ML19351E119
| ML19351E119 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 02/18/1964 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E116 | List: |
| References | |
| NUDOCS 8011250624 | |
| Download: ML19351E119 (11) | |
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o YANKEE NUCLEAR POWER STATION OPERATION REPORT NO. 37 For the month of T3
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O oV Substitted by YANKEE ATOMIC ELECTRIC COMPAIE Boston Missachusetts l
February 18, 196h l
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s This report covers the operation of the Yankee Atomte Electric Company plant at Rowe, Massachusetts for the month of January 196h.
At the beginnLng of the reporting period the plant was operating at rated capacity of 185 }We. Routine operations continued at that output until January 17 when an au+cmatic turbins trip followed by a reactor scram was experienced. The trbine trip sequence light on the scram sequence panel indicated that the turbine had tripped prior to the scram and comparison of traces taken from recordsrs in service have confirmed this.
It is now theorized that the trip was a result of a mechanical fault in the overspeed trip latch or associated mchanisms on the turbine control system. At the time of the incident, it was apparent that the trip was not the result of any abnormal condition. The reactor was (1
brought critical through programmed rod withdrawal and followed by a
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1/M plot. Apprnrimately tin ee hours folicwing the trip, the turbine was phased to the lir.e and punt output was raised to 167 FHe. The plant was bro"ght to licensed output of 185 FWe on January 18 and operations continued at nearly that load until the end of tha reporting period.
Vapor container inspections were made on January 2, January 16 and January 29. All three inspection tours were routine in nature and no abnormal conditions were noted.
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Periodically throughout the month control rod exercises and (J
movement for wear equlization were carried out as scheduled.
Plant Shutdowns Shutdown No. 67-3-$
lh7/6h A 3.1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> shutdown resulting from an automatie turbine trip (O
and corresponding reactor scram. The trip was traced to a echanical fault in the hand turbine trip nectriism.
Reactor Scrama
-Scram No. h2-3-h 1/17/6h An automatic reactor scram from a power level of 600 FWt following receipt of a turbine trip eignal by the scram brddktsr3.
Maintenance Followirg is a summry of mjor activities e trried out by plant naintenance personnel during January:
1.
No.1 Gravity Drain Tank Pamp was inspected.
2.
The universal handling tcol was diamantled and inspected in an attempt to trace down the cause of improper latching of drive shaf ts at Core II-III refueling.
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3.
A pola crane operated tool for use in handlbg control rod drive shafts was designed and submitted to a Incal machine chop fw an estimats. It appears that er h a bol may be necessary since an u?. resolved derign p-vblem is apparent in the shafts.
14. A leeking flange on No.1 Fesdvater Heater leml control was repah'ed by instalmg a new gasket.
5.
The exciter filters were exchanged ftr a c2esu set.
6.
The multi amp tester was inspected.
7 The overload protection on the Pressrizer lleaters Air C
Circuit Breakers were tested.
8.
A spent ion exchange unit was remved from ssr-rice.
9.
No. 2 charging pug was repacked.
10.
No. 21-strnrent air dryer tuAs were replaced.
- 11. The spare set of reactor vesaal st* cm coated with p'eservative and stored in the PCA stortgs bd_Idir:g.
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- 12. The control rod break joint aschaism f Lor r2ppert stand was align ~d.
13 The decontamLnation area in the mach' ne step was cleared and ele med.
s lh. De&2 3e month, a pressrirsr h@-r f.urd b o >ap 2 fa11+1. Visual inapaction 5 the vapor m%.'em vowed a
'trad.c 12 '.he its alation at the c',t>L. >c 'ra t & n place.
Sm cracking was also obserM on ihs.: c.'. ~3 s Prbing other hsat-r gror.ps. A rrMvc M & el.zn. impurem2ts are now beSg considemd to rect!fy %e u~ P h.
Chemistry Studies on oxygen buildup in the pr+ssT'.w
' r '.h. <d during the month.
Eari;r in the mnth continuou v-nthd d ' - p. wder to the Iow Pressure Surge Tank caused the hydrogen con %t oc' tne 'rapor phase to decrease from 510 to 360 cc of gas per lite of exd-c' nd etaam. At that time the preseurizer drain water dissal-d r>rygen vu bGm detection but later increased to 250 ppb. On Jan:A7 In W v?, <yhm was agr-iin sampled and the hydrogen contsnt of the vapor I e hwt d+reaud further h
to 325 cc of gas par liter of coniensed steam. D - c. e w 6 ~ h w l a ls o decreased to 70 ppb. Oxygen levels in vr.t u;br t.r y t.r;",tn.,
reporting period were below 0.1 cc/ liter bec'-36 u:. a ec O.J.ned relation-4 ship between 02 in ths vented gas a.dburc,n cox.datine. Er %s latter part of the reporting period, samples from ths prenriw wot initcated that the gas concentration had reached equilih-lu at 330 ce of ge per liter of condensed steam. At tha end of the repcWLrg p e ni,to f e'litate k
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further testing, the pressurh r vont was closed to allow the gases to build up to evaluate presatr ac oxygen conditions with unadjusted pH =ain
. coolant chemistry.
The main coolant oxygen concentration remained belor the point of attection throughou' a reporting period.
Early in the reporting period the main coolant specific activity was somewhat erratic due primarily to the control p d wear distribution program. - Activity levels ranged between 1.1 x 10- pc/ml and 3 3 x 10-lpc/ml.
Correspondingly, crud levels ranged between 0.12 ppm and 2.0 ppm.
At the beginning of the month the maic coolant boron concentration was approximately 55 1.pm.
This number was further reduced to 28 ppm on January 10 by anion e7. change, remaining essentially constant at that value O
until January 17 On January 16, a slow steady increase in the pipe chase cubicle gamma guard reading was noted (the gama guard is used as a qualitative indicator of main coolant activity since its detector is located immediately adjacent.to the bleed line). Coincidently, anion exchange was initiated for removal of the remaining boron in the main coolant. In the early evening of January 16, the gamma guard increased rapidly and it was noted that the anion exchanger was exhausted. The main coolant purification p
was therefore switched to catiot. sxchange followed by filtration and the
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flow rate was increased to 60 gpm with a 50 gpm feed and bleed rate. Main coolant samples indicated normal chemistry ari fission products except for excessive crud. ImmediatQ following the ret. 'er scram of January 17, the gama guard readings increased by a factor of three and then slowly decreased. Crud levels measured were,,70 ppm with a total specific activity in the main coolant of 3 pc/ml. Thereafter, the purification system (3
effectively removed the crud and on January 18, the specific activity decreased U
to 0.2 pc/ml. A new anion exchanger was placed in service and on January 20, the specific activity was measured at 0.2yc/ml and the crud level 1.5 ppm; the boron concentration was 0.8 ppm.
No apparent connection between the exhausted anion bed and the crud increase can be found since downstream samples of the bed indicated that although the resin was exhausted, it was still effectively removing crud. Also, the crud increase commenced before the exchanger was placed in service. The resulting reactor scram only served to increase the crud level since recent indications have shown nuvemnt of vessel components serve to increase crud levels due to system distrubances. Behavior of the gamma guard and main coolant bleed line samples indicated that crud level in the bleed line increased directly.with bleed flow rate which supports the theory that bleed crud levels are not ireiicstive of main coolant conditions. At the end of tria reportini; period the crud level had decreased to 1.3 ppm.
Two measurements of the I-131 specific act171ty were yde during It was neasured at specific activities a* 1.1 x 10- J1c/ml and the mont h 7.h x 10-b c/ml with corresponding I-131/I-133 atoric ratios of 7 2 and p
5.6 respectively.
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-h-O A typical main coolant crud analysis made during the period indicated:
Cr - 51 73x1 dpm/mg Iti - $h 1.6 x 1 dpm/mg Fe - 59 6.0 x dpm/mg Co - 58 1.9 x 1 dpm/mg Co - 60 h.6 x dpm/ag Reactor Plant Performance During the month core reactivity follow was continued to determine the variances in unexplained reactivity. At the cd of the reporting period the unexplained reactivity was measured at 0.20% 6(o.
Operation with boron in the main coolant ternd.nated on January 18 when the boron concentration was reduced to 0.8 ppm.
Three flux wim_ irradiations were analyzed during the period and-the results are tabulated below:
- @ 600 Wt 527 F Tavg.
all rods banked @ 77 2/8a F $ = 2.h3 O
couaa - 2.9o 0
Hot channel outlet = 600 F
@ $35 Nt
$1h0F Tavg.
Gps 2-7 @ 77 5/8a Gp 1@ $8 7/8a F
= 2.3
= 2.9 O-.
QDNBR = 3.60 Hot cha0nel outlet = $80 F 0
@ $96 Wt 527 F Targ.
All rods banked @ 78 O/8a F,%H=2.25
- % = 2.73 QDNBR = 3 16 Hot channel outlet = 5960F During the month measurements of Con III depletion rate were obtained:
Boron Equivalent of Depletion 0.13h ppm boron WD/WU Measured at average core conditions'cf:
527 F
- T avg.
600 N t Power
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Boron Cone. = 30 ppm Burnup
= 2600 WD/WU
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Temperature Equivalent of Depletion
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0.038 0F WD/MrU j
Measured at average core conditions of:
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$27 F T avc.
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600 Wt Power
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Boron Conc. = 0 ppm 183)WD/MPU Burnup
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I Analysis. of this data using boron worth measurements from low power tests at the start of. life result in a depletion rate and a moderator temperature coefficient oft s
aP 6
-8.3 x 17 gg
=
6B WD/MPU 69
-2.2 x 10.h 6$
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Prior to Core II operation, a stainless steel wear skirt was installed on a fixed shim rod to limit wear on the top adaptor as it contacted the mide blocks on the upper core support plate. The skirt was designed to e ntact the guide block. area and abso-b ag wear. During the past refueling the skirt was removed and examined. Inspection showed the h~
skirt effectively limited wear, however, its method of attachment to the shim rod was considered inadequate since the skirb lif ted from the shim rod and remained wedged in the upper core support plate when the plate was removed. A decision as to what method will be employed to limit wear during Core IV operation has not as yet been made.
Turbine Plant Performance A number of secondary plant performarre tests were conducted during the month in an effort to improve the gmes station output at
' licensed reactor power level. A condenser perfomance test was conducted to' determine an adjusted heat transfer coefficient and a cleanliness factor.
based on unit service.- Daily calorimetrics are now being run to check the established. We, Mt and "Hg. back' pressure cries.
Steam line vibration studies conYemd at the 185 We load. This data was compared to that measured at 170 We with only slight differences
. recorded.-
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. substantial modifications to the main steam line suspension system had The.two sets of data previously mentioned were measured after-taken place. Effectively, the amplitude of vibration, previously considered excessive at 150 We, has been substantially reduced at 167 We and 185 We. However, small local areas in the main steam piping
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will still csquire further refinements. Analysis of data pertaining to these areas is now underway.
During a rcutine inspection of plant components, it was noted that No.1 station service transformer had a Nwed top, thereby causing the high voltage bushings to be out of line.. Also a slight oil leak was fount at the C phase bushing. Nitrogen gas and oil samples were taken and found normal upon test. The pressure relief and alarm devices were inspected and found as factory set. A representative of the manufacturer inspected the transformer on January 10 and could find no abnormalities evidenced other than the bowed top. A more detailed inspection of the transformer is planned once it is available through a station shutdown.
Instrumentation and Control Routine primary and secondary plant maintenance continued during the month. Other work items consisted of the following:
1..
Replaced a defective relay in the turbine speed and position recorder switching circuit.
2.
Adjusted the pressure switch on the turbine valve position and speed recorder to eliminate clattering of the switching relay.
O 3.
Checked operation of the condenser level controls to find the cause of efaulty make-up valve operation and recalibrated the make-up and dump controller float chambers.
15. A new circuit was designed for hfg1 moisture separator level trip.
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A study was made on how to improve plant response in a loss of feedwater occurrence.
Health and Safety Cumulative waste discharges for the year 1963 are tabulated below:
Solid Waste Prepared 578 drums and 3 wooden boxes containing a total activity of 6.708 curies. 503 dnus sed 3 wooden boxes containing a total e.ctivity of 8.872 curies were shipped during the same period.
Liquid Waste Liquid waste containing a tots 1 of 3.514 me was discharged from the plant in 1963.
Gaseous Waste An estimated 7.377 curies of gas due to radiochenLatry sampling and charging pump leakage were discharged from the site in 1963.
o During the month of January 1%h 91 drums of routine radioactive 1
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waste containing a total activity of 1106 mc were prepared.
138 drums containing a total activity of 1113 me were shipped during the same period.
Liquid waste containing a total activity of 0.hh me was discharged from the plant durbg January. Gaseous release from the plant contained an estimated 7 me due primarily to radiochemistry sampling. At all times the concentration of waste products dischargsd from the site was well below the mmh =m pered.ssible.
A pre-overhaul survey of the universal handling tool showed radia ion and contamination levels of 30 m*/n maximm at 1 in and 2
- 1 dpm/f t. After washing and dismantling, radiation and contaminatign levels of the components were 2-10 r/hr at 1 in., and 1000-15,000 dpm/ft.
To assist in ascertaining a feasible method of disposal, a
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radiation survey of 11 spent ion exchange capsules was parformed. Maximum V
contact readings on the upper 3 feet of the capsules, raised above the water surface of the ion exchange pit, ranged from 200 mr/hr to a 500 r/hr.
Daring the month the incinerator stack air particulate filter was replaced. Radiation levels of the spent filter on the affluent and effluent sides were 10 r/hr and h r/hr respectively.
Contamination levels on both sides of the filter and inside srfac of the stack were 2
v $00 dpm/f t,
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Routine decontamination in the spent fual pit building has reduced contamination levels to N 1000 dpm/f t2 at the periphery of the pit and ~ 200 dpm/f t2 on the manipulator platform.
A survey of the ICA -storage building shoed radiation and contand. nation Igvels of 2 mr/hr at the door, 5-10 mr/hr general area, and
~ 1000 dpm/f t en the ficor. An air sample taken in the same building m
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showed no air-bcrne activity above backgrouM.
Following the main coolant crud temass of Jaraan 16, the radiation level in the PAB valve room, as measmed by the gama guard located therein, reacned a maximm of h50 mr/n. After the reactor scram on January 17, the radiation level reached a maximm of 600 mr/hr. At the and of the reporting period, the valve room gamma guard reading was 20 mr/hr.
A contamination survey of the vapor container charging floor showed conti ulnation levels of 1000 to 2000 dpm/f',2 Pe sonnel exposure for Yankee plant v vonnel as ceasured by film badge for the month of January 196h were.
136 mr Average for all stat.ico pesomi
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Newly Issued Emrgency Instructions During the month Emergency Instruction 50$El was iscaed dealing with:
Primary and Secondary Plant Action in the Event of a Missile Attack Warning.
' Design Changes The main coolant vent header to the primary vent st.ack was repiped to remove a water leg in the line which on occasion has caused flow restrictions.
Plant Operations Attached is a summary of plant operation statistics for the month of January 1%h and a plot of daily average plant load for the same period.
An error in computation on the data sheet in Operation Report No. 35 for November 1963 has been corrected and reported below:
Station Service (while not Gen. Incl. Losses)
O' nerorted Enth Year To Date November 1,380,900 3,8hh,213 16,813,051 December 232,200 h,076,h13 17,0h5,251 Corrected November 1,380,900 3,8hh,h13 213 17,813,051 O
December 232,200 h,076, 18,0h5,251 i
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YANKEE ATOMIC ELECTRIC COMPANY - OPERATING
SUMMARY
JANUARY 196h E MCTRICAL MONTH YEAR TO DATE Gross Generation KWH 135,503,100 135,503,100 2,8hl,063,000 Sta. Service (While asn. Incl. Losses)
KWH 8,0h3,062 8,0h3,n62 205,815,097 Net Generation KWH 127,h60,038 127,h60,038 2,635,2h7,903 Station Service 5.9h 5.9h 7.2h Sta. Service (While Not Gen. Incl. Losses)
KWH 16,900 16,900 17,062,151 Ave. Gen. For Mon +,h (7hh HRS)
KW 182,127 Ave. Gen. Running (7h0.87 HRS)
KW 182,900 4
PLANT PERFORMANCE Net Plant Efficiency 29.05 29.05 Net Plant Heat Rate Btu /KWH 11,7h8 n,7h8 Lbs. Stea d et KWH 13.7 13.7 Circulating Water Inlet Temp.'
a Maximum F
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OF 35 Plant Operating Factor 98.28 98.28 66.01 NUCEAR MONTH CORE III TO DAT_E Times critical 1
16 323 Hours Critical HRS 7h2.12 1880.35 23,h23.h6 Times Scrammed 1
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Equivalent Reactor Hours @ 600 Mit HRS 731.17 10h9.79 1h,5h7.ed Average Burnup of Core MID/mtU 879.53 1982.03 Control Rod Position at Month End"F T avg.
Equilibrium at 600 Mit $27 Group 1 Rods out-inches 78 Group 2 78 4
Group 3 780 Group h 780 Group 5 780 Group 6 780 Group 7 780 Boron 0 ppm 4
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