ML19351E111
| ML19351E111 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/23/1964 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E109 | List: |
| References | |
| NUDOCS 8011250613 | |
| Download: ML19351E111 (10) | |
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OPHIATION REPORT NO. 38
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FEBRUARY 196h N.
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O Submitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts March 23,1%h O
802223060 A
4 This report covers tha operation of the Yankee Atomic Electric Company plant at Rcwe, Massachusetts for the month of February 196h.
At the beginnirg of the reporting perhd plant electrical output was 180 We.
On Febnuary 5 plant electrical output had decreased to 175 We at a correspondirg min coolant average temperature of $19 F, following.rhich, ammonia was added to the main coolant system. On Fetiruary 6 the load had increased to 185 Ne, main coolant average temperature was $260F ar4 all control rods were banked at 77 $/8" being hserted two steps from their pre-test position of 78 34".
Plant output remained constant at 185 We until February 12 when a scheduled shutdown for control rod drep testing and minor maintenance was made. During the speed coastdown of the tubine, abranml vibration was
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again recorded at No. h glard seal on the low pressure section. Repzwsen-tatives of the turbime mnafecctrer recorded masuremnts for future analysis during the coastdcyn. A more datailed description of the work can be found in the Tt:rbine Plant Performance section of this report.
On February 13 the plant was returred to the line.with electrical output reaching 158 We that night ar.d 185 We en Feb.w 1h. Operations continued at that cutput, with high min coolant pH vith ammonia throughout the balance of the reporting period.
The weekly control rd exercise program was carried out as scheduled as was the rod withdrawal seque.ce for wear distribution on the rubbing strap surfaces.
Plant Shutdowns
,m Shutdovn No. 68-3-6 2/12/6h A 21.8 hou scheduled shut-(
dcun for control rod. drop testirg and minor maintenance.
Paintenance Fo11cwing is a summary of major activities carried out by p_ at maintenance personnel during February:
1.
The rain exciter and battery charger brushes were inspected and replaced where necessarny.
2 The Waste Disposal Bttilding monorail hoist was cleaned and inspectal.
3.
Maintarance items on No.1 coabol air compraccor included new valves, replacemnt of wom carbn piston rings and replace-mnt cf the main bearirg on the flywhe l erd.
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- h. The Service Bel 1 ding rcef venLilaMrg fans were inspected and cleams.
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5.
During the shutdown No. 3 feedwater heater tube bundle was hydro tested. Results were negative.
6.
A lirdted inspection in the Vapor Container during the shut-down revealed th ee leakirg valves whose packing was subsequently tightened.
7.
On February 19, No. h prasstirizer heater air circuit breaker tripped out twice. The resistance values, mgger test, and multi amp testing of the ACB gave no indication of the cause of the trips. A visual inspection of the connectors, Vapor Container penetrations and the ACB itself were all negative. On Febraary 20 the heater was returned to service.
The heater current was normal upon restart and has remained
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so through the end of the reporting period.
v 8.
Fuses were installed in Nos. 3, h, 5 and 6 pressurizer heater circuits, being mounted da the spare compartent of No.1
& tor Control Center.
9.
A recorditioned ram and new carbon ring was installed on No. 3 charging pump,
- 10. A stea:2 valve bonnet leak at the rxxn rsturn valve staticn
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was repaired by welding the bonnet closed.
- 11. Two damaged seal strips en No. h gland seal were replaced.
- 12. No.1 caustic pump was overhauled.
13 No. 2 charging pump was rapacked.
lb. The turbine hall crans was inapeted.
- 15. A leak was repaired in the pressure tubing leading to the detector of the charging flew irdicatcr. The leak was caused by a vibration re.b cf the tubird against a supporting I beam.
Previous Operation Repcets have discussed a contint. Lng study of oxygen buildup in both sne pressurizer and main coolant system. This study was continued into February follcwirg the gradual removal of bcron from the main coolant system in January. Erly in the reporting period the pressurizer vent gas system was sampled and fo:nd to contain < 0.1%
oxygen while the pressurizer liquir' was fc=d to contain 0.0h ppm iissolved oxygen.
During the shutdown on Fecruary 12 the vent system was again sarpled and no oxygen ns obsarved in either the flashed gas or the pressurizer i
drain sample. In su:eation, there appears te be a ecrrelation between oxygen buildup and boren aime all maarcramnts to date have indicated the presence of oxygen in the pressurizer gas only when the main coolant system
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was borated. Following the most recent deberation, the pressurizer drain 0.
water dissolved oxygen contir.noasly decreased whsreup it has since reached an undetectable value.
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l x Throughout the reporting period the main coolant oxygen levels were below the point of detection.
On February $ nmmnnia in ths form of NIQ30H was injected into the main coolant system stabilizing at a concentrs, tion of approximately 8 ppm.
On February 17 while normal ammonia feed was in progress, the main coolant ammonia concentration increased to 119 ppm with a corresponding pH of 10.2.
This condition resulted from a batch of ammonia feed solution that was made up to a con:entraticn that was approximately twice that specified.
No adverse chemistry or other effects were noted and the conceatration decreased to 8 ppm on February 12.
Late in the month a study was made to determine correlations between main coolant crud conditions and plant operation.
Previous
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increases in crud concentration have been attributed to main coolant bypass line flushes and control rod movement.
Wre recently, it has been theorized that such increases in crud level may have been a result of variations in purification flow parameters.
On February 10 a crud imrease from 1.9 ppm to 9 7 ppm was experienced closely follcwing a changeover from anion to mixed bed ion exchange, and decrease accordingly when the anion bed was returned to service.
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On Febraary 25 an attempt was made to correlate increases in
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crud concentration with purification f1cw rates using both the gauma guard whose detector is located close to the charging and bleed lines and the inlet-outlet sample points on the ion exchanger as indicators. Numerous tests at low puriiication flows produced negative results. However, once the ficra was increased to 60 gpm, the gamma guard reading increased n
immediately by a factor of three. Inlet samples were negative while thos]
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taken at the outlet cf tha ion exebarger wra m asured at approximately 335 ppm.
Two conclusicas can thus be reached.
1.
The resin columns, under certain cerxiitions of operation, either a flow rate change or a charge in system arrangemnt between anion and mixed beds, are capble of discharging crud back to the rain coolant system.
2.
Bleed samples taken thus far rrw com under suspicion since it has been fairly well established that they are not indicative of actual main coolant conditions but vary in crud content based on bleed lire flow.
Additional testing using both new and partially spent ion exchangers is planned in an attempt to fird possible mechaniems for the aforementioned crud problem.
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-h-A typical min coolant crud analysis made during the period indicated:
Cr - 51 6.5 x 1 dpm/mg Mn - 5h 1.h x 1 dpm/mg Fe - 59 6.0 n dpm/mg Co - 58 9.8 x 1 dpm/mg Co - 60 1.5 x 1 dpm/mg Ag - 110m 2.2 x 1 dpm/mg A min coolant gas m1ysis made during the month indicated:
7.h x 10-2 A - h1 7.3 x 10-2 pc/cc Ie - 135 j1efee l
Ie - 133 6.3 x 10-1 pc/cc Throughout the reporting period the main coolant specific activity averaged 1.9 x 10-1 pc/ml with the exception of a brief period at the latter part of the mnth during which the aforementioned testing was accom-plished.
Reactor Plant Performance (7
On February 5 ammnia.at the form of NH 0H was injected into the h
main coolant system. The injection commenced at 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> and by 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> the main coolant NH3 concentration reached 8 ppm. At 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, when the concentration was v '2 ppm, a slight reactivity gain was noted. The gain begap quite slowly and had increased to a rate of approximately 2.0 x 10-4 A P/hr at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br />. At 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> on February 7, the total reactivity increase was equal to 16 r in main ccelart temperature amunting 3
to approximately 0.35% 6 to in h6 hours. In the succeeding two weeks additional reactivity gaina vers recorded etch that the total gain masured amounted to approximate 3y 0.65% 69 During the shutdev: all centrol rods were drop teeted twice from the fully withdraw position of 90 0/8 inenes. The results of the test were shown to be in acellert apser.t with the data obtained at the beginning of Core III life. The average drop idas for all 2h control rods was measured at 1.$h0 seconds. At the begi='.rg of Cora III life it was measured at 1.5h3 seconds.
The fol'cwing wers determined by means of in-core instrumntation measurements at a power level cf 600 IWt with all rods banked at 80 5/9.
F
= 2.51 q
F 2*3 6H 2.98 QDNER
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Hot Chansi Outlet = 597*F s
On Febrrary 27 a slight rec,tiwity lose amounting to approximately 0.25% 6(O was rscorded. No sp5:cific causes for the loss have as yet been determined, however, partial nspect has thus far been a entover to mixed bed ion exchange since the loss was recovered in approximately two days J
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following the removal of the mixed bed from service. The mixed bed was placed in service five hours before the first effects of the reactivity loss were noted.
Turbine Plant Performance Main steam line vibration studies continued during the month as polishing adjustments and modifications to tae pipe vibration sunbbers were n.ade in an attempt to further reduce system vibration.
In February the following was accomplished:
1.
On loops Nos. 1 and h piping under the Vapor Container a filler plate was added to each transverse spring anchor to
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increase thair effectiveness.
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2.
On the spring suppressor at the inlet piping to the turbine stop valves, the right hand side was stiffened with the addition of angle iron.
3.
In the Vapor Container one Grinnell snubber on each main steam lead was reconnected.
O As a result of the modifications the only significant improvement U
noted was a reduction of approximately 50% of the vibration frequency in the transverse direction at No. 3 loop. Generally speaking, at 185 We the vibration frequency continues to show a tendency to occur at a6.5 cps.
A typical feedwater heater terndnal difference masuremnt made during the period indicated:
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@ 177 We,15 Hg" backpressure 520.1 F Tavg h80 psi throttle, all control valves wide open No. 1 11.60F 0
No. 2 16.0 F No. 3 6.h0F During the month the moisture content of the moisture separator discharge steam was masured at various loads using a throttling calor-imeter. The following data summarizes the results of these masurements:
We lh8 170 177 18h Discharge Press-Psia h7.10
$3.h5 56.50 59 10
% Moisture 1.52 1.h9 1 53 1.60 As mentioned previously the coastdown of the turbine on February 1h was accompanied by shaft vibration at No, h gland commncing at Ih00 rpm.
Manufacturer representatives observed the coastdown and have since defined
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the problem as differential shaft-casing expansion. Reference gauges have
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been installed on the machine to masce the differential expansion and appropriate operating memos have been issued such that all load changes on the unit will be governed by the shaft differential.
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As reported in Jamtary 196h Operation Report a bow was evidenced on the top of No.1 station service transformr. During the shutdown the transformer was inspected. Under test, the presses relief device failed to lift at the set pressure, although it functioned nornally during a bench test. After further inspections it was concluded that all systems'of the transformer were normal and th3 unit was returned to service. As to the discrepancies between the fieli and bench test on the pressure relief device no apparent connection could be fourti other than the possibility of terperature dependence.
Instrementation and Control Duri2g the shutdown the operation of the spa e BF3 co'mters presently installed in thimbles 2 and 6 was checked using the refueling
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channels with the preamplifier and ama11fier located in the control room.
During refueling this equips'at was drstalled in the Vapor Container blister in an effort to reduce euspected noise prchlems. No difference in operat?on was recorded.
Health Physics During the month cf February 196h, 16 druu of routine radioactive waste and 1 drum of special waste (expended irrinerator filter) containing
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a total activity of 62 ::c nre prepared. No drums were shipped from the
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Liquid waste containing a tott" activity of 0.13 m: was discharged from the plant during February. Gaseou release from the plant contained an estimated 7 nu due to radiochemistry sampling.
77 An air sample taken ouzing ircinnatgr operation showed air-()
borne radioactivity cereentration of 6.7 x 104 p /c;.
Due to this high effluent concentration, the incinerator his been removed from service and will remain so persiing remelial investigatin.
During repe. irs to a lesking pipe tap to the charging line flow meter, radiation and contandnation levels of the work area in the pipe trench beneath the Primary A liary Buthtirg ctrrider floor were measured at 70 mr/hr and 2 x 106 dpm/ft prior to wasnLng. Ho9ing down reduced
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contamination by a facter of 3.
Personnel expenre for Yankee plant personnel as measured by fihn badge for the sonth of February were Averag+ for sll station personnel
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Maxir. ram iniiridual uposee
= 270 mr Design Changes
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During the month a amber of ndar design chriges wie incorporated in the wasts disposal system:
1.
The evaporator tever reflux lire was rerreved and blanked off.
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The evaporator reflux column is no longer used, the gross entrained water now being removed by cyclone separatica.
2.
The strippar bottom praps seal water lines were removed and blanked off s!.nce service water is now used.
3.
The component cooling water lines to the seal water cooler of the strippe-bottom pumps were removed and capped. The coolers themselves have also been removed since seal water has now been transferred to the service water supply.
h.
The cooler and steam operated trap on the accumulator vent line to the primary vent stack were disconnected and removed.
This equipment was installed originally to force purge the j
accumulator when the electrode efaporator was ge*.erating an explosive mixture.
5.
The distillate pump effluent demineralizer was replaced with a filter. The d6mineralizer, a replaceable cartridge unit, was originally installed to determine if it would polish the distillate so that it would be satisfactory for reuse.
The cartridge unit expends itself quickly because of volatile
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boron and hence its use was abandoned except for course filtering
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only.
.a 6.
A portable shield wall of concrete block has been installed around the drum roller to limit exposure at the drum filling station.
Plant Operations V
Attached is a sum: nary of plant operation statistics for the month of February 196h and a plot of aaily average plant load for the sam period.
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YANKEE ATOMIC ELECTRIC COMPANY -- OPERATING
SUMMARY
FEBRUARY 196h ELBLTRICAL 70 NTH TEAR TO DATE Gross Generation WH 122,h38,200 257,9hl,300 2, % 3,501,200 sta. Service (While Gen. Incl. Iosses)
WH 7,319,671 IS,362,733 213,13h,768 Net Generation WH 115,118,529 2h2',578,567 2,750,366,h32 Station Service 5
5.98 5.96 7 19 Sta. Service Nhile Not Gen. Incl. Losses)
WH 150,600 167,500 18,212,751 Ave. Gen. For Month (6%
IRS)
W 175,916 Ave. Gen. Running (67h.27IES)
W 181,586 PLANT PERFORMANCE Net Plant Efficiency 28.97 29.02 Net Plant Heat Rate Btu /WH 11,780 11,760 Ibs. Steam / Net W H 1h.05 13.87 Circulating Water Inlet Temp.
Mar 1==m 38 a
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F 3g Plant Operating Facto-I 95.1h 96.76 66.86 NUCLEAR
}ONTH CORE III TO DATE Times Critical 1
17 32h Hours Critical IES 683.72 256h.07 2h,107 18 g
Times Scramned 0
h h2 w
Sprivalent Reactor Hours @ 600 Nt HRS 662.22 1712.01 15,209.86 Average Burnup of Core WD/mtU 796.57 2783.36 Control Rod Position at Month 3x10 Equilibrits at 600 Wt $27 F Tavg.
Group 1 Rods out-inches 83 2/8 Group 2 83 2/8 Group 3.
83 2/8 Group h 83 2/8 Group 5 83 2/8 Oroep 6 83 2/8 Group 7 83 2/8 Eoron O
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