ML19351E036
| ML19351E036 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/23/1965 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E035 | List: |
| References | |
| NUDOCS 8011250492 | |
| Download: ML19351E036 (10) | |
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YANKEE NUCLEAR POWER STATION r'*
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OfERATION REPORT NO. 50
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p'EBRUARY 1965 O
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Submitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts March 23,1965 801125ty]
e This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts for the month of February, 1965.
At the beginning of the reporting period the plant was operating at full rated power of 185 Mle. Output remained essentially constant at that point until February 9, wher, a brief load reduction to 175 Mie was required to remove No.1 feedwater heater from service for maintenance on the extration steam piping. Following replacement of a failed gaoket on a bolted closure at the non-return valve packing box, No. 1 heater was returned to service and plant load raised to 185 Mle.
At 12h8 hours on February 12, the plant was shut down to repair three faulty electrical connections between the h4gh voltage lines and the T1 air break in the outdoor switchyard. T,his shutdown marked the first separation of the plant from the line since October 23,196h, a period of 112 days, during which plant output remained above 175 Hie at an times.
Electrical repairs were completed at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on the same day, however, plant startup was delayed due to malfunctioning of intermediate range channel 3, one of the plant nuclear detectors.
Investigation in the
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i vapor container indicated a defective connector in the detector thimble cabling which was subsequently replaced.
At Oh00 hours of February 13, the generator was phased and loaded to 166 Mle. Output remained essentially constant until 1125 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.280625e-4 months <br /> on February 1h, when load was raisad to 18$ Mie.
The Oceration Report for January,1965, discussed an abnormal 8 occurrence with control rod No.10 when it failed to insert u 0
t a fully withdrawn position of 90 /8 inches. A similar malfunction occurred on February 17, during weekly rod exercising as the rod failed to insert from 88 7/8 inches, its present withdrawal limitation. As experienced previously, one inward step with the bulldown coil was sufficient to free the rod where-upon it was driven to 81 /8 inches in normal sequence. As this malfunction has now been experienced at two different elevations, the possibility of step wear type hang-up does not appear plausible.
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Plant output remained at 185 Mie until February 1h, when the load was allowed to drop off at the normal burnup rate reaching 182 Mie on February 23. The load reduction was performed to avoid boron dilution and reboration of the main coolant in conjunction with a scheduled ammonia addition to the main coolant.
At 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> on February 23, ammonia was injected into the main coolant system. The expected reactivity gain, occurring as an increase in main coolant temperature and gross generation, was experienced within a few hours of injection time. At 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> the first of a series of compensating boron injections was made. The plant chemical control systems satisfactorily provided reactivity control, without control rod motion, throughout the transient change resulting from the ammonia injection. A more detailed description of the test can be found in the Reactor Plant Performance section of this report.
For the b11ance of the reporting period, the plant operated at o
full rated capacity of 185 Hie.
2-During the plant shutdown a Vapor Container inspection was made m
with no adverse conditions noted.
On February 15, Westinghouse reported that a sample of main coolant had been analyzed for tritium and that the concentration found was 2.8 pc/ml.
A program of investigation was immediately begun and was in progress at the end of the reporting period. Preliminary results indicate that all releases from the plant have been within acceptable concentrations and that personnel exposure from the source has been insignificant.
Plant Shutdowns Shutdown No. 77-h-6 2-126[
A 15.2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> forced shut-down for switchyard eleetrical and primary plant instrumentation repairs.
O Plant Maintenance
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The following is a sumnary cf major activities carried out by the plant maintenance staff during February.
1.
Machining of spare control rod drive shafts continued throughout the month.
S 2.
A leak at the discharge side of the relief valve on No. 3 charging pump was repaired.
3.
The motor bearings for No. 1 gravity drain pump were replaced.
Ibtor and pump alignment was checked.
h.
Replaced the mechanical seal on the prinary water storage tank circulator pump which had been leaking.
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5.
No. 2 evaporator bottoms pump was inspected and necessary repairs made as required.
6.
Repaired a leak on the line to the evaporator condenser.
7.
Replaced two inlet valves and one discharge valve on No. 3 charging pump.
8.
The turbine hall crane was inspected and lubricated.
9.
Installed additional pipe hangers on the oil piping under the turbine.
- 10. Repaired the exhaust pipe and hanger on the diesel generator.
Chemistry c
Throughout the reporting period the main coolant oxygen levels were 3
below the point of detection.
measured at 1.6 x 10-genth the main coolanj iodine-131 concentration wasJic/ml; the I-131/I During the Jic/ml and 8.8 x 10
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ratio was 0.55 and 0.60 respectively.
At the beginning of the raporting period the main coolant crud level was measured at 0.5 ppm. Following the plant shutdown on February 12, the crud level rose to 1.6 ppm but following startup decayed to the pre-shutdown value of approxiuately 0.5 ppm. Following the ammonia injection on February 23, particular attention was given to crud surveys to determine the buildup, if any, of crud with increasing main coolant pH.
However, at the end of the reporting period, or approximately five days following injection, no increase in crud level was noted as the concentration was measured at approximately 0.h8 ppm.
At the beginning of the month the main coolant boron concentration was measured at 155 ppm. IM.lution follow of burnup continued to February 23, when the concentration was measured at approximately 50 ppm. Following ammonia injection on February 23, and the attendent reactivity gain, the i
boron concentration in the main coolant was increased as required reaching 120 ppm at the end of the reporting period.
Following initial injection, the ammonia concentration in the main coolant was raised to 8.5 ppm remaining essentially stable at that point throughout the balance of the reporting period.
8 indicated:
A typical main coolant crud analysis performed on Fetnary 23,1965 Cr--51 13x1 dpm/mg Iti-$h 6.3 x 1 dpm/mg Fe-59 70x dpm/mg Co-58 3.3 x 10 dpm/mg Co-60 17x1 dpm/cg Hf-181 77x1 dpm/mg
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In-116m Not Nasured A typical main coolant gas analysis performed on February 25,1%$
indicated:
Xe-133 9.9 x 10~ Ac/cc gas A-hl h.6 x 10 Ac/cc gas Xe-135 1.1 x 10~ Ac/cc gas Reactor Plant Performance Reactivity increases following the ammonia injection on February 23, were similar to those experienced previously. The total gain recorded was approximately 0.7% 6 K occurring at a mwNm rate of.023% 6 K/hr. At all times during the gain control rods were at the full out position of 88 7/8 inches with reactivity control being maintained by the plant chemical control
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systems.
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-h-Following the snutdown on February 12, all control rgds were drop
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tested. Drop times, as measured from breaker opening to tne nine inch coil, were in excellent agreement with those measured during Core IV startup testing.
The results of a five ($) wire flux wire irradiation weres
@ $99 Mit 52 ppa C,
$27 F Tavg.
g Group A @ 90 inches, Groups B, C, and D at 88 7/8 inches F
2.2
=
q 2.6 F
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g 2.6 0 90 inches DNBR
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Hot Channel Outlet 599 F
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Turbine Plant Performance m
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Routine plant calorimetric and secondary plant performance data obtained during the month indicated the following:
1.
The condenser cleanliness f actor was measured at 68%, thus indicating tube fouling has not progressed beyond measured conditions at Core IV startup.
S 2.
The loss in secondary side efliciency, presently approximately 9 Mi, had stabilized at that point by February 15, and no t
further drops were experienced throughout the balance of the month.
Instrumentation and Control Principal maintenance items performed by the p? ant Instrumentation
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and Control group during February were:
1.
Completed a new trip valve check-off procedure.
2.
Checked the calibration of the main coolant pump component cooling temperature channels.
3.
Checked operational aspects of all emergency survey meters.
h.
The low bearing oil trip annunciater alarm wire was isolated at the turbine pedestal. The wire was found to be grounded in the pedestal and repair is therefore not possible until the refueling outage.
5.
During the February 12 shutdcwn, the CIC detector and in-thimble cables for channel 3 were replaced as was the connector
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on the channel 3 high voltage cable in thimble 5.
The log i
microammeter for channel 1 was also replaced and all nuclear channels were recalibrated.
6.
A calibration check of No. 2 loop narrow range temperature amplifiers found them to be within 0.5 F of their exact calibration.
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7 Relocated and calibrated tho waste gas loop seal high and low level alarm detector.
8.
Recalibrated the safety injection flow detector and indicator.
9 Initiated assembly of t,he spent fuel pit monitoring instru-mentation.
Health and Safety During the month of February 1965, no dntms of radioactive wastes were prepared or shipped.
Liquid waste containing a total activity of 0.07h me were discharged during February. Gaseous wastes containing a total activity of ~19 me were discharged during the same period.
Leakage from the ion exchange pit accounted for an additional 3152 m during the month.
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Following waste disposal plant shutdown on February lb, misoperation of valving in the evaporator cubicle resulted in the release of a small volume of cover gas to the evaporator cubicle and then to the atmosphere.
Valve No. WD-V-739 was lef t open which allowed cover gas to bleed back into the overhead condenser. The vent valve No. WD-V-7hl on the steam line between the evaporator and the evaporator overhead condenser was opened when the equipment was shut down, permitting the gas to escape. The flow path 8
WD-V-7hl.
established was from the overhead condenser to the distillate accumulator, then into the evaporator overhead condenser and to the atmosphere via Gas inventory following the release showed that approximately 1h50 cubic feet of gas containing a total activity of 9h3 Ac of Xe-133 had escaped. Radioanalysis of the remaining gas indicated a concentration of 2.3 x 10-3Ac/cc of gas. 'lhe probability of a recurrence of this incident h a s been reduced through mandatorv check off lists for waste disposal operation. Engineering will review the problem and consideration will be giver. to possible piping changes which will make the system less susceptible
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to operator error.
A hinged, self-closing plexiglass window has been installed in the pass-through opening between the machine shop and the secondary plant auxiliary bay. The purpose is to restrict flow of any possible airborne radioactivity from the potentially contaminated machine shop to the clean area.
Radiation levels in the work area at the bottom of the shield tank cavity for replacement of the channel 3 CIC detector were 70-120 mr/nr.
The levels were noted ~10 hours after plant shutdown. Air samples taken inthecavit{Oand on the vapor container charging floor indicated activities of s h x 10-Ac/cc in both areas.
Health physics coverage was provided for general clean-up in the N A Storage Building. Air samples taken in the building general area, and e
from the ductwork downstream of the exhaust system absolute filter showed activities of 1.7 x 10-10Ac/cc and background, respectively.
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During the month the routine weekly chemistry check of the ion exchange pit water indicated a specific activity of 1.2 x lo-5 cfm1, an e
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increase from the normal specific activity of 1 x 10-7Ac/ml. Investigation revealed a leaking cation bed capsule that had been recently installed.
Hydro testing pinpointed the leak on the outlet connection at the standpipe joint.
Initial chemistry samples indicated that the activity was due to Fluorine 18 with a half life of 1.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and an unidentified isotope with a 0.]h inv gamma and half life of d60 hours. This isotope has since been identified as Mo 99 A sample of the pit water, taken on the day following isolation of the qsule, had an activity of 5.6 x 10 Ac/ml with no detec-1 table F 0 prennt. Storm sewer samples indicated only background levels.
Assuming that the capsule had leaked continuously while in service and that the specific activity of the pit water was at the highest measured value (1.2 x 10-5Ac/ml) for the entire period, the total activity release in the 7h,000 gallons which leaked from the pit during the period was 3.h me.
Il Procedural changes initiated to limit future recurrences include
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hydro testing of each capsule as it is installed and chemical analysis of pit water following installation of any capsule to an "in service" position.
Personnel exposures for plant personnel as reasured by film badge for the month of February, 1965, were:
8 61 mr Average for all station personnel
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250 mr Maximum individual exposure
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Plant Operations Attached is a summary of plant operation statistics for the month of February, 1965 and a plot, of daily average load for the same period.
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o-YANKEE ATOMIC RLWRIC COMPANY -- OPERATING
SUMMARY
M0!ITH YEAR M py., _
ELECTRICAL IGlH 120,613,500 238,580,600 h,; 21,6 96,800 Gross Generation Sta. Service (While Gen. Incl. Losses) 1GG 7,176,171 1$,377,73 cy$,039,333 Wh 113,h37,329 2h3,102,S$6
- , M,656,9M Net Generation
$ 95 C. 9h 6.99 Station Service Sta. Service (While Not Gen. Incl. Iosses)
WH 106,902 100,702 19,ygg,3g3 Ave. Gen. For Month (672 !RS)
W 179,h8h W
183,633 Ave. Gen. Running (666.8 HRS)
PIANT PERFORMANCE 29.16 29.16 Net Plant Efficiency Btu /WH 11,703 11,703 Net Plant Heat Rate 13.70 13.77 Lbs. Steam / Net WH i
Circulating Water Inlet Temp.
F h3 w
Maximum F
37 Minimum 96.h9 98.16 70.39 Plant Operating Factor 98.01 9j.C6 8h.79 Reactor Plant Availability MTH CORE IV TO DATE NUCLEAR 1
20 3h5 Times Critical HRS 658.63 h231.62 32,032.31 Hours Critical 0
hp Times Scrammed HRS 6h8.hh ho$0.29 22,938.99 Equivalent Reactor Hours @ 600 Et WD/mtU w.
Average Burnup of Core Control Rod Position at Month Ihd REGION MTJ TOTAL BUP.NUP
$27 F Tavg Equilibrium at 600 W Rodsout-inckes 88 7/8 Group A Group B 88 7/8 INNER 865.71 13,938.17 Group C 88 7/8 MIDDLE 965.70 10,92$.31 Group D 88 7/8 OUTER
$90.12 3,699.87 E-6 713. %
26,579.$$
fior..n 120 ppm
YANKEE ATOAIC ELECTRIC COMPANY DAIL( AVERAGE LOAD
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9-CORE : 1 REDION IDCATIONS
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