ML19351E029
| ML19351E029 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 05/28/1965 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E028 | List: |
| References | |
| NUDOCS 8011250473 | |
| Download: ML19351E029 (10) | |
Text
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I Q C )/G YANKEE NUCIEAR PG4ER STATION
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g OPERATION REPORT NO. 52 l
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For the month of APRIL 1965 O
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l Submi.tted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts May 28,1%$
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e This report cosers the operation of the Yankee Atomic Electric j
Company plant at Rowe, Massachusetts for the month of April 1965.
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At the beginning of the reporting period the plant was operating at a power level of 182 We.
As the end of core full power life was experienced on March 30, 1965, the beginning of the month saw the initiation of the core " stretch-out" or core life extension program.
Core extension is accomplished by allowing main coolant temperature and reactor porter level to fall, thereby, yielding the reactivity necessary to compensate for reactivity lost through burnup.
Plant electrical output decreased gradually for the first few days of the month reaching 17h We on April 13 At 0920 hours0.0106 days <br />0.256 hours <br />0.00152 weeks <br />3.5006e-4 months <br /> on this date all control rods were driven to 810/8 inches in accordance with the continuing main coolant crud follow program. The purpose of the test was to determine the effect of uniform control rod movement on the main coolant crud concentration. A description of the test and the results r
obtained can be found in the Chemistry section of this report.
O Positioning all control rods at 810/8 inches resulted in a decrease in plant output to 161 Wo.
Plant electrical output remained constant at that point until 1020 hours0.0118 days <br />0.283 hours <br />0.00169 weeks <br />3.8811e-4 months <br /> on April 15 when all control rod groups were withdrawn to their original positions prior to the test.
As rodi moved out, plant capability increased reaching a high of 177 We.
As equilibrium xenon was reached the load decreased to 172 We.
8 at a fairly uniform rate.
For the balance of the month plant capability continued to drop At the end of the period plant output had decreased to 163 We thus establishing a capability drop off rate of a 2/3 We/ day.
During the month removal of the last spent ion exchangers and filter capsules from the Ion Exchange Pit was accomplished. Dewatering of the pit began on April 28 and it was available for inspection on
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April 30. The source of the abnormal pit leakage was readily ascertained V
being traced to a crack in the vertical joint at the W corner of the pit.
At the completion of the resin capsule pumping operations, the waste disposal process plant and gravity drain tank were found to have experienced an abnormal increase in the amount of soluble silver in the waste Itquid. Apparently the silver nucU de was exchanged or absorbed by the crud and subsequently deposited in the associated piping and equipment.
Processing of the waste material through 1-3 micron filters was successful in removing over 90% of the gross activity which was present as suspended material; however, chemical cleaning was required for removal of the silver nuclide. This latter work is discussed in more detail in the Chemistry section of this report.
No plant shutdowns or reactor scrams occurred during April.
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Plant Maintenance l
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Following is a sumaciry of major activities carried out by the plant maintenance staff during Aprilt 1.
Completed pumping operations and disposal of all ion exchange capsules and filters from the ion exchange pit.
2.
Control rod drive shaf t weight tube fabrication continued throughout the month.
3 The overhead condenser in the stripper cubicle in the waste disposal building as well as associated piping and valves were relocated for safety and ease of operation.
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Adjusted pipe supports and rollers as required on piping in the pipe chase.
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5 Replaced two towers and necessary piping at the No.1 instrument air dryer.
6.
Installed ventilation ducts for the charging pump ram
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8 7.
Installed a new program timer in the No. 1 instrument air dryer.
8.
Installed a new crank shaf t on the hydrazine pump.
9 Completed lubrication of the travelling screens.
10.
Pumped dry and cleaned all concrete surfaces of the ion exchange pit.
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l'... Installed rebuilt valves in No. 2 instrument air compressor.
Chemistry Throughout the reporting period the main coolant oxygen levels were below the point of detection.
The main coolant ammonia concentration was held at 10 + 1 ppm throughout the month.
The iodine-131 concentration was 1.8 x 10-5 pc/ml; the I-131/I-133 atomic ratio was 0.60.
On April 11, the first phase of the Core IV stretchout period crud test involving system operation without control rod movement for
11 days and with the coolant ammoniated, boron free, was completed.
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The average system crud leve measured over the period was 0.h2 + 0.10 ppm,
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corresponding to a 3.9 mg/d / month release rate for the system wetted V
area.
On April 13, all control rod groups were inserted to 810/8 inches being followed, as expected, by an increase in main coolant crud level from 0 58 ppm to 6.h ppm. Initial crud sampling on April lh indicated a 27 ppm crud level which decreased rapidly over a seven hour period to 1.2 ppm. Initial sampling on April 15 showed a 1.0 ppm coolant crud level.
Following the latest sample the control rod groups were withdrawn to the pre-test level. Midway through the rod withdrawal the bleed line gamma guard reading increased from lh to 20 mr and then decreased to 10 mr/hr over a 20 second period. A M. sample taken during this period indicated a 17h ppm crud level, while one taken ten minutes later indicated a 2.0 ppm crud level. An increase in bleed line temperature (U3 from the normal 1750F to 2h00F was also noted. Tracing the bleed line temperature increase back revealed that as rod withdrawal progressed, main coolant temperature and, therefore, main coolant volume increased.
The volume increase, seen as a rise in pressurizer level, caused charging flow to be cut back with no corresponding decrease in bleed flow, thus increasing the bleed outlet temperature from the regenerative heat exchangers.
8 released crud from the regenerative heat-exchangers or flashing in the It is now apparent that either the increase in bleed temperature letdown orifices released crud from that area. It is now felt that this system behavior can explain much of the abnormal crud behavior that has
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been experienced in the past few months.
l On April 21, the main coolant purification loop was secured to permit dewatering of the ion exchange pit. Operation in this mode continued throughout the balance of the reporting period.
The waste process system was decontaminated with a 3% citric acid solution, pH adjusted to 3.5 with ammonium hydroxide.
Evaporator cubicle radiation levels decreased from 200 mr/hr to 15 mr/hr. Similar reductions were achieved on process piping and equipment.
A typical main coolant crud analysis performed on April lh,1965 indicated:
dpm/mg crud Cr - 51 5 8 x 106 Mn - 5h h.5 x 1066 Fe - 59 3 3 x 107 Co - 58 2.3 x 106 Co - 60 5.6 x 105 CT Hf - 181 8.3 x 10
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In - 116m None detected QJ
-h-(~N A typical main coolant gas analysis performed on April 20, 1965 indicated:
s Ie - 133 1.6 x 10-2 Jic/cc
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Ie - 135 1.9 x 10-2 pc/cc A - h1 6.1 x 10' pc/cc The metallurgical and physical tests of the purposely defected Boral samples which had blistered in laboratory tests were completed during the reporting period. The test results indicated that no new corrosion mechanisms had developed. The original defects (purposely drilled holes) were still the only penetrations of the aluminum clad.
There were no metallurigical changes in the composition of the boron carbide and aluminum meat. The blisters were created by hydrogen evolution caused by accelerated aluminum cerrosion in the purposely defected specimens, Reactor Plant Performance g'
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Routine plant calorimetric datawTe obtained throughout the reporting period. The decrease in primary plant capability was fairly constant throughout the month amounting to approximately 2 Nt/ day.
The results of a four wire flux wire irradiation were:
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@ 566 Nt Group A @ 90 0/8" Groups B, C and D @ 89 2/8" 2.h Fq
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F 2.2
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6H DNBR @ 90" 3.2
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0 580 F Max. Outlet Temp.
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Turbine Plant Perfornance b
Routine secondary plant performance datawem acquired and analyzed during the month. The data haveindicated a slight drop off in condenser performance, the cause being traced to the silt now being carried in the river water due to the spring runoff.
Instrumentation and Control Following is a summary of major activities carried out by the plant Instrumentation and Control group during April:
1.
Repaired the generator temperature recorder.
2.
Performed preventive maintenance on the radiation monitoring recorder, nuclear recorder, process recorder and conductivity recorder.
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Recalibrated the safety injection flow transmitter and xj) indicator.
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Changed the filter tape on the vapor centainer air particulate monitor.
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Calibrated the waste holdup and activity dilution decay tank level transmittere, and filled the reference legs.
6.
Performed preventive maintenance on the air particulate detectors at off site monitoring stations.
7.
Readjusted the loop seal level alarm system.
Health and Safety During the month of April 1965, the following solid radioactive wastes were prepared and shipped off site for disposal:
1.
Four concrete shipping casks containing the resins from light ion exchange capsules plus the filter used to filter the contents of the gravity drain tank and the waste n
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liquid evaporator.
The total activity of the four ship-ments was 256.96 curies.
Liquid wastes centaining a gross beta gansna activity, exclusive of tritium, of 1.38 me and 22.71 curies of tritium were discharged during April. Gaseous wastes containing a total activity of 21.56 =c were discharged during the same period.
Ieakage from the ion exchange pit 8duringAprilaccountedforanadditional19.15mcofgrossbetag activity, exclusive of tritium and hh8 me of tritium.
April saw the completion of the resin pumping and shipping operations. Four casks were prepared and the contents disposed of.
Radiation levels on the casks wore 35-80 mr/hr contact and h-8 mr/hr at one meter. The curie content in each of the casks was 75.2,73.5, 61.h and h6.86 curies respectively. Cuno filters used for filtering evaporator bottoms and the gravity drain tank contents, both containing (V3 the liquid effluent from the loaded shipping casks were included in the last cask and contributed 3.36 of the h6.86 curies thersin. One filter capsule and one resin capsule were removed from the pit and placed in casks for on site storage during leak proofing of the pit.
As the Ion Exchange Pit was drained, radiation levels measured at various stages of che draining were as follows:
Water Remaining in Pit Radiation Level at l' above Water 6'
l-2 mr/hr l'
5-20 mr/hr 2 " - h" 10-35 mr/hr Following several washings of the pit walls and subsequent removal of the residue from the floor the radiation levels were reduced r]
to 1-2 mr/hr general area. Smears taken on the walls following three
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2 washings showed 20,000-100,000 dpm/ft. After several additional washings
/m) the contamination was reduced to generally 1500-6000 dpm/ft2 with a The airborne particulate radioactivity
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detected maximum of 28,000 dpm/ft.
concentration in the pit since the onset of draining and during the first N h x 10-11 pc/cc.
phases of repair work ranged between background and Personnel exposure for Yankee plant personnel as measured by film badge for the month of April 1965 were:
183 mr Average for all station personnel
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910 mr Maximum individual exposure
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Plant Operations Attached is a summary of plant operation statistics for the month of April 1965 and a plot of daily average load for the same
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The following Emergency Instruction and Operating Instruction k/
were issued during the month:
50hH Operation Instruction - Purification System 505B3 Emrgency Instruction - Primary Pla-b Fuel Cladding Failure 8
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YANKEE ATOMIC ELECTRIC COMPANY -- OPERATING SUlffARY APRIL 1%$
ELECTRICAL MOICH YEAR TO DATE Gross Generation KWH 123,h25,700 516,h9h,500 h,h79,610,700 Sta. Service (While Gen. Incl. Losses)
WH 7,687,533 31,056,503 310,718,61h Net Generation WH 115,738,167 h85,h37,997 h,168,892,086 Station Service 6.23 6.01 6.9h Sta. Service (While Not Gen. Incl. Iosses)
WH 0
155,936 19,95h,387 Ave. Gen. For Month (719 HRS.)
Kg 171,662 Ave. Gen. Running (719 HRS.)
g 171,662 PIAIC PERFORMANCE Net Plant Efficiency 28.h6 28,95 Net Plant Heat Rate Btu /WH 11,991 11,788 1h.06 13.86 Lbs. Steam / Net WH hl Circulatirg Water Inlet Temp.
OF hl Maximun
'F 35 97.08 71.h9 ftinimum Plant Operating Factor 9h.26 99.53 82.99 Reactor Plant Availability 100
!ONTH CORE IV TO DATE NUCLEAR 0
20 3h5 Times Critical HRS 719 569h.62 33,h95.31 Hours Critical 0
5 h9 Times Scrammed Equivalent Reactor Hours @ 600 Et HRS 677 7h 5h55.30 2h,3hh.00 Average Burnup of Core ND/mtU Control Rod Position at Month Ehd Equilibrium at 578 *t 0 509 h F Tavg.
REION *
!ONTH TOTAL BUMdP g
Group A Rods out-inches 90 Group B 89g INNER 896.59 15,807.8 g
8Y MEDDLE 976 53 12, % 7.87 Group C Group D 895 OUrfR 650.6h 5,030.55 E-6 727 93 28,115.80 Boron
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CORE IV R EION IDCATIONS OUTER REDION MIDDIE y
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RE: :0N E-6 O
E-6 Assembly No. A-8
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