ML20076M663

Rept Entitled Design,Operating & Insp Considerations to Control Stress Corrosion of LP Turbine Disks, Presented at American Power Conference on 830418-20 in Chicago,Il

ML20076M663
Person / Time
Site:	Comanche Peak
Issue date:	04/18/1983
From:	Engelke W, Jestrich H, Schleithoff K KRAFTWERK UNION AKTIENGESELLSCHAFT
To:
Shared Package
ML20076M648	List: ML20076M663 TXX-4008, Discusses Suppl 3 to SER (NUREG-0797) Requiring Bore & Keyways of low-pressure Turbine Discs Be Inspected Ultrasonically During First Refueling Outage.Licensing Condition Unnecessary & Should Be Deleted
References
NUDOCS 8307210034
Download: ML20076M663 (33)

Text

.

' Design, Operating and Inspection Considerations to Control Stress Corrosion of LP Turbine Disks l

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Wilhelm Engelke Hans-Achim Jestrich Manager, Steam Turbine Design Division Material Inspection &

Kraftwerk Union Quality Control Department Kraftwerk Union Kurt Schleithoff Heinz Termuehlen Manager, Chemical & Physical Manager, Application Engineering Material Properties Subdivision Utility Power Corporation Kraftwerk Union 8307210034 830718 PDR ADDCK 05000445 (Of pTOSentation at the E

PDR AMERICAN POWER CONFERENCE CHICAGO,ILLINOlS, APRIL 18-20,1983 l -

Dosign, Oporating and Inspoction Considorations to Control Stress Corrosion of LP Turbine Disks I

?

i INTRODUCI' ION Nuclear PWR and BWR steam supply systems provide low-energy steam. As a result, the steam Disk type LP turbine rotors have been designed for a large variety of power plant applications.

II

• I"""CI. ear turbine ss about 70% 1arger than that of a fossil turbme of equal rating. Also, con-The authors' companies and one of their founders, l

i.e., Siemens, utilize solid forging rotors for all s,idering that the output of nuclear units today has risen up to 1300 MW, the application of high-speed high speed (3600 rpm and 3000 rpm) turbine.

turbines cannot be economically justifiedN Low or generators. Disk-type rotors have been adopted half-speed LP turbines, developed by the design only for low speed (1800 rpm and 1500 rpm) tur-laws of geometric scaling, feature annulus areas l

bines in nuclear power plants with PWR and BWR that are four times larger.

steam supply systems. However, the second founder of Kraftwerk Union, namely, AEG, has The deterrent to building such large turbines was supplied disk type LP turbine rotors for high-speed the fact that low-speed LP turbines would require fossil reheat and non-reheat units.

solid rotors weighing 300 metric tons (660,000 lb)M Forgings of this size were not available when the This paper describes the design, the operating firstI W-speed LP turbmes were designed about 2a experience and the inspection method of the disk.

years ago. Even though such large forgings have type LP mtors for nuclear turbine-generators.

recently become available, present nuclear LP Additional information about the obsolete AEG turbine rotors are of the disk-type design, which disk type LP turbine rotor design and the oper-g ating experience gained in various countries will U"IY. require a 70 metric t,ons (154,000 lb) step shaft i

f rgmg and ten disks with a maximum weight of also be provided.

10 metric tons (22,000 lb). Figure I shows a low-speed, 4 flow tandem compound nuclear turbine with two disk-type LP turbine rotors.

NUCLEAR LP TURBINE ROTOR DESIGN Developing disk-type rotors required a concerted y

The applicatio,n of, solid rotor forgings for high-effort to design a shaft / disk shrink fit with a min-speed LP turbmes is possible becaut.e the major imum of tensile stress concentrations in order to forge masters are able to provide high quality provide for the lowest possible susceptibility to y

forgmgs,of the required size. Independent,of the corrosive attack.

rotor design concept the rough machm, ed weight of even the largest LP rotor is less than 100 metric The regions of greatest concern are the shaft steps, tons (220,000 lb). Metallurgical inspections and the shrink fit boundaries and last, but not least, a

machining 9f such rotors can be effectively per-the keyways. Photoelastic model tests, finite ele-I formed. The integrity of these rotors has been ment stress calculations and full-size testing in the l

proven by excellent operating experience. The overspeed facility to measure local stress risers solid rotor design concept without axial through-were performed before finalizing the disk / shaft, i

bores reduces the tangential stress level and elim-shrink-fit and keyway configuration shown in inates corrosion in the rotor center.

Figure 2. This design features five cylindrical b

""T"*BiPJGE n rq=

Fig.1 Low-Speed 1300 MW Tandem-Compound Nuclear Turbine with Disk-Type LP Rotors.

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How:vtr, th2 stresses in keywry 2 incr=se by io,,,,,,

02' ^l sirN.I.*t c"rU h_

only a smtll atmount bec%use of pl= tic elongation.

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i Bringing the rotor back to standstill reduces the 7

local stress levels at both keyways to much lower levels as shown by points Ci and C2. At this time,

/),( 1 1.:

the stress level of keyway 2 is lower, but keyway 2 q ( "{;f -L]

underwent more plastic elongation. Subsequent j

v power plant operation between zero and rated 8

2'**

speed results in stressing keyway 1 and 2 between ss Shrink-Fit points Ci Di and C2-D2 respectively. An overspeed event during plant operation would raise the stresses only to Ei and E2, since overspeed is limited to about 10%. A different stress corrosion Detall A sensitivity of the two described examples cannot T,

be concluded.

y 5 Locking Pins ka The stress-strain diagram additionally shows how misleading a theoretical evaluation can be when V

calculating stress levels under elastic material be-havior. Such evaluation would not only show

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much higher design and overspeed stress levels, U

but also higher operating stresses. Basing the cal-il

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culations on this wrong assumption would result Shriak Fit theoretically in operating stresses roughly 1.1 and i

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f 1.5 times higher than yield strength for disks I h

and 2 respectively. (D'i and D'2). However, the Section B B stress-strain diagram clearly reveals that under actual material behavior, the operating stresses Shrink Fit d'

Fr n.eions Di and D2 in disks I and 2 are about the same.

DisN #5 Fig.2 Shrink-Fit and Keyway Configura-tion of LP Turbine Disk #5 o; u n,02

'k op' ll o; u n,02 o, = 0.9 Rp0.2 keys for each disk, assembled into keyways fllll j

D, = 0.9 Rp02 located in the shrink-fit free region on the down-

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t i

l iTheoretical stream sides of the disks. The sections adjacent to Ag/

ilI Elastic the shrink fit areas at each side of the disks, as I Evaluation e

well as the large radius circumferential stress s;/li ll relief grooves in the shaft and disks are optimized g

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to minimize shrink-fit and keyway stresses and f

i theirinteraction.

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keyways only to the evaluated design stresses,

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Relating stress corrosion susceptibility of disk 5',

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however, is inappropriate. Other factors are

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equally important, such as the formation of crev-r,/ ' /'/

operating f

Range ices and steam / water flow conditions. Design ci p

stresses also reflect an unrealistic picture since the e,J factory overspeed test already causes local plastic

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deformation of the keyway and reduces subse-g examples in Figure 3.

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quent local operating stressea as shown by the two 4 2 x.y y sir.. s:

a aa. sa-=-o S = Dunng 20% overs.eed Tesi Examples 1 and 2 represent two different LP tur-C #

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• • • • "",C"'"""'*"5 bine disks with different keyway configurations.

o. am.*d s.o The diagram shows the stress-strain curve of the

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disk material. When shrinking the disks onto the

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shaft, the keyways of disks 1 and 2 are stressed as indicated by points At and A2 respectively. Note o

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u u

strain that the local stressing in keyway 2 is higher than in keyway 1. Stresses increase during the 20%

Fig. 3 Stress Levels of Two Different Disk overspeed test as indicated by points Bi and B2 and Keyway Designs.

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Longterm experi:nce with verious LP disk mate-EXPERIENCE WITH DISK-TYPE rials has not revealed significant diff:rences in LP ROTORS OFOBSOLETE DESIGN stress-corrosion behavior. However, extensive test-Prior to the introduction of the Kraftwerk Union ing indicated that disk materials when heat disk type rotor design for low speed turbines in treated to achieve the highest possible yield 1969, AEG built disk type LP rotors for fossil and strength levels (above 1200 MPa or 174 Ksi) nuclear applications. The disks of these rotors became more susceptible to stress corrosion. Nu.

were secured by either rectangular keys or anti-clear LP turbines of the authors' companies em.

rotation pins as depicted in Figure 4. Typically, ploy disks forged from material 26 NiCrMoV 14 5 the first stage disks employed one rectangular similar to ASTM A471. The disks are modestly keyway over the entire width of the disk with 2.5 heat treated to achieve yield strengths of 1000 mm (0.1 in.) radii for stress relief. The key was MPa (145 Ksi) or less. This modest heat treatment bolted to the rotor with a maximum total side also provides a high fracture toughness. This is clearance of 0.5 mm (20 mils) and a 0.1 to 0.3 mm (4 important in regard to stress corrosion crack.

to 12 mils) radial clearance between the key and ing because a high fracture toughness provides a larger critical crack size, and therefore a longer keyway. Each of the remaining disks was secured by three anti-rotation pins located in bores at the mean time between in-service inspections.

disk hub faces. Variations of this design were LP I

rotors with rectangular keyways in all disks or in To date a total of seven million disk service hours only one of the first stage disks. Most of the LP i

E have been accumulated with Kraftwerk Union turbine rotors were applied with conical sleeves i

nuclear turbines without a single indication of between the step shaft and the disks.

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stress corrosion.

The non reheat 200 MW turbine in Figure 4 with one double-flow LP turbine utilizing eight disks, is a typical example of this obsolete AEG impulse-type turbine design. A large number of such tur-bines were operating in various countries without nny indication of disk cracking, until 1978, when Total cearance cracks were found in shrunk on disks of a South O.5mm (20 mils)

African unitD2 N[ hy,,,

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k"/Mi'Mo, U 0.1 to 0.3mm y,ep, n (4 to 12 mils) 4 Radius

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Main Stream:1500 psig/1000*F Pins

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LP Turbine inlet: 45 psi /1.3% Moisture QN3(T, Back Pressure: 2.1 in. Hg abs 7

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Fig.4 High-Speed 200 MW Tandem-Compound Non-Reheat Turbine with Disk-Type LP Rotor.

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l Subsequ:ntly, Kr:ftw:rk Union his inspected sin tion. The cr:ck initiation locations w:re often pit-teen of the total of twenty AEG LP rotors in South ted and heavily expanded by corrosion. Corrosion Africa, after 20,000 to 140,000 service hours. All products penetrated to the crack tips and were these turbines are of the non-reheat design, rated analyzed to be magnetite (Fea04). None of the between 100 and 200 MW and operate with a small cracks had any significant deposits of salts or moisture content in the LP turbine admission sodium hydroxide (NaOH). All these findings are steam. Disk cracks were found in fifteen of the six-typical indications of stress corrosion. The maxi-teen turbines in three different power plants. The mum crack depth found in one of the 128 inspected test results from the 128 disks revealed stress cor-disks was 18 mm or almost 3/4 in. As plotted in rosion cracking in 49 disks as listed in Table I. In Figure 5, the inspection results from the three forty disks, cracks were found only in the vicinity South African power plants indicate a conserva-of the rectangular keyways. However, seven disks tive maximum crack propagation rate of 2mm/10*

without keyways and two disks with keyways had hours (approx. 80 mils /104 hours) from initial unit stress corrosion cracks in the disk hubs, the disk start up.

faces and/or the anti-rotation pin holes. Only one Other turbine suppliers have discovered similar disk showed corrosion cracking in the shrink fit corrosion cracking in the United Kingdom on region. All the remaining disk-hub cracks were fossil-fueled non reheat turbines. These turbines located in the non-shrink area.The shrink fit area were inspected after the disk cracking event in the of this disk design covers approximately 60% of Hinkley Point nuclear power station. Stress corro-the disk width and the adjacent 20% overlaps at sion cracking was reported to occur in pure stag-each side actually have small clearances. Cracks nant saturated steam or condensate at elevated in areas other than the keyway regions occurred temperatures N These temperatures correspond to in three of the sixteen turbines after 40,000 to LP turbine operating temperatures at and below 75,000 service hours.

the Wilson line. Stress corrosion cracking of LP All the disk cracks found revealed an intergranu-turbine disks has alsobeen found in fossil and nu-lar crack pattern with branched crack propaga-clear power plants in the USA as reported by EPRI N TABLEI Disk Inspection Results from 16 Non-Reheat Turbines Operating in Three South African Power Plants.

5 LP Rotors with Keyways in all Disks Number of Disks Disks with Keyways Disks without Keyways Disks inspected 40 40 0

Corrosion Cracks in Disks 22 22 Corrosion Cracks in Keyways only 22 10 LP Rotors with Keyways only in the First Stage Disks Number of Disks Disks with Keyways Disks without Keyways Disks inspected 80 20 60 Corrosion Cracks in Disks 26 19 7

Corrosion Cracks in Keyways only 17 1 LP Rotor with Keyway only in one First-Stage Disk Number of Disks Disks with Keyways Disks without Keyways Disks inspected 8

1 7

Corrosion Cracks in Disks 1

1 0

Corrosion Cracks in Keyways only 1

TOTAL RESULT Number of Disks Disks with Keyways Disks without Keyways Disks inspected 128 61 67

)

Corrosion Cracks in Disks 49 42 7

Corrosion Cracks in Keyways only 40

l O Power Plant A m

Power Plant D

.TABLEII In. To A Power Plant C LP Turbine Di:k Matsr:. 12.

2 3,4_

Maximum MATERIAL CHEMICAL COMPOSITION IN %

Operating 3"n~A"a

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=

v:

c-C Cr Mo NI V

(194'F to 230'F) 35 28 NiCrMo 7 4 026/032 0.90/1.2 030/040 16/1.8 ASTM-A294 t/2, 34 CrN.Mo 6 030/038 14/1.7 020/030 14/1.7 g

ASTM A294 g

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26 NiCrMoV 14 5 026/035 1.2/1.7 030/045 34/36

<015 ASTM-A471 N

o All these LP turbine disks were forged from low-alloy, heat treatable steels listed in Table IL For

,,e most units, the steel 34 CrNiMo 6 (similar to a

5-ASTM-A 294) with an Rpo.2 yield strength of 700 to 1000 MPa (100 to 145 Ksi) after heat treatment was utilized. The heat treating procedure was modified for each specific application to achieve optimal properties. The disks for the last five South Afri-can units were forged from 26 NiCrMoV 14 5 steel 8'

C a

soooo

,oo ooo isoooo (similar to ASTM A 471) with a maximum yield Service Hours strength of 1000 MPa (approx.145 Ksi) after heat Fig.5 Keyway Inspect. ion Results of Three treatment. A few older LP turbine disks were South African Power Plants.

made from 28 NiCrMo 7 4 steel, which is similar to ASTM A 294 material.

After Kraftwerk Um.on discovered the first corro-Tests revealed no significant difference in the sion cracks in the South African turbines, an inspection program for all disk-type LP rotors was susceptibility of these three materials to stress corrosion. Not one of the disks with cracks showed introduced. In the meantime, several LP rotors have even been disassembled and the disks were evidence of temper embrittlement. The fracture toughness of the disk material 26 NiCrMoV 14 5 tested using magnetic partical techniques. The (ASTM A 471)is at least 178 MPa /is at 204C inspected LP rotors have been operating over long (approx.163 Ksi /IE at 680F) and the minimum time periods in various European countries, such as Germany, Denmark and Greece. Results of toughness of the older 34 CrNiMo 6 and 28 NiCrMo 7 4 materials is about 95 MPa /fi at these inspection programs are depicted in Figure

6. The disks of seven of these turbines have been 200C (approx. 87 Ksi /iE at 680F). At 1000C inspected and no disk cracking has been disco.

(212oF) however, the fracture toughness of both later materials reaches a higher level which cor-vered after 10 to 20 years of operation.

responds to the fracture toughness achieved with the presently employed 26 NiCrMoV 14 5 (ASTM-A 471) disk material at 20oC. The high fracture

,m y,,,,,,,

o,

.v,,. n toughness of the three LP turbine disk materials at operating temperature provides a relatively large critical crack size.

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POWER PLANT WATER CHEMISTRY Since the disk inspection results from the South African and the European power plants were so o

o o

different, a comparison of the imwe-plant water an. m. w.n i.,. e r.ii

... an..,,

'a "7*

chemistry was conducted. Major differences and typical analysis values from the turbine conden-io c.iac mo..

n sate of European and South African units are shown in Table III.The cation conductivity of the turbine condensate is higher in the South African m

g oOUa power plants and the pH level does not correlate with the ammonia content. In general, a high

n. c,.c..

=. c,.c..

"*a**aT *

• cation conductivity reveals an increased salt con-Fig. 6 Hub and Keyway Inspection Results tent in the condensate, but even under these condi-of AEG-Design LP Turbine Disks.

tions, the relationship between the pH-level and 5

TABLEIII Ccmparison cf Powcr Plant wit:r Ch:mi; trim.

Europe South Africa Boiler Design Mainly Once-Through Drum-Type Make-Up Water Storage Closed to Atmosphere Open to Atmosphere Venting of Deaerator To Atmosphere into Condenser Condensate Polishing System Normally 100% Capacity None Water Treatment AVT*

Combined Coordinated Phosphate Turbine Condensate impurities During Normal Operation:

Conductivity Downstream of a Strong-Acidic Cation Exchanger gS/cm (pmho/cm)

< 0.2

<0.2 0.3 Sodium (Na) ppb

<1

<1

<1 Ammonia (NH3) ppb 600

~ 50 200-600 pH Level 9.3

~8.5 8.4-9.2 Oxygen (O2) ppb

< 20 200-300

< 15 Carbon Dioxide (CO2) ppb

<100

<100 300-400 calculated

• AVT - All Volatile Treatment the ammonia content should not dive ge.The data atmosphere by steam blanketing, nitrogen blank-from the South African units tend to indicate the eting or soda lime absorption devices. Additional presence of free acids in the turbine condensate make-up water is often stored in tanks at elevated and consequently, in the steam. Compounds such temperatures of 105 C (221 F) to 115oC (240oF).

as carbon dioxide, sulfur dioxide, muriatic acid, or Gases from the deaerator are normally vented to organic acids (formic acid, acetic acid, etc.) could the atmosphere. All modern plants are equipped be present W Ongoing investigations indicate that with fullsize condensate polishing systems. All the presence of carbon dioxide CO2 in the steam is modern boilers are of the once-through design, and most likely. The logical source for CO2 would be are operated without any chemical feedwater the make-up water supply, since the make-up treatment other than the injection of hydrazine water is stored open to the atmosphere. In addi-and ammonia.

l tion, routing the deaerator vents back into the l

condenser keeps CO2 impurities in the system.

l Because there is also no condensate polishing sys-LABORATORY TESTING tem, only the degassing in the condensers could actually lower the CO2 level of the system.

An extensive stress corrosion investigation pro-gram was started in 1978 immediately after Kraft-Other possible sources for CO2 contamination can werk Union found the first corrosion cracks in LP be the boiler water additives, such as polyphos-disks of an AEG turbinein South Africa. Smooth phate and sodium hydroxide polluted with car-and notched test specimens were taken from disks bonates. Air in leakages at the LP turbines, con-of affected turbines to perform stress corrosion densers, BFP turbines, LP feedwater heaters, tests up to full 100% yield strength in demineral-pumps, piping and expansion joints are also sour-ized water with low oxygen and saturated oxygen ces for CO2 impurities. Presently, investigations content. Test samples from disk material with up have been started to find the reason for the high to 1000 MPa (145 Ksi) Rpo.2 yield strength did not cation conductivity of the condensatein the South crack during the 20,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> test period. However.

African power plants.

cracking occurred in material samples with higher l

Even though there are major differences between than 1200 MPa (174 Ksi) yield strength, when the European once-through boiler cycles and the stressed to full yield strength. During these tests, l

South African plant cycles,it should be noted that the test environment was constantly cleaned by l

the South African plants were designed in accor-mixed bed ion filters to maintain the low conduc-l dance with the state-of-art for drum-type boiler tivity level of the water.

power stations. Investigations confirmed that all Figure 7 depicts the results of tests with speci-the South African units have been operated with mens stressed up to 90% of their yield strength.

very low salt impurity levels.

Adding carbon dioxide to the water cycle resulted In European power plants the cation conductivity in corrosion cracking, even of the low yield is generally smaller than 0.2pS/cm (0.2gmho/cm) strength material after less than 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />. The which can be attributed to several measures.

specimens tested in water saturated with carbon Make-up water storage tanks are closed to the dioxide exhibited extensive corrosion pits and G

Tes3at 90% of Rp0.2 Yield Strength 1

in Domineralized Water i

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woCreen cract after at 30 000 hrs. Tirne y

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' Results at 100% Yield Stress Corrosion Test 5$

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Strength 6n High Purity Water Saturated with

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South Afr6can Turbine d

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i i i s N i i i Disk Material with Yield Disk Material with Y6 eld Strength <1000 MPa Strength > 1200 MPa

(<145 ksi)

(>174 ksi) 6 Fig.7 Stress Corrosion Test Results with appros.100;t Oxygen and Carbon Dioxide.

appros.100:1 crack initiation as shown in Figure 8. The test Fig.8 Stress Corrosion Caused by Carbon sample surfaces were already covered with black Dioxide.

Oxide (magnetite) shortly after the tests began, coefficients, most probably cause a significant whereas samples tested in oxygen poor and satu.

reduction of the pH-levelin the LP turbine at and rated demineralized water looked clean and had only a thin, light-colored passive layer even after below the Wilson, lin,e. These undesirable condi-tions do not exist in European power plants 20,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> of testing. Spot checks with a weak because of the absence of carbon dioxide. It is sulfuric acid solution showed results similar to the important to note that especially nuclear power test in carbon dioxide saturated water.

plants designed and built by Kraftwerk Union In conjunction with the tensile tests, compact, ten-have been carefully scrutinized to eliminate any sion (CT) specimens with fatigue crack mitiations, potential sources for stress corrosion. Routine test-were tested in the laboratory water cycle. T,ests in ing of disk type LP rotors of these PWR and BWR demm, erahzed water showed no mdication of plants has not revealed any disk cracking. Re-crack growth whatsoever. Spot-check type testing cently all disks of such an LP turbine were tested must now be confirmed by systematic test pro-both shrunk-on and disassembled from the shaft.

grams which have already been started.

The crack free condition of all the disks and the With a sufficiently low cation conductivity of the absence of any corrosive attacks, after 76,000 ser-vice hours in a PWR power plant. confirm our turbine condensate, stress corrosion can practi.

cally be eliminated, since low cation conductivity laboratory findings.

lI confirms the absence of acidic compounds such as carbon dioxide, sulfur dioxide, muriatic acid, l) organic acids and possibly salts. Oxygen in the ULTRASONIC DISK INSPECTION l

steam or condensate has no influence in this Inspection of completely assembled and bladed regard. This passivity of oxygen is also confirmed disk-type LP rotors for stress corrosion cracks is a

~

by the fact that BWR and fossil fueled plants with difficul,t task. The most critical regions of these combined feedwater treatments operate with high r tors m regard to stress corrosion are the disk l

oxygen contents. It can also be safely assumed hub bores with their keyways., The ultrasonic that sufficient alkalinization of the condensate at inspection technique and test equipment described and below the Wilson line could eliminate stress below has been developed to perform a 100'~o volu-corrosion or pitting corrosion in LP turbines.

metric hub bore and keyway inspection to detect i

l Concentration ratios of ammonia and carbon axial / radial stress corrosion cracks without dis-dioxide in the. cycles of the South African power sasembling the disks from the shaft and without i

plants, depending on the different distribution detaching any blades from the disks.

7 a

~

m 1

Tha follswing con' itirns hxd to be con:id: red in d

dzvtleping thesein-serviceinspection mrthods:

• The ultrasonic probes must be positioned on the disk faces to detect axial / radial cracks.

e The disk face geometries are very complex, I

complicating the probe positioning for the hub bore and keywayinspection.

e There is only a 50 mm (2 in.) axial distance between the rims of disks 1 and 2 which the pwsk i

probes must clear before they can be positi-unresonic

[ pron,s oned on the disk faces.

Unresonic e The configuration of the keyways complicates Probes the ultrasonic testing and test result evalua-tion.

• The ultrasonic signals must travel 150 to laspecnoa, 650mm (6 to 26 in.) through the disks.

"'8'*"*

h e An acoustic signal transparency with a high iI I

~

t coefficient of transmission is to be expected at I

/

the shrink fit.

l Tendem Pulse / Echo Method These problems have been solved by optimizing the crack detection, capability of the corner reflec-tion method, utihzmg a large number of specially Fig.9 Ultrasonic Disk Inspection Methods.

designed ultrasonic probes and positioning the probes on the disk faces with the aid of several specially developed mounting plates which are The incidence and inclination angles of the probes attached to two remote-controlled robot arms.

must then be determined as a function of the probe position at the disk faces and the diameter of the The corner reflection method provides a double disk hub bore. For a complete LP rotor with two reflection of an ultrasonic signal at a corner times five disks, a total of two times 80 probe formed by the inspected surface and a crack. This regions with two times 120 probe positions are reflection signal returns parallel to the sensing required, when testing half of the regions with the signal. In the case of disk inspection, the corner is pulse / echo and the other half with the tandem formed by the disk hub bore and an axial / radial method. To precisely fulfill the corner reflection oriented crack.

criteria for each position, the exact combination of For the side regions of the disks the pulse / echo incidence and inclination angle would not be iden-technique is applied. An ultrasonic probe, posi-tical for any of the positions, and c;onsequently,120 tioned at a specified disk face location, is used as ultrasome probes would be required. However, a transmitter and receiver. The center regions of the a mewhat broader range of application can bejus-disks are tested with the tandem technique. For tified resultmg in a red,uced number of ultrasome this technique probes have to be positioned at each probes. The investigation revealed that 40 ultra-side of the disk. Accurately synchronized position-sonic probes in combmation with 50 different ing with two independent robot arms is required m unting plates are required to adequately per-since one probe functions as transmitter and the f rm the ultrasom,e mspection of all ten disks of an other one as receiver. (Fig. 9).

Prior to the actual tests of shrunk-on disks, investi-Each mounting plate carries for the pulse / echo gations were performed to determine the possible test method two ultrasonic probes, whereas for the acoustic transparency of shrink fits. Perpendicu-tandem method only one probe is attached to each l

larly applied signals at the shrink fit of a test disk in untingplate. Accuratepositioningof the mount-behaved similarly to signals applied to a back-ing plates at the disk faces is contrglied by three wall, indicating that the signal transparency of position transducers. Contact fluid ts supplied to shrink fits has no or only a minor influence. The each,dprobe and hydraulic pressure is applied to orthe s next step in preparation for testing was to graphi-

$'fy';

e contact of the probe to cally analyze a complete rotor to define the var-

{,ce,

g ious probe positions and the number of test The test device features two robot arms to simul-regions.This was followed by the determination of taneously position two mounting plates at each required probe characteristics. It was found that a disk face for the tandem testing of the disk center.

total of 20 to 30 different ultrasonic probe posi-Since the axial distance between disk 1 and 2 is tions on the faces of each disk are needed to per-only 50 mm (approx. 2 in.), the robot arms have to form a 100% volumetric inspection of the disk hub bring the mounting plates to a vertical position for bore with its keyways.

clearing the disk rims (Fig. II). After passing the 8

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Fig.10 Ultrasonic Inspection with Two Probes in Position.

rims, the plates are turned 90 into the horizontal operating position. The test probes are then positi-E 8, oned on the disk faces and the ultrasonic inspec-tion commences by turning the rotor at about

'I, I rpm and testing one specific test region of the hub bore over the entire 360" (Fig.12).

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Fig.11 Mounting Plate in Vertical Position Fig.12 In-service Inspection of Fully Bladed Clearing the Disk Rims.

LP Rotor.

9 I

The major components of the test system as depicted in Figures 12 and 13 are the manipula-tor with two robot arms to position the ultrasonic n-

/.~ < f probes with the aid of position transducers, the

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circumferential position measuring device to deter-c

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C mine the rotor angle position during testing and t.. -

t the multi channel ultrasonic test device with line

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t recorder, CRT and magnetic tape data storage.

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To check the test technique and inspection system, A,..

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about 60 axial / radial oriented notches simulating F

d' corrosion cracks of different sizes were eroded into

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c.

3.,

c.

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)..t, '.I. < [E; ' 'fpN -

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the hub bore of a test disk. The disk was shrunk onto a shaft for the purpose of calibrating the f

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4 inspection system under full-scale conditions.

f '; ' i t

These test results could then be directly related to 3, g ]h 3 y7I real disk-type rotor inspections.

dN, K '? 9 e[rl [ } 2.,. f v

This newly developed system was applied for the

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$ g. t y< :' 1

'g.4 first time to inspect an LP rotor after roughly

n. +

L 4

f:.

't#*

"f h' h i Q p \\ s.c;i, f(f :

76,000 service hours in a German PWR nuclear r-I power plant. The 100% volumetric inspection of

'* 8 f ~

the hub bores and keyways was performed on a completely bladed LP rotor.The ultrasonic testing 4

l showed a maximum indication of a 3.3 mm (0.13 Direction of installation During Shrink-On Process in.) equivalent flat bottom hole over a maximum axial distance of 100 mm (4 in.)in one of the ten Fig.14 Installation Score Marks at the disks at the shnnk fit.

Shrink Fit of a Disk.

As part of the development program of this spe-cific LP rotor test all disks were removed from the shaft,after the ultrasonic inspection. The ultra-CONCLUSION some mdication on the aforementioned disk was found to be caused by score marks wph a maxi-While minor design modifications to upgrade the j

mum depth of 0.5 mm, (20 mils). The score mark resistance of LP turbine disks to stress corrosion configuration clearly indicated that aconng had may still be possible, the actual improvement from l

occurred during the shnnk-on and not the shnnk-methods such as different anti rotation devices, off process (Fig.14). All the shrunk-off disks were sealing of the hub region, coating of the shrink fit closelg' inspected without indication of any stress cr adding keyway ventilation is questionable.

corrosion after approx. 76,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> of operation.

Only long-term experience would allow drawing any conclusions about such methods.

j' pg /

The step toward the application of solid rotors e

i

& f2.

y _ C

would most certainly provide a new concept with E.

1*

improved and predictable corrosion performance.

Stress corrosion in the hub section would be com-pletely eliminated with this " mono-bloc" rotor

, ~..he,fg.g*

. a rotors presently applied, because much heavier

....h-design. It must, however, be noted that such an LP y

yi rotor design requires a 300 metric tons (660,000 lb)

T s

rotor forging. Such a forging must be machined to

.c about the same configuration as the disk-type l

non-contoured rotors would require much larger N

1. 1,i LP turbine components such as bearings and sup-port structures, which are not presently considered l

l ti

' W'

~

in LP turbine design concepts. Also, non con-toured rotors would not be interchangeable with I

--g present disk-type rotors and could, depending on the missile analysis concept, increase the mass and energy of hypothetical missiles.

'!x f'

Most important in controlling stress corrosion is the water / steam cycle chemistry. Units operated Fig.13 Ultrasonic Test Equipment.

without any major cooling water and air in-10 l

1:ckag:2 h:ve shown no stress corro: ion prob-lems. It is necenny to svoid not only cooling

[1] F.J. Spalthoff, H. Haas and F. Heinrichs, water in. leakage, but also air in. leakages of low-

"First Year of Operation of the World's Largest pressure plant components. Air in,take with the Tandem-Compou nd Turbine-Generator", Paper make up water must also be ehminated. Large presented at the American Power Conference, condensate polishing systems mimmize conden-Chicago, Illinois, April 21,1976, Vol. 38, pp.

sate impurities when operated properly. Sufficient 555-569,1976.

degassing of the feedwater cycle is another impor-tant method to keep impurities away from the

[2] J.S. Joyce, H. Haas and F. Heinrichs," Tandem-steam generator and the turbme.

Compound 1800 RPM Turbine-Generators to Match Very Large Superheated Steam Supply In plants where stress corrosion attack is sus-Systems", Paper presented at the American pected, testing of LP turbine disk type rotors is Power Conference, Chicago, Illinois, April 22, recommended after 5 to 10 years operation. The 1980, Vol. 42, pp. 233-242,1980.

ultrasonic inspection method developed by Kraft-5 werk Union, allows the detection of axial / radial

[3] K. Schleithoff, " Stress Corrosion Cracking on stress corrosion crneks larger than 10 mm (0.4 in.)

Steam Turbine Components - Case Histories, in depth. This sensitive 100% volumetric inspec-Laboratory Tests and Service Experience",

tion method provides a large mean time between Paper presented at EPRI/CERL Workshop on 3

in-service inspections. For prolonging.the period Turbine Disc Cracking, Central Electricity of time between early in-service inspections, a Research Laboratories, Leatherhead, England, benchmark inspection may be justified before November 28-30,1979.

shipping. An inspection method is presently under development to precisely determine crack

[4] J.M. Hodge and I.L. Mogford,"UK Experience of Stress Corrosion Cracking in Steam Turbine size and growth. It is our goal to develop a system whichcan measure stress corrosionerack depths in Discs", Proceedings, The Institution of Me-the entire hub bore and keyway region of disks chanical Engineers, Vol.193, No.11,1979, pp.

with less than 5 mm (0.2 in.) tolerance.93-109.

[5] EPRI Report NP-2429 LD, Vol.1-7, " Steam Turbine Disc Cracking Experience, Research Project 1398-5, Final Report", June 1982.

[6] K. Schleithoff and H. Termuehlen," Steam Pur-ity in German Power Plants: Standards, Oper-ational Data and Effects on Turbine Compo-nents", Paper presented at the Joint ASME/

IEEE/ASCE Power Generation Conference, Dallas, Texas, September 10-14,1978.

O I

11

ATTACHMENT 3 European KWU Nuclear Turbines (Low Speed-1500 rpm Units)

Unit MW Commercial Operation Stade 662 1976 Biblis A 1200 1975 Biblis B 1300 1977 Wuergassen 670 1975 Brunsbuettel 806 1977 Unterweser 1300 1979 Isar 907 1979 Philippsburg 864 1980 l

..u n n

=1. n

ATTACHMENT 3

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7 uti:ityPowercorporation 191d ma. au R. J. GARY EXECUTIVE VICE PRESIDENT TEXAS UTILITIES GENERATING CO.

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Lilifty PowerCorI> oration N 2' m LBJ Freeway. P.D. Box 344109. Dallas. Texas 75234 / Gl4) 2474511 November 13, 1981 Mr. P.

3.

Gary D:e::tive Vice President Te:.:ss Otilities Generating Co:pany 2001 Eryan Tower Callas, Texas 75201

ear Ecb

Ir response to your recuest, enclosed is a listing of the operating statistics as well as explar.ations for each plant outage for those large nuclear power plants in Europe with Kraftwerk Union turbine generators.

The data presented ecvers operation for the years 1976 through 1980.

As ycu recall, the 54" last stage blade running at 1500 rpm is in the same blade family as the 44" last stage blade for Comanche, Peak and Grand Gulf.

The

" last stage blades on both Handley units are also cf the same blade fa.ily.

f additional information is needed, please do not hesitate to contact us.

Very t uly yours, v

C-ary M.

Coon Regicnal Vice President Enclosure GMC:pm An Af'Jhose o'Nto!!urrk L'nnon to meml,er of thr Sotment Crnt t;,* and Alit < Chntrner.<

STADE 662 MW, TC-4F-54 1500 RPM 0

Commercial Operation : May 19, 1972 Operation Statistics From January 1, 1976 To December 31, 1980 1976 1977 1978

_1_g21 1980 Power Generation, MWHRS 5,452.3 5,430.5 5,518.2 4,637.0 4,347.3

~

Availability Factor, %

94.5 94.1 95.1 77.3 76.7 Cum. Availability Factor, %

84.5 86.2 87.7 86.3 85.2 Capacity Factor, %

93.9 93.6 95.4 76 5 76.2 Cum. Capacity Factor, %

83.3 85.1 86.7 85.4 84.3 LIST OF OUTAGES BY YEAR Cause and Duration 1976

1) Turbine extraction leaks (9 hrs) 2)

Fourth refueling outage (455 hrs) 3)

Reactor scram during reactor protection test and leak in secondary cooling loop

' valve (7.5 hrs) 4)

Outage of main r'eactor coolant pump N.o. 3 (0.5 hrs)

5) Turbine trip caused by lightning striking outdoor switching station (8 hrs) 6)

LP preheater repair (5 hrs) 1977 7) 5th refueling outage scheduled maintenance inspection work (473 hrs)

B)

Voltage collapse due to lightning striking the 220 kV power line causir.g outage outage of main reactor coolant pumps Nos. 3 and 4 (1.5 hrs) 9)

Repair of the HP turbine exhaust end flange (6 hrs)

10) ' Repair broken wire in the control voltage supply of the feedwater pumps (1 hr) 11)

Repair of the drain piping for the HP turbine extraction (9 hrs) 12)

Leak in the closed cooling water piping (3 hrs)

Y

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1 1973 13)

Eypass pipe was drilled during field service work (1 hr) 14)

Unscheduled shutdown because of defective measuring device (0.7 hrs) 15) 6th refueling outage (403 hrs) 16)

Scheduled shutdown:

turbine overspeed test (1 hr) 17)

Unscheduled shutdown because of leak at check valve in main steam pipe and condenser tube rupture (6 hrs)

IS)

Leaky seal in pressure relief drain system (6 hrs) 19)

Reactor trip (2 hrs),

20)

Leak in secondary loop (7 hrs) 1979 21) 7th refueling outage (1924 hrs) 22)

Functional test of main steam valves and overspeed test (12 hrs) 23)

Reactor trip during test of reactor safety protection (I hr) 24)

Leaky condensate drain pipe on feedwater tank (47 hrs}

19S0 25)

Eth refueling and maintenance outage (2065 hrs)

26) Test of overspeed and main steam valves (11 hrs) 27)

Reactor trip due to defective level measurement in steam-generator No. 4 (2 hrs)

O Y

'7_" ". C*[_El.*_~ _7,* '_,..'[_ _ _

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~*'

BORSSELE. 469 HW, TC-6F-25, 3000 RPM Commercial Operation : October 26, 1973 Operation Statistics From January 1, 1976 To December 31, 1980

~

1976 1977 1978 1979 198o Power Generation, MWHRS 3,444.8 3,329.3 3,628.9 3,083.1 3,706.9 Ava'ilability Factor, %

85.5 83.2 91.3 77.5 96.7 Cum. Availability Factor, %

78.8 79.6 81.7 81.0 83.3 Capacity Factor, %

83.9 80.6 88.4 75.2 92.3 Cue Capacity Factor, t 73.4 75.4 77.8 77.4 79.9 LIST OF OUTAGES BY YEAR Cause and Duration 1976 1)

Feed pump outage (4 hrs) 2)

Second refueling (1236 hrs) 3)

Secondary drain valve leaks (10 hrs) 4)

Leak in hydraulic accumulator pump (19 hrs) 1977 5) 3rd refueling and scheduled maintenance inspection work (1128 hrs)

Actuation of the vacuum safety valves (4 hrs) 6)

7)

Refueling and maintenance inspection (413 hrs) 1978 8)

Unscheduled shutdown because of malfunction in the reheater circuit during changeover; valve was closed rather than opened (4 hrs) 9)

Unscheduled shutdown because of outage of main feed pumps (9 hrs) 10)

Unscheduled shutdown because of oil leak at submersible pump (8.5 hrs) 11)

Turbine trip during checkout of automatic turbine protective system (2 hrs) 12) 5th refueling (768 hrs) 13)

Unscheduled shutdown for balancing of LP rotor (6 hrs) 14)

Unscheduled shutdown for balancing of LP rotor (7 hrs)

1979 15)

Leak at main steam pipe of HP turbine (252 hrs) 16) installation of insulation in hot reheat system (LP bypass) (4 hrs) 17)

Power network failure.

Outage of 150 kV transformer (9 hrs) 18)

Laak at compensator of HP turbine (257 hrs) 19) 6th refueling and maintenance inspection (1223 hrs) 20)

Malfunction of load control, turbine (7 hrs) 21)

Outage of feedwater pumps (12 hrs) 1950 21)

Malfunction of generator voltage regulation (3 hrs) 23)

Fire at auxiliary station transformer (96 hrs)

21). Replacement of insulator on generator transformer (50 hrs) 25)

Reactor Trip via activity measuring point (3 hrs) 26)

Repair of main coolant pump seal (137 hrs) 27)

Outage of oil supply for main coolant pump (1 hr) o 6

9 9

e w

s.

+ - - - - - - - - - - -

BIBLIS A 1200 MW, TC-64-54.1500 RPM Commercial Operation : February 25, 1575 Operational Statistics From January 1,1976 Through December 31, 1980 1976 1977 1978 1J13 J38,0,0 Pow 2r Generation, MWHR5 5,436.9 6,567.7 7,524.3 7,027.4 4,107.4 Availability Factor, %

52.6 67.3 74.6 85.7 46.9 Cum. Availability Factor, %

68.6 68.2 70.0 73.2 68.4 Capacity Factor, t 51.3 62.9 75.2 85.6 43.6 Cum. Capacity Factor, %

68.4 66.4 68.0 71.5 66.2 LIST OF OUTAGES BY YEAR Cause and Duration 1976 1)

Reactor protection system shutdown (126 hrs) 2)

Steam leakage at inlet chamber of HP turbine (51 brs) -

3)

Malfunction of generator load controller -(8 hrs,)

4)

Faulty actuation of " generator short circuit to ground" alarm (2 hrs) 5)

Malfunction of secondary loop control (5.5 hrs) 1er leakages (37.5 hrs) 6)

Generator H e 2

7)

Condensate system leak (3 hrs) 8)

1st refueling and scheduled maintenance work:

(3377 hrs)

- repairs on main coolant pumps for improving bolted joints

- extensive tests and repairs on feedwater tank

9) Test of feedwater tank (656 hrs) 1977 10)

Physical (radiological) tests imposed by the regulatory authorities (202 hrs) 11)

Repair of HP turbine shrouds (299 hrs) 12)

Repair of leaky pressurizer spray valves (72 hrs) 13)

Replacement of main coolant pump seal (96 hrs) 14)

Replacement of main coolant pump frame (72 hrs) 15)

Checking of bolt locking devices of main coolant pump motors (21 hrs) 16)

Outage of main coolant pump seal water (2 hrs) v

Malfunction of main staam pressure controller (3 hrs) 17) iB)

Replacement of turbine load controller (6 hrs)

IS)

Sealing of LP preheater pipes (11 hrs)

Malfunction of turbine speed measuring unit (7 hrs) 20)

Vacuum reduction in the condensers (1 hrs) 21) 22)

Br.oken valve spindle (6 hrs)

Scheduled repair of main steam inlet piping (5 hrs) 23)

Scheduled shutdown for replacement of generator primary water filter (4 hrs)

$ 4) 25)

Maintenance inspection (1,317 hrs) leak in the generator (54 hrs) 26)

H Expansion joint repair in suction line of one main feedwater pump (33 hrs),

2 27 )

25)

Repair of emergency diesel (24 hrs) 1978 Turbine trip during exchange of an electronic circuit card in the turbine load 29) control system (1 hr)

Unscheduled turbine trip because of alarm signal LP preheater level too high, the same occurred during return to service with HP preteater (1 hr) 30) elimination of leakage in secondary reactor loop (3 hrs 31)

Scheduled short-term shutdown:

leakage in HP preheater branch 2 (1.5 hrs)

32) Turbine trip following reactor trip:

elimination of leaks in reheater cor.densate cooler and HP 33)

Scheduled shutdown:

prehester (24.5 hrs)

Turbine trip and reactor trip occurred following a switching operation in the 34) transformer unit (8 hrs)

Turbine trip and reactor trip resulted f rom a rotor short to ground in the generator 35)

(214 hrs)

Malfunction of generator circuit breaker due to high humidity (66 hrs) i I

36) 37) 3rd refueling (2176 hrs) 1979 Retrofit of thermocouples in loop lines 2, 3 and 4 (1 hr) 38)

(2 hrs)

Faulty actuation, NZ 16 main steam activity measuring point 39)

Shutdown for inspection of reactor pressure vessel because of structure-borne 40) ultrasonic indication (780 hrs)

Reactor tripped (6 hrs) 41)

During repair of coolant pressure control system, 42)

Repair of secondary drain pipe (6 hrs) 43)

Repair of A6 extraction (10 hrs')

e

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s L4)

Malfunction of speed monitor (referancs limiter)

Turbina Trip (52 hrs) is)

Examination and remounting of emergency backup line between units A and B (92 hrs) 46)

Repair of bracket for turbine control valve No. 3 and sealing of HP preheater (16 hrs) 1980 47)

Alarm signal, HP preheater level too high (1 hr) 43) 4th refueling and maintenance inspection (20 hrs) 15)

Shutdown extension since compact (waste) storage facilities were not available (24 hrs) 50)

Main coolant pump outage (oil supply for motor)

(3 hrs) 51)

Repair of main coolant ' pump motor (109 hrs) 52)

Leak at shut-of f gate valve (46 hrs) 53)

Leak in recuperative heat exchanger (31 hrs) 54)

Alarm signal, coolant pressure controller (2 hrs) i M

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e e

W

WUERGASSEN, 670 MW, TC-4F-59, 1500 RPM Commercial Operation : November 11, 1975 Operation Statistics From January 1,1976 To December 31, 1980 1325.

1221

11Z8,

.1321 J38,oq Power Generation MWHRS 3,840.7 3,793.5 2,857.7 1,598.9 3,969.3 Avoilability Factor, %

82.8 81.1 62.3 35.8 94.8 Cum. Availability Factor, %

B3.5 82.5 76.0 66.3 71.8 Capacity Factor *, %

66.1 64.6 40.7 27.2 67.4

~

Cum. Capacity Factor *, %

65.3 65.2 60.1 52.2 55.1

• includes 20% mandatory load reduction to 540 MW LIST OF OUTAGES BY YEAR Cause and Duration 1976 1)

Elimination of a leak on main steam instrument line (12.5 hrs) 2)

Elimination of a turbine leak, in the steam pipe between HP and IP section (70.5 hrs)

,3)

Elimination of leak on check valve in feed water line (22.5 hrs) 4)

Elimination of H leaks on generator (57 hrs) 2 5)

Malfunction of pressure regulator (4 hrs) 6)

Damage to thrust bearing of turbine - s; peed governor cutage (129.5 hrs) 7)

Scram af ter error made during isolation of a sub-distributor (46.5 hrs) 8)

Scheduled shutdown for refueling (1060.5 hrs)

S)

Elimination of valve leaks in pressure suppression system (65 hrs) 1977 10)

Elimination of auxiliary equipment leaks in the pressure suppression system (31 hrs) 11)

Trip because of. malfunction of the initial pressure regulation (5 hrs) 12)

Defective fuse in the generator exciter unit (19 hrs) 13')

Shutdown because of malfunction in the waste gas unit (23 hrs) 14) 3rd refueling and annual maintenance inspection (1417 hrs) 15)

Unscheduled shutdown because the emergency diesels did not jointly run up to speed (82.5 hrs) 16)

Shoutdown for steam dryer inspection (93 hrs) 17)

Unscheduled shutdown because of high neutron flux (8 brs) y

___--.___m_

Jiza Unscheduled shutdown because of repair of (auxiliary) seal steam supply v 18)

Unscheduled shutdown because of interchange and replacement of auxiliary s 19) supply valves (34 hrs)

)

Unscheduled shutdown because of malfunction in the wast 2 gas unit (10 hrs (1 hr) 20)

Unscheduled shutdown because of leaky valve gland seal In the turbine buildin 21)

Cracks were found in the Scheduled standstill for inspection of the steam drie r.

22) partition plates (2101 hrs)

Unscheduled shutdown because of malfunction in the compressed air supply (sux111ary) seal steam supply valve and additional load (11 hrs) 23)

Unscheduled shutdown b6cause of f ractured blade in the LP se 24) in addition, a weld joint (1110 hrs) of 1.D.-0.D. mismatch.

Arranged shutdown because of malfunction in the control air supply (5 hrs 25) line in the pressure Unscheduled shutdown because of defective main steam instrument 26) suppression system (44 hrs)

(5 hrs)

Arranged shutdown because of repair to the auxi,liary seal steam supply valv 27) l*79 instrument line for humidity measurement, torn off turbine (10 hrs) 23)

Instrument line for humidity measurement torr, off turbine (7 hrs')

Cause: solenoid coil burned out (67 h-29) l

30). Blocking of auxiliary seal steam supply valve.

Defective timing element in functional group " waste gas" (6 hrs) 31)

Defective timing element in functiona'l group " waste gas" (8 hrs) 32) 4th refueling and annual maintenance inspection, inspection and repair of 33) weld joints (5256 hrs)

Assembly error on a jet pump head in reactor pressure vessel (169 hrs) f 34) short circuit in turoine initial pressure regulator because of incorrectly so 35)

(5 hrs) joint Malfunction in hydraulic system for isolation valves (4 hrs)

(51 hrs) 36)

Mechanical malfunction of suction gate valve in recirculation loop 37)

Leaky capped stub on relief pipe (19 hrs) 38)

Improperly adjusted limit switch on valve connecting line train steam emerge 39) condenser system (5 hrs)

==

^*

• • • ** =

• ii3 4 : ',.

Machanical malfunction of recirculation loop valve (4 hrs) 41)

Leaky instrument line for main steam flow rate measurement (34 hrs) 42)

Inaccurate setting at recirculation loop valve (2 hrs) 43)

Lsak in pressure suppression system because of crack In an instrument line for maLn steam measurement (60 hrs) 44)

Laak in pressure suppression system because of crack in an instrument line for r.ain steam measurement (21 hrs) 45)

Oil fire at turbine resulting from oil leak at a control line (21 hrs) 46' Leak at turbine drain (2 hrs)

' 47)

Outace of No. 2 control air compressor for relief system (40 hrs)

LE:

Relief valve test, limited movement of solenoids for pre-control valves because of harciened rubber sleeves (61 hrs) 45}

2 functionally inoperative isolation valves due to mechanical damage of stuffing

-box (222 hrs) e I

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i BIBLis B, 1300 HV, TC-6F-54, 1500 RPM Commercial Operation : January 31, 1977 Operational Statistics From February 1, 1977 To December 31, 1980 1977 1978 1979 1980 Power Generation, MWHR$

7,802 9 6,164.3 6,517.4 5.984.4 Avallability Factor, %

86.6 68.7 82.8 65.6 Cum. Availability Factor, %

86.6 77.0 79 0 75.4 Capacity Factor, %

75 2 63.6 81.7 61.8 Cum. Capacity Factor, %

75.2 69 1 73.4 70 9 LIST OF OUTAGES BY YEAR Cause and Duration 1:77 1)

Outage of control oil supply, generator-end (21 hrs) 2)

Scheduled inspection of No. 3 LP bearing -(10 hrs) 3)

Remeasuring & localizing of rotor short circuit to ground (22 hrs) 4)

Generator maintenance inspection (768 hrs) 5)

Intentional manual coastdown for elimination of leakage at the main steam inlet pipe & at the HP ' casing (10 hrs) 6)

Turbine trip actuation because of faulty triggering of signal, generator main current i

lead because of bypass system outage: reactor trip (5 hrs) 7)

Cooling water outage in transformer closed cooling loop (4 hrs) 8)

Rotor ground fault at generator stator and leak elimination in secondary system (236 hr:

i 9)

Changing of an electronic circuit card in rod control system led to actuation of reactor trip via power limiter (5 hrs) 10)

During startup: outage of a main feed pump resulting in turbine trip actuation (3 hrs) j 1978 11)

Shutdown for elimination of an H leak in the generator (52 hrs) 1 2~

12)

Main coolant pump seal replaced and reheater repaired (509 hrs) 1 13)

Unscheduled shutdown for elimination of a leak on the condensate collecting tank (3 hrt l

14)

Physical (radlological) tests specified by the regulatory authorities (25 hrs) v

13)

Unscheduled shutdown because of crack in a weld joint behind the seal-steam condenser (seal steam system) area (13 hrs) 16) ist refueling (1734 hrs) 17)

Manual shutdown - cracks in the dryer connection on the main steam inlet pipe of the HP turbine (52 hrs) 18)

Turbine trip and reactor trip - electrical defect in the automatic turbine tester (2 hrs)

IS)

Replacement of main coolant pump seal (333 hrs) 20)

Faulty signal from measuring point (4 hrs) 21)

Unscheduled shutdown for cleaning of a filter in the generator cooling circuit (5 hrs) 1979 22)

Rotor ground fault (leakage) resistance too low (31 hrs) 23)

Filter replacement in ' generator cooling circuit (6 hrs) 24)

Checking of filters in generator cooling circuit (4 hrs) 25)

False actuation Phase R Turbine Trip (1 hr) 26)

Repair of leak in turbine drain (weld joint) (3 hrs) 27)

Defective adapter plugged in (outage of main feedwater,, reactor trip) (1 hr) 25)

Momentary load increase of reactor after faulty lowering of 4 control rods Reactor Trip (7 hrs) 25)

Ala.re " stator winding flow rate too low", turbine trip, cause unclear (1 hr) 30) 2nd refueling (1325 hrs) 31)

Examination and remounting of emergency backup line between units A & B (92 hrs) 32)

Repair of bracket for turbine control valve No. 3 (9 hrs) 1980 33)

Leakage at the generator circuit breaker (22 hrs) 34)

Faulty actuation of signal for feedwater tank, level too low, Reactor Trip (2 hrs) 35)

Repair of LP pre-heater (18 hrs)

36) Malfunction in control of main stop valves (4 hrs) 37)

Faulty actuation, generator stator cooling control (1 hr) 38) 3rd refueling and maintenance inspection, extension of the shutdown period due to repairs of core baffle bolts and main steam pipes Loop 2 & 3 (2800 hrs)

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BRUttSBUETTEL. 806 MW. TC-4F-54. 1500 RPit Com.wrcial Operation.: September 2, 1977 Operational Statistics From September 2, 1977 To December 31, 1980

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1.2298

.19.2 1

.138q Fower Generation, MWHRS 3,466.0 2,437.9 0

750.9 Availability Factor, %

51.7 38.9 0

32.2 Cum. Avallability Factor, %

49.8 44.0 26.8 29.7 Service Factor, %

49 3 34.7 0

27.4 Cc.. Service Factor, %

47 7 45 1 26.7 26.9 LIST OF OUTAGES BY YEAR Cause and Duration 1

i c77_

1)

Reactor trip (4 hrs) 2)

Generator protection. trip as a result of underexc.1tation (11 hrs) l 3)

Reactor trip.

Outage of steam Jet air ejector (5 hrs) 4)

Shutdown of unit for repair of a valve leak in secondary condensate circuit (30 hrs) 5)

Reactor scram due t,o drifting of a level, measuring line (66 hrs) 6)

Repair of valve leaks (41 hrs) 7)

Feedpump outage (13 hrs)

.8)

Faulty closing of turbine trip valve (8 hrs) 9)

Outage of 'one condensate pump (4 hrs)

Shutdown because of faulty closing of Isolation valve (I hr) 10)

Scheduled shutdown for checking reactor protection system with simultaneous maintenance 11) inspection of various unit components (703 hrs) 12)

Unscheduled shutdown for repair of valve leaks (44 hrs)

Unscheduled shutdown for repair of No. 2 axial pump and shutdown of No. I, axial pump 13) as well as work in the turbine condenser area (98 hrs)

Unscheduled shutdown for repair of No. 3 axist pump (3213 hrs) y4

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Jammed control rod and replacement of the rear turbine bearing in the HP section (186 hrs:

4 ! 6)

Reactor trip during repeat test of inverter for reactor protection (4 hrs)

';7)

Lcaky gland seals on three valves of (pressurized) bearing water system and because of a gland seal leak-off pipe which was not fully penetration welded, as well as o leaky gland seal on a valve of the (pressurized) bearing water system withi.n the pressure suppression system (146 hr3) 1B) Malfunction in the feed pump area (10 hrs)

'13: Turbine trip because of fluctuation in 380 KV power network during changeover on load cistributer (1.5 hrs)

D)

Erroneous measurement of, generator cooling water temperature (5 hrs).

!11)

Shutdown during changeover of scram accumulator tanit (6 hrs)

2';

Shutdoan for inspection (4704 hrs) 4 1979 22)

Continued - Outage, No commercial operation due to inspection work (8760 hrs) 1950

' 22)

Continued - Shutdown because of malfunction on 6/.18/78.

Finishing of repair worn and improvement of unit in accordance with requirements of the German Ministry of the Interic tne licensine authority, the Reactor Safety Commission, the government examiner, and the Supreme Court decision of 7/2/79 (5683 hrs) Total shutdown period: (19125 hrs)

,23) Malfunction of turbine initial pressure control.

Shutdown by order of Supreme Court of E/29 because of formal (technical) erfor in the licensing procedure (1536 hrs) i 24)

Steam leaks in the pressure suppression system.

Load reduction because of repeat tests (145 hrs) 25)

Faulty actuation on 2 scram accumulators (9 hrs) l l

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s UNTERWESER, 1300 MW, TC-6F-54, 1500 RPM Commercial Operation : September 1, 1979 Operational Statistics From September 1, 1979 To December 31, 1980 1979 1980

.Pcwer Generation, MWHRS 3,529.6 3,813.9 Availability Factor, %

93.3 89 9 Cum. Availability Factor, %

93.3 30.1

Capacity Factor, %

92.8 86.7 "um. Capacity Factor, %

92.8 86.0 LIST OF OUTAGES BY YEAR Cause and Duration 1979 1)

Inspection of reheater (197 hrs) 1950 2) ist refueling and maintenance outage (325 hrs) 3)

Espair of HP drain p'iping (6 hrs) 4)

False signal : Reactor trip (3 hrs)

5) Transformer disconnected for oil conditioning (5 hrs)

6) Transforner disconnected for oil conditioning (5 hrs)

7) Transformer disconnected for oil conditioning (9 hrs) v

l ISAR 907 MW, TC-4F-54,1500 RPM i

Commercial Operation : March 21, 1979 Operational Statistics From March 21, 1979 To December 31, 1980 1979 1980 Fewar Generation, MWHR$

4,693.0 4.396.2 Availability Factor, %

77.8 65.9 tum. Availability Factor, %,

77.5 82.6 lapacity Factor, %

68.4 57.7 Oum. Capacity Factor, %

77.7 62.3 LIST OF OUTAGES BY YEAR Cause and Duration l

1979 1)

Elimination of leaks in turbine condenser (64 hrs) 2)

Elimination of leaks in turbine condenser '(76 hr-s) 3)

Incorrect operation of temporary start-up device in the area of the condensate pumps (12 hrs) 4)

Leaky valves in feedwater circuit (164 hrs) 5)

Leaky radial-stage throttle drain valve (3 hrs) 6)

Replacement of machine transformer (699 hrs) 7)

I & C change for reactor pressure vessel level measurement; circuit was not properly decoupled (10 hrs)

B)

Leak elimination at cover seal of various valves (79 hrs) 9)

Replacement of primary c19aning filter for generator cooling (8 hrs) i 10)

Logic error in the interlock of the refueling platform caused shutdown (19 hrs) 1980 l 11)

Seal leakage on valves in feedwater, turbine arer (61 hrs) l 12)

Defective handhole cover seal on drain t'ank of main steam piping (144 hrs) l 13) ist refueling and annual maintenance inspection (2341 hrs) 1-)

Leakage on cover seal of a relief valve (72 hrs) i'

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t 13; Leaky handnole cover on reheater (61 brs) 16;

• 1 arm signal resulting from spray water during filling of sprinkler unit (2 hrs) 17)

Leakage in weld joint in the HP area of the residual heat removal loop (301 hrs) 15)

Leaky valve in control line of an isolation valve (5 hrs) e i

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,i PHILIPPSBURG 1, 864 MW, TC-4F-54,1500 RPM Commercial Operation : February 18. 1980 Operation Data From January 1, 1980 To December 31, 1980 1980

o 2r Generation, MWHRS 1,850.6 Availability Factor, %

27.3

^;u. Availability Factor, % -

21.7 Capacity Factor, %

24.6 Ou.. Capacity Factor, %

20.0 LIST OF OUTAGES BY YEAR Cause and Duration 1950

1) Maintenance inspection work (324 hrs) 2)

Seallne of leaks at condenser (29 hrs) 3)

Saaling of leaks in seal steam leakoff system in containment structure (98 hrs)

4)

Exchange of generator transformer (457 hrs) 5)

Checkout of automatic turbine tester carried out as part of internal test program (14 hrs) 6)

Drip leak in area of start-up line (58 hrs) l7)

Faulty signal in turbine protection (9 hrs)

!B)

Retrofit (modification of scram system, erection of new decontamination building, re-installation of H -

placement of feedwater line in the pressure suppression system, recombinationsystem,exchangeofHPpreheater& reheater-condensatecooler,etc.f par requirement of regulatory authorities (4710 hrs) l l

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