 20, 23, 26 and 29 5.2.2 Monthly Testing A. OX1431.03, Maln Control Valve Test,1-M3-CV-1, 2, 3, 4 14
4 i 4
- 5.2.3 - Refueling-Outage Testing A. OX1431.02, Main Turbine Stop Valve Operability Test,- 1 MS V 135, 136,137 and -138 B, OX1431.03, Main Control Valve Test,1.MS-CV-1, 2, 3, 4 C. OX1431.04, Combined Intermediate Valve Cycling Test,1-MS-V159 through 170 D. Extraction System Check Valves 1 EX V 2, 5, 8,11,14,17, 20, 23,26,29 After each major inspection (Til 891), the valve stroke time will be verified, Stroke times which are greater than those specified in.
UFSAR, will be evaluated for impact on the missile probability study - for correction at the next refueling outage, 4
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15. I
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l INSTRUCTIONS YALVE STUDS TIGitTENING, INSPECTION & REPLACEMENT RECOMMENDATIONS (FOSSIL AND NUCLEAR UNITS) (General Revision. Maz 1982) I, INTRODUCTION quence should be performed at least three times to arrive at the final tightening level (clongation). The purpose of this article is to recommend tight
- Sequential tightening is illustrated for an 8 stud, ,
ening levels for turbine steam valve studs used to 16 stud, and 20 stud arrangement (see Figure 1). l secure the upper heads on main stop valve and reheat The number on each stud represents the order in valve casings and the stands on control valve casings. which that stud is tightened,i.e. stud labeled 1 is par-Recommendations are also provided for inspection tially tightened first, stud labeled 2 is partially and replacement of valve studs to minimite the prob. tightened next, etc. Continue this tightening se. ability of in service failure. 'luence until all the studs have been partially tightened. Repeat the same sequence at least twice to Studies have been made of the variables affecting arrive at the final lightening level (elongation), valve stud life. Some of the variables are: length of time in service, number of relightenings, tightening All studs, regardless of how many in in actual . stress avel, thermal cycling, and differential expan. arrangement, should be tightened sequentially in a ; sion. It has been determined that the major factors manner similar to that described in the preced:ng ; on fossil units are tightening stress level and number paragraph. of tightenings to that stress level. As a result, a re* For thread lubricants, refer to 01%72351, which duced tightening strtu, called the "1970 level," was lists approved thread lubricants for fossil as well as implemented for the valve stud materials used on nuclear service. most fossil units. The "1970 level" and its applica. tions are described under " Tightening Recommenda. A. Fossil Valve Studs (800'F and higher) tions." B5F5B and B50Al25E are by far the most com-Factors alTecting the life of nuclear valv: studs monly used stud materials on fossil valves (800'F (operating at temperatures below 800*F) differ from and higher). B5F5B studs are stamped with the sym-those affecting fossil valve studs. Nuclear valve studs bol L or FS B50Al25E studs are stamr'ed XD or are not operating in the raaterial creep range. There. F25. fore, stud life is not related to tightening stress or Tighten E5FSB and B30Al23E studs per Figure 2 number of tightenings in the same manner as for fos- (drawing 123AJ906). This is the "1970 Level" which sil valve studs. Iloweser, stud life can be aff ected by is approximately 70% of the pre 1970 stress level, excessive overtightening, corrosion, and other fac- Drawing 223A3906 takes precedence over instruc-tors, making it advisable to establish a regular inspec- tions on valve assembly drawings issued before' the 1 tion program. Recommendations for fossil and nu* "1970 Level" was implemented. clear valve studs, being somewhat different, are l covered separately. Austenitic stud materials have been used on a limited number of fossil valves at 1050'F and higher, , Austenitic studs are non magnetic and are stamped with one of the following symbols: S or A6A, X A, II, TIGitTENING RECOMMENDATIONS X B. All valve upper head and stand studs should be Tightening of austenitic studs should be continued tightened in a sequential manner. The tightening se- per the original valve assembly drawing mstructions. These instructions do not purport to cover all details or variations in equipment not to provide for every possible contingency to be met in connection with installation operation 0: maintenan:e. Should further information be desired or should particular problems arise which are not covered sufficiently for the purchaser's purposes the matter should be referred to the General Electric Company. COPYRIGHT 1942, GENERAL t:LECTRIC CO. Ti. - _ . _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ -__ _ _ m
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p ***a e .' 'O no sive. G l \O @j 2 n 3 1[N.ca_#lZ e ke, q _ q,eil Figure 1. Typical Tightening Sequences Applicable to B5F5B and B50A125E studs for fossil valves (1970 Level) and B5F5B and B5F4C studs for nuclear valves. NOTE: Where differences exist, this drawing takes precedence over instructions on valve assembly draw. ings issued before the 1970 Stress Level was implemented. 0 4 8 12 16 20 24 28 32 36 40 32 3E l l l f.yM4Qt.: l&f 1 /;' : lll , y/ f ':7 %* ?_f
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0 III -~ 0 0 4 8 12 16 20 24 28 32 36 40 Effective Stud Length (Inches) Figure 2. Elongation for Prestressing Valve Upper Head and Stand Studs (Dwg. No, 223 A3906) 2
VALVE S10DS. GEK.3793?B B. Nuclear Valve Studs (below goo'F) The followirs additional recommendations apply units (800'F and higher) which have gone B5F4C and B5FSB will be found on nuclear valves to (below 800'F). 85F4C studs are stamped N or F4. Int foss{ ser ce pdor t 6. B5F5B studs are stamped L or F$. 1. All B5F5B valve upper head and stand studs in Tighten B5F4C and D5F$B studs per the valve
' ore 1966 should be replaced by the assembly drawing or Figure 2 (drawing 223A3906). end f1981' (They should be in agreement.) This is essentially 2. All BiOAl2$E valve upper head and stand studs the pre.1970 stress level before it was reduced for in service before 1966 should be replaced by the those valve studs operating in the material creep end of IPt).
'8"8 Consult your GE Service Engineer for assistance.
B. Nuclear Valve Studs (below ge0'F) 111. REPLACEMENT RECOMMENDATIONS Nuclear valve ssuds operating below 800'F are not A. Fossil Valve Studs (g00'F and higher) in the material creep range and do not suffer plastic strain and loss of rupture ductility in service. There. - Most valve studs operati at 800'F and higher fore, there are no replacement recommendations re. are in the creep range of tb stud material. Each lated to number of tightenings. Inspection and re. time a stud is tightened to tL. Initial stress level' placement, if cracks are found, should be as discussed some of the stress creeps out in service and the stud under " Inspection Recommendations." suffers some plastic strain damage. The plastic s' rain accumulates with each tightening cycle until, fiv'ly, after some number of cycles, the rupture ductility of the material is used up and a crack will develop, IV, INSPECTION RECOMMENDATIONS Although valve stud life is affected by several Any studs that e'e found cracked must be re. variables, creep rupture damage, as described in the placed iramediately. it is desirable to also replace all preceding paragraph. is considered to be the primary the other studs of the same age in that valve if new damage mechan /sm forfossil Valve studs and the number studs are available. If less than 30% of the studs in a of tightenings is the primary measure of the amount of valve are cracked, however, it is generally satisfactory stud i/c t expended, to replace only the cracked studs, provided that the other studs of the same age are replaced within one The following recommendations assume the valve year. If more than 30% of the studs are cracked, all studs were tightened to the recommended stress studs of that age in that valve and mating valves levels and that recoramended rates of. temperature should be replaced immedistely.- change were observed at the valves. liigher stress levels or temperature rates can be expected to cause At a minimum, the number of spare studs recom-earlier stud failures. mended in the parts catalog should be kept on hand. Stud Replacement Material Recommendation A. Fossil Valve Stude (s00'F and higher) B5F5B Replace studs arter it tightenings or it t. B$FSB Stud Material cracks are round during periodic inspections. (ses " inspection Recommendations"L lt is recommended that B5F5B studs for valve upper B50At25E Repiace studs artet 25 tightenings or it heads and stends be testedfor cracks at least after every cracks are round during periodic inspections. ) lightenings or- every 6 years, whXheVer comes first. (see " inspection Recommendations"L The studs should be replaced at the next valve inspection.
- Austenitic Austenitic studs have not shown a tendency following Il tighten /ngs. This is shown in tabular form to crack due to loss or rupture ductility, and below; so there are no replacement recommenda.
tions related to number or tightenings. In. Stud Inspn. No. I 2 3 4 spection and replacement, ir cracks are Tightening No. J 6 9 found, should be as discussed under "In- (or) Years Service 6 12 to 24 spection Recommendations."
. Replace arter il lightenings.
3 m
OEK.379378. VALVE STUDS As was discussed under " Replacement Recom. B. Nuclear Yahe Studs (below 800'F) mendations" the stud replacement recommendition it is reconimended that studs for nuclear valve in the above table is based only on number of tight
- upper heads and stands be tested for cracks at least enings, not on years in service, The years in service every 6 years.
are shown in the above table only to help establish the minimum inspection frequency. Because they are operating below the material creep range, any cracks found in nuclear valve studs
- 2. B50Al25E Stud Material should be reported to the GE Service Engineer im-It is recommended that B50Al23E studs for valve upper heads and stands be tes:edfor cracks at least after esery 3 tightenings up to 18 and after every 2 tightenings Iherra.fter, or every 6 years, whichever comes first. This V. INSPECTION PROCEDURE is shown in tabular form below. If the number of tightenings reaches 23, the studs should be replaced at Magnetic particle testing of magnetic materials and the next valve inspection: red dye testing of non magnetic materials are satisfac-D" " '
stud insp. No i 4 2 3 5 Tightenins No. ) 6 9 12 15 casing. An ultrasonic test procedure has been (ot) Yeus Struce 6 12 la N 30 developed which has preven to be a dependable
/ stud insp No. e 7 s TM method of Iccating cracks. The ultrasonic test aethod is recommended because it does not require Ifahienins No. is 20 22 l 7 4: , .. rtinoval of the studs. In some instances, the grain h el Yem $ervice 36 42
"" sin in austenitic ms,erials may prevent ultresonic in-
*nTrine arter 25 tightenins,.
speuton, but this must be determined by trial.
- 3. Austenitic Stud Material To assist in the ultrasonk inspection of valve it is recommended that austenitic studs for salve studs, a detailed test procedure (TO.19A) has been upper heads and stands be tested for cracks at least prepared and can be obtained through your OE Ser-every 6 years. vice Engineer, j
1 l l GEMER AL @ ELECTRIC l Rev. B (5 82) 5 82 (1M)
New llanipshire Yankee May 25,1992 ATTACllMIINT 3 Seabrook Station Maintenance Manual (SSMA) and-Management Manual (SSMM) (Reference 1.2.2) { n- - - - - _ - - - . - _ _ . .
RMD CONTROL COPY # g ...... STATION .
- HANAGEMENT MANUAL .
* (SSMH) *
- 1. Does this manual / manual revisions
- a. Make changes in the facility as described in the Yes No ,
UFSAR7
- b. }hke changes in procedures as described in the
"O UFSAR7
- c. Involve tests or experiments not described in y p the UFSAR7
- d. Involve changes to the existing Operating License or require additional license requirements? # "O
- 2. If a ny of the above questions are answered vee, a safety evaluation per NHY Procslure 11210 is required.
PREPARED BY: E. J. EDVETSKY, TECHNICAL PROJECTS SUPERVISOR SUBMITTED BY: r/ O . E. J. spfETSKY, TECHNICAL PROJECTS SUPERVISOR DATE , SORC REVIEW COMPLETED DURING MEETING NUMBER: M-O DATEJ/d 7. APPROVED BY: ~ kG DEM1 h/M k Dy -E. M00W STATION MANAGER DA'TE APPROVED BY: ( d d A6/A ) F ' T.i . DRAWBRIDGE, EXfgUTIVE DIRECTOR - / /DATE NUCy 0 DUCTION l-REVISION 33 -- EFFECTIVE: 03/20/92 l^ DATE OF LAST PERIODIC REVIEk: 1/7/92 l DATE NEXT PERIODIC REVIEV DUE: 1/7/94 l
STATION MANAGEMENT HANUAL (SSMM) TABLE OF CONTENTS CONTE!!I .ge t CHAPTER 1: INTRODUCTION 1.0 OVERVIEW 1-1.1 1.1 FUNCTION 1-1.1 1.2 MISSION 1-1.1 s 1.3 OPERATING ACTIVITIES 1-1.1 2.0 CRGM1I2ATION 1-2.1 2.1 STRUCTURE 1 2.1 2.2 RESPONSIBILITIES 1-2.1 2.2.1 Station Manager 1-2.1 2.2.2 Assistant Station Manager 1-2.1 2.2.3 Group Hanagers 1-2,1 FIGURE 1-2-1 STATION ORGANIZATION: FUNCTIONAL GROUPS 1-2.2 { 2.3 FUNCTIONS 1-2.3 2.3.1 Operations Group 1-2.3 2.3.2 Maintenance Group 1 2.3 2.3.3 Chemistry and Health Physics Group 1-2.5 2.3.4 Technical Support Group 1-2.6 2.3.5 Planning, Scheduling and Outage Management 1-2.7 2.3.6 Security Department 1-2.8 FIGURE 1-2-2 OPERATIONS GROUP: FUNCTIONAL ORGANIZATION 1-2.9 - FIGURE 1-2-3 MAINTENANCE GROUP: FUNCTIONAL ORGANIZATION 1-2.10 FIGURE 1-2-4 CHEMISTRY AND HEALTH PHYSICS: FUNCTIONAL ORGANIZATION 1-2.11 FIGURE 1-2-5 TECHNICAL SUPPORT GROUP: FUNCTIONAL ORGANIZATION 1-2,1r FIGURE 1-2-6 PLANNING. SCHEDULING AND OUTAGE MANAGEMENT GROUP: FUNCTIONAL ORGANIZATION 1-2.13 FIGURE 1-2-7 SECURITY DEPARTMENT: FUNCTLONAL ORGANIZATION 1-2.14 3.0 STATION MANAGER'S STAFF 1-3.1
. 3.1 GENERAL 1-3.1 (m .j. 3.2 TECHNICAL PROJECTS SUPERVISOR 1-3.1 Page 1 SSMH Rev. 33
)
- - _ _ _ _ . _ . . - -.____- . ~. _..-. _ _ - . . _- . . _ . _ . . . . - . _ -
CONTENT ff,01 . CEAPTER in INTRODUCTION 3.0 STATION MANAGER'S STAFF (I)b 3.3 TECHNICAL STAFF 1 3.1 3.4 MANAGER OF OPERATIONAL SUPPORT 1 3.2 3.5 MANAGER OF MAINTENANCE SUPPORT AND COORDINATION 1 3.2 3.6 HEALTH AND SAFETY STAFF 1 3.2 4.0 COMMITTEES AND TASK FORCES 1-4.1 4.1 GENERAL 1-4.1 , 4.2 STATION OPERATION REVIEW COMMITTEE (SORC) 1 4.1 l 4.3 STATION SAFETY COHHITTEE 1 4.1 4.4 RADIATION SAFETY COMMITTEE (RSC) 1-4.2 4.5 NUCLEAR SAFETY AUDIT AND REVIEW COMMITTEE (NSARC) 1-4.2 4.6 RADI0 ACTIVE WASTE MINIMIZATION COMMITTEE 1-4.2 4.7 STEAM GENERATOR RELIABILITY COMMITTEE 1 4.3 4.8 STATION MODIFICATION RESOURCE COHKITTEE 1-4.4 5.0 INTERFACES 1-5.1 5.1 GENERAL 1-5.1 5.2 ADMINISTRATI'd E SERVICES 1 5.1 5.3 LICENSING SER'lICES 1-5.1 5.4 TRAINING GROUP 1-5.1 5.5 NUCLEAR QUALITY GROUP 1-5.1 5.6 SUPPORT SERVICES ORGANIZATION 1-5.2 5.7 ONSITE NRC PERSONNEL 1-5.2 1 5.8 PUBLIC RELATIONS 1-5.2 5.9 ENGINEERING 1-5.3 5.10 PROJECT CONTROLS 1-5.3 5.11 EHERGENCY PREPAREDNESS 1-5.3 5.12 MATERIAL REQUIREMENTS 1-5.3 Page 2 SSHM Rev. 33
- . _ , _ . . _ _ . - _ . . _ . .-- = . _ . . . _ .
S2pTENT EAGE CHAPTER 2: FOLICIES
) 1.0 $TATION POLICIES 2-1.1 l
1.1 OBJECTIVE 2-1.1 1.2 POLICY 2 1.1 2.0 PERSONNEL SAFETY 2-2.1 2.1 OBJECTIVE 2-2.1 2.2 POLICY 2-2.1 3.0 QUALITY ASSURANCE 2-3.2 3.1 OBJECTIVE 2-3.1 j 3.2 POLICY 2-3.1 l 4.0 CONFIGURATION CONTROL 2-4.1 4.1 OBJECTIVE 2-4.1 4.2 POLICY 2-4.1 4.2.1 Standard Requirer ents 2 4.1 fil.i. 4.2.2 Critical Plant Operations 2-4.2 V;./ 5.0 PROCEDURE COMPLIANCE 2-5.1 5.1 OBJECTIVE 2-5.1 5.2 POLICY (PROTECTED: REF. NHY PROCEDURE 10000) 2-5.1 5.3 ADDITIONAL PROCEDURE COMPLIANCE GUIDANCE 2-5.2 5.3.1 Procedures 2-5.2 5.3.2 Forms 2-5.2 5.3.3 Vendor Manuals and Documents 2-5.3 5.3.4 Corrections 2-5.3 5.3.5 Acceptance Criteria 2-5.3 5.3.6 Invalid Data 2-5.3 5.4 CCHPLEX PROCEDURES 2-5.4 (PROTECTED: REF. NYI-91025 AND SOER 91-01) 5.4.1 Definition 2-5.4 5.4.2 Examples of Complex Procedures 2 5.5 5.4.3 Examples of Procedures That Are Not Complex 2-5.6 5.4.4 Requirements 2-5.6 5.4.5 Senior Line Management Briefings 2-5.7 5.4.6 Preparing the Procedure 2-5.7 5.4.7 Personnel Responsibilities 2-5.7 5.4.8 Complex Procedure Briefing 2-5.9 Page 3' SSHH Rev. 33 l
CONTENT Pact CHAPTER 2: POLICIES 5.4 COMPLEX PROCEDURES A ( .' ROT ECTED : REF. NfI-91025 AND SOER 91-01) 5.4.9 Test Commencement 2-5.9 5.4.10 Test Ferformance 2-5.9 5.4.11 Test Interruption 2-5.10 5.4.12 Test Termination 2-5.11 5.4.13 Complex Procedure Completion 2-5.11 5.5 GENERAL PROCEDURE PERFORMANCE GUIDELINES 2-5.11 5.6 PROGRAM MANUALS 2-5.12 5.6.1 Overview 2-5.12 5.6.2 Deviations 2-5.12 5.7 A'D MINISTRATIVE PROCEDURES (SH 6.1) 2 5.13 5.7.1 overview 2-5.13 5.7.2 Deviations 2 5.13 5.8 STATION OPERATING PROCEDURES (SH 6.2) 2 5.14 5.8.1 Overview 2-5.14 5.8.2 Special Procedures 2-5.15 5.8.3 Deviations 2-5.15 dy 6.0 WORKING HOURS
'?.)Q 2 6.1 6.1 OBJECTIVE 2-6.1 6.2 POLICY , 2-6.1 6.2.1 General 2-6.1 6.2.2 Extended Vork Hour Requirements for satety Related Functions 2-6.2 6.2.3 Extended Work Hour Requirements for Non-Safety Related Functions 2-6.3 7.0 HOUSEKEEFING/ CLEANLINESS 2 7.1 7.1 OBJECTIVE 2-7.1 7.2 POLICY 2-7.1 8.0 SECURITY 2-8.1 8.1 OBJECTIVE 2-8.1 8.2 POLICY 2-8.1 is Page 4 SSMM Rev. 33
_ - . _ - . = - _ _ - _ _ - . . . . _ _ . . . CONTENT I1EE CHAPTER 2: POLTCIES t ."Jf 9.0 RADIATION PROTECTION 2-9.1 9.1 OBJECTIVE 2-9.1 9.2 POLICY 2-9.1 l 2-10.1 10.0 RESPIRATORY PROTECTION 10.1 OBJECTIVE 2-10.1
^
10.2 POLICY 2-10.1 11.0 VERIFICATION OF CORRECT WORK PERFORMANCE 2-11.1 11.1 OBJECTIVE 2-11.1 11.2 POLICY 2-11.1 11.3 SCOPE 2-11.1 11.4 VERIFICATION REQUIREMENTS 2-11.2 11.5 VERIFICATION TECHNIQUES 2-11.2 11.6 MANAGEMENT OVERSIGHT ACTIVITIES 2-11.4 ' Ug) d# 12.0 QUALIFICATION POLICY 2-12.1 12.1 OBJECTIVE 2-12.1 12.2 POLICY 2-12.1 2-13.1 13.0 COMMUNICATION POLICY 13.1 OBJECTIVE 2-13.1 13.2 POLICY 2-13.1 13.3 ADDITIONAL CCH4UNICATION POLICY REQUIREMENTS 2-13.1 13.3.1 Department Shift Turnover 2-13,1 13.3.2 Work Control Shift Turnover (Protected: Ref. Memo STGl 3665 Recommendation 12) 2-13.2 i l 14.0 COMMAND AND CONTROL 2-14.1 14.1 OBJECTIVE ~ 2-14.1 i 14.2 POLICY 2-14.1
., 15.0 CONTROL ROOM ACCESS 2-15.1 i
2-15.1 15.1 OBJECTIVE 1 Page 5- SSMM Rev. 33 l- - -_ _
CONTFNT I401 CHAPTER 2: POLICIES 15.0 CONTROL ROOM ACCESS l 15.2 POLICY 2-15.1 i 16.0 CONTROL ROOM VISITS BY MANAGEMENT 2 16.1 l 16.1 OBJECTIVE 2-16.1 1 16.2 POLICY (PROTECTED: REF. NYN-89088 AND LIC #89086) 2-16.1 17.0 VENDOR TECHNICAL ASSISTANCE 2-17.1 l 17.1 OBJECTIVE 2-17.1 ' 17.2 POLICY 2-17.1 18.0 USE OF ACTIO14 REQUIREHENTS TO PERTORM MAINTENANCE OR A TEST 2-19.1 18.1 OBJECTIVE 2-18.1 18.2 POLICY 2-18.1 l 18.3 VOLUNTARY USE OF ACTION REQUIREMENTS 2-18.1 18.4 ACTIVITIES APPROVED FOR VOLUNTARY ENTRY INTO ACTION REQUIREHENTS 2-20.1 /6 '3 18.5 ACTIVITIES E01 APPROVED FOR VOLUNTARY ENTRY INTO ACTION REQUIREMENTS OR PERFORMANCE DURING P0'IER OPERATIONS 2 18.2 CHAPTER 3: PROGRAMS 1.0 STATION PROGRAMS
- 3-1.1 1.1 OBJECTIVE 3-1.1 1.2 SCOPE 3-1,1 1.3 PROGRAM RESPONSIBILITIES 3-1,1 2.0 RnDIATION PROTECTION PROGRAM 3-2.1 2.1 OBJECTIVE 3-2.1 2.2 SCOPE 3-2.1 2.3 PROGRAM RESPONSIBILITIES 3-2.1 3.0 SECURITY PROGRAM 3 3.1 3.1 OBJECTIVE 3-3.1 3.2 SCOPE 3-3.1 Page 6 .
SSMH Rev. 33 l
CONTENT EA21 CHAPTER 3: PROGRAMS
',yk 3.0 SECURITY PROGRAM 3.3 PROGRAM RESPONSIBILITIES 3 3.1 4.0 HAINTENANCE PROGRAM 3-4.1 4.1 OBJECTIVE 3-4.1 4.2 SCOPE 3-4.1 4.3 PROGRAM kESPONSIBILITIES
- 3-4.1 3.0 TECHNICAL TRAINING PROGRAM 3-5.1 5.1 OBJECTIVE 3-5.1 5.2 SCOPE 3-5.1 3.3 PROGRAM RESPONSIBILITIES 3-5.1 6.0 HAZARDOUS WASTE MANAGEMENT PROGRAM 3-6.1 6.1 OBJECTIVE 3-6.1
,, 6.2 SCOPE 3-6.1 6.3 PROGRAM RESPONSIBILITIES 3-6.1 7.0 HEALTH AND SAPETY PROGRAM 3-7.1 7.1 OBJECTIVE 3-7.1 7.2 SCOPE .- 3-7.1 7.3 PROGRAM RESPONSIBILITIES 3 7.1 8.0 PIRE PROTECTION PROGRAM 3-8.1 8.1 OBJECTIVE 3-8.1-8.2 SCOPE 3-8.1 8.3 PROGRAM RESPONSIBILITIES 3-8.1 9.0 PLANNING AND SCHEDULING PROGRAM 3-9.1 9.1 OBJECTIVE 3-9.1 9.2 SCOPE 3-9.1 9,3 PROGRAM RESPONSIBILITIES 3-9.1 Page 7, SSMH Rev. 33 l
~
CONTENT EAqi CHAPTER 3: PROGRAMS 3-10.0 CHEMISTRY PROGRAM 3-10.1
- W; 10.1 OBJECTIVE 3 10.1 10.2 SCOPE 3-10.1 10.3 PROGRAM RESPONSIBILITIES 3 10.1 11.0 OPEP.ATING EXPERIENCE PROGRAM 3 11.1 11.1 OBJECTIVE . 3-11.1 11.2 SCOPE 3-11.1 11.3 PROGRAM RESPONSIBILITIES 3-11.1 12.0 EQUIPMENT QUALIFICATION 3-12.1 12.1 OBJECTIVE 3-12.1 12.2 SCOPE 3-12.1 12.3 PROJRAM RESPONSIBILITIES 3 12.1 13.0 MODIFICATION AND TESTING 3-13.1 13.1 OBJECTIVE 3-13.1 h 13.2 SCOPE 3-13.1 13.3 PROGRAM RESPONSIBILITIES 3 13.1 14.0 PERFORMANCE APPRAISAL . 3-14.1 14.1 OBJECTIVE 3-14.1 l 14.2 SCOPE 3-14.1 14.3 Ph0 GRAM PTSPONSIBILITY 3-14.1 CHAPTER 4: ADMINISTRATIVE ACTIVITIES 1.0 STATION MANUALS 4-1.1
1.1 INTRODUCTION
4-1.1 1.0 TYPES OF STATION MANUALS 4-1,1 l 1.2.1 Station Management Manual 4 1.1 1.2.2 Group Management Manuals 4-1,1 1.2.3 Program Manuals 4-1.2 1.2.4 Reference Manuals 4-1.2 Page 8 , SSMK Rev. 33
CONTENT g6gg CHAPTER 4: AIMINISTRATIVE ACTIVITIES
/,'*
Id[) 1.3 MANUAL REQUIRDdENTS 4-1.3 1.3.1 Responsibility 4 1.3 1.4 FORMAT AND C0!! TENT REQUIRDO.NTS 1.4.1 General 4-1.4 1.4 2 Protected Text 4-1.4 1.4.3 Cover Sheet 4-1.4 1.4.4 Table of Contents 4 1.4 1.4.5 List of Effectiva Pages . 4-1.5 1.4.6 Section Format 4-1.5 1.4.7 PaBa Identification 4-1.5 1.4.8 FJgures 4-1.5 1.4.9 Forms 4-1.6 1.4.10 Chapter Content 4-1.7 1.4.11 Appendices 4 1.7 1.4.12 Revision Status 4-1.7
-1.4.13 Reproduction and Distribution 4 1.8 1.5 MANUALS PREPARATION, REVIEW. AND APPROVAL 4 1.8 1.5.1 Responsibilities 4-1.8 1.5.2 Manuals Preparation and Update Process 4 1.6 (31- 1.6 REVISING A MANUAL 4-1.11 -QW 1.6.1 Requesting Revisions 4 1.11 1.6.2 Processing Revisions 4 1.11 1.6.3 Identifying Revisions 4 1.11 1.6.4 Revision Identification 4 1.11 l 1.6.5 Procedure Revisions 4-1.13 1.6.6 Periodic Reviews ,
4-1.13 l 1.7 CANCELLING A MANUAL 4-1,13 1.8 DOCUMENT DISTRIBUTION SYSTEM (DDS) REPORT 4 1.13 1.8.1 General 4-1.13 1.8.2 Responsibility 4-1.14 1.8.3 Checking Revisions 4 1.14 FIGURE 4-1-1 STATION MANUALS 4-1.15 i l FIGURE 4-1-2 MANUAL RESPONSIBILITIES 4-1.16 l 2.0 IDENTIFYING AND COMPLETING FOLLOV UP ACTIONS 4-2.1 2.1 GENERAL 4-2,1 2.2 PROCESSING 4-2.1 l V1 Page 9 SSMH Rev. 33
[ CONTENT [603 I CHAPTER 4: AININISTRATIVE ACTIVITIES 3.0 POST. MAINTENANCE CRITIQUE 4-3.1 (' 3.1 GENERAL 4-3.1 3.2 POST MAINTENANCE CRITIQUE PROCESS 4-3.1 l l 4.0 AUTHORIZATION FOR EXTENDED VORK HOURS 4-4.1 i 4-4.1 4.1 CENERAL 4.2 PROCESSING , 4-4.1 5.0 SAFETY RELATED VENDOR HANUALS 4-5.1 5.1 CENERAL 4-5.1 5.2 OPERATING PROCEDURE - VENDOR MANUAL INTERFACE 4 5.1 6.0 QUALITY ASSURANCE 4-6.1 6.1 QUALITY ASSURANCE AUDITS 4-6.1 6.2 QUALITY ASSURANCE SURVEILLANCES AND INSPECTIONS 4-6.2 7.0 CHAPTER 4 SSMM FORMS 4-7.1
'0 CHAPTER 5: STATION OPERATION REVIEW COMMITTEE (50RC)
,@d; 1.0 STATION OPERATION REVIEW COMMITTEE ($0RC) 5-1.1 1.1 OVERVIEW 5-1.1 2.0 RESPONSIBILITIES ,
5-2,1 2.1 SORC CRAIRMAN 5-2.1 2.2 SORC SECRETARY 5-2,1 l 2.3 SORC MEMBERS AND ALTERNATES 5-2.1 2.4 TECHNICAL PROJECTS SUPERVISOR 5-2.2 3.0 SCRC KEETINGS 5-3.1 3.1 QUORUM 5-3.1 3.2 AGENDA 5-3.1 3.3 FORMAT 5-3.1 3.4 FREQUENCY 5-3.2 - 3.5 TELEPHONE MEETINGS 5 3.2 Page 10 SSMM Rev. 33
CON 1 ENT lAGE C11 APTER 5: STATION OPERATION REVIEW COMKITTEE (5010) f.s
')' 3.0 50RC KEETINGS 3.6 UNSCHEDULED MEETINGS 5 3.2 3.7 VALK THRU REQUESTS 5-3.3 3.? MINUTES 5-3.4 FIGURE 5-3-1 TELEPHONE SORC HEETING CHECKLIST 5-3.6 4s0 SAFETY EVALUATIONS ,
5-4.1 4.1 OVERVIEW 5-4.1 5.0 SORC DOCUMENT REVIEW 5-5.1 5.1 SUBMITTING ITEMS TO THE SORC 5-5.1 5.2 SORC REVIEW 5-5.1 6.0 SORC SUBCOMMITTEE DOCUMENT REVIEW 5-6.1 6.1 SUBCOHKITTEE COMPOSITION 5-6.1 _, 6.2 SUBC0KHITTEE REVIEW 5 6.1 kd
*~4 6.2.1 Document Submittal 5-6.1 6.2.2 Review Schedule 5-6.1 6.2.3 Review Cycle 5 6.2 6.2.4 Documents in 50RC Review in Excess of Three (3) Honthe 5 6.2 6.2.5 Review Process 5-6.2 6.2.6 SORC Member and Alternate Review 5-6.3 6.2.7 Document Review Sheets (SSHM FORMS 5 6A and 5-6B) 5-6.4 6.2.8 Document Review Complete
- 5-6.4 l
l 6.3 GUIDELINES FOR SORC SUBCOMMITTEE REVIEW 5-6.5 FIGURE 5-6-1 SORC SUBCOMMITTEE DOCUMENT REVIEW MATRIX GUIDELINES 5-6.6 7.0 NSARC INTERFACE 5-7.1 7.1 SORC SECRETARY 5 7.1 7.2 SORC 5 7.1 i 8.0 SORC ACTION ITEMS 5-8.1 8.1 CRITERIA 5-8.1
. , 8.2 TRACKING 5-8.1 8.3 EXTENSIONS 5-8.1 l
l Page 11 SSMH Rev. 33 l
CONTENT g CHAPTER 5: STATION OPERATION REVIEW CODMITTEE (8010)
.x 8.0 SORC ACTION ITEMS g; 8.4 COMPLETION 5-8.1 0.0 COMPLETING SORC FORMS 5-9.1 9.1 TELEPHONE SORC MEETING (SSMM FORM 5 3A)- 5-9.1 9.2 SORC DOCUMENT REVIEW COMMENTS
SUMMARY
-(SSMM FORM 5-5A) 5-9.1 9.3 50RC DOCUMENT SUBH1tTAL (SSMM FORM 5-5B) 5-9.3 9.4 SORC SUBCOMMITTEE REVIEW (SSMH FORM 5-6A) 5-9.4 9.5 SORC MEMBER / ALTERNATIVE REVIEW ($$MM FORM 5 6B)- 5-9.4 10.0 CHAPTER $ SSMH FORMS -3 10'.1 CHAPTER 6: . MASTER PROCED"'LES SM 6.1 Administrative Procedures SM 6.2 Station Operating Procedures CHAPTER 7: AININISTRATIVE CONTROLS g SH 7.1 Repetitive Tasks h-SM 7.2 Station Labeling Program SM 7.3 Supervisory Walkdown Program SM 7.4 CANCELLED SH 7.5 fecondary Water Chemistry Program 1 CHAPTER 8: TEST PROGRAM SH 8.1 CANCELLED CHAPTER 9: OVERTIME ACTIVITIES SM 9.1 Production overtime Authorization ! SH 9.2 Production' Overtime Distribution. l-APPENDICES: APPENDIX At CLOSSARY APPENDIX B: STATION OPERATION REVIEW COMMITTEE CHARTER.
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i \ Page.12 _SSMM Rev. 33-
f
- STATION
- l
- HAINTENANCE MANUAL *
( * *
* (SSMA) *
. e
- 1. Does this manual. nual revisions
- a. Mah changes in the facility as described in the y,,
- b. changes in procedures as described in the 79, 9
- c. Involve tests or experiments not described in
, y,,
l the FSAR7
- d. Involve changes to the existing Opera)ing License Y ~#
or require additional license requirements? ,
- 2. Ifanyoftheabovequestionsareansweredyys.asafethevaluationper NHY Procedure 11210 is required.
P/,EPARED BY: M. D. McNAMARA MAINTENANCE SUPPORT SUPERVISOR (. SUBMITTED BY: R. M. COONEY. TTENANCE MANAGER
//DATf M8 k SORC REVIEW COMPLETED DURING MEETING NUMBER: M"N DATE: d D D E '
.e,r APPROVED BY: / #1 Mf J- .t
,D. . M0pY, (ATION MANAGER / BXTE APPROVED BY: I - / 48W4 8*2 B. M DRAVERIDGE, EX TIVE DIRECTOR - / DATE Q LEAR PR CTION REVISION $8 -- EFTECTIVE: 04/01/92 l
l DATE OF LAST PERIODIC REVIEW: 10/02/90 l .A - DATE NEXT PERIODIC REVIEW DUE: 10/02/92 i
\
g3 STATION 3- ' l HAINTENANCE HANUAL
~'
(SSHA) TABLE OF CONTENTR (VOLUMES I & II) l CONTENT PACE VOLUME I CHAPTER 1: INTRODUCTION 1.0 PROGPJJi POLICY 1-1.1
1.1 INTRODUCTION
1-1.1 1.2 SCOPE 1-1.1 1.3 PROGRAM RESPONSIBILITIES 1-1.1 1.4 PROGRAM IMPLEHENTATION 1-1.3 1.5 CLASSIFICATION OF MAINTENANCE 1-1.3 (hv 1.6 MAINTENANCE PROCEDURES 1-1.5 1.7 V0P2 CONTROL 1-1.7 1.8 E0.UIPMENT CONTROL 1-1.9 1.9 RELATED PROCEDURES 1 1.11 1.10 CALIBRATION AND TESTING 1-1.12 1.11 MAINTENANCE HISTORY 1-1.12 1.12 TRAINING AND QUALIFICATIONS 1-1.13 FIGURE 1-1 STATION MAINTENANCE MANUAL RESPONSIBILITY LIST 1-1.14 Page 1 SSMA Rev. 58 l f;.
TABLE OF CONTENTS , (VOLUMES I & II) CONTENT VOLUME.I CHAPTER 2: MAINTENANCE CONTROL MA 2.1 Maintenance Activities MA 2.2 CANCELLED MA 2.3 Control and Calibration cf Measuring and Test Equipment MA 2.4 CANCELLED CHAPTER 3: WORK CONTROL MA 3.1 Work Request MA 3.2 Repetitivo Task Sheets MA 3.3 Bousekeeping MA 3.4 Foreign Material Exclusion ([D
.<c HA 3.5 Post Maintenance Testing MA 3.6 Failure Cause Description Codes CHAPTER 4: EQUIPMENT CONTROL MA 4.1 Switching and Tagging List MA 4.2 Equipment Tagging and Isolation MA 4.3 Temporary Modifications MA 4.4 Temporary Setpoints MA 4.5 Configuration Control During Maintenance and Troubleshooting MA 4.6 RDMS Data Base Item Control l
MA 4.7 CANCELLED MA 4.8 Temporary Equipment in Seismic Areas Page 2 SSMA Rev. 58
TABLE OF CONTENTS
;7,? (VOLUMES I & II) j I
CONTENT l V0LtHE I CHAPTER 4: EQUIPMENT CONTROL HA 4.9 Bench Stock Program HA 4.10 Installation and Removal of Temporary Equipment l HA 4.11 Tool Control MA 4.12 Abandoned Equipment Labeling HA 4.13 Design Change Implementation and Post Hodification Testing VOLUME II CHAPTER 5: SPECIAL PROCESS CONTROL HA 5.1 Special Process Control MA 5.2 Velding and Haterial Control Oft
'we HA 5.5 Cleaning MA 5.4 Control of Expendable / Chemical Products HA 5.5 NDE Performance Program MA 5.6 CANCELLED HA 5.7 Penetration Seals and Fire Barrier Wrap MA 5.8 CANCELLED i
l l
-- Page 5 SSHA Rev. 58 + ,-~-,e-* , , . . - .
TABLE OF CONTENTS (VOLUMES I & II) - h CONTENT VOLUME II CHAPTER 6: INSERVICE INSPECTION PROGRAM MA 6.1 Inservice Inspection of Class 1, 2. and 3 Components HA 6.2 ASME Section XI Repair and Replacement Program MA 6.3 Balance of Plant (BOP) Repair and Replacement Program HA 6.4 Inservice Testing of Pumps MA 6.5 Inservice .?esting of Valves MA 6.6 Primary Reactor Containment Leakage Test Program CHAPTER 7: SURVEILLANCES HA 7.1 Technical Specification Surveillance Scheduling and Ferformance CHAPTER 8: PREDICTIVE HAINTENANCE ^> iy HA 8.1 Vibration Monitoring and Analysis HA 8.2 Lubrication Analysis MA 8.3 Thermographic Inspection Program MA 8.4' Check Valve Performance Monitoring Program APPEND 7X A GLOSSARY APPENDIX B: LIST OF LOCATIONS Page 4 SSHA Rev. 58 x ..
New llampshire Yankee May 25,1992 ATTACilMENT 4 Generic Electric GEK 4652713. "l'eriodie Operational Test Summary * (Reference 1.2.3)
g, INSTRUCTIONS Otx..ic m B 3 m3 ^ l PERIODIC OPERATIONAL TEST
SUMMARY
M- _ \
!N- .,
(Revision B. Februarv 1980) l ! Malfunctions of turbine equipment and auxiliary work is beyond the scope of this periodic test l equiptrent can occur. When they do, they may put summary. l the turbine in potential danger or closer to poter.' i tial danger of a catastrophic failure. This publication summarizes the periodic tests ! called for in the individual publications in this In. sku n , an mmm o ac 9 be An essential part of the turbine protective sys. l tems is the testability of various components. It is a en f U ng an unmecusM M DMs of VITALLY IMPORTANT for the safety of the tur. e u 8, pnformance requM b a mecasful ! u , an acuon to W h foHodng an unmcens. bine that the components or systems be tested at ul test are found in the individual publications ref. the presenbed intervals as given in this publication, erenced in each summary. This publication covers only regularly scheduled IN ALL CASES OF MALFUNCTION, Tile OP. periodic tests. When equipment has been disassem. ERATOR S110ULD BE FULLY AWARE OF ALL bled, repaired, readjusted or otherwise received POSSIBLE PROBLEMS TilAT COULD AFFECT maintenance work, proper operation of the equip. Tile SYSTEM AND TAKE ACTION IN TiiE BEST ment must be verified before returning to service. INTEREST OF SAFE OPERATION WITliOUT Such checkout and testing following maintenance LOSS OF GENERATION. l These instructions do not purport to cover all details or variations in equipment nor to provide for every possible contingency to be met in connection with installation, operation or maintenance. Shoula further information be desiredor shouldparticular problems at:se which are not covered sulficiently for the purchaser's purposes, the in atter should be referred to the General Electric Company. _____ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ . . _ _ _ . . _ _ _ . _ _ _ . . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . . . _ _ _ _ _ _ _ _ _ _ . . _ _ _ _ _ _ . . _ - . . _ _ _ . _ . n
1 GEK.46587B. I 2RIODIC OPER ATIONAL TEST SUMM ARY
SUMMARY
OF TESTS TO BE BERFORMED DAILY
SUMMARY
OF ACTION FOLLOWING SUMM ARY OF TEST UNSUCCESSFUL TEST Lamp test EHC control room panel. Replace failed bulbs and retest. Fully close the main stop valves and combined Shut down immediately by unloading and then valves by sequence testing at the EHC Test Panel. tripping from the EllC panel. DO NOT OPEN the Observe fast closure near end of stroke to confirm generator breaker until ZERO or slightly NEG A. that FASV and disk dump valves have functioned TIVE load has been reached. The cause of the properly. problem should be corrected before restarting. In all cases of malfunction, the operator must make For details see " Flow Control" in Volume 111. his decisions with a thorough knowledge of the system and act in the best interests of safe opera. tion and minimizing potential damage to the turbine (e.g. Water Induction may be a problem if an open steam path exists to the turbine). Test for movement of the extraction check isolate the extraction line immediately. For de. valves provided with positive assist devices, tails, ;eo " Extraction Check Valves", and in. $ vestigate also per Extraction Check Valves"in For details, see " Extraction Check Valves" in Volume I. Volume 1. Check Loss of Power Pressure Signal Light at If Power Pressure Signal lost indicator is on, both EllC control room panel. Power Load Unbalance and Fast Closing Intercept / Intermediate Valve functions have been lost. To l mainta5 overspeed protection load must be re. i deced io under 10% for normal mode operation ! on units with and without trip anticipators. For standby mode load must be limited to 60% of maximum unit load on units with trip anticipators and 80% for units without trip anticipators until l Power Pressure Signal has been restored. g/ T l l Individual units may have a higher permissiole load. Requests for a higher load point can be di. rected to you1 General Electric Representative. To , j replace Power Pressure Sensor see procedure
" Maintenance (Mk II)"in Volume III.
Check Electrical Trip Test " LOCKED OUT" If this indicator is lit the Electrical Trip portion of Light at EHC Control Room Panel. the Protective System is assumed to be disabled, h) Follow instructions applying to unsuccessful Elec. trical Trip Test. 2
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\ a , i PRRIODIC 01FRATIONAL TEST
SUMMARY
, GEK 46527B ! f - bdMMARY OF TESTS TO BE PERFORMED
~
DAILY (CONT'D)
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST UNSUCCESSFUL TEST Check Mechanical Overspead and Piston Trip Test If either of these indicators is lit the Mechanical
" LOCKED OUT" and " RESETTING" Ughts at Trip portion of the Protective System h assumed EHC Control Room Panel, to be disabled. Follow instructions appl /i ng to unsuccessful Mechanical Overspeed Trip Test.
For nuclear reheat units check reheater on-stream Remove two, four or eight reheater tube bundles leak detection system readings, from service in accordance with " Moisture Sepa. rator Reheater Heating Steam or Tubeside Steam For details, see " Moisture Separator Reheater Supply and Control Systems" in Volume IV. Tubeside On Stream Leak Detection Systems"in Locate and repair leak at earliest opportunity as Volume IV, described in Volume IV. 1
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3- 4
GEK 46527B, PERIODIC OPERATIONAL TEST
SUMMARY
SUMMARY
OF TESTS TO BE PERFORMED WEEKLY AND START UPS*
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST ON AN UNSUCC;SSFUL TEST Perform the " Backup Overspeed Trip Test" at the Go through the trouble shaoting scheme in " Trip EHC panel to test the 2 out of 3 logic circuits, and Monitoring"in Vo' m 'll. Shutdown should only N. secomplished i J.e w 'oading at the EHC For details, see " Trip and Monitoring" in panel. The generator bt *& nould not be Volume Ill, opened with any load on ene machine. Perform the Mechanical Overspeed Trip Test (oil Unload the machine from the EHC panel. Open trip) at the EHC Panel to test for operation of the the generatcr breaker when ZERO or NEGATIVE Overspeed Trip Device and Mechanical Trip Valve. load has been reached then perform the checks outlined in " Trip and Monitoring" in Volume III Note that if the test hangs up in the locked out before shutting down to correct the problem. mode, or resetting light remains on after test, these have the same impact as an unsuccessful test so n.llow general instructions for unsuccessful test. For details, see " Trip and Monitoring" in Volume llI. , Perform the Mechanical Trip Piston Test at the Unload the machine immediately from the EHC EHC panel ta test for electrical activation of the panel. Open the generator breaker when ZERO or trip mechanism, slightly NEG ATIVE load has been reached then perform the checks outlined in " Trip and Moni-Note that if the test hangs up in the locked out toring"in Volume III before dutting down to mode, or resetting light remains on after test, these correct the problem. have the same impact as an unsuccessful test so follow generalinstructions for unsuccessful test. The following is an exception to immediate un-loading. The unit may be run up to a week if the For details, see " Trip and Monitoring" m Mechanical Overspeed Trip Test and Electrical Trip Volume 111. Test are successful and if after the testing, the EHC panel resetting lights and lockout lights are not lit. i Gese tests should be performed during start up if it has been more than one week since last testing. 4
PERIODIC OPERATIONAL TEST
SUMMARY
, GEK 46527B
SUMMARY
OF TESTS TO BE PERFORMED WEEKLY AND START UPS' (CONT'D)
SUMMARY
OF ACTION TO BF. TAKEN
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST Perform the Electrical Trip Test at the EHC panel Unload the machine immediately (within one week to test for operation of the Electrical Trip Valve. if conditions listed below are met). Open the gen-erator breaker when ZERO or slightly N'iGATIVE If the test hangs up in the locked out mode, it has load has been reached ther perform the checks the same impact as an unsuccessful test so follow outlined in " Trip and Monitoring" in Volume 111 - general instructions for unsuccessful test. before shutting down to correct the problem. For details, see " Trip and Moritoring" in Unit u'thout Trip Anticipator-Volume 111. Unit can be run for one week at fullload if-Mechanical Overspeed Trip Test and Mechanical-Trip Piston Test are successful. Unit is to be run - only in Normal mode and not in Standby mode. Unit with Trip Anticipator
- Jnit can be run for one week at 50% maximum load if Mechanical Ov rspeed Trip Test and Me.
chanical Trip Piston Test are successful. Unit is ; to be run only in Normal mode and not in the Standby mode. i , (
*These tests should be performed during start up if it has been more than one week since last testing.-
5
GEK.46527B, PERIODIC OPERATIONAL TEST
SUMMARY
SUMMARY
OF TESTS TO BE PERFORMED s WEEKLY
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST Fully test ALL Main Turbine Steam valves and Shut down immediately by unloading and tripping OBSERVE the travel of the valve stems and link- from the EHC panei. DO NOT OPfN the generator ages locally. It is recognized on nuclear fueled breaker until ZERO or slightly NEGATIVE load plants that it may not be practical to approach the has been reached. The cause of the problem should , valve during valve testing on a weekly basis due to be corrected before restarting. In all cases of mal-the high radiation level. Nevertheless, testing of function, the operator must make his decisions each valve should be observed from a safe distance with a thorough knowledge of the system and act once a week to check for fast closure at end of in the best interests of safe operation and mini-travel, changes in noise, vibration and other beha- mizing potential damage to the turbine. (e.g., l vior. For details, see " Flow Control" in water induction may be a problem if an open Volume !!!. steam path exists to the turbine). Perform the Power Load Unbalance test at the Check forloss of Power Pressure Signal (See Daily EHC panel to check for correct operation. For Tests) and proceed per that section if it has failed, this test unit load has to be over 40%. If Power Load Unbalance fails to test and the Power Pressure Signalis functioning, only the Power Load For details, see " Rate Sensitive Power Load Unbalance function is lost. Unbalance Analog and Logic Circuits"in Volume III. To maintain overspeed protection load must be , reduced as follows until Power Load Unbala .., problem has been corrected. 1 Unit without Trip Anticipator Don't exceed 55% load in Normal mode and 80% load in Standby Mode. Unit with Trip Anticipator Don't exceed 40% load in Normal mode and 50% load in Standby mode, Individual urdts may have a higher permissible load. Requests for a higher load point can be directed to your General Elect 6 Representative. To replace Power Load Unbalance board see pro-cedure " Maintenance (Mk II)"in Volume IIL For details see " Rate Sensitive Power Load Unbal-ance Analog and Logic Circuits"in Volume IIL Test the Thrust Bearing Wear Detector for Investigate immediately and reset or repair within satisfactory trip points and operation. one week. While the device is out of service, avoid maximum load and switching in or out of feed, For details, see " Thrust Bearing Wear Detector water heaters. Testing" and " Thrust Bearing Wear Detector" in Volume I. For details, see " Thrust Bearing Wear Detector" in Volume L 6 m
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PERIODIC OPERATIONAL TEST SUMM ARY. GEK-46527B
SUMMARY
OF TESTS TO BE PERFORMED a WEEKLY (CONT'D)
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST Test automatic starting of ALL motor driven lube Investigate and correct IMMEDIATELY malfunc. oil pumps by actuation of their pressure switches, tions of all DC motor driven pumps. Investigate and and exercise each standby pump, correct within one week malfunctions of all AC motor driven pumps. For details, see " Automatic Pump Starting Weekly"in Volume I. For details, see " Automatic Pump Starting . Weekly"in Volume I. Test for alarm annunciation on the oil tank level Investigate immediately and repair within one gauge, week. Check oillevel once per shift. Replenish to normal levels as necessary. For details see " Oil For details, see " Oil Level Gauge Testing"in Level Gauge Testing". Volume I. s ,- Check the air gap on the silver brushes in the Replace the silver brushes and/or check for shaft front standard for wear and wear rate,if. - voltage per " Removable Shaft Grounding Device"
. provided. In Volume I.
For details see " Removable Shaft GroundMg Device" in Volume L Perform the EVA test if early valving is provided. Replace with the factory spare per "Early Valve Actuation Analog and Logic Circuits"in Volume For details, see "Early Valve Actuation Analog III. and Logic Circuits"in Volume III. Test the EHC fluid for water content. If the value is above the limit as given in "EHC Fluid Specifications and Maintenance" correct For details, see "EHC Fluid Specifications and situation per diagnostic data in "EHC Fluid Spe-Maintenance"in Volume I. cifications and Maintenance." ' Remove inspection cover on top of reservoir and visually check for free standing water on top of fluid. ( Test EHC pumping system by starting standby Follow procedure in section IV D of " Hydraulic L system; switching systems; measuring and legging Power Unit for Electrohydraulic Control Sys. motor current.- tems". Take pump out of service and investigate if l .. . required. 'j For details, see " Hydraulic Power Unit for Electro. v hydraulic Control Systems"in Volume I. 7
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l GEK.46527B, PERIODIC OPERATIONAL TEST
SUMMARY
SUMMARY
OF TESTS TO BE PERFORMED WE E KLY (CONT'D)
SUMMARY
OF ACTION TO BE TAKEN SUMM ARY OF ! 2ST ON AN UNSUCCESSFUL TEST l Check the condition of EHC hydraulic pump suc- Change filter elements if any indicators or gauges , tion strainers (and auxiliary pump strainer when show a change is required per section IV C and ) applicable) and the pressure drop across the Fullers-Earth and 1/2 micron backup filters in the IV G of " Hydraulic Powet Unit for Electro- g hydraulle Control Syst-ms." '/ EHC hydraulic system. Check for piping fluid ' leaks and fluid levelin reservoir. Tighten leaking connections. Add fluid if level is low. For details, see " Hydraulic Power Unit for Electrohydraulic Control Systems" in Volume I. Check that the air dryer on the hydraulic power Reactivate or change the desiccant immediately, unit has active desiccant. For details, see "Hydraude Power Unit for Electrohydraulic Control Systems" in Volume I. s l
- l s
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8
PERIODIC OPERATIONAL TEST SUMM ARY, GEK.46527B
SUMMARY
OF TESTS TO BE PERFORMED a MONTHLY
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST Taka 2 samples of the EHC fluid and analyze fully. If values are above the limits as given in "EHC Log results. Fluid Specifications and Maintenance" correct situation per diagnostic data in "EHC Fluid For details, see "EHC Fluid Specifications and Specifications and Maintenance". 6 Maintenance"in Volume I. Check flow tnru EHC Hydraulic Power Unit If Gow is not as specified in " Flow Control Valve TAFEFU flow control valve as outlined in - EHC-Hydraulle Power Unit" adjust per that
" Flow Control Valve EHC - Hydraulic Power instruction by the procedure outlined in the Oper.
Unit" Operation Section, in Volume 1. ation Section. Test the response time and the final speed of the Investigate and correct IMMEDIATELY for details - emergency bearing oil pump motor on the weekly see " Automatic Pump Starting Monthly". starting test. For details, see " Automatic Pump Starting Monthly"in Volume L Check the voltage between the turbine shaft and Check the carbon and silver brushes if provided per k the station ground. " Removable Shaft Grounding Device" in Volume I. For details, see " Removable Shaft Grounding Check the copper braid shaft grounding device, if Device" or " Shaft Grounding Device, Copper" provided, per " Shaft Grounding Device, Copper" , in Volume !. in Volume I. A check of th urbine supervisory instruments Correct the problem immediately. Contact Gen-should be made to ensure that instruments show- eral Electric Co. if problem cannot be fixed within ing differential expansion, casing expansion, one week. 1 eccentricity, vibration, rotor position, metal temperature and water detection temperatures For details, see the appropriata part of the TSI are in working order and calibrated, section in Volume III. Fr details, see publication relating to Water Induction in Large Steam Turbines in Volume I; 6 the TSI section in Volume III and ASME 3tandard TWDPS Part 1 Fossil Fueled Plants or Part 2 Nuclear Fueled Plants. Perform the " TEST BACKUP SPEED AMPLI- Investigate the problem if the " BACKUP SPEED FIER" at the EHC monitor panel to check that - AMPLIFIER OUT OF SATURATION" light does no sudden load increase would occur if the pri- not come on. Omline trouble shooting can be per. I mary speed signal was to be lost. formed in standby mode. Correct on or before first outage.
, For details, see " Speed Control Unit"in Volume
.( IIL For details, see " Speed Control Unit" and "Mainte-nance MKII"in Volume IIL 9- _ _ _ _ _ _ _ _ - _ .~
GEK 46527B, PERIODIC OPERATIONAL TEST
SUMMARY
SUMMARY
OF TESTS TO BE PERFORMED MONTHLY (CONT'D)
SUMMARY
OF ACTION TO BE TAKEN SUMM ARY OF TEST ON AN UNSUCCESSFUL TEST Check the Main Oil Tank oillevel upstream of the if more than 2 inches clean screens immediately, screens. lias the level risen less than 2 inches? For See " Maintaining A Clean Oil Lube Oil System details, see " Maintaining A Clean Lube Oil Sys- and Correcting One Found Contaminated". g tem and Correcting One Found Contaminated" in J Vol. I. 1 s l 10
- _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . . . _ . _ . . _ . . . _ _ _ _ _ . _ - . _ . . _ . _ _ _ . _ , _ _ _ _ _ . _ , _ . . _ . ., m
PERIODIC OPERATIONAL TEST
SUMMARY
, GEK 46527B
\
SUMMARY
OF TESTS TO BE PERFORMED EVERY THREE MONTHS
SUMMARY
OF TEST
SUMMARY
OF ACTION TO BE TAKEN ON AN UNSUCCESSFUL TEST Check gas precharge in EHC accumulators. I If precharge pressure is low, recharge per " Fluid Accumulators for Electrohydraulie Control ( For details see " Fluid Accumulators for Systems". Electrohydraulic Control Systerns" in Volume I. Collect lube oil samples: See:" Maintaining A Clean Lube Oil System and
- 1. Main oil tank near booster pump inlet. Correcting One Found Contaminated,"
2, Main oil tank upstream of screens. 3, Main oil taak - oil discharging from the oil purification system. Compare to standard in " Maintaining A Clean Lube Oil System and Correcting One Found Contaminated"in Volume I. I For units so provided, check lift pumps, Opera-tion of the lift pumps will not affect rotor Check pressure switch calibration (See Control performance at speed. Diagram). Check suction line filters (See GEY 432, GEY 433), if pump case drain flow is approxi. Test interlock pressure switch before testing mately 2 GPM pump should be rebuilt or replaced. l a lift pump. Then start pump motor, The "LO" (See GEY 366A) contacts of PS15 should change state. See
" Lift Pumps"in Volume I.
l l l 11 m
GEK46527B, PERIODIC OPERATION AL TEST
SUMMARY
SUMMARY
OF TESTS TO BE PERFORMED EVERY SIX TO TWELVE MONTHS
SUMMARY
OF ACTION TO BE TAKEN-
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST Test the trip settings of the mechanical overspeed Repeat the test twice more to obtain repeatable trip device by taking the unit up in speed to the results.- Check both of the speed measuring instru-trip point. ments to check that speed is correctly recorded. ' Correct any problems and reset if required. Do For details, see " Trip and Monitoring" in not tie the unit to the system until the problem Volume 111. has been corrected.- By setting the load set at 100% and gradually Check both of the speed measuring instruments to increasing the speed of the machine, test the check that the speed is correctly recorded. Correct action of the " Trip Anticipator" to determine any problems and adjust if required. Do not tie that it will trip all the valves at the spned indicated the unit to the system until the problem has been on the " FIELD LINE UP DIAGRAM"in Volume corrected. IIL (10.5% rated speed.) . For details, see " Trip & Monitoring" in Volume For details, see " Trip & Monitoring" in Volume III. III. Perform the " ACTUAL 105% TRIP OF BOST Investigate the problem per." Trip and Monitoring" OFF LINE" test on the EHC panel to check the in Volume III. Do not tie r.he unit to the system 105% rated speed test point of the backup over- until the problem has been corrected. speed trip. For details, see " Trip and Monitoring" in Volume !!L Test the control valves and main stop valves for - Take immediate steps to repair the corresponding tight seating following a daily test of the main - valves to meet or exceed the test requirements . stop valves. - before resynchronization to the system. For details, see Valve Tightness Tests Main Stop 1 and Control Valves 6-12 months" in Volume I.
)
Leak test EHC coclers as outlined in " Hydraulic Take corrective actions as outlined in " Hydraulic Power Unit for Electrohydraulic Control Sys- Power Unit for Electrohydraulic Control tems"in Volume L Systems". , i Test the emergency bearing oil pump motor speed Place the AC turning gear pump in operation, and the oil pressure dip on automatic startup. INVESTIGATE AND CORRECT before rolling off turning gear, i For details, see "Autonutic Pump Starting 612 l Months and ' Automatic Pump Starting - Initial ' L Startup" in Volume I. 12
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PERIODIC OPERATIONAL TEST
SUMMARY
, GEK 46527B
SUMMARY
OF TESTS TO BE PERFORMED EVERY SIX TO TWELVE MONTHS (CONT'D)
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST _ Check the pressure switch and relief valve settings Set pressure switches and relief valves to values for the EHC Hydraulic Power Unit as outlined
. (, listed on " Turbine Control Diagram" by the pro.
in " Hydraulic Power Unit for Electrohydraulle cedure outlined in " Hydraulic Power Unit for Control System"- Section llI.B in Volume I. Electrohydraulle Control System". Check for proper operation of fluid level gage. Test the mechanical and electrical operation of all Investigate and correct the prAlem. If the pro-turbine drain valves. Operate the valves from the blem is not resolved and operation is continued, control room and determine that they open and the operator should be aware of the potential close by observing control room indicating lights, dangers and should take appropriate actions as Someone should be observing the valves as they needed, i are being tested in order to verify that the valves
.Je moving, and that the controllights are working as intended.
For details, see publication relating to Water Induction in Large Steam Turbines in Volume I. B i ( 13
GEK 46527B, PERIODIC OPERATIONAL TFST
SUMMARY
)
AUXILIARY EQUIPMENT TESTING THE FOLLOWING TESTS ARE RECOMMENDED ON EQUIPMENT NOT SUPPLIED BY GENERAL ELECTRIC CO., BUT WHOSE FAILURE COULD HAVE AN IMPACT ON TURBINE GENERATOR SAFETY AND RELIABILITY, THE EQUIPMENT TESTS INCLUDE BUT ARE NOT LIMITED TO THE FOLLOWING: i l 1 14
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PERIODIC OPERATIONAL TEST SUMM ARY, OEK 46527B AUXILIARY EQUIPMENT TESTING
SUMMARY
OF RECOMMENDED TESTS TO BE PERFORMED MONTHLY
SUMMARY
OF ACTION TO BE TAKEN SUMM.sRY OF TEST ON AN UNSUCCESSFUL TEST ( Test the mechanical and electrical operation of all Investigate and correct the problem. If operation drain valves, (Feedwater heater drains and steam is continued the operator should be fully aware of pipe drains.) Where applicable, operate the valves the potential dangers and take appropriate actions from the control room and determine that they as needed, open and close by observing < ontrol room indi-cating lights. For details, see publication relating to Water Induc-tion in Volumn I. Test mechanical operation of all power assisted check valves, including all solenoid valves, air filters, air supply, air sets, etc. For details, see publication relating to Water Induction in Large Steam Turbines in Volume I, and ASME standard TWDPS Part 1 Fossil Fueled Plants or Part 2 Nuclear Fueled Plants. Test feedwater heater extreme high level controls, Correct the problem immediately. If the turbine switches, alarms and interlocks. This should be has to be reduced in load substantially, isolate ! done in a manner that approximates as closely as the appropriate extraction line and open extraction possible the actual flooding of a heater without drains (or bypass the feedwater side on condenser endangering the turbine or other s:stion equip- neck heaters) until problem is corrected. . ment and without tripping the t.c.it, (The design l of the feedwater heaters and extraction systems For details, see publication relating to Water should embody features permitting such testing.) Induction in Large Steam Turbines in Volume I. Check all annunciators for alarm indications. Avoid by passing of interlocking devices but when this is necessary for testing critical water prevention equipment, make certain the equip. l ment 1. restored to the original condition of
; operation.
For details, see publication relating to Water Induction in Large Steam Turbines in Volume I and ASME Standard TWDPS Part 1 Fossil Fueled Plants or Part 2 Nuclear Fueled Plants. 15 m
-GEK 46527B, PERIODIC OPERATIONAL TEST
SUMMARY
AUXILIARY EQUIPMENT TESTING - n
SUMMARY
OF RECOMMENDED TESTS TO BE PERFORMED ; EVERY THREE MONTHS - I
SUMMARY
OF ACTION TO BE TAKEN
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST Test all drain lines, traps and orifices by using con. Investigate and correct the problem,if the unit j' tact pyrometers or thermometers to determine if continues operation without correcting the prob. they are plugged, lem, the operator should be fully aware of the dangers that can exist and should take appropriate i For details, see publication relating to Water steps to compensate for the problem. The unit - Induction in Large Steam Trebines in Volume I should not be started with plugged drain lines, and ASME standard TWDPS Pad 1 fossil fueled plants or Part 2 nuclear fueled pit.ats. For details, see publication relating to Water . Induction in Large Steam Turbines in Volume I, I l'
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PERIODIC OPERATIONAL TEST
SUMMARY
, GEK 46527B AUXlLIARY EOUlPMENT TESTING SUMM ARY OF RECOMMENDED TESTS TO BE PERFORMED EVERY SIX TO TWELVE MONTHS
SUMMARY
OF ACTION TO BE TAKEN i
SUMMARY
OF TEST ON AN UNSUCCESSFUL TEST l' ( Test the mechanical and electrical operation of all The operator should be fully aware of the dangers dram valves (feedwater heater drains and steam each problem could cause and should take steps pipe drains) Where applicable operate the valves - to ensure water induction does not occur. Do not from the control room and determine that they start up with inoperable drain valves, open and close by observing control room indi-cating lights. This inspection should include veri-fication that control room ir.dication of valve position is working as intended by physically checking the actual valve movement. For details, see publication relating to Water Induction in Large Steam Turbines in Volume I and ASME TWDPS Part 1 Fossil Fueled Plants,. or Part 2 Nuclear Fueled Plants. l All valves essential to water induction prevention Correct the problem Lt. fore startup, l (such as attemperator spray valves, extraction shutoff and check valves, etc.) should be tested or i inspected for tight shutoff, or an internal visual inspection made, This test should also include all interlocks and controls, All level actuated drain valves should have their level actuated rnschanisms tested to be sure they - are functioning properly.. For details, see publication relating to Water Induction in Large Steam Turbines in Volume I
' ed ASME Standard TWDPS Part 1, Fossil Fueled l' Plants or Part 2 Nuclear Fueled Plants, i
e i i 17 a
New flampshire Yankee - May 25,1992 ATTACHMENT 5 Generic Electric TIL 969., ' Periodic Turbine Steam Valve Tests Nuclear Units," May 22,1984 (Reference 1.2,4) .
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f N. 9 l l
"e GENER AL h ELECTRIC a#
c LARGE STEAM TURBINE GENERATOR DIVISION GENERAL ELECTRIC COMPANY SCHENECTADY, NEW YORK Technical Information tetter No. 969 MAY 22, 1984 Periodic Turbine Steam Valve Test - Nuclear Units GE recommendations for periodic nuclear turbine steam val.e tests as contained in the Turbine Instruction Book call for daily test of the main stop, inter-mediate stop, and intercept valves and weekly test of the control valves. These recommendations are similar to the test frequencies that have been in practice since the late 40's and early 50's on fossil-fueled turbines. The operating experience accumulated on in-service nuclear units during the past 24 years has shown considerably lower valve failure raten than those values upon which the recommendations were based. These reduced failure rates are due to many design improvements to the nuclear turbine valves and controls that have been incorporated through Technical Information Letters (TIL's) and Engineering Change Notices (ECU's). In the " Memo Report - Hypothetical Turbine Missiles - Probability of Occur-rence," dated March 14, 1973, the probability of runaway failure and wheel burst of a GE nuclear turbine was given, based on the nuclear experience up to that time. Included in the probability calculations . were the recommended valve test intervals; i.e., daily for main stop and intermediate stop & inter-cept valves, weekly for control valves. The Nuclear Wheel Information Letter No, 2, dated November 8, 1982, gave comparative values for the increased over-speed probabilities due to increasing test intervals. Based on past in-service experience with nuclear turbine steam- valves, turbine steam inlet valve reliability and testing intervals are no longer the major contributing factors in determining hypothetical turbine missiles. The over-all probability of a hypothetical missile is therefore increased only a negligible amount by increasing the test interval of the valves. Increasing test intervals will correspondingly decrease the probability of a system upset during such testing and should therefore increase the nuclear plant avail-ability. of course ac.y pechlems detected during any testing should be brought. to the attention of your local A&ES service engineer. The service engineer may call on the LST-G Dept, if further assistance is necessary. COPYRIGHT GENERAL ELECTRIC COMPANY, 1984 The tafortoauan furnlohed to uus Techsucal Infortnauon btter le of fervd to you by Generaj Electrie ln conunuation of its ongoing sales and service relaHonahsp with yout k[ organtaatson However,elace the operation ef your plant involvee many f actore not withta our knowledge, and eines eperauon of the plant le willun your sontrul and ultamate i~ responetbility for its coattaulng successful operauon test, with you, General Electric spectitsally disclaime any responenbiltty for 144attity based on claims for damagee of
** E ,, ony type i e diron toneet]venual or spechal that may be alleged to have been IP e ed to a result of applying this informahon regardlese of whether at le slaimert that General C c1 Electric le otrtetty liable, in breach of contract, bresen 6f warranty, negl.gt % se to in other twopects responsable for any ausged anjury or damage sustaaned by your organtastion as a roeult of applying Utle information.
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f. 969 . l
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Ef fective with- this Technical ^ Information Lettee - the recomended valve .. test intervals for nuclear turbines are: Main Stop Valves -- Weekly. ' Intermediate:Stop-Valves -Weekly i Intercept Valves _ Weekly-Control Valves Monthly. Recommended tost intervals for other control. components remain unchanged. Utilities ~ should revise ' their Instructio. Books 1 to the --new test--intervals
- - based Jon i this mTIL.~ ' Revisede Instruction Book Articles will- not be sent from General Electric Co.
Because of the higher temperature ' and resulting increased oxidationibuild-up ; on the stems and' bushings. of. fossil-fueled . turbines, the. valve ' test ' interval-- , recomendations remain. unchanged;- 1.'e. , daily test =of the main;stop. combined intercept and reheat stop valves andLweekly test.of the control, valves. If your Technical- Specification ~ or otherI documentation upon which your NRC - - operating license is based contains any obligation > or: commitment to --test- on a specific schedule,.it is suggested that you take appropriate : steps to' modify' that document 'if. you. wish -to change- your test intervals to these- new-recomendations. i 1
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New 1-lampshire = Yankee May 25,1992 - ATTACllMENT 6 Generic Electric TIL 1008 3, "In Service inspection of 1500. and 1800 RPM Nucleur- Turbine Rotors" (Reference 1.2.5)
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, Turbine Marketing and Projects Operation
-=C~7 h General Electric Company 1 River Road g 6 '" ~"""j u Schenectady, NY 1i345 Custorner Servue Departrnent 5
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=- Til 1008-3 Technical Inforrnation Letter 1 IN-SERVICE INSPECTION OF 1500 AND 1800 RPM NUCLEAR TURBINE ROTORS APPLICABLE TO: SELECTED TURBINE-GENERATORS PURPOSE DE TIL The purpose of this Technical Information Letter is to update TIL 857-3 which is now obsolete and to give the latest recommendations for l inspecting all 1500 and 1800 RPM -uclear turbine rotors. The procedure ,
for ultrasonically inspecting shrunk-on turbine wheels and the inspection results.obtained are reviewed. The mechanisms for initiating and/or growing cracks in nuclear shrunk-on wheels are also described, with particular reference to stress corrosion cracking and steam purity. INTRODUCTION Nearly all of the turbine-generators produced to date by General Electric for use with nuclear reactor cycles are tandem-compound units with a rotational speed of 1500 or 1800 RPM. These units are gp?
- constructed with .ntegral rotors (rotor machined from a singie forging) and/or built-up rotors (shaft with shrunk-on wheels and couplings). In most nuclear turbines the HP rotor is of integral construction. The original low pressure rotors are generally of built-up design.
Replacement rotors for nuclear LP turbines can either be of built-up design or can be constructed with integral wheels. General Electric has available an ultrasonic test for inspecting the critical regions of shrunk-on nuclear turbine wheels without removing them from the turbine shaft. This test has been available since 1978 and has undergone several refinements. This testing has been applied to most GE built nuclear LP rotors with the old axial key construction. ! General Electric has available the capability of ultrasonically inspecting the vicinity of the axial and radial keyways, the tab region, and the bore of nuclear wheels with the wheels in place. Similarly, sonic test techniques for inspecting integral rotors are available. The recommended inspections to be conducted on nuclear turbine rotors, the available inspection techniques, and the recommended intervals for such inspections are described below. COPYRIGHT GENMiAL ELECTRIC COMPANY 1987 issue Date: June 15, 1987 GENER AL @ ELECTRIC rwwa a - anaym--ia u aao yeewos-a1.em.a- - - e,L gog.63 w ,reia.o.au,. m argaat==an=== Erweger, sunse the eportaa e ed year p4aas Lacedoes ammay tasesre een wisin.a ser kaseboegs, and mass oportaan er me 94ama no e*tata yearesaarol had uitLan.aes
' ",y $st its emanaming aussemeral m ~ remus Wut ye% Oenertl Tametrie spee16se.Hy de=ala t-a tay . **y tar LLaan.11ry be.and se elaulte har dassatse ed say ,ype, La, stress, esamegosamaa er opostm2 taas unay he n.l.Leque an hace some Laeurred as a resmis et applytag als Lakerumamma rogsst.ses et wfoseber 11 to a 'a
- mas pen.orst uhm ares is sortssty Ltanae, ta be esa et e=== mas treman ed worrsasy, maqrugees er is an esmer respeese ,
- am may cagee La ary er sammage -- '--' ty year ergesamentam me a reenit et applyt,eq take L b --
TIL 1008-3 Page 2 INTEGRAL ROTOR INSPECTION RECOMMENDATION General Electric recommends that nuclear integral rotors, both high pressure and low pressure, be given a thorough external inspection at each outace when the rotor is exposed. This inspection should include a magnetic particle test of all external surfaces, including rotor body, buckets, covers, packings, journals, and couplings. Normal visual inspections should also be conducted at this time. Last stage bucket erosion shields should be given a red dye inspection. Buckets which are flame hardened for erosion protection need only be magnetic particle testeo. A more complete inspection of the rotor after an initial operating time of 10 years is recommended. This should include magnetic particle and ultrasonic inspections from the rotor periphery and from the bore. A sonic test of the wheel dovetails (tangential entry) on each stage and of the last stage bucket dovetail downstream finger in the area of the upper pin hole should also be performed at this time. BUILT-UP ROTOR INSPECTIUN RECOMMENDATION During any nutage when a turbine section is open, the built-up rotor chould also be given a thorough axternal inspection. This inspection _ should include a complete magnetic particle test of all external b f.) surfaces, including shaft, wheels, buckets, covers, packings, journals, couplings, and gears. Last stage buckets with welded erosion shields should be given a red dye inspec tion. Buckets which are flame hardened for erosion protection need only be magnetic particle tested. All finger dovetail pins markea with a "Y"-stamp should be sonically inspected. A more extensive in-service inspection after an initial operating time of 6 years is recommended, including the ultrasonic inspection of the tanger.tial entry wheel dovetails, an ultrasonic inspection of the last stage bucket dovetail downstream finger in the area of the upper pin hole, and an ultrasonic inspection of the shrunk-on wheuls' bore and keyway. The inaccesible wheel bore and keying surfaces, including the material in the vicinity of the bore, should be inspected using the ultrasonic test described in the following section. f WHEEL BORE SONIC TEST PROCEDURES The ultrasonic test of the wheel bore and keying arrangement regions must be conducted with the rotor being turned at a constant speed not to exceed 2.0 RPM. Ultrasonic transducers positioned on the hub and the web of the wheel by specially designed manipulators are used to transmit ultrasound toward the bore. If a crack is present, a portion of the ultrasonic energy is reflected, either back to the dual transmitting / receiving crystal (" pulse-echo"), or to a single receiver
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. .. GENER AL f -ELECTRIC m Turbine Marketing and W Projects Operation Customer Servue Department Technicallefonssoon Laew No.1008-3 Page 3
(" pitch-catch") located at the appropriate location on the wheel . An analysis of the reflected signal is made to determine whether a crack is present. The material within 2 or 3 inches of the bore, including the keyway, is inspected by varying the location of the transmitting and receiving crystals. Rotor turning can be accomplished in some cases.with the turning gear. In other cases, it may be necessary to make special provisions or modifications to achieve the required speed. The exact speed requirement and related recommendations for the specific machine to be
- tes ted wi-l l - tur -furni shed - pr ior. to the' outage. The turbine owner.may wish to purchase a set of powered rolls. These could afford the advantage of permitting the rotor to be tested separate-from the turbine, so that other maintenance can be accomplished concurrently.'
Your GE Service Engineer can provide the functional description of such rolls.
.b" The expected elapsed time for the WFeet bore ultrasonic.. test is about l seven days for the fir st rotor and six days fce each additional rotor inspection performed sequentiallu at the same site. This time does not l
! include work required to prepare the wheels for the testing, cleaning the wheels,-removing grease, rust, innsG Ecale, etc., to permit close coupling between the ultrasonic trariaducers and the surface. The ALES Service Engineer can discuss the requ' ired cleaning, and how it may be l best accomplished. The above described testir, method is intended to detect cracks near the bore of the shrunk-on wheels. The internal portion of the wheel l away from the bore, which is not inspected during this test, is of much less concern. This is bectuse a flaw of unacceptable size and location l l in the wheel, as manufactured, is unlikely. The manner in which the l wheels ar e forged essentially precludescthe possibility of producing an L internal crack-like defect in the plane normal to the. maximum stress (the axial-radial plane). Furthermore, all modern nuclear wheel l -forgings are scblected to a stringent 100% volumetric' ultrasonic inspection at the time of manufacture. All nuclear. rotors are factory spin tested clur ing manuf ac ture al 20Y. overspeed , which further minimi:es'the probability of having an undetected crack or crack-like flaw with a critical size which rould lead to spontaneous propagation at r.o r ma ' rotation speeds. Thus, the likelihoo'd of a modern wheel entering service with an unacceptable defect is extremely lcw. It therefore becomes more important to concentrate on the potential for the initiation and growth of cracks in service.
TIL 1008-3 qs.
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.CAUSE.OF SHRUNK-ON WHEEL CRACKING There 57e two possible mechanisms for-initiating and/or; growing cracks -
in nuclear wheelsiin service
- 1. Stress Cycling 2.15 tress _ Corrosion-Cracking.
The likelihood of initiating land/or growing a crack'due to the stress
-cycling associated with1 starts,fstops,-'or load changes'is small.. The variation-in stress amplitude resulting from operating:_transientsfis too low. to: produce significant crack growth,-in"the unlikelyJevent that a defect exists'-in the wheel when it is placed in service.- Thus, the-major-source of--concern with' respect to thefin-service initiation and growth of, cracks is that; associated with stress corrosion.
The main source forestress corrosion cracking exists-at the-bore oflthe shrunk-on wheel near the' axial keyway. Stress corrosion crack!"g at the wheel axial keywayris believed to-be' caused-by two combined-factors:
- 1. The condensation of steam and-subsequent-oxygen enrichment of-the condensate inithe axial keyway-and relief groove-cavity. g f.hh
- 2. Concentrated stress levels near the axial keyway. ~
Other potential locations _for stress corrosion crackingLinclude=the
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whee 1 dovetails. For this reason, periodic sonic inspections'of all s wheel dovetails (tangential entry) .is1 recommended.whenLwheels are inspected. INSPECTION RESULTS -. FROM 1 P_ - WHEEL. BORESONIC . TESTS' Wheel boresonic inspections conducted on nuclear low pressure rotors - witheshrunk-on wheels have revealed.the-presence 1of crack-like-
. indications.in:the> axial > keyway l location of;the wheel' bore. .
We have-not observed 1 stress, corrosion-(or.other) crackingsin<the remaining I
, portion of the' wheel' bore.
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- c. In all cases where ultrasonic tests wereLconducted, includingJthose-swhere sonic indications were'found--above theLwheelz axial keyways',7an eva lua t ion ' of: the particular wheels-was made-and reinspection- _
recommendations.provided which'were specifichto'the rotor--involved.- In ! some cases,- the ruse of LP: section prewarming L prior ' to; cold . star ts.'is possible and-has-been used to extend reinspection intervals.
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GENER AL O rtscraic a Turbine Marketing'and
- l Projects Operation Customer Service Department Testaical latenndse unit No,1008-3 Page 5
_ INSPECTION INTERVAL CONSIDERSTIONS FOR LP ROTORS WITH SHRUNK-ON WHEELS A great amount of investigative work on stress corrosion cracking has been conducted, and although our understanding of this phenomenon is much improved, it is still impossible to predict the precise time required for crack initiation and the rate of crack growth in a corrosive environme t. Stress corrosion crack initiation and growth is a complex process, influenced by many factors, such as material properties, stress levels, environment, etc., and there is still considerable uncertainty about their. interaction. Data generated to date show a great-deal of scatter on both crack initiation times and growth rates, so that it is impossible to specify absolutely " safe" inspection intervals to precl,ude the possibility of initiating 6nd growing a crack to critical size between inspections. Recognizing that periodic inspections at reasonable intervals cannot ffg provide absolute protec tion against a wheel burst, we nevertheless
't > believe-that such inspections will greatly' reduce the probability of such occurrences. After having_ considered this and other factors, we conclude that inspection should be conducted after a maximum operating time of 6 years, as described above, unless previous inspections have resulted in shorter reinspection intervals.
The inspections can usually be coordinated with reactor refueling schedules'and/or-sectionalized maintenance plans. TURBINE STEAM PURITY In addition to the condensation mechanism associated with the axial keyway construction, stress corrosion cracking can also be caused by steam contaminants. r We believe the control of steam purity is therefore very important in further orotecting against stress corrosion cracking for all rotor constructions. Numerous studies have_been made over the years to determine realistically achievable steam chemistry-levels, and attempts have been made to relate impurity levels to the stress. corrosion suscept!.bility of turbine materials. The attached instruction, j GEK-72281, describes our recommended practices which we currently feel are workable and prudent.
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l New Hampshire Yankce M ay' 25, 1992 ATTACHMENT 7 Generic Electric TIL 922, " Moisture Separator / Reheater Drain Control System Maintenance" (Reference 1.2,6)
Ah 4W MOISTURE SEPARATOR / REHEATER DRAIN CONTROL SYSTEM MAINTENANCE (TIL 922, 3/16/81) , PURPOSE OF TIL The puroose of this TIL is to transmit GEK 72336 and GEK 72337, which contain moisture separator / reheater drain control system maintenance recommendations l for BVR clants and PWR plants, resoectively, t These-GEK's have been orecared to assist our customers and service recresenta-tives in the clanning and execution of drain control system maintenance in order to improve the system's reliability and availability. DISCUSSION Ooerating the-turbine cycle in a nuclear power plant at maximum efficiency is of utmost imoortance. An increase. in the ef ficiency of the turbine cycle -in a nuclear oower plant is evaluated at millions of dollars oer one percent. However, it is possible for some nuclear power plants _ to -coerate several g.g percent less efficient because of imoroper calibration and/or limited _ pre-Sp ventative maintenance of the moisture separator / reheater (MS/R) drain control systems. The losses due to limited system maintenance of turbine associated equipment are more visible in nuclear plants than in fossi.1 plants, in a. fossil fuel power plant, the thermal output of the steam generating equicment i s _ not - limited -by a license. Most of these plants have excess capacity in their
- i. boilers and turbines and, therefore, the electrical . output usually exceeds I design which more than comoensates _ for losses due to imorocer oce: : tion of turbine associated equipment. They,simoly burn more fuel and product greater than-design thermal output.- .Thus the cycle losses are not obvious. However, c,n -a . nuc l ea r unit the cycle losses.cannot be made up by additional thermal outout since the maximum licensed oower cannot be exceeded. Thus cycle losses will result in an electrical output lower than shown ' on_ the design - heat "
balance. _ Nuclear cower plant ooerators not ice - the di screcancy . between f' electrie:al .outout ' and tnermal cutout but have not always'been able to directly determine the-causes for the lost power. l Over the past several years the~ General- -Electric Company has worked with l ' l several' utilities to help them imorove the system maintenance and,-therefore, the'oceration of their turbine associated equipment. This TIL,:GEK 72336, and GEK-72337 are issued: to cermit all owners of our. nuclear turbines'to benefit from these experiences and how they caa be acclied.to the MS/R drain control system.
p g, ;- P.atsturc Sepa rato r / ?.ehea:cr - (Cont 'd . ) Drain Control Svste : Maintenance . 4 (TIL 922) Turbines shipoed to which GEK 72336 and/or GEK 72337 acoly will be identified to you by turbine number with the distribution of this Til. For turbines shioping in 1981 and later, the GEK will be included in the Turbine Instruction Book. The GEK's will also be added to the aoolicable instruction Books for units shipped in 1980 and e -lier as their Instruction Books are uodated.
SUMMARY
OF RECOMMENDATIONS
- 1) Study GEK 72336 and/or GEK 72337. carefully.
- 2) Utilize the exoerience and training of your General Electric Service Representative to assist you in olanning your maintenance outages, ordering the cerrect carts at the acorooriate times, and providing technical direction during the outage. ..
- 3) ' Add GEK 72336 and/or GEK 72337 to' your permanent maintenance 'ile so that it will be readily available as a reference for future maintenance activity.
- 4) Icolementation of this Til and GEK 72336 and/or GEK 723;7 is judged to be imcortant to the turbine-generator unit reliability and availabil- -
,[-['j ity. Your incorporation of these recommendations in your unit's main-6' tenance is soecifically requested. ,,
THE INFORMATION FURNISHED IN THIS TECHNICAL INFORMATION LETTEii IS' 0FFERED BY CENERAL ELECTRIC AS A SERVICE TO YOUR ORG3NIZAT!ON. IN VIEW OF THIS AND SINCE OPERATION 07 YOUR PLANT INVOLVES MANY FACTORS NOT WITHIN. OUR ;R.UVLEDGE,. AND SINCE OPERATION IS VITHIN YOUR CONTROL'AND RESPONSIBILITY, IT SHOULO BE UNDERSTOOD THAT GENERAL ELECTRIC ACCEPTS NO LIABILITY IN NEGLIGENCE OR OTHERVISE AS A RESULT OF - YOUR APPLICATION OF THIS INFORMATION.
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New llampshire Yankee May 25,1992 f e ATTAcilMENT 8 General Electric TIL 891, ' Valve Studs Tightening, inaptellon und Itcplacement llecomnb.dations' (iteference 1.2.7)
VALVE STUDS - TIGl!TENING, INSPECTION G REPLACEME!TT RECOMMENLATIONS (TIL- 8 91) INTRODUCTION ' d The purpose of this Technical Information Letter is to recommend
. tightening levels for turbine steam valve studs used to secure
({J the upper heads on main stop valve and reheat valve casings and the stands on control valvo casings, g ([ Recommendations are also provided for inspection and replacement of valve studs to minimize the probability of in-service failure. BACKGROUND Last year an operating fossil unit experienced sudden failure of 10 out of 14 main stop valve upper head studs. The upper head lif ted partially, permitting steam to escape and resulting in a forced outage. It appears likely that the he~ad would have come of f altogether if the contering 'm.bbet had not become wedged in the cylindrical casing fit. A elmilar incident occurred 13 years earlier when 9 out of 16 upper head studs failed suddenly on an-other fossil main stop valve. Studies were made of the variables affecting valve stud life fol-lowing the 1st incident. Some of the variables are length of
~ time _ in_ service, number of retight enings, tightening stress icvel.
thermal cycling and differential expansion. It was determined that the major f acts s are tightening stress level and number of tightenings to that stress level. As a result, a reduced tight-ening scress, called the "1970 level", was implemented for the valve stud materials used on most fossil units. Also, recogniz-ing that valve studs may have limited service life regardless of the stress level, ,it was recommended that they be inspected for cracks at least everv 6 years _. _ This Technical Information Letter will repeat and re-emphasize the tightening and inspection recommendations made earlier for fossil valve studs. In addition, the recommendations are being expanded in two respects. First, the useful life is predicted and replace-l[ ment is recommended for certain studs regardless of whether cracks are found at inspection. Second, the recommended frequency of in-
- spection is related to number of tightenings as well as to number l( of years 1.1 service.
Factors afjiecting the life of nuclear valve studs (operating at temperaturps below 800"F)_di_ffer from those__affecting fossil valve studs. Nu-lear vrive studs are .iot operating in the material creep range. Th eref ore , stud lifs is not related to tightening stress or number of tightenings in che same manner as for fossil valve studs. Stud life can be affected by excessive overtightening, corrosion and other factors, however, making it advisable to establish a regu-lar inspection program. Recommendations for fossil and nuclear valvestuds,bein!crmationLetter.somewhat this Technical In different, are covered separately in
VALVE STUDS - (Cont'd.) ... - 9 STUD MATERIALS ( Table I lists the materials and idnntification stampin, c have been used for valve upper head and stand studs. P5F4C and B5F5B will be found on nuclear valves (below 800*F). B5P5B terials AnWiDM23Drp_by_far,r on fossil valves (800 and higher)the. most commody_ If any studs of Sad S BSD-stud me-A12SB or C remain in service, the recommendations for B50A125E ap- 3 1 ply. W Austenitic stud. materials _have been used on_a_ limited nu.ber of fos-sil valves at 1050"F and higher. Austenitic_. studs are non-magnetic. It is expected that most c'mers can identify their stud materials from previous inspection and tightening records. If not, the mater-ial should be determined from the stamping at the next inspection. In those-cases where the material is not known, and needs to be known es an input for scheduling maintenance (for example, on pre-1966 units), the necessary information can be obtained through your G.E. Service Engineer. STUD LUBRICANTS I FEL-PRO N1000 and CRAME COMPOUND JC 60 at2_ Approved thread lubricants. See TIL 824 for more detail. TIGHTENING RECOMMENDATIONS A. Fossil Val'vS Studs (8000F and higher) The recommended elongation ranges for B5F5B and B50Al2SE studs are given on attached drawing 223A3906 This is the "19'O Level" which is approximately 70% of the pre-1970 ctress level. Draw-ing 223A3906 takes precedence over instructions on valve assem-bly drawings issued before the "1970 Level" was impicmented. Tightening of austenitic studs (see Table I) should be continued per the original valve assembly drawing instructions. g{ B. Nuclear Valve Studs (below 800 F) Tne elongation range for B5F4C and B5F5B, operating below 800 F, 4k is also given on drawing 223A3906. This is essentially the pre-1970 stress level before it was reduced for those valve studs operating in the material creep range. REPLACEMPN" RECOMMENDATIONS A. Fossil Valve Studs (800 F and higher) ( ' Most valve-studs operating at 800 F ar.d higher are in the creep range of the stud material. After the studs are tightened, and the valve brought up to operating temperature, the material will creep and the stud stress will be gradually reduced. This must
. VAINE STUDS _ - (Cont'd.) % REPLACEMENT RECOMMENDATIONS.- (Cont ' d . )
(:::) be accounted for in determining the initial tightening stress < level in order to prevent leakage from developing in service. Each time a stud is tightened to the initial stress icvel some of the stress creeps out The in service plasticand theaccumulates strain stud suffers with some l plastic strain damage. each tightening . cycle until finally, af ter some number of cyc es, k will the rupture ductility of the material is used up and a crac q Q devt 4c4 l Ai ing stress is also imposed on valve study due to the dif- l { for nce in expansion of the Low valvo casing cycle anddue fatigue upper head during to bending is heating and cooling cycles. ) a contributing cause of valve stud failure but is not the prim- h ary damage mechanium when recommended rates Creep rupture damage, as described in the greced- of temperature c an are observed. inq paragraph, is considcre.d' to be the primary dam 4 mary measure of the amount of stud life expended _. Using analytical methods calibrated by laboratory and field be data ; we now believe that the useful life of with predicted based or number of tighteningsThe fossil suave accur-sufficient studs can 1 end of useful acy to be helpful in maintenance planning. life is considered to hs.ve been reached af ter that number of tight
,, enings which corresponds to a 50% probability of stud cracking.
p) point it is recommended that all studs that have exper-At this that ionced number of tightening cyclesductility be replaced regardless of The rupture will have , whether cracks are detected.been nearly used up and the probability o , next inspection will be high. The following recommendations assume the valve studs were tight- ' ened to theand the tightening, recommended that recommended stress levels rates of in effact temperature h c ange at the tim Higher stress levels or tempera-were observed at the valves.ture rates can be expected to cause earlier BSF5B Stud Materials ( All valve upper head and stand studs Assuming in service b i those years were stressed to the pre-1970 level. I ( one tightening as defined above. every 2 years on the average, the It is recommended that all B5F5B fossil ife l
- valve studs in service before 1966 be replaced by the end of_
1981. g should be re- ,! Newer B5F5B studs (in service in 1966 and lator) placed after 11 tightenings or if cracks are found during per-f iodic inspections. This is discussed in more detail under v " INSPECTION RECOMMENDATIONS" . b i I l b - - - - _ . _ _ _ _ _ }
\ VALVE STUDS - (Cont'd.) - B5FSB Stud Material - (Cont'd.) ( Replacements for B5F5B studs will also be made of B5F5B. It is true on that fossil all new B50Al25E has a longer life expectancy and is used valves. ials have different coefficients of expansion and differentThe problem is tsghtening on the samestress valve. levels, making it unacceptable to mix them gll ials on similar valves on the same unit,It is also undesirable to mix the mater-tion, because of the bookkeeping problems created.or in the same sta-expectancy of replacement BSF5B studs is 11 tightenings The life g timated to correspond to about 22 years) . (es-an acceptable ments. life expectancy on most unitsThis is feltreplace-requiring to be B50Al25E Stud Material: All valve upper head and stand studs in service before 19 those years were stressed to the pre-1970 leve one tightening every two years on the average,l.theyAssuming would have been tightened life as defined above. at least 7 times and are near the end of useful fossil valve studs in se_Itrvice end of 1983 is recommended before 1966 that all B50A125E be replaced by the renmin in service).(This also applies to studs of B50A125B&C if any Newer B50Al25E studs ful lifetightening duced expectancy stressof about level. 25 tightenings because of the re(in ser Assuming one tightening overy lasting as long as the turbine.2 years on the average, these studs have However, tighten.ing records enings if this number is reached.should be kept and tne studs should b if cracks are found, should be Inspection and replacement, RECOMMENDATIONS". is discussed under " INSPECTION Austenitic Stud Material Austenitic studs have not shown a tendency to crack lb du ationsifrelated ment, cracks to arenumber found, of tightenings. Inspection and replace-TION RECOMMENDATIONS". should be as discubsed under "INSPEC- l( B. Nuclear Valve Studs (below 800 F) . Nuclear valve studs operating below B00 F are not in the material ductility in service. creep range and do not suffer plastic strain and- loss of rupture ' mendations related to number of tightenings.Therefore, placement, Inspection and there re- are no replacemen 4 - if cracks are found,
" INSPECTION RECOMMENDATIONS".should be as discussed under j
VALVE STUDS - (Cont ' d. ) - INSPECTION RECOMMENDATIONS (i.Q' The previous recommendation has been to inspect studs for cracks at least every 6 years, regardless of material or application. The new recommendation relates inspection frequency to number of tight-enings, as well as to years in service, for fossil valve studs of B5F5B and B50A125E material. Any studs that are found c~acked must be replaced immediately. It f~) k> is desirable to raise replace all the other studs of the same age in that valve if new studs are available. If less than 30% of the studs in a valve are cracked, however, it is generally satisfactory to re-g( place only the cracked studs, provided that the other studs of the same age are replaced within one year. If more than 30% of the studs are cracked, all studs of that age in that valve and mating valves should be replaced immediately. At a ndnimum, the number of spare studs recommended in the parts cat-alog should be kept on hand. This may vary from 10% to 50%, depend ~ ing on the type of valve. If the studs are B5FSB or B50Al25E, and in fossil service before 1966, the spares on hand should be increas-ed to 100% in preparation for complete replacement. A. Fossil Valve Studs (800 F and higher) B5F5B Stud Material: 1
;];
2 It is recommended that B5F5B studs for valve upper heads and stands be tested for cracks at least after every 3 tightenings or every 6 years, whichever comes first. The studs should be replaced at the next valve inspection following 11 tighten-in s fs own(for studs in service af ter January 1, 1966). This is in tabular form below: Stud Insp. No. 1 '2 3 4 Tightening No. 3 6 9 * (or) Years Service 6 12 18 24
- Replace after 11 tightenings.
b As was discussed under "REPLACEHENT RECOMRENDATIONS" the stud replacement recommendation in the above table is based only on a number of tightenings, not on years in service. The years in M service are shown in the above table only to help establish the minimum inspection frequency. ( ') _ - _ _ - - a
VALVE STUDS - (Cont'd.) % INSPECTION RECOMMENDATIONS - (Cont'd.) { B50A125E Stud Material:
't is recommended that B50A125E studs for valve upper neads and stands be tested for cracks at least after every 3 tightenings up to 18 and af ter every 2 tightenings thereaf ter, or every 6 years, whichever comes first. This is shown in tibular form be-low. If the number of tightenings reaches 25, the studs should be replaced at the next valve inspection (studs in rurvice after
.anuary 1, 1966):
gg Stud Insp. No. 1 2 3 4 5 6 7 8 9 - Tightening No. 3 6 9 12 15 18 20 22 24 * (or) Years Service 6 12 18 24 30 36 42 48 54 -
- Replace after 25 tightenings.
Austenitic Stud Material: It is recommended that austenitic studs for valve upper heads and stands be tested for cracks at least every 6 years.
} B. Nuclear Valve Studs (below 800 F)
It is recommended that studs for nuclear valve upper heads and stands be tested for cracks at least every 6 years. Because they are operating below the material creep snge, any cracks found in nuclear valve studs should be reported to the G.E. Service Engineer immediately for assistance in diagnosing the cause. INSPECTION PROCEDURE Magnetic particle testing of magnetic materials and red dye testing of non-magnetic materials are satisfactory methods of checking for cracks, but both methods require removal of the studs from the casing. An ultrasonic. test procedure has been developed which has proven to be a dependable method of locating cracks. The ultrasonic test method is recommended because it does not require removal of the studs. In l[ some instances the grain size in austenitic materials may prevent ultrasonic inspection, but this must be determined by trial. To assist in the inspection of valve studs we have prepared the at-tached detailed test procedure TG-19A entitled " Ultrasonic Testing Of Steam Valve Studs After Periods Of Service", and report form TG-19AU entitled " Ultrasonic Examination of Valve Studs". STUD REMOVAL ' ( When a stud is removed from a casing, care should be taken to avoid damage to the casing threads. A generous application of penetrating oil will often help. Other techniques which have been used with some success include cooling the stud with nitrogen and/or heating __ a
VALVE STUDS - (Con t ' d . ) ~7-STUD REMOVAL - (Cont'd.) b ' the casing locally to about 300 F. It should be expected that some percent of the studs to be removed will not yitid to the above tech-niques, and equipment should be available to drill out these studs.
SUMMARY
O? RECOMMENDATIONS 0 (g Fossil Units (800 F and Higher):
- 1. Tighten B5F5B and B50A125E valve studs per 223A3906. Drawing 223A3906 takes precedence over instructions on valve assembly drawings issued before '.he "1970 Level" was' implemented.
- 2. Tighten austenitic valve studs per the original valve assembly drawing.
- 3. Replace all B5FSB valve studs in service before 1966 by the end of 1981.
- 4. Replace all B50Al25E valve studs in cervice before 1966 by the end of 1983.
- 5. Inspect all B5F5B studs for cracks at least every 3 tightenings or 6 years, whichever comes first. Replace after 11 tighten-ings (for studs in service after January 1, 1966).
E 6. Inspect roll B50A125E studs for cracks at least after 3 tighten-ings up to 18 and every 2 tightenings thereafter, or every 6 years, whichever comes first. If the number of tightenings reaches 25, the studs should be repleaed at the next valve in-spection (for studs in service after uanuary 1,1966).
- 7. Inspect all austenitic studs for cracks at least every 6 years.
Nuclear Units:
- 1. Tighten studs per the valve assembly dra"ing or drawing 223A3906 (they should be in agreement).
- 2. Inspect studs for cracks at least ever*/ 6 years.
( : THE INFORMATION FURNISHED IN THIS TECHNICAL IhTORMATION LETTER IS OFFERED BY GENERAL ELECTRIC AS A SERVICE TO YOUR ORGANIZATION. IN VIIM OF THIS AND SINCE OPERATION OF YOUR PLANT INVOLVES MAhT TACTORS NOT WITHIN OUR KNORLEDGE, AND SINCE OPERATION IS WITHIN YOUR C0hTROL AND RESPONSIBILITY IT SHOULD BE ' UNDERSTOOD THAT GENERAL ELECTRIC ACCEPTS NO LIABILITY IN NEGLIGENCE OR OTHER-( WISE AS A RESULT OF YOUR APPLICATION OF THIS IhTORMATION.
(TIL _891 Attcch.)
, TABLE I -s (ii #
VALVE STUD MATERIALS e Identification Stamping e G.E. Material Spec. NEW OLD
- B5F4C Ferritic N F4 B5FSB Ferritic L F5 B50A125B Ferritic F --
B50A125C Ferritic W -- B50A125E Ferditic XD F25 B50A146A Austenitic S A6A B50A199B Austenitic XA -- B50A199D Austenitic XB --
.~. .)
- In use from about 1960 to 1967.
( i i
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, ELONGATIONU FOR ). ))ygTg_ D AND S SING VAg1D STUDS-1970 LEVE
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ULTRASONIC TESTINO OF STEAM VALVE STUDS AFTER PERIODS OF SERVICE t 1. Introduction (TIL 891 ATTACH.) ( .,? These instructions outline the procedure to be followed when performing ultra-soniclongitudinalwave tests on valve studs, in place, after periods of 6 vice.
- 2. General Tests shall be performed by well trained and properly qualified personnel.
Tests shall be performed while the studs are in place and pnerally after the cover has been removed. However, where the end of the stud protrudes above { the nut, the studs may be tested without disassembly. A Sperry Reflectoscope, Type UR or equivalent, shall be used. The ultrasonic f astrumentvertica1 presentation shallbe linear within + 5% of the full scale de-fle ction. The exposed end of each stud shall be free of all scale and oxide. Caution should be exercised to maintain a flat surface for search unit contact. A suitable couplant such as SAE 20 oil shall be used. The distance calibration markers shall be adjusted on a calibration bar of ma-terial similar to that of the stude, for accurate distance measurements.
- 3. Method of Test Tests shallbe performedusing a 5.0 Mc 1/2 or 1 inch diameter type ZR aearch unit. Experience has shown that these searchunits give the best results. How-
- ever, due to variations in type of material and geometry it may be necessary to use other frequencies and diameter searc units.
The sweep length shall be adjusted until the 1st back reflect' in of the stud is visible on the right hand side of the oscilloscope screen as sht wn in Figure 1. The distance from the top of the stud to the valve joint surface chall be meas-ured and recorded. The oscilloscope screen shall be marked at the measured distance determined in the previous paragraph. The results obtained to date indicate that crack in-dications will appear at the 1st or 2nd thread, 0 - 1/4 inch below the valve joint surface as shown in Figures 1 and 2. The sensitivity shall be adjusteduntil the amplitude of the indications from the valve end threads is 5% of 1 1/2 inches sweep to peak. ( The studs shall be tested completely from the exposed end by scanning 360 degrees in a see-saw manner as shown in Figure 3. Each stud shall be assigned a number indexed with respect to the dowel pin as shown in Fij ure 4. 1 _________.._.__J
v Tha scanning procedure shall be rep 3ated on all studs. e All indications shall be marked on the test surface as they occur. The circum- ' '?g ferential distribution of indications shall be indicated with respect to a clock system. The 12 o' clock position on each stud is toward the OD of the valve and ( in radial line with the center of the valve bore. RECORD OF TEST RESULTS: The ultrasonic test report shall contain all pertinent information regarding the test as outlined in this instruction. A sample test report is shown in Figure 5. ACCEPTANCE AND REJECTION Copies of the ultrasonic test report should be made available to General Elec-tric Company personnel at the earliest possible time ic11owing completion of the tests in order that acceptance or rejection can be made of the rtuds that were tested. r m ,,a w mo tna Search M t 11 p.fJJ s
.. _, . p :s::
._ _ = _ _ _ _ _
1 __ _ _ _ _ _ _ _.m _ _ _= _= .____ =~_
- j. (
l j-shou 16., Renection Ren.etson tro. fir *ada inistal rui.. First Back Reflection SCREDI PATn3R Figure 1 I
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... .,t Probable mmti..
Tirc.ro 2 _ _ - - _ - _ _ _ _ - _ _ - _ _ _ _ _ _ l
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( q, m-STID trJ@ma0 SICD4 ricur. 4 in addition to customers' requirements for copies of the test reports, two copies should be forwarded to: STGMD, Product Service - Mgr. Maintenance Fupport Bldg. 269 - Pa. 200, North Ave. Schene'.tady, NY (12345) RETURNING STUDS FOR LABORATORY EXAMINATION k LST-G Produt., Service should be contacted for instructions before returning cracked studs to the factory for metallurgical examination. There is not a s ufficient number of Laboratory Technicians to perform routine testing of cracked studs and arrangements to make such tests, if desired by the pur-chaser, sho uld be made with local testing organizations.
ULTRASONIC EXAMINAT20fl QF VALVE STUDS stomar Niarara Mohawk Corp. Stop Valve Type
- Station A*'*" Stud Length 2618 Diam. 4, Turbine No. 933W __11 nit No. 100 Prequency 5 D "0- Sise I, TYPE Stui Mag . Circum. Distr. Dist. Tested ByA.B. Fish Cog any G'"'""' El'"tfic C*"
lio. 5 (Time) Top E"h *""# F : N Y. ~ Address 1 96 grm - 12,m 19" Date of Test unv. 30. 1966 2 OK _3 OK Dosel Fin 4 100 0:00 - 3:03 19"
\
7 OY. Last Stud Indicate # o a \ '
-it tStui
_8 9 20 OK 12:00 - 3:D3 19"
- T k g N 10 11 OK OK s
f 7o l la OK _ h _\ 13 OK g 14 OK / 16 OK e N Q 's /
\i T a:;, r i 18 . /
19'
'!O (
21 22 61,000 23 Stud bolt hour service 24 Times studs were tightened 5 Number of cold starts 25 26
! Number of studs questioned sonically 3 Number of studs replaced 15 GE-DSE Representative ,D_ mtewinonn 29 Additional Information 30 31 32 __ Indications in the studs were vari.fied __
33 usine a 2.25 me. 4" dian, ZR search unit.
=
34 I 35 { [36 37 38 39 _ LO I,
- w= t
sale CADIATEGI OF VALVE STUDS (TIL 891 ATTACH.) 7)
\ Customer Valve Type _
Station Stud Length Diam. lurbineHo t; Unit No. _ _
- Prequency Size Type S t,ud Mag. Circum. Distr. Dist. Tested By No. 5 Top C g any (Time)
Address 1 2 Date of Test 3 Dovel Pin 4 I Last Stud , ,
,g ,1,g stg 7 Indicate # e 8
9
,o 7 0
10 s ,A l 11 12 0- \ 13 h* 1L 15 15 17 18 19 ,, 20 2.L Stud bolt hour service g Times studs were ti Chtenad 25 Humber of cold starts 26 Number of studs questioned sonically ~~ 27 Number of studs replaced ~~ 28 .GE-I&SE Representative 29 Additional Information
'40 31 -
32 33 34 35 36 37 33 39 Lo i IO *' 0-$ V _ N _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -
New llampshire Yankee May 25,1992 ATTACHMENT 9 General Electric TIL 930, *1mproving the lleliability of Journal Bearings" (Reference 1.2.8) m gRh'NA'E
l t# IMPROVING THE RELIABIf.ITY OF JOURNAL BEARINOS (TIL 930, Jaced 8/12/81) PURPOSE The purpose of this TIL is to trar. smit GEK 72345, entitled " Main Journal Bearings". This GEK contains the latest recommendations for the operation and maintenance of main journal bearings in order to improve the reliability of
. Journal bearings. This TIL also describes main journal bearing design improve-ments which can be made for increased reliability.
DISCUSSION A review of recent main journal bearing related outages indicates that inade-quate and/or inappropriate attention has been given to the operation and main-tenance of main journal bearings. GEK 72345 summarizes in one document the information necessary to operate and maintain main journal bearings. Proper attention-to the informat un in GEK 72345 will lead to: increased reliability. In addition to the information contained in GEK 72345, there are design improvements which, under proper circumstances, can be-made to improve reli-ability. These are summarized as follows: y 1) Bearing Metal Thermocouples The importance of journal bearing metal thermocouples is explained in GEK 72345. Some earlier turbine units were not originally equipped-
- i. with bearing metal thermocouples. Recommendahions for' retrofitting l these units have previously been described in TIL 530, dated 3/30/70 and entitled "Thermocouples for Turbine Operation" and. again in TIL 579, dated- 3/26/71 and entitled " Bearing -Metal- Thermocouples". - We -
agein recommend the installation of bearing metal thermocouples on all your units not yet so equipped. The installation of these thermocouples also requires recording equip-ment. The requirements for a suitable strip chart recorder system are outlined in GEK 72345, Appendix A. Many customers with newer turbine "aits using computer based supervisory instruments have not realized
,, that. continuous recording of these thermocouples is necessary if they are to cerve as a proper diagnostic tool. For operation without a strip chart recorder proper scanning rates, data storage, and printing-requirements are outlined in GEK.72345, Appendix A.
-IT:- it is not feasible to add additional. recording equipment!and the capability exists to record either bearing oil outlettor bearing metal temperature, it'is preferable - to record and monitor bearing. metal rather than bearing oil outlet temperaturer.
y.my- %w , u-%>#<-t ,,-w,.,,,,.,91m,w -
t. (TIL 930) - Cont'd. .. s
)-q Installation of thermocouple wells requires bearing machining which )
most efficiently secomplished during planned verhauls. Preplanning is imperative so we recommend that you utilfe the expertise of your General Electric Service Representative to aid in the material pro-curement and installation of new thermocouples.
- 2) . Conversion of Grooved Bearings to Shortened Elliptical Design In the past the lower halves of bearings have been circumferential1y grooved during startup activities to centrol oil whip. New 3000 and 3600 RPM machines'are equipped with shortened elliptical bearings with increased unit loadings in most low pressure hood and generator posi-tions and with double tilt pad bearings in the high pressure and reheat turbine - sections. The shortened elliptical bearing is a preferred design over the grooved elliptical bearing.
C Conversion to the shortened elliptical design is best accomplished during a planned outage. The drawings and planning necessary to make this conversion can be furnished by your General Electric Service Representative. . A typical conversion would consist of babbitt welding the bore using-the TIG process and machining to the shortened configuration. Oil feed and drain pockets at the horizontal joint will also be made narrower. Sinco a short bearing reouires less oil (due to lower horsepower) the - inlet orifice may need to be made smaller. Orifice changes, when required, will also be provided by your General Electric Service Representative. When a number of bearings are shortened a slight adjustment to the oil system pressure may be necessary to maintain 25 2 2 PSIG at the front standard centerline.
- 3) Conversion to Double Tilt Pad Bearings Double tilt pad.(DTP) type journal bearings possess excellent dynamic and self-aligning properties. They are, however, a more complex design with a slightly lower load capacity and higher power loss than fixed bore ellipti' al types. Taking these properties into considera- .
tion their use must be discretionary. For modern GS Turbine-Generator ! designs the use of DTP bearings -in limited to the high-pressure and intermediate-pressure elements and first low-pressure bearing position of 3000/3600 RPM units. The high pressure and intermediate pressure-applications are necessitated by dynamio requirements. whi.e applica-tion at the first low pressure location is due to both dynamic and alignment considerations. 4 _._.__._m___m ._...a
(TIL 930) - font'd. g Retrofitting of certain fixed bore bearings with tilt-pad types has proven very effective in resolving specific journal bearing problems. TIL 870-3a entitled " Conversion of Axial Grooved T-1 Bearings to Tilting Pad Types" dated 6/20/78 and TIL 724-3 entitled " Double Tilt Pad Bearings to Minimize #2
Dearing Hisalignment on D1,
D2 Designs" dated 2/25/74 are two previous recommendations aimed at resolving such problems. If your unit (s) is affected by these tit's, we again urge you to effect their recommendations. x New 3000/3600 RPM units are being supplied with a double tilt pad type journal bearing at the first low pressure position. At this position, there can be considerable change in bearing loading over the range of 2 operation of the turbine-generator. This results in the necessity for installing the first low pressure bearing in an elevated position relative to the adjacent bearing when the unit is at ambient- temperature. This minimizes rotor bending stresses under normal running condicions, since thermal transients in the foundation will cause the adjacent bearing to rise so that, at full load the two bearings are in-line. There have been a few incidents where outages have been caused, at least in part, by the thermal transients described above. These out-ages can take the form of undesirable oil whip vibration as the first
'- hood bearing is unloaded, or bearing failure (wiping) should the first hood bearing load become excessive. Generally, these outages coeur during startup when other abnormal conditions, e.g., poor vacuum or high exhaust hood temperature may occur. These conditions can lead to poor alignment which can cause excessive tilting of the hood bearing relative to the rotor (resulting in edge wiping).
One way to minimize the effect of these transients is to retrofit a double tilt pad bearing in the first exhaust hood position. This bearing design is extremely resistant to oil whip type instability. The axial self-alignment feature of this design also minimizes the possibility of edge wiping during exhaust hood transients. Several units have been retrofitted and the problems being experienced were aliminated. Large tandem compound four and six flow low pressure units with 30" or 331/2" last stage buckets tend to be more prone to such incidents. If this problem has been experienced, we recommend retrofit of a double tilt pad bearing at the first exhaust hood location. Retrofit installation of a double tilt pad bearing can usually be accomplished during a maintenance outage of one week. . Machining of the bearing bore will t e required to provide correct clearance based on actual journal diameter. A numbec of General Electric Service Shops s._. .....
t (TIL 930) - Cont'd. i p have the capability of performing this work. It is necessary to fit the bearing to the pedestal ring and also align the bearing to estab-lish proper rotor position. Changes in alignment will sometimes be required when installing the new bearing. It will usually be necessary to increase lube oil feed orifice size to provide additional oil flow to the new bearing. Bearings ordered for conversion should have an additional 1/4 inch stock on the bore to permit final bore machining at the time of instal-lation. If a finish machined bearing is preferred, then the. order must ' state the preseni journal diameter to ensure that the bearing is bored to suit. Factory records concerning journal diameters can possibly be in error due to field changes and cannot be relied on to determine finish bore size. k%n a new bearing is ordered the requisition must contain information on any interchangeability requirements, including journal diameters for all units on the interchangeability list. COPYRIGHT GENERAL ELECTRIC COMPANI, 1981.
~~
THE INFORMATION FURNISHED IN THIS TECHNICAL INFOR-MATION LETTER IS OFFERED BY GENERAL ELECTRIC AS A SERVICE TO YOUR ORGANIZATION. IN VIEW OF THIS AND SINCE OPERATION OF YOUR PLANT INVOLVES MANY FACTORS NOT WITHIN OUR KNOWLEDGE, AND SINCE OPERATION IS WITHIN YOUR CONTROL AND RESPONSIBILITY, IT SHOULD BE UNDERSTOOD THAT GENERAL ELECTRIC ACCEPTS NO LIABILITY IN NEGLIGENCE OR OTHERWISE AS A RESULT OF YOUR APPLICATION OF THIS INFORMATION.
INSTRUC710NS ma<.= u (New information, June 1981) O O i MAIN JOURNAL BEARINGS i i O i i i It. e These instructions do not purport to cover all details or variations in equipment nor to provide for every
\l t possible contingency to be met in connection with installation, operation or maintenance. Should further j information be desired or should particularproblems arise which are not covered sulficiently for the purchaser's
; purposes, the matter should be referred to the General Electric Company.
'Ic COPYRIGHT 1981, GENERAL ELECTRIC CO.
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GEK.72345. .\1 AIN JOURNAL BEAltlNGS CONTENTS s PAGE G E N E R A L D E S C R I PTIO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 O PER ATION AL ltECOhth1EN D ATION S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 h1 AINTEN ANCE R ECOhlh1EN D ATION S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 . APPENDIX A. BEARING h1ETAL TEh1PERATURES WHILE STARTING OR STOPPING . . . . . . . . 16 4 ILLUSTRATIONS Figure 1. Generator Insulated Bearing Ring . . . . . . . . ..................................... 4 Figure 2. Alternate Insulated Bearing Rin g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... 5 Figure 3. Tem perature E f fect on Viscosity . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 4. Lif t Pu m p S y stem Bleed Po rt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 5. Ty pical Li f t Pu m p Co n trol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 6. Alignment Nomenclature . . . . . . . . . ......................................... 11 Figure 7. Bearin g Rin g Pad Shim Chan ge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 g Figure 8. Tigh tenin g Bearin g S trap Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 9. TILT ...... ......................... .................................13 F i gu re 10. T WI ST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
. Figure 11. Torque Curve for Fittin g Ball Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 12. Characteristic Temperature Spike . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 0
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l M AIN ml3NAL BE AiUNG. gh ~0M GENER AL DESCRIPTION The upper half generator bearing rings are
# Turbine-generator main journal bearmgs are designated as No.1, 2, 3, 4, etc. starting with the fastened to their respective caps by bolts tinsulated on the collector end) as shown in Figure 1 or, in an alternate arrangement, Figure 2. The upper turbine-end bearing at the front of the machine, bearing cap and ring (s) are to be removed as an All bearings are oil-cooled, with a pressurized oil assembly; hence, there an no bolts at the hori-supply to maintain suitable operating temperatures. zontal joint of the generator beardIg rings. A gap of approximately 10 mils should exist at the ring On high pressure and reheat elemer.ta of 3000 horizontal joint when assembled around the or 3600 RPM (314 or 377 rad /s) units, relatively bearing. The joint of the bearing cap should be light rotor sections are used and bearings are closed.
lightly loaded. To prevent shaft instability in such g cases tilting pad bearings are used, providing maxi-mum stability d freedom from vibration. Both turoine and generator bearings are split horizontally to facilitate their removal without displacing the shaft. The halver tre bolted tightly The first low pressure hood position on some together when the bearings ars in place. Tapped 3000 and 3000 RPM (314 or 377 rad /s) units is holes are provided in both halves for the use of sensitive to changes in loading and alignment eyebolts when lifting, during startup as the unit warms up, and double tilt pad bearings may be used to provide stability. The bearing shells are lined by centrifugal cast-Other bearings are of the fixed bore type with ing with tin base babbitt, General Electric metal spherical outer surfaces, and are mounted in B50A502 (84 percent tin. 7.5 percent copper, bearing rings having an internal spherical surface 8 percent antimony, .35 percent lead maximum), that is fitted to the ball seat on the bearing. which may also be retained in dovetailed grooves in tne shells. The tilting pad bearings and the rings of the fixed bore bearings are bolted to the standards The bearings are lubricated by oil supplied at or generator end shields. Axial position is main. 25 PSI (172 kPa) from the main oil pumps to the f] tained by use of tongue and groove fits. Shimmed bearings. The oil flows through a cooler which con-pads are provided on the bearing or ring OD to trols the temperature of the oil befwe it flows to adjust bearing alignment. For the fixed bore the bearings. Feed orifices are provided in bearing bearings an anti rotation pin is located in the ring pipelines to meter oil flow to each bearing. Further ,i and extends into the bearing shell to prevent informetion can be found in the Instruction Book, bearing rotation. See ensuing bulletins in this Tab 12; " Oil Pumping System." Tab for more detailed descrintions of each bearing type. A portion of the oil flowmg through the bear-The bearing ring at the collector end of the ing is carried between the lower half of the lining generator is insulated from the end shield to nd the journal by the rotat,on i of the si' aft. This avoid the possibility of stray shaft currents circu- 11 f rms a hydrodynamic oil film which supports lating through the bearings. As sho'vn in Figure 1, the weight of the shaft and prevents metagto-metal a " double insulated" ring is provided which actu-
$ ally consists of two bearing rings, with insulation mounted on both the inner and outer diameters Most of the oil from the bearings discharges of the outer ring. Separate test connectors are into the bottom of the standard or end shields, provided for the upper and lower halves of the where it is returned to the oil tank through the ring with external terminals on the cap and end drain pipe. On generator bearings the drain oil shield. This arrangement makes it possible to passes into an auxiliary detraining tank and through periodically check the bearing ring insulation with a loop seal, and is then carried back to the oil the unit in operation. By connecting a Unimeter tank. A portion of the discharge oil from each or a 500 volt megger between a test terminal and main bearing i ,iped into a sight box on the side the generator frame, the insulation resistance may of the turbine and generator to permit visual flow a be readily determined; a minimum of 100,000 verification and temperature measurement of the V ohms is considered satisfactory. discharge oil from the bearings.
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[5i. - A SE BLYl N SSARY INSULATING SLEEVE SECTION A- A Figure 2. Alternate insulateel Bearing Iting 5
GEK.72M5. Al AIN Jol'ItN AL BEAHINGs A relatively small number of units, mainly nu- 6. Lift pumps should be running on units so clear turbines and some 1500/1800 ItPhl cross- equipped until the unit is above half speed. compound LP sections, are equipped with hit pumps for turning gear considerations. The lift 7. Stany times during a start-up a unit is held at pumps supply high pressure oil through the bearing or near rated speed at no load with poor lower half into recessed pockets located in the vacuum while leaks are being located or babbit' i surface of the bearing. When sufficient other problems are being resolved. Conditions pressure is built up in the pocket and surrounding of rated speed, no load, and poor vacuum may wetted region the shaft will lift approximately 2 cause the exhaust hood to overheat, which in to 5 mils (0.5 to 1.3 mm). turn may cause hood bearing pedestals to rise excessively with respect to bearings in stand-ards or generator end shields. The end result OpER ATIONAL RECOMMENDATIONS is that first and last hood bearing carry more $. than design load and may fail if placed on turning gear, especially if oil temperature is STAHTING not reduced as outlined in item 2 above. If the hood temperature approaches the alarm
- 1. Before starting the turbine observe each sight setting, ' .s recommended that the unit be box to assure that each bearing is receiving a returned to turning gear until the cause of the good flow of oil, high temperature condition is determined and corrected.
- 2. On turning gear the bearing oil inlet temper-ature must be in the range of.
RUNNING
- a. 50 90 F (10 32 C) for units without lift pumps 1. Pen. dically check the oil discharge sights to see that oil is being delivered to each bearing.
llearing header pressure should be 2512 PSI
- b. 80 90 F (27 32 C) for units with lift pumps (172 kPa) at turbine centerline. {3 The higher minimum temperature for unita with lift pumps is necessary for proper lift 2. Regularly check bearing metal temperatures, pump operation.
The most ir portant bearing diagnostic tool available h a properly installed and main.
- 3. When starting the oil temperature should be tained bearing metal thermocouple. Many close to but not exceed 90 F (32 C). The oil problems can be detected early if thermo-temperature should be 100 F (38 C) before couples are properly and continuously moni-exceeding 3000 RPM (this limit does not tored on a strip chart recorder or suitable apply to 1500/1800 RPM units). :omputer equipment. Their usefulness has been established in diagnosing such problems if the oil temperature is too iow there is a as inadequate oil flow, improper alignment, dancar of excessive shaft vibration due to and detection of scored journals. Bearing oil whip. metal thermocouples have been standard
- 4. Closely monitor bearing metal thermocouples turbine operating instruments for many years; k, ,
additionally, many units have been retrofit, while increasing speed. Spikes in these tem-peratures are indicators of possible problems in the bearing. Details of necessary observa- Bearing metal temperatures should be f.irly tions are given in Appendix A. constant under full load conditions. Any sudden increase in temperature of more than
- 5. When the oil inlet temperature reaches 110 F 10 F (6 C) should be considered abnormal.
(43 C), or sooner if the rise is rapid, start the When operating under conditions of partial flow of water through the oil cooler to main. are admission, valve forces acting on bearing tain a ternperatire range of 110 to 120 F (43 to 49 C) when the unit is at rated speed. load may result in hotter or cooler bearings near the front of the unit. g G 1: j
hl.\lN JOl'!!N.\L HE.\it!NGS. GERJ20 M i The recording instrument should be set to STOPPING alarm at '.'25 F (107 C). A journal bearing should not be operated with metal temper- Sequential with a turbine unit trip the operator atures above 250 F (121 C). Normal oper- should ensure that maxin..sm cooling water flow is ating tensperatures for various bearing de- introduced through the oil cooler so that when the signs are: turbine comes to rest for turning gear operation the oil temperature to the bearings is 90 F (32 C) Tilting Pad or less, it is recognized that during hot weather 180 220 F (82104 C) Elliptical e nditions it may not be possible to achieve 90 F 170190 F (77 88 C) Short Elliptical 190 210 F (88-99 C) (32 C) or less. In such situations the lube oil should be cooled as much as possible by operating with both oil coolers ir. senice and the cooling water Appendix A describes desired recording control valves wide oren. We recommend that the { equipment and scanning rates, customer consider ins'talling a water control system that automatically provides maximum cooling
- 3. Itegularly check bearing oil temperatura. The water flow at the time the turbine unit is tripped.
inlet oil should be 110 to 120 F (43 to 49 C), and the oil temperature rire should not ex- The bearing oil viscosity and thus oil f;1m ceed 50 F (28 C). The bearing should oper- thickness is proportional to the oil temperature ate at a fairly constant temperature rise while as shown in Figure 3. It can be seen that viscosity at rated speed. Any sudden increase in the decreases significantly with increased oil temper-average temperature rise (greater than 5 F ature. (3 C)) should be considered abnormal even though the total rise remains within the limits Failurc to lower the tube oil temperature during specified above. low speed operation car. result in light bearing 300 I W h250 ! 8 VISCOSITY CURVE FOR g TYPIC AL TURBINE OIL d m h 200 i a g 90*F y 130 ( fk h 3 10 0 itS'F so x SO 10 0 15 0 200 250 Oil TEMPERATURE 'F Figure 3. Temperature Effect on Viscosity 7 1 1 I
GElMOM. M AIN JOl*ltN AL BEAltlNGS wipes or t.meared habbitt, particularly if a journal of We rotor. Each journal should be measured in is scored. Each F.me the unit is started or stopped two planes. 90# apart, at 1" intervals along the the condition may progressively become worse active surface. A convenient reference for these until eventually the un" will not properly run. measurements is near the oil deflector radius, if Appendix A gives details of bearing metal tem- c. meter measurements vary by more than 0.004 perature observations to be made during coast- inches n.1 mm) from each other, or if there is down. more than one major score mark (one which is greater th $ 1/04 inch (.397 mm) in depth) per On those umts equipped .7ith lift pumps, the inch (25.4 mm) it should be restored by complete pumps should be on whenever the unit is below re machining. Information on causes and cures for half speed. Circuit diagrams to automatically start scored journals can be found in the instruction pumps at half speed are available from your Book article on lube oil properties and main- , General Electric Service Engineer. tenance, Tab 12. Volume 1. I Always place the unit on turning gear immedi- When refinishing journals in place it is generally ately after coming to rest. necessary to use temporary beirings to support the rotor. Note that: MAINTENANCE RECOMMENDATIONS TURNING ROTORS ON TEFLON SUPPORTS CAN LEAD TO BEARING FAILURE. INSPECTION Du' to the chemistry of this material, oil does During regular turbine inspection the bea* .(s not wet the surface and normal hydrodynamic and rings should be fully inspected for any evi- lubrication will not occur. A rotor suspected of dence of wear or distress, in the event that any being turned on teflon should be strap lapped of the babbitt surface is scored or smeared, upset with 500 grit emery cloth until normal oil wetting portions of metal may be carefully scraped off, of the journal occurs. Excessive scraping of the bore, however, should hs be avoided. Any indicationr, of cracks in the The generator insulated bearing ring should be babbitt should be investigated with a liquid pene. inspected, if the insulation resistance has checked trant test; if cracks actually exist the bearing less than 100,000 ohms with the bearing and ring should be re babbitted at the earliest opportunity, assembled, the insulation should be completely The elliptical bearing bores should be measured, removed and thoroughly cleaned. Also refer tc so as to provide a record of the degree of wear, gel 74413 in the Generator Instruction Book. if any, which nay have occurred. The curvature of the pads of tilting pad bearings should be It is customary following an outage to wrap s checked by bluing to a mandrel of diameter equal fine mesh screens over the bearing orifice strainers to shaft diameter plus diametral clearance. Light while circulating oil with the turning gear oil scraping to restore curvature is acceptable, but if pump. Unfortunately a number of bearing failures heavy scraping is needed or if pads have been have occurred when these screens were left in-previously scraped, si,are pads should be installed stalled and became progressively clogged with or existing pads repaired by TIG welding fresh debris. It is imperatiec that these fine mesh screens babbitt and reboring. be removed prior to a roll to speed. In addition, I blanks which may have been used to shut off The condition of the journals should also be oil to bearings must be removed before the unit observed. Minor circumferential score marks and is placed on turning gcar, nicks in the surface are not uncommon and gen. erally do not affect bearing operation. Any sharp Another item which requires attention at main-ridges or upset metal may be carefully smoothed tenance outages is correct placement of feed ori-with a fine stone or by lapping with very fine fices. Hot bearings and even failures have resulted emery cloth. No attempt should be made, however, when orifices were mixed u . Orifices on new units to completely remove such imperfections, because have the bearing numbers and size stamped on the hand operations may change the contour of the plate, and this should be done for older units. journal sufficiently to adversely affect the balance Properly identifying each orifice as to size and g-8 l
MAIN JOURN AL BEARINUF. GEK.72315 g location can help to ensure proper installation. cleaning" or " bypass" operatm... The cartridge l When in doubt refer to the " Oil Feed and Drain should be changed prior to reaching the bypass Piping" drawing, or (on modern units) the ' Main mo+ Bearing Feed Orifice Sizes" tabulation in Tab 12 of the Instruction Book. If the drawing is unavailable n third but less common cause of lift pump contact your GE Service Engineer for assistance. problems is use of a particular pressure switch scheme by the customer which teruits in excessive For units so equipped a check should be made cycling on and off, which can damage motors and i of the lift pump system. Proolems which may be pumps. Our recommended control circuit is shown encountered generally fall, into two major cate- in Figure 5. The arming portion of the circuit, gories: cavitation and contamination. required to prevent cycling, is indicated on that { circuit diagram. Action of PS-14 is usually caused ( Cavitvion may be caused by loss of prime and/ or excessive air in the system at startup. Air bind-by clogged filters. We recommend that the reset switch be placed in proximity to the filters to ing is eliminded by installing a bleed port in the encourage maintenance of filters when purns are filter casing as shwn in Figure 4. The resulting de-activated by loss of suction pressure. , vil leak will bleef .o $6 guarded compartment. Lc s of prime my u.s occur if tL edge type The amount of oil flow from the pump casing t filter on the inlet becomes alogged. drain is an indication of pump condition. A new pump should leak less than one half (1/2) GPM. Most lift pump problems stem from contami- If ler -e exceer kvn (2) CFisi the pamp is worn nated lube oil. The cartridge filter in the suction and i rt d be o 2uled at the pump manufac-line provides indication of " cleaning", "needs turer's service cente, e { ' TUBE FTTG TvemG DlA.
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t N01t$ : 1, Cli.Culf$ ABOVE AP'tY TO ONE LIFT PwP (NCtD$URE,P3, . Pg.LP AND 20-LPT tlLL St EPf Af!D FOR L ACH INCLOSURE f uttel$ht3. 3 CPiRAY10N OF P$.14 UAT $1 ItSTEL ST OPERAYlNG THE f t$f V4lf t,94tN REv0ft TESTING MAS 4 TEN PeJvl010. OPinafl0N Of PS-14 941 et CutCRED ST OastRvlNG INE STAPOST LIGHT IN THE LIFl PUMP 90f 0R C:RCul t .
- 1. Cf. Ln. OtPf, 00!? hof NORhALLT FURNi$N 90fCR $fARf tR$, CONTROL StifCHil. IN0ttaflNG LIGHTS.
OR RELAfl. UNLi$$ IdCLUDER IN IUP*lhi CONTRACf.
- 4. ARMING CIRCUlf "GulMO to PREVENT INE LIFT PUWP 40T3R$ FR04 CYCLlas Of flit Acil0N OF PS.14 DUt 10 CLOGGt0 eltitR$.
- 1. THESt $httil ARE $f ANDARO REFlatNCE ORAtlNGS AND WILL NOT tt #1Vi!!O OR RillSut0 70 APPLY ft 4 PARfiCULA4 UNaf INE CIRCulTS SHOWN NtM AM GilelRAL ELECTRIC L$f DEPARTulNT RfCCMMEN0All0NS AND ARE INTENDt0 TO $ttyt As A Gulot TO INE Custoutt IN PREPARlhG Mll.0VERALL STAfl0N ANO flRING 014GRAu$.
e t- Sit 4.E. REC 0WWENDED CIRCUlf 15382102,
- f. LOW Lif f PUuP PRES $unt. (fur 8tNE ON TURNING GE AR)
- 8. Lif f PU4P OFF 04 "O Ptu? Outruf.
- 9. Los LIF1 PUk8 PRt$$URE ALARu (TURRint Dit TURNINC Gl4R10tLAY 2 5 sic.
- 10. LITT PUWPS IlUNNING (TVRNING GI AR INTIELOCX.Pituit$lvt BTt) it. TURNWG CI AR $1GNAL $31fCH AU11(14RT RELAf CONF ECT ACflV4f t$ LIFf PWP PRES $URE WONt f 0 RING CIRCUlf SHEN TUR5 tnt il QM TURNING St AR, ONLY.
t REFER TO TURIINE CONTR01, LI AGRAW FOR PRt$$UF StifCH $tfilNG1. 6 Figure 5. Typical Lift Pump Control 9 10
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31AIN JOURN.\L BEhRINGS. GEK.7"045 REFERENCE FIGURES 6 AND 7
- 1. To raise or lower bearing, draw a straight line from desired rise on shift scale through pad angle (6) on vertical scale ,
and read: shim change for each pad on shim scale. Ex- # ample:-To raise 5 mit (127 ym) with 35' pads, add 4 mils (101.6 ym) shim to each pad.- f ',1j- d' h Ns s 2.To thift bearing horizontally, draw a straight line from desired movement on shift scale through pad angle (6) on
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's 's horizontal scale and read shhn change on shim * - e.
[/ Remove that shim from side in direction of motion and
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. # i i( ' add it to the other side. Example: To shift left 5 mils (127 ,
( l', pm) with 35' pads, change 3 mils (76.2 ym) shim from left -
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- 3. When adding shim to one pad only, bearing will move g
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one-half the amount vertically and one-half the amount
/ s - \- I horizontally of motion read on shift scale by using above
/ \ 2 methods.
'- 4. For values off scale, divide shift by_ some number (2,3, or
!- I BEARING RING 4 say) to bring value on shift scale and multiply answer by
- 2 BEARING PLATE that number. -
3' 8"I" NOTE: After maldng a pad shim change, reassem-ble the complete' bearing ring, and _" blue-check" : j the pad contact with' the bore of the supporting standard. If pad contact is not adequate, loosen the -
% Figure 6. Alignment Nomenclature
- pad nolding screws and slide the pad slightly_ until at least 80fc contact is obtained, or if necessary-scrape the outside diameter of the pads.
(254.0) 10 - SHIM s VERT. SMiFT a COS. e . 0 (000.0) SHIM s HOR. SHIFT x SIN. e - -- (228.6) 9 - l (025.4) (203.2) 8 - 2 2 (050.8) k. 1 (17 7.8) 7 - - 3 (076.2) f
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(025.4) 1 - (228.6) (000.01 0 - Figure 7. Bearing Ring Pad Shim Change 10 (254.0) Fig. 2 Bearing ring pad shim change 11 ,
GEK.7?346. AIAIN JOURN AL BEARINGS ASSEMBLY AND DISASSEMBLY. (100% around feed and drain holes). Be sure * - that shims placed under pads containing feed
- 1. Remove all slushing compound with solvent und drain holes are provided with openings to and clean rags. Do not use cotton waste, as pass oit After making contact checks and -
this leaves lint on the bearing surfaces. completing assembly of the bearing a feeler check should be made between- alignment
- 2. Remove any burrs and smooth any damaged ~
pads and the supporting fit to be sure the-ipots on the rings or bearing shell with a fine - bearing is not riding on a burr. For this check oilstone and kerosene. Also, make certain a .0015" (.038 mm) feeler should not fit be-that all oil passages are clean and free from tween the parts, obstructions'
- 6. Bearing or ring hold down bolts should be 3.When assembling ot dicassembling the lower tightened so that the outermost edge of the ear is deflected 1 to 2 ils. This can be
{ half with the rotor in place the journal should be lifted approximatelv 0.010" (0.25 mm), ace mplished by use of an indicator at the
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The bearing should be rolled with a light end of the ear, or by. measurement of the gap chainfall. The use of excessive force, as might between the ear and the pedestal flange, be exerted by a crane, should be avoided. Figure 8 shows details of this' measurement. Loose bolts can lead to subsynchronous vibra.
- 4. At assembly cover the journal and lower half tien, while overtight bolts lead to undesirable -
bearing- with heavy lubricating oil. Observe stress at the ring / ear interface, the direction of rotation stamping to be cer- 7. On bearings with a ball seat it is necessary tain of correct assembly. Make certain that to measure " TWIST" & " TILT", and make-locking pins on tilt pad bearings art properly comparisons to allowable limits. Figures 9 engaged. and 10 show examples of- this procedure.
" TILT" limits fcr hood bearings are estab-
- 5. To change bearing position shims- can be I shed such that with proper alignment, the added- or removed under alignment pads bearing outboard end is set slightly low, kyJj located on the bearing or ring OD Figures When vacuum is drawn the botton, of the 6 and 7 desenbe the procedure for ' changing bearing becomes more nearly parallel to the bearing position and provide a convenient journal, chart to obtain required shim changes for any desired bearing shift. The double tilt pad type bearing (no ball seat) is the only journal bearing design with The fit between alignment pads and the stand- truly self aligning capability, and it does not ard should have a minimum of 75% contact require " TWIST" & " TILT" measurements.
00 NOT SLUG THESE 80LTS
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- 1 J L _
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'N e. ooof4 Figure 8. Tightening Bearing Strap Bolts k 12
MAIN JOURNAL BEARINGS. GEK.72345 Date f Bro 8 0 = in. IV e in. ( # f OT = mils
/'I 4 li = _ mits IT OT f, i
TILT; (0Y ty)-0T+1T
= mels TILT Alignment Limas (mils)
I . O to + 0.1 m Beg, Die (in) j e s ) . ..,a (Note: Oweboard End set Low) IN80ARD OllTBOARO ELEVATION VIEW EIAMPLE Sanie 20 in Die Beg; OY = 20.025 in, IV = 20,026 in, OT = 27 mils, IT = 28 mile (OV-IV) = 20.025 in - 20,026 in = -1 mil (NOTE $1GN) TILT = 27+28 = 0 mils MAX TILT Allo.oble . O to +0.1 = 20 in Dio. = 0 to +2, mils: . . TILT OK TILT C NOTES 3000/3600 RPM UNITS 1, Establish correct radial rotor position, including preliminary coupling alignment.
- 2. Align beadng to journal, checking for twist and tilt. Make corrections as required and record results.
- 3. Any subsequent bearing pad shim changes (bearings and rings rolled out) must be followed by another bearing alignmet check, corrections, and recorded results upon reassembly, 1500/1000 RPM UNITS
( ( 1. Establish correct radial rotor position, including preliminary coupling alignment.
- 2. After unit is closed, establish correct final coupling alignment. Close coupling faces permanently.
- 3. Align bearing to journal, checking for twist and tilt. Make corrections as required and record results,
- 4. Lvery time a bearing and ring are rolled out and/or coupling unbolted, another bearing alignment check, corrections, and recorded results are required upon reassembly.
Figure 9. TILT 13 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ - - _ I
I GEK 72M5. MAIN 'OURNAL BEARING 3 j necuten I i jyvm ev. Erg a oc. y B,g e i h By By IR OR et , . ,;l, et, ,;l, IL IL s 14 . ' IR = OR. " " OR. IL OL Twi3T; (OL -IL iIR - OR)/2 Twist;(OL- lL + IR -OR)/2 g s > . .. , s . .cs l'I o l'I TWIST Alignment Limits Twl5T Alignment Limits 11100 A RD OUTBOND =
- 03= Beg,0 e (in = a 03nB,s. Die (m)
PLAN VitW EIAMPLE: Soy 20 in Die Brg; OL = 24 mile, IL = 26 mils, IR = 20 mils. OR = 22 mila TWIST = 24-?6+20,.2) = -2 mils 2 MAX. Twl5T Allowebt = t 0.3120 in Dio. = 2 6 eiils. .'. Twl5T OK Figure 10. TWIST REPAIRING BEARINGS It is not possible to reliab'y spin cast tilting pad liners. For this reason it is recommended that a (~i As the maximum allowable vertical bore clear. spare set of pads be kept on hand for each bearing ance is approached (see specific bearing description of this type. In cases where the bond is sound,it is sheet) consideration should be given to repairing acceptable to TIG weld and remachine the bore. the bearings. The necessity of repairing the bore Special procedures are required to machine the will also depend largely on the successful operation bore of this bearing type; therefore, it is recom-of the bearing as regards balance of the machine, mended that this be done in a qual.fied General throwing of oil at the ends of the bearing (leakage Electric Apparatus Service Shop. of oil deflectors), and maintenance of oil pressure. Bearings with ball seats have been fitted to the Several General Electric Company Service Shops rings at the factory by hand scraping to give the have been certified by the Large Steam Turbine-proper contact. Whenever a bearing or bearing ring Generator Department to centrifugally recast ellip- is repaired, it is essential that these parts be blue tical journal bearings. The shops are periodically checked and fitted together so that the area of con-audited to assure conformance to rigid standards. tact is at least 80 to 85 percent. To obtain this con-
'u Consult your General Electric Service Engineer for (',_
tact, it may be necessary either to scrag the spher-the location of the nearest certified GE Service ical surface of the bearing or the bearing ring, or to Shop. scrape the horizontal joint of the ring. Under no circumstances machine or file the bearing at the Additionally, many General Electric Apparatus joint. A further check should also be made to see Service Shops employ technicians certified in the that the bearing can " ball" satisfactorily in the ring att of babbitt welding. When the babbitt.to-steel seat. This can be done by assembling the bearing bond is sound, welding via the TIG-welding process, and ring together and measuring the torque re-followed by remaciCring, may be used to restore quired to move the bearing. Suitable values of the bearing bore. Many shops are equipped to torque for various size bearings are shown in check bearing bond by ultrasonic testing. Figure 11. g v_ I 14 i i
MAIN JOl'RNAL SEARINGS G2K ~2045 If it is not possible to make the torque check, tightly and then disassemble: the difference in experience :.,J tuown that a suitable check may be thickness of the shims and the lead wire will be the - made by determining the amount of vertical pinch amount of pirch on the bearing, on- the bearing. With strap type bearing rings the fit should be from " size and size"_to one mil pinch : - To change 'he pinch on the turbine end gener-on the bearing. Bearings which share the ring with - ator. bearing ihim changes are made beneath the - the thrust bearing should have the pinch set- alignment padh on the OD of the upper half bear. according to thrust bearing requirements,i.e., zero ing ring. In order to change pinch on the insulated to two mils loose. On bearing and ring assemblies collector end bearing the thickness of the insula-held down by a cap, as on generator bearings, the tion strip on the upper outer bearing ring must be pinch on the bearing may be two to three mils. To changed. To decrease pinch this insulation strip i check this pinch place temporary steel shims of may be lightly sanded. To increase pinch it is k.. known thickness at the horizontal joints of the necessary to replace the strip with a thicker piece, bearing cap, and then assemble the bearing with a which may be ordered through your General Elec. lead fuse wire on the top of the ball. Bolt the cap tric Service representative. tomo-
/
seem ie.gt.o.tnme,e,.) 16,000 : - / 20,000- ' Force Obe) ; (Newtons) 4s* 44,000 ' f Torque a force a length e Ib-f t ' # [ / (N *nt ) . It,000 15,000 - h10,000 s / / 5 / f. 1
! 8,000 / /
t 10,000
- kanimum \/' ['<
Smo ,
/ ' /
/
/ / Fitting Of Bearing Belt Seats 3,noo . 4400 ir / Torque requked to move beer 6ng efter fittag wita bearing ring. The bearing ring should be
/./ / firmfy supported cad the halves bolted fightly
[ g 2,000 together. with bearing ossembled in the
-y # machina, multiply the above values by !.S 0 0 10 .- 14 le 22 25 30 34 38 42 46 50 - 54 58 Seering ball diemeter (inches) i i 2S+ $00 750 i
1000 1250 t500 seerme bell diameter (mm) Figure 11. Torque Curve'for Fitting Ball Seats 15
GEK 72345. .\l AIN JOURN.S L BE.\ RINGS APPENDIX A BEARING WlETAL TEMPERATURES WHILE STARTING OR STOPPING Journal damage in the form of scratches and A bearing ueing wiped can be detected by the grooves is caused by dirty oil. Journals with wavy bearing mctal thermocouple. All units now being Furfaces may also result from particulate matter in shipped are equipped with bearin;; metal thermo-the oil, which, in time, wear away shaft material. couples as standard equipment, it is strongly Scratched, grooved, and/or wavy journals are prone recommended that older units not equipped with to wipe their bearirg as described below. When this bearing metal therinocouples be retrofit in order occurs both the bearing and journal must be to properly monitor their condition during opera-5 repaired. tion, coastdown and startup. - 4 When a journal becomes scored the oil film pres- The time at which a scored journal can normally sure profile across the length of the bearing is first be detected is either during startup or coast-chopped into segments. The consequence of this is down. With the turbine below rated speed temper-that the journal rides closer to the babbitt surface. ature excursions with a characteristic spike similar This is not necessarily a problem at rated sreed; to Figere 12 may occur if a scored journal is however, below rated speed, during coastdown or present. It should be recognized that this curve is startup, the oil film thickness is reduced in proper- generalized. Temperature spikes may not be as tion to the speed. As the film thickness decreases a pronounced in J1 cases since wiping may be only transition from hydrodynamic to boundary layer momentary with only a small amount of heat lubrication occurs. During this transition the oil generated. fifm becomes tSinner and, when already reduced by the scored journal, the film may not provide Both 3600 and 1800 RPM units will exhibit sufficient support. The result is oil film break- these temperature spikes on severely scored jour-through, metal-to-metal contact, and wiping of the nals. Generally the temperature spikes have been s bearing. found to occur between 2,00 and 2000 RPM. h TURBINE TRIP 250' -
@ COASTDOWN SCORED JOURNAL g - NORMAL JOURNAL METAL a:
T EM P(O F) TYPIC ALLY l- 10 MIN.
/ %
4-e-t TIM E - Figure 12. Charactaristic Temperature Spike 16 I - _ _ - _ _ - _ _ _ _ _ _
M AIN JOURN AL BEARINGS. GEKJ2345 Again, should patterns similar to Figure 12 occur, 1. Check the main oil tank screens and appro-it is likely that the mating bearing to that journal priate oil drain areas for evidence of wiped has wiped. babbitt. As one can deduce from Figure 12 instrumen.' tation should be available which has the ability t 2. Compare the turbine speed decay curve of record bearing metal temperatures at a fairly rapid the suspected wipe occurrence to a previously rate. This can best be accomplished with a chart recorded typical speed decay curve. Is there recorder with the following approximate capabil- any evidence of increased friction due to ities. w p ng as might be indicated by an abbre-viated or irregular decay curve? (Note: Devia-
- a. chart speed: 3" per hour (or faster) n fr m a n rma y cune generaHy occurs within the last 100 RPM.)
- b. chart paper: temperature range - O to 300 F
- 3. What are the metal temperatures on bear-
- c. printhig rate: approximately 50 points /TC/ ings adjacent to the suspected wiped bear-hour ing? If the wipe is severe load will be trans-ferred from the wiped bearing to adjacent For units with computerized instrumentation bearings. Higher metal temperatures on the systems scanning rates and alarm settings for bear- adjacent bearings are the usual result.
ing metal thermocouples should be as follows:
- 1. When the unit is below rated speed tempera. 4. Were there any abnormal vibration readings ture should be scanned every 30 seconds. A on the suspected wiped bearing at the time rate of change alarm should be set to function of the wipe or on a subsequent startup? If should the temperature increase or decrease a bearing wipes on a coastdown increased by more than 15 F (8 C) per minute. All data vibration levels may not occur. Generally, i
g', should be stored until synchronous speed is abnormal vibration levels will reveal them-selves on a subsequent startup. reached, and should be printed should an alarm occur Periodic printout of startups and coastdowns should be made for comparative If the evidence of bearing wiping is present purposes, in the form of a temperature spike, with or without additional facts confirming a wiped
- 2. When at synchronous speed the scan rate may bearing as itemized above, the affected bear.
be reduced to once/ minute. The unit should ing and its journal should be inspected as soon be set to alarm at 225 F (107 C), and should as possible (before the next startup) to allow be manually tripped should any bearing metal plans to be started for repair efforts. If no temperature exceed 250 F (121 C). Temper- inspection is made and no action is taken the atures should be printed once/ hour under possible scoring and wiping can be expected normal conditions, and once/ minute during to get progressively worse with each startup alarm conditions. Also, should an alarm occur, and shutdown until the point is reached data from the previous hour should be avail- where the unit cannot be operated. In addi-g- able from storage. tion debris generated by the scoring of a journal will be added to whate ter fornign ma-If a temperature spike is detected each of the terial is already contaminating the oil and pos-following items should be checked for additional sibly result in damage to other bearings and evidence of bearing wiping due to journal scoring. journals. h_ 17
New 11ampshire Yankee -
- May 25,1992 L
ATTACI1 MENT 10 General Electric TIL 883, Hydraulic Thrust _ Bearing Wear. Detector Adjustment- and Maintenance" _(. Reference 1.2.9)- L E' A
)
HYDRAULZC THRUST BEARING WEAR DETECTOR { , ADJUS7 MENT AND MAINTENANCE
,b (TIL- 8 8 3) \-
PURPOSE The purpose of this technical information letter _ is to provide adjust-ment and maintenance recammendations to help you improve the reliabil-ity of your hydraulic thrust bearing wear detectors and avoid false tripouts. BACKGROUND Hydraulic type thrust bearing wear detectors (TBWDs) have been provid-ed on all LSTG units shipped since about 1956, and have been installed on some earlier units by retrofitting. Although there has been some variation in the details of various models over the years, the basic principle has remained the same. All models have a hydraulically bal-anced differential piston that continuously follows the axial position of the turbine shaft, maintaining an oil gap of approximately .010 in- _ _ _ _ ches,_The_ follower.. piston min _ turn 4_ positions _ Lhydraulic_ pilot _ valve _ _ which will actuate an alarm and trip the turbine in case of abnormal axial movement of the turbine shaft. There are approximately 600 hydraulic TBWDs in service on LSTG units, and in recent years, an average of 6 to 7 false tripouts have been an-nually repor:ed. The most common causes include out-of-adjustment, out-
'l
' of-location (missing dowels), pressure switch failure and foreign mat-erial in the oil system. Although 6 or 7 false tripouts per year re-present only 1% of the TLWDs in service, it ,is an unnecessary expense and inconvenience. Most of there false tripr, can be avoided if a mod-est amount of attention is given to correct adjustment and timely main-tenance.
RECOMMENDATIONS General recommendations and considerations in determining the frequency of turbine inspections are discussed in TIL 820 (subsequently reprinted as GEK 63355 for inclusion in Turbine Instruction books). The recom-mendations' of TIL 820, which call for complete disassembly & inspection and cleaning of turbine-generator components at 3 to 5 year intervals in normal circumstances, are applicable to TBWDs. Where potential pro-g blems are known to exist, such as a contaminated lube system, the in-spection should be more frequent. ADJUSTMENT & MAINTENANCE - DETAILS The following recommendations are provided to assist you in the plan-ning and performance of maintenance activities. Most of the false trips that have occurred can be traced to one or more of the problems discuss-ed. Therefore, implementation of these recommendations can be expected to m:Le a significant improvement in TBWD reliability.
\
(TIL- 6 8 3) - (Cont.) - lADJUSTMENT & MAINTENANCE - DETAILS - (Cont.) ( Your Turbine Instruction book should contain a GEK and an assembly drawing, providing you with details of your specific TBWD. Topics dis-cussed in the GEK include Design, Principle of Operation, Adjustment
-_and-Testing. The material in-the Instruction ~ book-is-needed to supple--
ment the information in this technical information latter. If for some reason the Instruction book material is not available at the station, please request additional copies through your General Electric servic. representative. A. Adj us tmen t : Thrust bearing wear detector out-of-adjustment is the largest sin-gle cause of TBWD false tripouts. The TBWD article in your Turbine Instruction book contains a detailed adjustment procedure which will not be repeated here. The following information and recommendations, however, should be used to supplement the Instruction book article.
lv-The-TBWu should always-be adjusted to-have adequate tripmargi~n--
in both directions. (For minimum trip margin recommendations, see Item 4 below). On some turbines,the thrust direction re-verses as the unit goes from light load to full load while other turbines appear to always load the thrust bearing in the same di-rection. There are many things which can affect the thrust how-
's ever, and almost all turbines can be expected to reverse thrust
_' direction at one time or another. On turning gear, the rotor position may change depending on the condenser vacuum. Other turbines may shift rotor position while coming to speed. A re-heat turbine may reverse thrust following a load rejection that j bottles up reheater pressure in the HP turbine. And, any tur-bine might fee) a thrust reversal due to unsymmetrical deposit or steam path damage.
- 2. A rotor " bump check" provides the best information for setting the TBWD. This involves jacking the rotor forward and back a-gainst both thrust plates, so as to obtain readings of the ex-treme rotor positions. The force must be la ge enough to move the rotor through the thrust clearance, flatten any warpage of the thrust shims anS move the ball and ring fits through their axial clearance, but not large enough to damage the thrust plates. Additional jacking information may be obtained from
.the maintenance section of the Turbine Instruction book (for l[
un ts shipped since the early 1960's) or from your General Elec-i tric service representative.
- 3. Always check the TBWD settings before.startup if either the thrust bearing or TBWD have been disassembled or worked on. The settings should be rechecked when the turbine is at low load and again at high load.
/- '
(TIL- 88 3) - TCor.t.)- '3-
'{ ,
A. Adjustment: - (Cont.) y;4 , (G 71 . If the'TBWD has less than .010" trip margin in either. direction - it'should be readjusted:right away. 'Af ter careful adjustment, the TSWD should have:at Lleast .020" trip: margin in both direc- _ _ - _ m tionsH(requiring;a-TBWD--range-at-least .'040"-greater than-the- - - total' rotor movement) .-- IfLthis trip margin;is not obtainable, it means .the rotor has e'xcessive movement Land /or Jthe: TBWD_has insufficient range.- In either case,-the problem'should be-in-vestigated and corrected'at the.next available_ opportunity. f 5. Not-all'TBWDs:have been. built with-the same range ~between trip points. Many of those built before 1974 have a' total, range of approximately .060" to .065".-More'recent TBWDs_have-a range of-approximately .075" to 090" between trip points.~ Where a TBWD with a narrow range is on a turbine with--larger than normal ro-tor-movement,-it may not be-possible to adjust forc.the1 trip _ mar-gin recommended above. InJthis case, it-is a simple matterito order a: replacement hydraulic pilotxvalve for'the TBWD. -The.re- - 31acement pitotmraive,ritl-huve7tbout-1)l5"7;freater port 7ver1ap -
- and will increase-the_rangelbetweenitrip-. points by that" amount.
This should be-done in addition to, not-in_ lieu of, adequate maintenance to the thrust bnaring assembly. B. Dowels: S) _ Af ter the TBWD - is aligned :to - the turbine: shaf t, it must be dowelled to keep it in alignment and to permit' reassembling it in the right' location after. maintenance.- Several tripouts that_ appeared'to~be caused by incorrect adjustment have been tracedcto= dowels lost dur-ing maintenance or dowels that were never' installed;at erection. Every-TBWD:has two alignment surfaces, eachTof;which-requires.2:dow- - els.(4 dowels _per TBWD)..-The probe?assemblyb(also_' called 1 relay as-sembly) mounts on _ a support bracketuor' on-~ theTTBWD : enclosure. --Two dowels-are required at that interface. The: bracket' or; enclosure', i n-- - turn, mounts on the front or middle standardLassembly. lTwo dowels are:also required at that_ interface. Figure'sil'and 2 illustrate typical dowelling arrangements for front and middle standard mounted TBWDs, respectively. e l(' The location of these-dowels on a specific ~ unit--should.be apparent:en
'the~ assembly drawing"in the Turbine' Instruction-book...It is suggest-1 ed that an immediate check be made to see that:these dowelstare in place, and that:a:-recheck be'madeJat the conclusionJof:each mainten-'--
- .ance outage.
C.- Cleanliness:. In recent years, the second most frequent'cause of TBWD false' trip - outs has-heen. foreign material:in the lube. system. Solid particles 4 - i
- _ -f,---4-4 % +. ,, ., _U .W c wer.,.t vi ., g, - , . q.h 7 -g yw,-, .-- 4,9 ,4sg-m ,m,w % y, y op
(TIL- 6 8 3) - (Cont.) ( O. cleanliness: - (Con t . ) ( will tend to collect in the close clearances at the follower piston. In addition, water in the lube oil can cause rusting and sticking of parts.
~ ~ ~ ~
'Where the lube oil system ha's b'een maintained consistently clean, the TBWD should be completely disassembled, inspected and cleaned every 3 to 5 years. The strainer in the oil feed line to tne TBWD should also be cleaned. On the EHC Mark II TBWD there are two orifices lo-cated in the manifold block inside the pressure switch enclosure (see Figure 's 3 and 4) .
block should also be cleaned. the orifices and the passeges in the manifold g Whare the lube oil system has been contaminated with dirt or water, tne inspection and cleaning of the TBWD should be more frequent. Of course, steps should also be taken to maintain a clean lube system. D. Pressure Switches: The pressure switch settings should be checked each t[me the TBWD is inspected. The third most frequent cause of T3WD false tripouts has been pres-sure switch bellows failure. All reported failures have been on units with mechanical-hydraulic controls where the oil to the pressure switches was supplied from the hydraulic header. The hydraulic '3ad- ( er pressure is approximately 200 to 250 psi and subject to transtant pressure spikes due to hydraulic shock waves when the control mechan-isms move. All EHC units,. and some MHC units shipped since 1968, have the oil to the pressure switches supplied from the bearing header ut approximately 25 psi. There have been no bellows failures reported on these units. The control diagram for each unit shows whether the pressure switch oil supply comes from the hydraulic or bearing header. A retrofi package is available to convert from the hydraulic to the bearing header, and is recommended as a reliability improvement, especially on units that have experienced bellows failures. , Also available as a reliability improvement is a conversion package from two to four pressure switches, wired for 2 out of 2 trip logic and providing an alarm function before tripping. This is standard on { Mark II EHC units and available for retrofit on MHC and Mark I EHC < units. When a TBWD is being conearted from hydraulic to bearing header pressure, we will include the additional pressure switches and 2 out of 2 trip logic in the package. THE INFORMATION FURNISHED IN THIS TECHNICAL INFORMATION LETTER IS OFFERED BY GENERAL ELECTRIC AS A SERVICE TO YOUR ORGANIZATION. IN VIEW 0F THIS AND SINCE OPERATION OF YOUR PLANT INVOLVES MANY FACTORS NOT WITHIN OUR KNOWLEDGE. AND SINCE OPERATION IS WITHIN YOUR CONTROL AND RESPONSIBILITY, IT SHOULD BE UNDERSTOOD THAT GENERAL ELECTRIC ACCEPTS NO LIABILITY IN NEGLIGENCE OR OTHER-WISE AS A RESULT OF YOUR APPLICATION OF THIS INFORMATION.
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lI-et ORIFICES ' ' ~' i FIGURE 4 - Manifold & Solenoids for TBIO DWg.125D4594 (Rev. 2) - (TIL 883 Attach'.) Rev. 0(5-77) 7. 5-77(DO
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- New 11ampshire Yankee May 25,1992 4'
ATTACHMENT 11 General Electric TIL S77, "EllC Hydraulic Power Unit"- (Reference 1.2.10)'
- i
l l D s EHC HYDRAULIC PCWER UNIT (TIL 877) - f PURPOSE OF TIL k The purpose of this Technical Information Letter is to inform you of the following: A. Various design improvements which can be made to several of the components in the EHC Hydraulic Power Unit (HPU). B. Availability of equipment which allows for improved testing, fluid monitoring, fluid dehydration, and 0-ring storage and identification for easier maintenance. C. Provide an HPU periodic maintenance chart and re-emphasize cri-
, tical items. 'h,,3 DISCUSSION A. DESIGN IMPROVEMENTS _
In our continuing ef forts to enhance the reliability, perfor-mance and maintainability of the HPU we have identified several areas where improvements can be made. These improvements, dis-cussed in more detail below, have been implemented on new units as they were developed. They should be retrofitted to your earlier units, particularly where problems in such areas have been experienced.
- 1. Micron Back-up Filter: (Ref. Figure 1)
The design change in this filter assembly, was -made to give positive centering of thg filter element in the hous- { ing. This, then ensures 360 sealing between the fluid-in (dirty side) and fluid-out (clean side). In the origi-nally specified filter assemblies, element centering re-lied upon a coil spring lightly held to the center post by means of a shallow groove. Field experience has shown that this upper spring can inadvertently be removed with the element when servicing the filter assembly. Loss of the spring allows the element to f all over to the side of the housing and in this condition incomplete sealing be-tween the seal lip in the head and the element gasket can occur. This incomplete sealing thus allows incoming fluid to bypass the element. 1
EHC BYDRAULIC POWER UNIT- '; (Cont.). .:y. '
/
As can be seen-in Figure 1, the upper _ coil spring has been replaced _ -with-a " centering-device" which is a press-fit - in the hgad. The device has been designed to ensure comp-lete 360 sealing between the seal lip and upper gasket at all times. Due to remachining requirements to incorporate the centering device,- it is recommended that a complete new head assembly be purchased from the vendor. The-new head assembly can then be installed at any time-(with the fluid Transfer and Fullers Earth Filtering Unit (TAFEFU) shut down). Ordering information to obtain the new head assembly is: Vendor: Hilliard Corporation 100 W. Fourth Street Elmira, New York 14902 ATTN:-Mr. V. Scott Stevens Part 4 : FB-5434-22A (includes: modified head,- _ vent screw, vent screw gasket, head gasket, center 4 bolt gasket) D Quantity-Required: One (1) per turbine
- 2. Fullers Earth- Filter Assembly:' (Ref. Figure 2)
Some problems have - been experienced- in the field with obtaining a leak-free seal between the filter cover and body of the Fullers Earth filter assembly. To effect a greater sealing pressure on the gasket,_ the vendor has instituted a design change to the cover which-re-inforces the fabrication and allows a higher torque
~
value to'be_ applied-to the center-bolt. The torque value-
- specified for the present cover is 80 f t-lb. The higher torque _ value which can be applied to the re-inforced cover is 120 ft-lb. A number of-the new covers-have been field evaluated, and found to be most effective in curing fluid (
leaks at this joint. it is recommended _ that complete . new re-inforced Again,_ assemblies be purchased from the vendor. The new cover cover assen511es can then be installed at any_ time (with
~
the TAFEFU system -chut down). . ordering inf orma tion to obtain the new cover assembly is: Vendor: Hilliard Corporation 100 W. Fourth-Street Elmira, New York 14902 ATTN: Mr.-V. Scott Stevens >
f r c , EHC HYDRAULIC POWER UNIT .e . (Cont.) b) Part 4 : FB-lll7-33 (includes modiried cover, cover gasket) Quantity Recuired: Two (2) per turbine Note:
~" Always. replace the cover gasket on re-assembly of the cover. Take care to assure the gasket is seating properly.
- 3. Air Dryer / Breather: (Ref. Figurr J)
In 1975, a modified air dryer / breather was introduced, which incorporated a 5 micron pleated-paper filter cartridge in the downstream side of the air flow. The cartridge prevents any particles greater than 5 micron f rom being carried over in the air flow into the main fluid reservoir. The overall physical size of the air breather / dryer remains the same, the mo'difications being internal. (No modification kit exists to implement the 5 micron filter into old design breathers. No modifica-tions are required to the stand pipe mounting flange when installing a new design breather. This new design air
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dryer / breather can be ordered from General Electric Company as follows: G.E. Part f : 254A7280P0001 (Vendor Model i BR-50-SP) Quantity Recuired: One (1) per turbine
- 4. Space Heaters Field experience has shown that under unusually high am-bient temperatures, the space heater / fan assemblies presently used to heat the ERC fluid have encountered the following difficulties:
I
' a. The thermal cutout (TCO) buttons (red button located on the heater) have continually popped out due to thermal overload. This creates a nuisance because the TCO has to be manually reset; in the meantime the heaters are de-energized and fluid cannot be heated.
- b. There have been several spaceheater/ fan motor failures due to local overheating within the heater housing. Field tests have shown that when the ambient temperature surrounding the f an motor exceeds a particular temperature range, the fan motor de-energizes on thermal overload leaving the heater
EHC HYDRAULIC POWER UNIT- (Cont.) . c.. coils with no means of-distributing the-local-heat, This condition eventually forces the_ -TCO but ton ~ to - - pop out-de-energizing the heaters.. In the meantime; the temperature within ~:the heater may_ reach levels which in sone cases will burn the Neoprene insulation on the fan motor- leads andc damage- internal motor-windings. To eliminate problems a. and b. , a new temperature control-switch- (TCS) is available which is intended to de-energize h the heater coil before the f an -motor de-energizes due- to thermal overload; then automatically re-energize. the heater coil. when. the amgient teperature surrounding = the - fan motor has dropped 30 F to 50 F. The new-switch will be located on the protective f an motor shroud and - wired -in series with the present Thermal' Cut-Ou t - -(TCO) , all internal-to the_-heater housing. This de-sign improvement is simple and inexpensive and can be ac-complished with -the-_ unit running = (but heaters de-energiz-ed). This -item can -be ordered f rom General Electric Com-pany as follows:- ikwt vp G.E. Drwg . 6 : 208B8701G0001 (Installation of Temperature Switch) - for turbines with 208V to 240V heaters.
, G.E. _ _
E l: 155B2499G0001- (Installation of Temperature Switch) - for all other-turbines. Quantity Recuired: Two - ( 2 ) per turbine ~
- 5. Gages:
With - the- exception _ of EHC-HPU's shipped in the late
-1960's, .the fluid pressure _ gages are flushT mounted in the c
HPU - f r ame.- Vibr ations . created by normal; pump _ and motor - operation may - be - transmitted - through the frame - to -the (- gages (pumps and motors ; are solidly mounted to the top deck of the f rame)". - These vibrations prevent gages lfrom
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naintaining a steady reading .and,' in some cases, have damaged;the gage mechanisms. In instances .w here- the vibration - problem is not- too r severe, an insulating barrier (1/8" thick;- cork impr eg _-
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( nated gasket material) .placed between the steel framework and-gage: mounting flanges has shown-to be effective. This type of gasket material (or similar) is usually available in most power plants, and'can be easily applied.
-j
, , EHC HYDRAULIC POWER-UNIT Ns (Cont.)
Should the gasketing of these gages not provide suf ficiant improvement, the' existing dry- pressure gages may be re-placed with ones that are liquid filled. Since the gages-have dif f erent overall dimensions, the existing gage panel-would require modification. This would also necessitate minor tubing re-routing. The required liquid filled gages and other necessary mod-
- ification hardware can be ordered f rom General . Electric I Company as follows:
G.E. 3776 6: 281A6967 Quantity Req ui r ed : One (1) per turbine
- 6. Pressure Transmitter:
Some of the hydraulic power units in the past have shipped with the mounting for the Electronic Pressure-Transmitter (EPT-6) consisting of a vertic61 pipe suspended f rom the inner frame deck. This cantil:vered r ,pe in some cases
%'M vibrates excessively resulting in damagi to EPT-6.
This problem has been corrected on more recent units by bracing the- pipe to the HPU frame near its bottom. In addition, a 1/8" thick Neoprene material has been placed between the pipe and U-clamps that secure EPT-6. This modification can be easily done in place during any short outage. B. NEW EQUIPMENT In order to improve testing of some components or ease mainten-
-ance activity we have either developed in-house or alternately field evaluated vendor equipment for the purpose.. The delta P
- switch tester and r ing -. ki t - (desc r ibed below) are being pro-
% vided on new units. -The following items-are now available for your turbines:
- 1. A P Switch - Tester - PALL Filters: (Ref.-GEK-46540)
The - high pressure filters (PALL) installed in each main ERC pump discharge line are equipped with a pre-set, non-g adjustable AP switch. The switch will actuate an alarm when the pressure drop across -the filter element : reaches a predetermined value ( 100 + 15 PSID) . The alarm is an-indication that the element needs changir.g. j
EHC HYDRAULIC POWER UNIT ~6-(Cont.) , To check the operation and validity of the AP switch, a simple switch tester nas been developed. By using the tester, the switch can be checked for correct pressure setting and electrical continuity. It can also be used for checking out the electrical circuitry between the HPU and the customer's annunciator panel. A complete description of the tester, its operation, test instructions and ordering in f o r ma t ion , can be found in GEK-46540 (attached) . We recommend one (in some cases two are required - see GEK 46540) of these testers for each of your stations with EHC units.
- 2. _ Acuavid Water Meter A fast, accurate and relatively inexpensive determination of the water content of the EHC fluid can be obtained by use of the Aquavid water me t e r . This device has been fully evaluated by the G.E. Company and found to give ac-e yi curate water contents (within 0.05%) when compared with
- more expensive and complicated laboratory processes for water content determination. The Aquavid meter is portable, r equi r es about 1 cc of fluid sample, needs little expertise to operate and the water content is determined within minutes of taking the sample.
The simplicity of operation and relative low cost of water content determination by use of the Aquavid allows you to increase the frequency of testing. This gives you almost constant monitoring of the EBC fluid with respect to water content - a most important r equ i rement to ensure trouble-free operation of the EHC system (see TIL 796). The Aquavid water meter with full operating instructions can be purchased from: Ericsen Instruments POB 226 Ossining, New fork 10562 ( Our experience since the issuance of TIL 796 in December of 1976 leads us to urge you to assure that each of your plants with EHC turbines be provided with this device. Its relatively low cost more than warrants its usefulness in the ease of monitoring the EHC fluid for water. Water in the EHC fluid if gone unnoticed can lead to severe consequences. We recommend one of these meters for each of your stations with EHC units.
._.........,,.i....-..i..
EHC HYDRAULIC POWER UNIT --
;.,(g (Cont.) --,y,
- 3. Fluid Dehydration Units Extensive laboratory test work --has- shown that : EyC . fluid can-- absorb up to 0.500 water in solution 0 1104 F . -- The maximum __ allowable water content in the EHC fluid'is10.20%.
Conventional _ filtration -( Absorption / Adsorption)- supplied-on the EHC-HF'J, has.been found to'be only partially-suc - cessful in removing water in solution.- = To pr event- the { costly expense.of replacing __a-batch of-water contaminated EHC-fluid, a-review and: field evaluation has been-made of commercially available equipment that will Cehydrate1EHC. finid by removing water in solution., Two (2) such-pieces-of equipment have been- field tested and -found to bel most effective:-
,_"The-PALL Oil Purification System" Model t - HVAC-83 Vendor'- PALL Corporation _
j 30 Sea Cliff-Avenue - Glen Cove, New York 11542-ATTN: Mr. Dave Carson-
"Hilco Std. Oil-Reclaimer" j Model CM-1 Type-25 EHC Portable Vendor - The Hilliard Corporation-100 W. Fourth Avenue _
Elmira, New York'14902. ATTN::Mr. V. Scott-Stevens" NOTE: It is-.important'to understand that'the; devices-described herein: remove water and to some. extent- -
-particulate contamination.1: :Theyldoinot " recon- .
1
-{:
dition" (make _like new); the fluid. Chlorine ; content, _ conductivity,- neutralization- number- - 1 and' other = parameters ' determine 'everall'. ifluid ! system compatability' and control.:of - these -- f ac-tors.cannot:be reliably 1 accomplished by.-the de- ~ vices: described herein. ." Reclaimed"jEHC: fluid- y is not approveduby LST-G1unless each batch has' '
~ been found to E comply __with :?all aspects of the G.E. LST-G EHC fluid spec. (See - GEK-4 63 57 in - - ;] Tab 13 of the turbine's Instruction-Book).
s
EHC HYDRAULIC POWER UNIT h.w (Cont.) Both pieces of equipment are: portable, and fully equipped with their own motor-driven suction, discharge and vacuum pumps. The equipment can be used to dehydrai.e a batch of fluid contained in the HPU main -reservoir, or individual' drums of water contaminated fluid. To connect the system, all that is r equi r ed is an electrical power sou ce and pump suction and discharge lines (l" OD tubing) f rom the conditioner to the fluid reservoir /or drum. For drying a batch of fluid in the main reservoir, the spare ISD (1-5/16" - 12 thread) connection on top of the reservoir can be used for the pump suction and the fluid discharge can be temporar ily _ located through the small circular inspection cover:en top of the reservoir. Water removal is accomplished by " Vacuum Dehy-dration", and for both conditioners, 24 - 36 hours of continuous operation should reduce the water content below the new- fluid specs.
~
(0.10t. , , when treating a batch- of : fluid. in the min raservoir. A comprehensive set of literatureLeovering the fluid conditioner principles of operation,-etc. l can be obtained from the vendors. listed. We recommend one of these units for your-system.
- 4. ="0" Ring Kit (See Figure 4)
To better service the "O" ring r equi r ements for all sections of the EHC hydraulic system ( i . e'. HPU, front standard - & steam valve control pacs), a complete "O" ring kit has been formulated. =The kit (See Figure 4) consists of a wood carrying case inside of which are - housed - 46 dif ferent sizes of "O" rings -with a grand -total of ap-proximately 460."O" rings. The "O" rings lare retained on. g vertical- pegs, teach peg identified:with the--"0" ringu size, % and the pegs designed to r3curely retain each ring. Also-included in.- the kit are --metal nameplates giving a' full description of-the "0" rings-contained,-the quantity, .the-nominal over all - dimensions of - each ring and 1re-ordering information for the rings. The kit.hasibeen formulated to cover - all types (Fossil & Nuclear) of ~ machines and is a intended to only cover tube fittings , control- -pacs, F' flanges and mounting type "O" ring-: kits supplied for these-components. Typical drawings showing -the size and location of "O" . rings in the various areas of- the hydraulic system covered are either presently available-in the Instruction Book. or will be mad e- - avai lable when an order is received for an "O" ring-kit. _- ~. - - , . . ,.
l l EHC HYDRAULIC POWER UNIT (Cont.) Ordering information for the kits are: MARK I - EHC MACHINES - G.E. PART 4 361E40lP0001 MARK II - EHC MACHINES - G.E. PART # 861E402P0001 f We recommen6 one of these kits for each of your E'lC units, or one kit for a number of duplicate EHC units of the same b series in the same station. C. TESTS & MAINTENANCE Many of the recent forced outages related to the HPU have been attributed to lack of proper -testing or preventive maintenance. Low accumulator gas precharge, improper pressure switch trip settings, improper relief valve settings, and fluid contamination are but a few of the basic causes for these problems. Most of these could have been avoided with proper surveillance and timely preventive maintenance of the system. F.%
#$p 1. " Periodic Minimum Test & Maintenance" Chart The attached chart (Fig. 5) outlines the minimum test and maintenan e requirements for the HPU. It assumes normal operation oi sys tem components. Any problems discovered during these checks, er otherwise, should be resolved quickly (see Trouble Shooting Chart in GEK46355, Tab 13 of the Instruction Book) . Known problems may also require more - f r equent testing (see Instruction Book article for particular component).
The HPU is designed with two complete and separate high pressure pumping systems. This arrangement allows servicing of components while the turbine-generator is operating. led one way check valves prevent high pres-sure fluid -
- kflow into the system shutdown or in
{ standby. Pr2 mre gages located in each system give a visual indicstl .. of pressure conditions. Therefore, all r eq ui red maintenance work (except for_ work r equi r ing drainage of reservoir) can and should be done with the turbine-generator on line, so as to maximize its availa-bility. For full and detailed maintenance instructions and r equir ed precautions consult the unit's Instruction Book, Volume I, Tab 13. m k
y
#bT EHC HYDRAULIC POWER UNIT icont .)
The procedure to be fellowed when working on one of the high pr ess u r e systems with the unit running (extracted from the Instruction Book) ist
- a. Shutdown the syvtem to be worked upon after es- t tablishing system pressure on the other system,
- b. Disarm the pump motor in such a way (i.e. pull breaker) that it cannot " Auto" start the system.
- c. Check the gage sensing the shutdown system pressure conditions, to verify that it registers zero PS7. {
- d. Service component to be worked upon.
- e. P.e-activate system, pressurize to system pressure -
check components for fluid leaks, correct operation, etc.
}
- f. Operate system normally.
,1Q 2. Critical Items
'a Thr ee maj.or areas are critical in the reliable operation of the HPU and therefore, need to be given high attention.
These are: (a) EHC Fluid Quality Fluid quality, which encompasses solid particle cleanliness as well ac proper chemical makeup is of utmost importance. Solid particle contamination may lead to one or more control devices malfunc:ioning, s Excessive water content can lead to corrosion of ferrcus system components and ensuing malfunction. In either of these cases, this can lead to a possible overspeed event. This has been previously brcught to your attention in cur Technical Information Letter
'. T I L ) 796 "EHC Fluid Systemc Valve Tests" dated March 1975 and TIL 796 " Water Contamination of EFr Fluid
( Through EHC Coolers" dated December 1975. While a leaky cooler is the most direct way of get-ting excessive amounts of water in the fluid, there are other more subtle means. A common one is adding contaminated fluid when " topping off" the reservoir. (In one case, a liquid floor cleaner consisting most-ly of ':ter was added instead of EHC fluid.) This indicatus
. hat more care nia.d s to be taken in the proper storage, identification and handling of this fluid. Another way for water to enter the system, is ,
v - . - ------A
P"C HYDPAULIC POWER UNIT ;[j Bont'I 1 through the air br eather/ dryer . If the dessicant within it is not properly maintained, moist air snter s the reservoir and under some environment con-densation forms en the inside of the reservoir walls in the air space. Improper chemical makeup can lead to excessive wear of control device metering edges resulting in exces-c sive system flow demand. In severe cases, even with ( both main pumps running, a d equ a t e system pressure 1 ? will not be maintained and the unit will trip. It is, therefore, critical that fluid quality be mon-itored on a scheduled basis. Test results should be logged and analyzed for trends so that corrective actions can be initiated before major problems develop. (b) EHC Coolers The EHC coolers represent the most likely source for water to enter the system. TIL 796 (r e f er enced f Wd above) makes detailed recommendations on how to mini-mize this potential. If you have not incorporated these recommendations on all your EHC units, we urge you again to de so. (c) Main Pumos ' The two m . fumps are the working " heart" of the hydraulic pumping system. Their reliable operation is of the utmost importance. Bearing problems with some of the earl have been corrected through various actions.y units Recent ex-perience indicates good reliability. To ensure this will continue, you need to closely monitor pump pe r f o r ma nce . ( During the recommended weekly test and changeover of the pumping system you should be alert to any abnormal indications of pump performance. Such signs u be: excessive noise er vibration, increase in
.iotor system pressure, etc.
cut:ent, longer times required to build up to only lead to pump Excessive vibration cannot deterioration but also cause problems with other supporting equipment such as
- pressure gages, transmitters etc. (viz. items A5 and A6). Significant changes in motor current are either indicative of pump or system deterioration. If both
._..-....._.-o . . . - - ' - ' '
- - - - - - - - ~
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l EHC HYDRAULIC POWER UNIT I
; (Cont.) )
pumps show the motor curtent increase, this indicates that the system is demanding more flow and one or mor e of the control devices has worn and needs re-placement. Longer times to build up system pressure if gone uncorrected can ultimately lead to a turbine trip. For more details and trouble shooting guidance see GEK-46355 and the pump write-up, both of which are previded in the unit's Instruction Book, Tab 13. Any irregularities need to be promptly investigated and h Corrected. D. ORDERING INFORMATION In order to assist you with obtaining the correct parts and equipment which have been recommended in this TIT igure 6 has been prepared which summarizes the r equir ed c, . - *ing data. This in f or ma t ion should be utilized when ordering parts from G.E. or one of the other vendors.
.. s 5,{./
The information f urnished in this Technical Information Letter is of-fered by Ganeral Electric as a service to your organization. In view of this and since operation of your plant involves many factors not within our knowledge, and since operation is within your control and responsibility, it should be understood that General Electric accepts l no liability in negligence or otherwise as a result of your application I of this informaticp. l i I i
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CHC HYDE //AIC PO4R nli EL!.tnit htttim' lui 1 Fmtf m Lw.I (TIL 877) Pft!cD ccef47 A07] vit f !!wtrJ heekly Main Fumes /Poters 11) Test standty s,stea 1 2) $ witch systees Y **Y L3) Meanvre & log actne currents
$vsticn $ trainers Cheth condition irditater Austitary $ttainers ' '
Chest pressure drop *
- Fv11ers farth filter 1/2 y backup filter
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- Air Cryee ChMk tendition of alumtna Reservoir Check fluid level Add if low, trate leakage fluid (1) 5a=ple & test for water t' sing Aavid Water Mete' (2) U sually chett for free ihrevqn lespection cover on stancing water on top top of reservoir of fluid Pipiag Deck for fluid leaks lighten loose connections PbatAly Fluid Take 2 s. les & sealyte fully. See Gtt.4635/
Log resv..s. Flow Control Valve De.h setting See GtY-447 k>.! h tweer 3 AccuN 14 tor Chett gas pretharge See Llt-46355 Onths
- Fv11ers tarth filtee Dange elements
;very 6 tir Dryer CAange fttu.r el m nt Or sort of ten uten indicited tantes * * *
- HP Pall ft)ter
- 1/2 m backup filter * * * * * * *
- Every 12 Coolers (1) Leak test See Gtt 46355 Notns (2) ' clean tabes
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- 1; Pressure $witthes Check settingg Pall filter aP switch
- See Gtt 46540 Fluid Level Gage Chect for proper operation tvery 4 Main Puers (molett overkavl See pcp GtY tears Ntors Inspett See Ctt-2301 8ellef ial es inspett & Clean See GCY.448 Cheo Vaties Reservetr Drain & Clee $ce Gtr.-4t?91 Transfer Peo Inscett see Ctt.446
- Ash; nomal overettom of syste, aad its c:cooncats. Pretleas discovered dseirs trese
~ _ _ - _ _ _ _ _ _ _ _ _ _ _ - .
( O GEfdNG SHEET (TIL m) g Vtda Nde s t Ic'e dif e n gg equne.s 41 1/2 "icroa lachtp Filter Milliard Cerxration P a r t i t, fl.ta34 2:4 (includes: One (1) per t srstne (f gure i 1) 100 W. Fowrth Street modt fitt *eaf, vent screw, (leira New fort 14902 vent screw fastet. Pend AtiN: Mr. V. $cCU $levens gastet. ctette ; cit gasket) A2 Falle's (arif Filter Milliard CorKratien Part f; Fl.1117 33 (tecloofs: ino (2) per ts*bine (Figure t) 100 W. Four*.h S treet recified cover acier (1stra , New f ort 14902 gasket) ATTN: Pr. V. $cott $tertas 43 Air Cryer/treatter G. [. Co. Part f; 254A72108MCl C6e (1) ;tr turttee (Figure 3) (Vendce Mocel llt.!*.5P) A4 5;ste beater G. f. Co. Part #: 20!Bl?0100001 f.o (2) per ts e tire (Installation of tem:erature Seites)
= for torti*es with 204V.
240V hette*1 Part is 1$532:1;G0001 (Insta11at'en of fer.4rature
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. fcr a!) cther tsr*.tnes 15 Gages G. E. Co. Part f: 221A6967 Or.e (1) ;er turoine v,.s 31 8 5= itch fester . Pall Corporation Part f: 'In Line* Ftiter ty x . One (1) per station Fail Filters 30 Sea Cliff avee ve R:657v>017. ( P 5.ttcn) atta EdC wnit(s) 8sf; GLK.46540 Glen Cove, hew fort 11542 H0900075.Gt!*1 (* estar)
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Part f: #C7718Z017 ( P 1ritch) eD9000i5.;I941 (Teste*) 82 Acuavid utter me ter Ericsen Instrtrients One (1) ur statien P. O. Ben 226 with tat unit (s) Ossining, new fort 10562 t3 r1wid Oe feration Unit Pall Corcoration Pall Corocratica . *Tne Pall Cne (1) ;er customer 30 Sea Cliff Avenue Cil Partficattor Systern* sten Cove, New fort 11542 g3,y , , gygg,g) ATIN: Mr. Oave Carson + g The Hilliers Corpo'ation M1(C0 . *M11cc itandard 061 100 W, Fewrth aveeve IeC'aiMr' [1miri, men fort 14902 e i . CP.1 f x 21 !< Portable i 84 *0* Ring tit G. E. Ca. Part f* 161 tac 1PCC01 Mark 1 0'e (1) per sta ticn (Figure a) G. I Co. het 8: 561[& M 003; Mark 11 wt;n eacn tyx CMC u nt*(s) r1 Gust 6
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INSTRUCTIONS cn:-u m v.; OPERATING INSTRUCTIONS FOR DIFFERENTIAL PRESSURE SWITCH TESTER
- 1. GENERAL stalu d in the EHC system the upst ea.m side of tPe 4P Switch receives 1000 psi of hydraulle a
The EHC bigh pressure futer assemblies used fluid. while the downstreLn ;.ide receives hy-on Large Steam Turmne hydraulic power units draube pressure which can vary from 1600 psi incorporate a transducer which senses a pre. down 'o 1500 psi. The tester, however, does determined pressure drop across the filters' provide aar pressure of 100 i.s! (nominal) to the element. Once this vajue is reached a switch upstrean. side of the AP Switch port with its contact in the transducer is actuated and an downstream side ported to atmosphere. He nc e, electrical signal is produced which turns on a a 100 psi AP is achieved in this manner, waroing ly;ht or an alarm in the power plant con-trol roo:n. This signalindicates that the futer element has reached a pre-determined level of 2.2 Operation contamination and should be changed. To perform a checkout the AP Switch to be tested The transducer !s known as the Dtiferential is threaded into the te st block port. An eleetri-Pressure Switch - bereafter called the AP cal cable with mating connecters is then con-switch, and is threaded into the futer head at nected frorn the AP Sutch to the indicator Itght the f actory. The AP switch canbe removed frorn box. th" fLlter assembly for either checking or re- [y]; placernent as lenc as pressure ts first removed g frorn the futer asse:nbly. , g g g gg The purmse cf the EHC AP SwitchTester is to p int the pressure gauge is read, and it should provide a simple means of checktra the AP fan wWn 100 : 15 psid for a good unit. Switch and its associated system wiring. The device is portable and ean be hand-c artied to the The pressure is then relleved by turning the Hydraalle Power Urut (HPU). bleed valve bandle on the clock. , For ease of operation the air purnp was designed 2 TESTER DESCRIPTION such that the force '.o attuate the pump handle at 115 psid was no more than 20 lbs. 2.1 Mechanical As shown in Fig. I the AP Switch Tester con- 3. FIELD USE OF AP SWITCH TESTER sists of an air hand pump of special design, a mounting block for the AP Switch, pressure This tester was designed prima:Uy for field use, gauge and bleed valve. In addition, a battery- i. e. , testing aP Switche s at a power plant and at pwered indicating light ard two sets of cables the EHC bydraulle pwer unit location. A su g - 6 are provided with connectors. One cable ts used gested :rrthod is presented for various situa. during the ccciponent check to Inake a conne:- tions, tion between the AP Switch and the indicator lig ht. The longer cable is used for the wtrirg system checkout between the EHC bydraulte 3.1 To Test a SP Switch on Standby Pump Side power urut and the custorner's control room with HpU tn Operation (See Ftg. U annunciated panel.
- a. Lockout ard disahle auto:natic start circuit, i
It might be :nentioned that the tester does not and tag stanchy pump. Check, via gauges. provide a differentral pressure to the A P Switch that pressure is at zero psi on stardby sys-as in the actual hydr aulic system. When in- tern. n e sww 4. w s-,-, e, - . deau. . e-w , . ,r - ee c. *- --r 4 , y ,e be .e, . e wwei easede.ea, w.wwaoa - eemme. SA md fw*Aer ederniehwi be ==aed er se==sd so+inder prWm-== r== **=e we and cw ered a.# s.v., for she piaoamer's jwtose. see surer diendd be **Jerred se sie Gwieraf Bervre Ceampaar.
o i GEM.46540. OPERATING iSSTRUCTIONS FOR DiriERENTIAL PRESSURE SW1TC11 TESTER *
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GEX-46540. OPERATING INSTRUCTIONS FOR DIFFERENTIAL PRESSURE 5%1TCH TESTER
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- b. Disconnect System cabling from AP Switch b. Remove switch from tester ud re-install (
and careN11y unserew switchfrom filter herd in filter head. Make sure that the proper usmg ceep socket wrench. Install ternporary stae socket is used and torquing requtre-plug in filter head to keep out dirt, ete See ments are met, n g. 2.
- c. P.econnect wiring,
- c. Install AP Switch in tester block using deep em n e on pump 1 a c starung socket wrench.
circuit and remove tag,
- e. Check out this pump circuit in accordance
- d. Connect test cable frota switch to indicator with "HPU-GENERAL DESCRIPTION" and light tox. check for leaks around AP Switch. Correct putnp pressure, etc. If satisfactory opera-
- e. Close bleed valve on tester and stroke -tir tion 1:, observed, then activate pump in ac.
pump until indicator light Just comes on, cordance with "HPU-GENERAL DESCRIP-The light shauld come on at 100 e 15 psid. TION". If not, the switca is defective. 3.4 To Test a AP Switch on Active Pump Side
- f. Open bleed valve to relieve trapped air charge, then close. Disconnect cable from With active pump in operation turn on standby switch in preparation for system test cf 3.2 pump in accordance with "HPU-GENERAL DE-which follows. SCRIPTION". N_ ext shut down active pump per GEK and proceed to check out its AP Switch as described in paragraphs 3.1 through 3.3.
3.2 To Test Svatem Wirine (See Fig. 3)
- 4. IDENTIFICATION
,g If the switch passes test of 3.1 then proceed to ,t check out system wiring. This involves Inaking The Pall filter asse=blies on mostumts shipped an electrical cennectionbetween the switch and in 1975 have an "in-line" porting arrangement the HPU cabling as showu !n Fig. 3. The wir- in the filter head' ing checked would te tnat from the HPU filter Certain units shipping in late 1975 and there- (
to the control rocm. A walkie-talkie is needed after wul have Pall futer assemblies with an for this check or sotne other form oi communi- "L" head porting arranger::ent. cation with the control rootn. Both futer assembliesincorporate a AP Switch in the head, but there are some charq;es in the i
- a. Connect test cable between switch (in tester actual switches; block) to the cennector of the HPU cabling.
- 1. Different thread stres
- b. Energize hand pump as befcre untu control * *Aene has 2 pb.s, room operator reporte actuationof his alarm
,'t head has 3 pins) circuit. At this peint the pressure gauge 3. Different locations for the pressure sensing readirq; on the tester should read the same ports in the switches, as 3 le. If not, a systern malfunction is "
pusent, Due to these differences is a AP Switch tester for both typer of ik Jsemblie s, i. e. , one tester will M accommodate bcth types of 3.3 Reassembly
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The relationship between part numbers for the
- a. Remove trapped air in tester by use of bleed two filter assemblies, AP Switches, ard testers valve , sre as shown in the following tanle.
Futer er Assedy MM l Dsw
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.-Line" 234 A657E P1 HP57124YB2GE l 234A657BP4 RC657VH0972 271A6011P1 HD9000TS-GE571 "L" He ad 254 A7229P1 HZ3411D24 2 54A7229P4 RC771BZO97
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New llampshire _ Yankee May 25,1992 ATTAC11 MENT 12 General Electric TIL 914, 'I3ack Up Lube Oil Systeni-Reliability" c (Reference 1.2.11) e Y d"
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W, ., BACK-UP LUBE OIL SYSTEM RELI ABILITY (TIL 914, Sept. 8, 1950) This TIL supersedes Til's 443 and 490. PURPOSE The purpose of this Technical Information Letter (TIL) 15 to transmit recomenda-tions to Imorove the reliability of the back-uo lubricating oil system. This action has been ororre ted by a significant increase in the number of Incidents where turbine-generators have lost lubricating oil during coastdown. Ol5CU5510H Historically, the back-up lube oil system on large Steam Turbine-Generator (LST-G) Department units has always had at least two (2) Independent oower sources for the pumos. This double protection is an absolute necessity due to the critical function of this back-up system. Its failure to ooerate invariably leads to extensive damage ( to the unit and a long outage. On a modern large unit, repair expenditures can run into millions of dollars and outage times can extend for $6veral months. The back-up lube oil system is defined as the set of oumos (at least two) Intenced to orovide lubricating oil to the bearings whenever the main como(s) are inocerative. On mechanical-hydraulic controlled (MHC) unit s these are the auxillary oil oumo ( AOP), and either one or both o? the turning gear oil cumos (TGOP) and the e.mergency bear ing oil pume (EBOP). On electro-hydraulle controlled (EHC) units, these are the TGOP and tne EBOP. To assure maximum reliability of the back-up lube oil system, all its elements must be considered critical. In the cast , considerable attention h4 been given to the last line of defense, usually the EBOP. We have crevleusly issued three Til's relsted to this subj ect, as follows: TIL 443 entitled " Emergency Bear ing 011 Pumos", dated -12/15/67 TIL 490 entitled " Emergency Bearing tube Oil Pumo; Summary of P.esults", dated 5/29/69 TIL 775-3 entitled "0C Motor Emergency Bearing Oil Pumo Starting Circuits", dated 4/25/75. y These Til's trade recorTnendations as to the required actions needed to achieve enaximum reliability of the Emergency Bearing Oil Fun (EBOP) subsystem. By issuance of this TIL totn TIL L43 and 430 are superseded. TIL 775 will remain in effeet.
. . . . . .. . -.J
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/$ TIL 914 - (Cont'd.)
BACX-UP LUBE OIL SYSTEM RELI ABILITY - Ol SCUSSION - Cont inued, Ecerlence now indicates that more emohasis needs to be given to Imoroving the reliability of the first line(s) of defese of the '1ck-uo lube oil System, tyolcally the AOP and/or the TGOP. This puns subsystem is just as critical as the EBC. .bsystem. Any reliability deficiency in either subsystem greatly detracts from the reliability of the total system. - Most loss of lobe oil incidents have been due to oumo cower suocly f ailures and ooerator's erroneously turning pumos off. Few have actually been attributed to machanical f ailure of comoonents, carticularly pumps or motors. On electrically powered pumos, f ailures have been predominantly related to starting or cower suoply switching circuitry - both hardware and logic. On units with steam cowered oumos, invariably the steam supoly was valved of f due to steam leaks, and the situation allowed to go uncorrected for a long period of time. In some other cases, the units were ooeratea with one or all of the cumoing subsystems out of service. This Til makes numerous recomendations aimed at Improving the reliability of the cr i t ical b ack-up lube oil system on your units. These recommendations, which are your immediate
'.h..-snd primarily based on the experlence gained f rom recens lacider,ts,-need dedicated attention.
I
...C O MM EN D AT I ON S, The critical nature of the back-uo lube oil system requires all asoects relating to its relicbility 6: e rev8ewed. Procer design, operat ing p rocedures, maintenance oractices and periodic test' g must be given due consideration.
OPER AT ION . Whenever a Turbine-Generator shaf t is rotating, lubricating oil must be sueelled to Ehe bearings CONTINUOUSLY. This requirement must be fully understood by all operating personnel. In ref erence to this we recomend the following: A. Never a t t emp t to start a turbine unit until It has been verifled that a DC oumo olus one other sub-system of_the back-ce 15 fu'iv ooerational, A recent incident serves to illustrate the wisdom of this. During an cutsge of a large modern unit it was discovered.that a relay in the DC starter of the EBOP had burned out. The unit was rolled with the EBOP system unable to start autcmatically._ . Vhen the unit reached rated seced a vibration trio was exoerlerced along with loss of AC oower. Bef ore the EBOP could be manually started at the reservoir, severe damage occurred resulting in a sixteen week outage.
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TIL 914 - (Con t 'd. ) BACK-UP LUBE OIL SYSTEM REll ABILITY - OPERATION - Continued B. Never continue to ooerate a turbine unit for an extended cerlod wi t h k nown back-uo system def ielencies. Any deficiencies should be corrected innediately. An extreme exancle of this rule not being followed is la incident where the steam driven AOP had been valved out because of steam leaks. The situation went uncorrected for quite some time. Concurrently the AC driven TGOP was locked out for motor maintenance while the unit was running. Occrators forgot about both -deficiencies and proceeded with a planned shutdown of the unit. Severe unit damage resulted. C. Do not shut off back-uo system oumo s which have come on automatically, unless such action is extremely necessary and carefully considered, f9%l - Ts? i There are numerous examples of loss of oil incidents where the . b ack-up pumos have come on automatically as designed and then were une xp ec tedly stopoed. Saving battery capacity, for exaaple, i s not a sufficient reason to shut down the back-uo system pumos when comsared against the ootential consequences of oremature loss of tube oil. D. Based on recent experience a thorough revlew of your coeratlnq orocedures is recomnended. Such procedures should encomp ass both normal and abnormal conditions. BACK-UP SYSTEM DESIGN The critical nature of the back-up lube oil- system mandates that reliability be the i prime corsideration in its design. Excerlence has shown a good record of both system design and hardware for the portions provided with the Turbine-Generator unit. Continuous moni torlag - of coerating e xp er i ence has pointed to various incrovements which were incorporated into new designs and have been recommended for retrofit into existing units. An examole of.this is Til 775' referred to. earlier. However, particularly on electrically driven cumos a major oortion of the system including the power sucoly is designed and provided by others. This leads to n.any I
-design variations and our latest experience shows most eroblems are occurring in the power sucoly. Theref ore, it is recommended that a comclete desion review be n.ade on each of vcur units.
h TIL 914 - (Con t ' d. ) B ACK-UP LUBE Olt SYSTEM R Ell ABILITY - BACK-UP SYSTEM DESIGN - Cont inued A. AC Powered Pumos The AC motor driven tube oil pumos are usually the first line of defense in the back-vo system. Rellable coeration of these pumos is just as Imoortant as for the last line of defense (usually the EBOP). In reviewing station circuitry which provides cower for these oumos you should ensure that the following features are includedt
- 1. These pumos are in a very critical system. It is inc e r a t i ve that as long as AC power is available anywhere in the station it should be positively ava i l ab le to t he AC l ub e oi l p umo s.
- 2. It is highly desirable that the power supply be f rom the single most reliable source available (a critical buss). This eliminates the need for complex switching provisions which can introduce ' additional failure g3. . ,-
._ possibilities.
3 If other considerations require e design which provides o for multiple sources of power (i.e. primary and back-up ) , then emergency switching must be acconc!Ishsd automatically. Timely or correct manual transfer cannot be accorrelished re l i ab ly. There are too many activities and events going on during a unit trip for
~
coerators to properly cope with manual switching.
- 4. The design of the automatic switching needs to be carefully reviewed. The following must be considered (a) Redundr t power sources must be provided to actuate the transfer.
For e xane le, if DC station power is lost, boiler control can also be lost, resulting in a boiler and turbine trip. Power for the AC lube oil cumos may then have to Je transferred from unit buss to a back-up critical buss, sucolied by outside power.- If the only means of initiating the automatic transfer is by actuation of a DC powered relay, then the single loss of DC will also result in no AC
, cower being available for the AC motor driven l ub e o i l p umo s . A redundant AC powered relay, powered by an available AC buss, is needed in such a design, s
p!- TIL 914 - ( Con t ' d . ) . BACK-UP LUBE Oil SYSTEM REllABillTY - BACK-UP SYSTEM DESIGN Continued Vhile the deficiency of such a design may seem obvious, ex6ct y such a situation occurred recently. Two (2) units in the same station came down without oil. One had been in service for twenty (20) years, the other twelve (12) years. (b) If more than one source of back-up oower is provided, switching to a dead buss must not be possible. This also applies if the transf er is manual. (c) Once switching has occurred the circuit should
" lock-in" to the back-up power source as long as the primary source remains dead. This I again applies to manual transfer modes.
(d) On automated units, software and hardware inf r. design must not allow a failure of the
'OP automation equipment to cause a failure of power sucoly to the back-up lobe cumos.
A very recent incident again serves to illustrate. A momentary loss of power to the automated plant control system of a six month old turbine unit caused a boller trio. The Turbine-Generator was then - manually tr ipoed. The control logic was such that on oower loss to the controller many of the motors in the station became locked out and remained locked out even on restoration of power to the automatic controller, included in this scheme were all motors of the back-uo l ub e oil system. When the low bearing header pressure . alarm came on the back-uo lube oil pumps were started manually, but too late to prevent serious damage to the unit. B. DC Powered Pumos
/
The DC motor driven lube oil cumo is usually the last line of defense in the back-vo system and it must coerate crocerly, in your review of the design ot this sub system, due consideration must be given to the following features: s
m S TIL 914 - (Cont'd.) ' BACKr0P LUBE OIL SYSTEM REllABILITY - BACK-UP SYSTEM DESIGN - Continued I. Starting Circult*, TIL 775, ment ioned earlier, made two (2) lmoortant recommenda-tions. One, was the conversion f rom a one to a four pressure switch DC oump starting scheme. The other, was that de-energized type CC motor starters be replaced- with an energized type. The reliability gair.s to be achieved by lmolementing these changes are fully delineated in that TIL. If TIL 775 coes neolY to your turbine-cenarator unit and has not yet been imo lemented we again Strongly recommend that this be, cone.
- 2. Circuit Protective Devices Particular attention must be given to the use of thermal _ overload and short circuit protection on the DC motor and motor starter.
- 73 ..- (a) Over load erotective devices must not be wired to trio ~
$Y the motor, but only to sound an alarm. Keeping the'DC '
motor running a f ew minutes longer to pumo oil to the
- unit is of far more imoortance than protecting a relatively inexpensive motor.
(b) Short circuit protection should be in the form of a magnetic type circuit breaker, not fuses. Fuses cossess several -undesirabic characteristics that make them unaccectable for use in the emergency oumo circult:
- The fuse element exonriences deterioration f rom the chemical and physical stresses produced during repeated short duration _ overloads which may occur during motor starting. Though not present long enough to blow a correctly applied fuse, deterioration may cause failure which would go undetected until the next motor startue.
This type of fallure was the cause of a 8 engthy forced outage on an LST-G' unit. Following a loss of station service AC the OC .EBOP started auto-matically. But after runt,ing for about a minute the fuse in the DC sucoly failed causing a-loss of tube oli incident and severe damage to the Turbine-Generator.
- Str.ce a f use_ deoends on the mel t ing of -a metal link the exact failure oolnt is subj ect to con--
siderable variation..
,1 v
TIL 914 - (Cont'd.) { BACK-UP LUBE Olt SYSTEM RELI ABillTY - BACK-UP SYSTEM DE5IGN - Continued
- When a fuse falls it must be reolaced. This introduces the risk of an incorrectly rated fuse being eleced in the circult.
- The fuse ello size and its condition, together with the size of the (. nductor attached to it can have a considerable influence on fusa performance. Additionally, corrosion of furs and connecting clip, leads to fuse heating eroblems.
- Fuses cannot be tested whereas magnetic circuit breakers can be.
Magnetic circuit treakers wlll-In general, have two (2) o ratings indicating their time delay and instantaneous modes of ooeration. The " Nameplate" rating is that value below which the breaker will succort continuous current without ooening the circuit. The 3.4 '^
._ " Instantaneous" rating is that value of current surge that will cause the breaker to trip instantaneously.
The "Instarstaneous" rating must be at least 150% of the
-maximum In-rush current measured dur hg motor startuo.
This maximum In-rush current can be as high as five (5) times rated full load current. The in-rush current must be measured to verif y that the 150% margin exists. 3 OC System Alarms Stuales of l.ST-G's coerat ing excerlence with DC powered EBOP's indicate that an Im rovement in sub s'/ s t em reliab!llty can be effected by-the provision of a g oup of alarms which monitor the integrity of the DC power sucoly and controls for this cump. A list of-these reconstended DC comonents and alarms is given in Attachment A. Your design review sho*Jld consider the addition of any of these alarms which are not already installed. C. Steam Driven Pumes i Most f ailures of steam dr!ven cumo subsystems have been attributed to the steam source being valved out of service. Invariably this disabling action had been taken to stoo steam leaks which had develooed in the steam sucoly system. While this may be considered more of a maintenance deficiency, it may be that a review
. of the design of this steam sucoly system may lead to hardware imorovements which would alleviate leakage orobability, in your review, the following should.
te' considered:
- Hardware reliability (valves, flanged connections, etc.) im;rovements.
l _b
j ((; -' t 914 - (Can t ' d . )
"3 BACK-UP LUBE OIL SYSTEM RELIABILITY - BACX-UP $YSTEM DESIGN - Continued
- Supply cloing designed such that it is kept free of water. *
- Isolation valve (s) between the steam source and the pumo governor valve have provisions for locking open.
- Exhaust line has no valves and is well dralned.
- Alarm is orovided to indicate " Low steam su;Dly oressure".
PERIODIC KAINTENANCE & TE$ TING Procer, timely maintenance and testing of the back-uo _ lube oll pumolng system ccmoonents will contribute significantly to its reliability. Our analysis of loss of lube oil incidents indicates that lack of timely maintenance is a major cause of such f ailures. A number of other f ailures on record were. the result of malf unctions that are likely to have been discovered in a test. t#,.
%?.4 he attached Table B, sumnarizes our recommendations for periodic maintenance and testing of the back-vo lobe oil system. It represents what we consider to be the ,
minimum level of activity necessary to keep the system in reliable condition. Any deficiencies found during system testing or otherwise must be corrected oromotly as indicated in the remarks column of Table B. We recommend that you review your maintenance and testing procedures using Table B as a guide. NOTE: Table B only addresses hardware normally provided as part of the Turbine-Generator set. EMERGENCY BEARING Oil PUMP (EBOP) SYSTEM - PERFORMANCE DATA Performance Data Sheets for the EB0P System are accended to this TIL as Attachment C. These sheets supersede the Check-of f List which was issued by TIL 490 cublished in 1969 and currently in use. All data required to comolete these Data Sheets are available once the "Every 6 to 12 Months" tests c rescribed in Attachment 8 are completed. If the6e-tests have been done on a unit. within twelve (12) months of your receipt of this TIL, such data can be used to fill out the Data Sheets. s O
gg IIL 914 - (Con t ' d. ) 's. . BACK-UP LUBE Oil SYSTEM RELIABILITY - (MERGENCY BEARING Olt PUMP (EB0P) SYSTEM - PERFORMANCE DATA - Continued , Ve request that you perform the tests described in Attachment C If this has not been done within the last twelve months and answer all applicable questions of the Data Sheets and return a copy of these concleted Data Sheets for each of your units to yotr i t, $ E Service Reoresentative for review. Upon comoletion of this review soecific action will be recomended, if required. We recomend concletion of these data sheets within twelve (12) months after receipt of this Til. Whett you conduct subsequent oerlodic testing of the EBOP system, test data should be recorded strallarly and conpared to previous results. Any EBOP system deterioration noted should be investigated and corrected immediately, idL
' lu!
DIE INTOPP.ATION FURNISHED IN THIS TECHNICAL INFOP?.ATION LETTER IS OFFERED BY GENERAL ELECTRIC AS A SERVICE TO YOUR ORGANIZATION, IN VIEW OF nlIS AND SINCE OPERATION OF YOUR PLANT INVOLVES MANY FAC-TORS UNKNOWN TO US , AND. SINCE OPERATION IS WITHIN YOUR CONTROL AND RESPONSIBILITY, IT SHOULD BE UNDERSTOOD THAT GENEPAL ELECTRIC ACCEPTS NO LIABILITY IN NEGLIGENCE OR OTHERWISE AS A RESULT OF
-YOUR APPLICATION OF D.IS INF0FF.ATION.
s
New llampshire Yankee May 25,1992 ATTAcilMENT 13 General Electric GEK 46354, " Maintenance and Inspection of Turbine flotors and lluckets' P
MAINTENANCE AND INSPECTION OF TURBINE ROTORS AND BUCKETS GENERAL INTRODUCTION ings. Examples are - loss of bucket covers, loss of part or allof a bucket. Step changes in vibration Reliability, availability, and sustained efficiency, level are indicative of this conditionin many cases. are the benefitsto be realizedfrom proper mainten- - Acce and inspection of the turbine rotors and buckets. c) A means of detecting a water induction inct-Water erosion, solid particle erosion, rubbing of dent. Water backing up from extraction lines and rotating and stationary parts, water induction, and cold reheat lines will cause contraction of the shell chemical attack can all occur during the operation lower half, giving a humping effect that cu lift the of a turbine and leart to deterioration of the quality diaphragm patkingsagainst the rotor causing radial butit into a new unit. rubs. Dowing of the rotor resultswhenpacking rubs cause uneven heating on the rotor surface. This it is not possible to exactly predict the rate of further increases the intensity of the rubbing. A deterioration (if any) due to the many unknown con- bow in the rotor, of even a few mils, will cause a ditions that a urdt is subjected to during its life shift in the a.xis of rotation sufficient to produce a (Number of start-ups, varistbnin loading, variation change in vibration level at the bearings. In.the in steam conditions, feer
- water treatment, etc.). low pressure element of the unit, which contains There are, however, pNcedures which can be fol- longer buckets, severe mechanical damage can be lowed to monitor the condition of a unit during op. caused by water induction and this may be reflected eration, and proptr inspection and maintenance by a change in the vibration level at the bearings.
during majot inr,iection outages can do much to For specificdetails onwater induction, see " Design prevent deterirvation. Since the frequency of in- and Operating Recommendations to Minimize Water spection is dependent upon service duty, system de. Induction in large Steam Turbine", GEK 25504. mands, age of the unit, and many othe? plant re-quirements, the time intervals between inspections d) A means of detecting bo ved rotors. Insuf. must be determined by the owner. The following ficient clearance, created by mis assembly or are recommended monitoring and inspection pro- water induction, cancreatea bowwhen packing rubs cedures to follow during the life of a unit: cause uneven heating of the rotor surfaces. This shift incenter otrotation furthercompounds the rub MONITORING and increases distortion. A changein vibration can be detected at the bearings. Packings, spill strips. Between periods of normal maintenance, during and bucket covers are the most frequently damaged which the turbine is opened for inspection, there parts, but permanently bowed rotors may also occur, are a number of procedures a utt11ty can follow to monitor the condition of a Turbine-Generator unit: e) A means of detecting a deeply cracked rotor. A rotor may crack from repeated excessive ther. Vibration Level mal stresses orin rarecases, from fatigue. Ther-mal cracking can result from a few incidents of a) A means of detecting bearing problems. A extremely high thermal stresses (as in water in-change in vibration lovel or erratic vibration read- duction) or from repeated thermalstresses of lesser ing can be indicative of a wiped bearing and scored but stilldingerous magnitude (as in repeated startup journal, as can an increase in bearing metal or oil and shutdown beyond the recommended starting and temperature. (See section 9 MainJournal Bearings) loading limits). Fatigue of a shaft or rotor can be produced by periods of operation with adjacent b) A means of detecting problems in the rotating bearings misaligned. parts. Any circumferential variation in weight, in the rotating parts, will result in anunbalance which A crack will change the flexibility of the rotor will be reflected in the vibration level at the bear- and hence the vibration level, it will also cause the rk. we.vo d. .e ,-,ne e. m, .a do.a. , ,w.w 4. ., e an e. ,,w.d. rw --y w. . arm e. 6,. e 4 e.an.o a
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, fu s. pursk. ear's perpenas, s. orer k.Jd I,e t.twr.d ee ek. Gew.e Docste C.nv.ay. __.______-__---J~t
GEK-46354 MAINTENANCE AND INSPECTION OF TURBlNE ItOTORS AND BUCKETS rotor to react in an erratic manner to normal 2. Water Induction 9 ' attempts to balance. Serious mechanicaldamage to the latter stages Thermodynamic Performance may result from water induction. Visual in-spection of the last stage mayrevealif such a a) An increase in operating pressure within any problem exists in the unit. section of a unit can be indicativeof two things, (1) internal deposite within the steam path, or (2) in- 3. Stress Corrosion Craegg ternal damage within the steam path. The high chrome steel used for turbine buc. Contaminants and foreign material carried over kets and dovetails is susceptible to a phen-from the boiler can readily be deposited on the omenon known as stresscorrosion cracking - buckets and nozzle partitions of the unit, thus re- which is inter granular cracking of a highly ducing the steam guth area and restricting flow, s'.vessed part in the presence of a corrosive resulting in increased pressure. Likewise, me- agent. The most common corrosive agents chanical failure of any prt within the steam path are caustic, chlorides, and sulphides which can result in debris becoming lodged in the steam can be introduced into the steam path by path and result in an increased pressure from the carryover in steam, or as a residue left from steam flow restriction. a cleaning agent. Another factor required for such cracking is a warm, moist atmosphere,- b) A reduction in operating pressure could be which is exactly the condition found in the latter indicative of mechanical damage in which the failed stages of a steam turbine. Cracking from this part is digested to thepoint of not restricting steam - cause may be found in the covers, tie-wires, flow, but the loss of the part increases the flow ca- erosion shield, or vane. pacity of the steam path. Example - loss of or erosion on buckets or prtitions. 4. Mechanical Failure Efficiency, Mechanical failures of vane, covers, or tie-wires would be discovered during inspection, a) A loss of efficiency in any section of the unit can be indicative of internal deposits or internal 5. Foreign Material Damage - damage the same as described above in Thermody-namic Performance. There have been a number of instances when foreign materialhas been lef t in the unit during it should be noted that internal dantage, even to an installation or maintenance outage. Such the extent of bucket loss, is not necessarily re- material, as it becomes dislodged may pass flected as increased- vibration level, if the loss - through the steam path an.d result in damage occurs in a symmetrical manner. to the last stage as well as the partitions and INSPECTION OF LAST STAGE BUCKETS b"*****"P**** THRU MANHOLE inspection A turbine is occassionally shut-down for short durationsdue toother plantproblems. At that time, Considering the value of the information which an inspection of thelast stage exhaust region can be can be obtained by suchan inspection, the ease with made, with -little difficulty, through the access which it can be obtained, and the severe conse. manholes. This method of inspection can reveal a quences that may result from failure of last stage number of operational problems, last stage difft- and other low pressure parts,' it is recommended culties, or problems related to the internal condi- that the last stage buckets of all units be inspected tion in the machine upstreamof the last stage. The at the customer's convenience on an annual basis, following can all be detected by means of last stage This inspection would consist of a thorough visual inspection: inspection of parts visible from inside the exhaust hood plus a red-dye inspection of certain areas of
- 1. Excessive Last Stage Erosion the last stage buckets 1 The following areas should ae inspected:
Excess erosion onthe trailing orleading edge of the last stage buckets can be caused by 1. Tie-Wires mis operation or mis-direction of water sprays, running for extended periods with a Drated or weldedtte-wires shouldbe visually lower than normal reheat temperature, or inspected for cracks in the tie wire, the fillet because of waterinduction intothe steam path between tie wire and vane, or in the vane ad-from an extractionconnectionupstream of the jacent to thette wire. Inose tie wires should last stage, be inspected for evidence of tie wire cracks. 2
h1AINTENANCE AND INSPECTION OF TtJRDINE RO'IDRS AND BtJCKETS GEK 46354 Fretting, or other damage in the area of the the possibility of a forced outage. In addition, they tie wire hole, should also be luhed for, may also be symptomaticof other troubles upstream in the machine.
- 2. toose Tie wire sleev'"
MAJOR UNIT INSPECTION Some 3600 RPhi buckets utiltre tie wire Naturally, during a major turbine inspection, sleeves held on bosses. These should be vis- with all the rotors exposed, a more thorough in-ually inspected for slits or tears, for missing spection can be made. Two methods of instection sleeves, and for sleeves which may be cocked are av7 tble, visual and non destructive testing, between adjacent bu:.kets. A good visual examination will quite often reveal the majority of problemsthat might be encountered,
- 3. Erosion Shields and will generally reveal areas that should be more thoroughly examined by non-destructive testing.
Erosionshleids should bevisuallyand red-dye Visual examination, early in the outage, helps re-inspected to uncover evidence of cracking. cognize priorities for testing andacquiring replace. Visual inspection can also reveal cases of ment materials, and can domuch toassure comple-severe erosion or failure of brated joints, tion of necessary action within the planned outage time span.
- 4. Bucket Vane The vane should be visually inspected for 1. Visual
~~
Examination evidence of cracking or pitting, as well as trailing edge erosion. a. Rubbing
- 5. Peened Covers Rubbing can occur both radially and axially.
0 loni for rubbing on thecovers, ptekings, wheels The cover should be inspected for indication anddovetails. Significant tubbing in any of these of lifting or severe erosion of the cover or areas can be critical because of the effect cf tenons. In addition, any miss;ng covers can localized heating. Cover and bucket material be discovered, especially in the high temperature stages, is subject to cracking when severely rubbed. On
- 6. Inserted Covers the wheels and rotors, the heat affected zone may be moresignificantthan theamount of metal Severa11onger 3600 RPhi buckets employ an removed by rubbing.
inserted cover. Such covers should be in-spected for erosion, cracks in the tenon, or b. Erosion cocking of thecoverbetweenadjacent buckets. hilssing covers would also be detected. 1. Water Erosion - Excessive water erosion can be caused by misoperation or misdirection
- 7. Dovetail of water sprays, running for extended lwriods with lower than normal reheat tempertture, or The accessible area of the bucket dovetail because of water laduction irto the steam utth should be inspected for any sign of distress, from an extraction connection, pitting of the wheel or dovetail pins or loose pins. 2. Foreign Particle Erosion - Excessivefor-eign particle erosionusually ;s notedcu the gov.
- 8. Spill Strips ern4 stage or nrat stage of b reheat sdon.
The source of particles is an oxide carryover The radial spill strips should beinspected for from the boiler and steam pipes or shot peen severe rubbing. In the case of a honeycomb materialleft in the steam leads after welding, spill strip, missing filler material would be discovered. Photographs and/or casts (R.T. V. rubber, dental compound) can be an invaluable tool for comparison at a future outage.
- 9. hiechanical Damage
- c. Cracks All accessible rotating and stationary parts shouldbeinspected forevideneeof mechanical Close scrutiny can also teveal cracks in (impact) damage. covers, vanes, dovetails, or rotors. These cracks can be the results of rubbing, impact Problems in any of the areas described above damage, fatigue, thermal stresses, or stress can possibly lead to future last stage fallure, with corrosion. Early discovery, visually, can lead 3
m ;
GEK.46354 MAINTENANCE AND INSPECTION OF TURDINE ROTORS AND DUCKETS to proper nrn-destructive testingand analysis to e. Deposits > determine the cause and recommendations for correction, Deposits that have built up on the steam path, restricting flow and reducing the efficiency,
- d. Stross Con rosion should be removed, it is advisable that samples of deposits betakenfromthesteam path and rotor The materials and strass levels necessary to for I;tboratory Analysis. This analysis can in.
build the large, efficient units, required today, dicate whether contaminants are entering the makesvarious components s.abjectto stress cor. nit, the possible source of contamination, and rosion cracking t! caustic, sulfides, cr chlorides result in a recommendation to eliminate, or at are introduced into the unit. Erosion shields, least reduce the source of con amination; such dovetail pins, buckets, wheels, rotors, and as, a change in feedwater treatn ent. shafts, are allsubject to stresacorrosion crack. ing, f. Removal of Deposits To minimize the possibilities of stress cor. Removal of insoluable deposits from rotors rosion cracking, theprocedures given in" Clean. and buckets by blast cleaning has come to be an ? ing of Main Steam Piping and Provision for Hy. acceptedpractice. Tests indit ste that the use of s drostatic Testing of Reheater". GE!.169688, 220 mesh aluminum oxide, obtainable from L should be adhered to. grinding wheel- or abrasive manufacturers, is satisfactory, it produces asoft gray satin finish Chemical cleaning of the steam side of the and slightly increases the fatigue strength of the cos. denser without blanking off the low pressure material. in addition to the relatively pure na. elementa of the turbine should never be under. ture of the product, it also contains a corrosion taken. All L. P. elemtnts must be blocked off inhibitor. when chemical cleaning is being performed. There is concern that stress corrosion cracking Some of the materials that have been tested will result from fumes of chemicals of unknown in our I;tboratory were found to be inert compo. composition and their possible concentration sition, while in other samples, traces of sodium when entering tne turbine steam path. All in. chloride (Nacl),'which is highly detrimental to ternal areas can be affected, but of particular 12. chrome alloys, were found. Furthermore, concern are those areas which are not open and our tests have indicated that sand and fly. ash difficult to wash out. Such a condition exists blasting result in a lower fatigue strength, when the fumes condense and run down intothe finger-type bucket dovetails and other fit areas. While inherent sturdinessof General Electric Turbine buckets has been long recognized, care. When such a cleaning program is coatemplated, lessness in cleaning operations may seriously specific arrangements should be made to blank. affect the mechanical strength of the part. Hand off the arca at the joint between the condenser cleaning withfiles, scrapers, etc. often produces and the exhaust h ad, or some other suitable heavy transverse scratches which can cause block joint, with plastic sheet or canvas. The greatly reduced fatigue strength in turbine large risks of damage to the turbine from leaving buckets, the opening unblankedjustify therelatively small cost required to install an effective barrier. Blast cleaning in general is far superior to hand cleaning methods and results it . much During operation, chemicals in the boiler quicker, less expensive, and superior job. It - may also be carried over by entrainment or in reaches fillets and c revices that cannot be reached the vapor phase to deposit in specific terr 7erature by hand cleaning methods. and pressure regions of the turbine, Even low proportlanal carryover into the turbine, because Blast cleaning shouldbe done after a complete of the concentrating mechanism which exists in visual inspection and prior to any non. destructive the machine, canlead todamagingconcentrations testing. cd contamine ds. Both caustic and chlorides can e carried over in the vapor phase. In plants where derninet-alizera are employed, if resins 11 Non-Destructive Tuting become depleted or regeneration is carried out incorrectly, it is possible for sodium ions or There are several means available to test the chloride ions to beintroduced intothe feedwater. . soundness of the turbine rotor and buckets;X. ray, . Thus, close attention is required in this area. ul'rasonic test, magnetic particle test, and red. dye penetrant test or Zyglo. test. Each of these tests Also, see " Stress Corrosion Cracking", has its limitations and is 'noreapplicable to certain GEK25407, areas. 4-
1 MAINTENANCE AND INSPECTION OF TURBlNE ROTORS AND BUCKE*TS GEX 46354
- a. X-Ray CAUTION: Erosion shields 'are ' of non. -
magr. etic materials and must t,e tested by X-ray testing is most applicable during man- a dye-penetrant or fluorescent penetrant. - g ufacture of buckets and has not had widespread - usage as aninspection toolfor anin service unit; d. Red-Dye Penetrant or Zyglo - primarily, because the defects being tested for are not internal to the part. However, X-ray ' Red-dye penetrant or zyglo must be utilized testing can be used to check the ension shields in testing non-magnetic materials such as those on last stage buckets, used in erosion shields.- It is also ussful in verifying magnetic particle test results frained personnel should be used for this te% due to the
- b. Ultrasonic Testing possibilities of mis-interpretwn of results.
The use of ultrasonic testing is becoming The Turbine rotors _ and F.ading are highly more widespread. Areas that can be inspected stressed components, ut!"f .g high strength alloys, by ultrasonic means are:_ bucket dovetail pins, Proper application Lu utilization of monitoring buckat and rotor dovetails, and rotors. Special equipment and inspection procedures can do much tests have been developed, by General Electric,- toincrease thereliable, efficientlife of the turbine-to detect cracked dovetail pinn, cracked bucktk generator unit. dovetails and wheeldovetails, and to'determirro the depth of a crack in a rotor surface. Ultri- Properlyapplied andinterpreted non-destr.nettve sonic testing may also be recommenled for the testing also can do muchto inate the possibility bore, periphery, or both. It is recommesvlM of a future forced outage, that Gwneral Electric personnel, - especially trained, be utilized for these tests. The above discussion, by nece?sity,- is not in-tended to tv a detailed instruction for inspections. -! The local General Electric DAstrict Office can sup-
- c. Magnetic Particle Testing ply technical direction and trained ' personnel to
.i 1
make a: complete and, thorough inspection. The Magnetic particle testing has long been es- General Electric Cor oany will provide repair and tablishedas a reliableand quickmeans of testing operating - recommendations upon reporting of the the entire assembled rotor; however, care must results of any inspection. Upon recellt of a com-be exercised in testing the high temperature plete description of the problem, General Electric stages. Thehigh strength materials can be mag- Engineers will describe _the repair options avril-netic partic'e tested though it is a little more able, considering the design parameters on the difficult and time consuming then on the more stage, serdce experience with other similat 4e-readily magnetized materials used in the lower signs. and exprience obtained with various kind of temperature regions, repalc procedures. g 5 _ _ _ _ _ _ __--_ ---_- - - O
) GENER AL h ELECTRIC 12-76 (5M) T _ _ _ - _ _ _ - _ _ -}}