ML19351E083
| ML19351E083 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/15/1964 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E081 | List: |
| References | |
| NUDOCS 8011250579 | |
| Download: ML19351E083 (10) | |
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YANKEE NUCLEAR POWER STATION OPERATION REPORT NO. h1 For the month of MAY 196h b 0 1.S$
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YANKEE ATOMIC ELECTRIC COMPANY
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June 15, 196h i
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This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts for the month of May 196h.
At the beginning of the reporting period plant electrical output was 153 Mie. For the balance of the month the core life extension program remained in effect as plant electrical output decreased slowly following the decreasing reactor power level.
Operation with potassium controlled high pH continued until May 11 when a hydrogen cycled mixed bed ion exchanger was put into service.
As expected, a relatively large load drop of approximately 12 Mie was experienced as the main coolant pH was brought to neutral.
On May 13 load was lowered to 75 Mie for a brief period to permit further checu.stry testing.
On May lh ammonia in the form of NH 0H was 3dded to the main h
coolant. A reactivity increase following the NH3 injection resulted in a gain in electrical power of some lh Mie.
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On May 18 the plant was shut dowm by a manual scram from a power level of h70 Mie. The scram was initiated when feedwater flow to the steam generators was temporarily lost.
Prior to the scram the plant was operating with two condensate pumps and two boiler feed pumps in service.
No. 3 condensate pump was released from maintenance and preparations were made to valve it into service.
However, as the pump was vented, entrapped air temporarily pressurized the vent line which is common to all three pumps, causing a slight dip in No.1 and 2 condensate pumps discharge pressures and, therefore, tripping No. 1 and 2 boiler feed pumps on low
,m suction pressure.
No. 3 boiler feed pump had its control switch in the auto position and it, therefore, started on low boiler feed discharge pressure. The operator then restarted No. 1 and 2 boiler feed pumps.
With only two condensate pumps on, their discharge pressure was drawn down by the three operating boiler feed pumps, and as a result all three boiler feed pumps again tripped out on low suction.
Since the pumps could not be started sufficiently soon to maintain system generator level, the n
operator elected to manually scram the plant. At no time during the transient were the steam generator levels excessively low, but since feed-water flow was lost the operator elected to scram the plant in the interest of maintaining plant stability.
Since no abnormal conditions existed following the scram, the plant was returned to line approximately five hours following the trip.
For the balance of the reporting period operations continued based on the core " stretch out" program.
Plant electrical output continued to drif t downward as burnup progressed.
During the month fuel assembly A8 which has seen service in both Cores I and II was loaded into a single element shipping cask as part of a leak test program. The results of the test will permit evaluation of the integrity of the cladding and structural material af ter undergoing extended burnup, l'
Throughout the month control rod exercising and movements for wear distribution were carried out as required. All control rods operated in a normal manner during the scram on May 18.
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Twenty four Ag-In-Cd control rods used during Core II were J'
shipped off site for disposal on May 13. The shipment arrived at the burial grounds on May 19 On May 19 a vapor container inspection was made and no abnormal conditions were noted.
At the end of the reporting period plant electrical output had decreased to 128 We.
Plant Shutdowns Shutdown No. 70-3-8
$/18/6h A 5.h hour shutdown resulting from a reactor scram.
Scram No. hh-3-6 5/18/6h A manual reactor scram
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from a power level of h70 m t resulting from a temporary loss of feedwater to the steam generators.
Plant Maintenance Following is a summary of major activities carried out by the plant maintenance rtaff during May.
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1.
No. 2 component cooling pump ACB was found slightly misalignad such that the cellswitch would not contact.
The breaker was tested and set in the proper position.
2.
No. 3 boiler feed pump motor was sent to the manufacturer for balancing.
3 A shielding cask for pressurizer heater bundles has been fabricated, b.
A leak in No.1 feedwater heate-vent line was repaired.
5 No.1 waste gas compressor discharge line check valve was renewed.
6.
The spent fuel pit manipulator boom was removed to inspect the tool. Metal chips were found and heavy galling marks were cleaned up where necessary.
7 Inspection of all 2.hKV ACB and h80V ACB breakers continued during the month.
8.
The motor and brakes on the spent fuel pit manipulator crane were inspected.
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9 No. 2 battery charger was cleaned, the commutator polished and-brushes seated.
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10.
The expansion joint in the suction line ci :;r. 3 condensate pump was found leaking necessitating repic s wnt.
11.
Tne enclosure around the fuel chute dewater -.;; pap was completed.
12.
The new fuel element storage rack was placed lu position in the spent fuel pit.
13 Temperature readings of the motors in the ccree well were taken and found normal.
Chemistry On April 15, 300 grams of KM were added to the main coolant
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system for pH control.
High pH operation continued into M1y and at the beginning of this reporting period the main coolant potassiun concentration was measured at 3.9 ppm with no purification flow. Over a five day period the concentration decreased to 2.95 ppm. Normal main coolant dilution would account for N O.36 ppm du-ing the same period and it, was, therefore, verified that some potassium was ret,ained within the main coolant system.
The load drop to 7$ We on May 13 was made in an attempt to thermally dislodge the unaccounted for potassium and thus bring it into solution (1
whereit could be removed by normal ion exchange.
On May 11 operation with potassium was suspended and the coolant potassium concentration was reduced from 2.6 ppm to 0.08 ppm with a hydrogen cycled mixed bed ion exchanger. The demineralizer was secured on May 12 and frequent analyses were performed to determine any increases in the K+ concentration; none were observed. As explained previously, the load drop to 73 We was made to determine if decreased heat flux would r
release potassium, hwever, again no increases were observed.
On May lb, NH3 in the form of NH 0H was added to the main coolant h
system. The initial concentration was measured at 10 ppm. For the balance of the reporting period the main coolant ammonia concentration was maintained between 11 and 1/ ppm.
On May 18 an increase in the coolant potassium concentration frc,m 0.03 ppm to 0.3h ppm was noted.
After the reactor scram, the concentration increased further to 0 52 ppm, Early in the reporting period the average main coolant specific activity was measured at 1.h x 10-1 uc/ml. With the removal of the K-h2 nuclide and the return to ammoniated cycle mixed bed purification the specific activity decreased to h.2 x 10-2 J1c/nl.
The Iodine-131 concentration was measured at 2.8 x 10-3 pc/ml; the I-131/I-133 atomic ratio was lh.1, the ratio increase reflecting s
operations with no main coolant purificaticn.
During the month the coolant crud level was measured at 0.30, 0.58, 0.80, 0.9h and 1.1 ppm, the higher values being consistently recorded following weekly control rod exercising. Following the scram
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on May 18,.a purification filter was placed in service to reduce the high'
- coolant crud level-'that followed the system disturbance.
~A typical main coolant gas analysis made during the period indicated:
A - hl 1.2 x 10-1 pc/cc gas Ie - 135 3 9 x 10- pc/cc gas Ie - 133-8.1 x 10-1 pc/cc gas A typical main coolant crud analysis made during the period indicated:
'Cr - 51 2.3 x 10 dpWmg Mn - 5h h.0 x 10 dpm/mg O-re - 59 9 7 x 1o aP '=8 Co - 58 1.8x10jdpm/mg Co - 60 2.0 x 10 dpm/mg Hf -
ND' Reactor Plant Performance Normal reactivity depletion was experienced throughout the early portion of the reporting period. On May 11, a hydrogen cycle mixed bed O-ion exchanger was placed into service to remove potassium from the min coolant and, s expected, a reactivity loss, occurring at a maximam rate of 0.70 x 10 AF ~, was experienced.. Th potassium removal was measured at 3h.5 x 10gtotal loss associated with the
&g On May 1h the_ main poolant was ammoniated resulting in a reactivity gain of 36.8 x 10-4 6 8 Fquilibrium data measured following A
the scram indicated a burnup rate consistent with that experienced during -
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previous high pH operations.
Forthebalanceoftheheportingperiodthereactivitydepletion rate remained normal following in general the expected burnup curve.
The fo11'owing were determined by means of in-core instriunentation measurements at a power level of h66 Wt with all. rods banked at 881/8 inches.
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Hot Channel Outlet 5680F Turbine Plant Performance' As reported in the^0peration Report for April 196h, higher than normal: condenser back pressure was noted while analyzing routine plant-r
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' calorimetric data.- Higher than normal feedwater oxygen content indicated-the presence of air leakage into the condenser. During May a freon test I
- of. suspected l areas was performed with the results indicated that the inward l
leakage of air was occurring in-the area of-the expansion jcint of No. -3 l
condensate pump suction.-
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During the month plant thermal efficiency was '.ffected by above normal circulating water intake temperatures.
Maintenance on up river hydro stati,,.u h r W ited flow into the ecoling pond tnareby raising the average water temperature at the intake structure above that normally experienced this time of the year.
Condenser performance testing was accomplished during the month with the data indicating no adverse conditions were present within the condenser proper.
Instrumentation and Control The following is a list of major maintenanc9 items carried out by the plant Instrumntation and Control group during May:
p 1.
Recalibrated the T NR main coolant temperature channels as e
V required during the month to follow changes in the range of main coolant temperature.
2.
On a rramber of previous occasions, the zero setting on the charging pump flow indicator has shifted. The cause of the calibration shif t was found to be an accumalation of moisture on the back of the terminal block in the detector housing.
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3 Removed and recalibrated the level transmitter on the activity dilution decay tank. The detector has been quite sensitive to ambient temperature changes due to the heat tracing and cabinet heating.
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Recalibrated the component cooling flow detectors on the four main coolant pump cooling lines.
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5 Performed preventive maintenance on the component coolant, vapor container, low pressure surge tank and charging and bl'eed temperaturs indicators.
6.
Performed preventive maintenance on the process recorder, nuclear recorder, generator field temperature recorder, charging flow indicator, bleed flow indicator and the low pressure surge tank level and pressure indicators.
7 Eliminated the problem of noise on the transistorized radiation monitoring channels due to the alarm flasher and panalarm reset circuit by relocatiry; the alarm relays and shielding the alarm wiring.
Health and Safety During the month of May 196h, 26 drums of routine radioactive p
wastes containing a total activity of 25.7 me were prepared. No drums were V
shipped from the site during the same period.
Liquid wastes containing a total activity of 0.06 mc were
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O discharged during May. Gaseous waste containing'a total activity of 150 me due to radiochemistry sampling were discharged during the same period.
During the month all spare dosimeters were leak tested and
-calibrated.
During the month 2h Core II control rods were shipped off site for disposal at the AED operated land burial site at Oak Ridge, Tennessee.
Total activity of the shipment was approximately 60,000 curies. Radiation levels measured on contact with the cask were generally 100-600 mr/hr with a small area indicating 700-1500 mr/hr. MaM - = levels at one'and three meters were 275 mr/hr and 60 mr/hr. Cont tion levels of the cask at the time of shipment were 200-2500 dpm/ft. Shipment was acco:::plished under a special I.C.C. permit with two members of the Yankee technical staff acting as couriers.-
O Prior to maintenance on the lower end of the manipulator tool
-boominthespentfuelpit,radiationandcongaminationlevelsweremeasured at 20-75 mr/hr at one inch and ~ 106 dpm/ft respectively.
A radiation survey in No.1 charging pump cubicle showed ~100 mr/nr at the foot of the ladder, 50-100 mr/hr general area, h00 mr/hr at pump packing and 800 mr/hr m=M== contact with suction line. This cubicle has been posted "High Radiation Area - Work Permit Required."
h3 mr Average for all station personnel
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250 mr Maximum individual exposure
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Plant Operations.
j Attached is a summary of plant operation statistics for the month of May 196h and a plot of daily average plant load for the same period, i
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O YAKEK AT0flIC EEETRIC COIfnNY - OPERATING SU10ERY M EAL MEITH YDR TO DATE Gross Geenration EWH 101,381,600 606,598,700 3,312,158,600 sta. Service (While Gen. Incl. Iosses) m 7,236,852 37,810,513 235,582,5h8 Not % tion IWH 9h,1hh,7h8 568,788,187 3,076,576,052 Statina Service 7.lh 6.23 7.11 Sta. Service (While Not Gen. Incl. Iosses)
IWH 35,800 230,000 18,275,251 Ave. Gen. For Itath (7hh HRS)
EW 136,265 Ave. Gen. Rumedag (738 58 IES)
IW 137,265 h
PIAIrf PERFCIDENCE Not Plant ErN4m g
26,76 28.h9 Not Plant Heat Bate Btu /DiH 12,753 11,979 Ibs. Steam /het IWH 15 0h Ih 17 Circulating Water InIst Temp.
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Plant Operating Flactor 78.81 91.22 68.62
)ONTH CORE III TO DATE EUCIRR 1
19 326 Times Critical Hours Critical IES 739 58 h763 30 26,306.h1 Timme Scra==wi 1
6 hh Epd. valent Reactor Hours a 600 st IRS 586.32 36h5.h1 17,1h3.26 Average Bernap af Core ND/mtU g
Contrul Red Posit $m at Month hm!
W h flibrium at h90 Wt h88.2 F Tavg.
OM 1 Rods out-inches 88 h/8
- Pagion Group 2 88 h/8 og 3 88 h/8 Inner 935.2 7166.1 Group h 88 h/8 Middle 876.7 11,356.6 oroup g 88 h/8 Outer 508.1 389h.7 Group 6 88 h/8 oroup 7 88 h/8 Baron
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