ML19351E091
| ML19351E091 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 05/21/1964 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E090 | List: |
| References | |
| NUDOCS 8011250590 | |
| Download: ML19351E091 (10) | |
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1 YANKEE NUCLEAR POWER STATION i
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OPERATION REPORT NO. h0 t
i For the month of 4,
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APRIL 196h
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1-i Submitted by YANKEE ATOMIC ELFUTRIC COMPANY l
Boston:
Massachusetta i
l May 21,'196h t
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E This report covers the operation of the_ Yankee Atomic Eleetric h
Company plant at Rowe, Massachusetts for the' month.of April 196h.
At th'e beginning of the reporting period plant electrical output was 168 W e.
All control rods have essentially reached their upper with-
'drawal limit and the plant is now operating on the " stretch out" or care life extension program. Core extension is accomplished through gradual main coolant temperature and reactor power level reductions yielding ~the reactivity necessary to compensate for reactivity lost through burnup.
Early in the month plant electrical. output was influenced not
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only by the core extension progrc.m but also by the effects of termination of NH3 feed to the main coolant. The latter was part of a~special reactivity test begun in late March and is reported in'more detail in both the Reactor Plant Performance and Chamistry sections of this report.
O on igr11 15, noteseium in he form of xoH wae edded te the main-coolant system for pH control. As was expected, a moderate reactivity gain was recorded following the initial injection. A more detailed description of the test can be found in both the Reactor Plant Performance and Chemistry sections of this report.
Throughout the nr. nth routine weekly operational checks of the reactor control rods, turbine control valves and Safety Injection System were performed as required.
q on April 7, a Vapor Container inspection was made and no abnormal b
conditions were found.
At the end of the. rep-ting period plant electrical output had dropped to 153 We.
No plant shutdowns or reactor scrams occurred during April.
Maintenance Folk wing is a summary of major activities carried out by plant mintenance personnel during April.
1.
Replaced a defective bearing in the Spent Fuel Pit cooling pump.
2.
Reworking of spare valves in anticipation of use at the next refueling continued during the period.
3 Replaced a shaft sleeve on No. 2 component cooling pump.
h.
A spent ion exchange resin column was removed from the ion exchange pit and backflushed to permit capsule recycling,.
- 5. ~ A spare ion exchanger capsule was charged with resin ar.d
,placed into service position.
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V 6.
The Battery Room exhaust fan was cleaned and inspected.
7.
All Vapor Container external electrical penetrations were inspected.
8.
A ground on No.1 battery wac detected ard traced to water in the Hi-Lo level alarm on the demineraf.ized wate" tank.
Rain had entered the conduit. The ground was cleared and the conduit made tight.
9 Threo Core I drive shafts were machined to permit installation of c)mplete Core II type dashpot assemblies.
10.
An enclosure has been under construction to house the fuel
(')
chute dewatering pumo.
U 11.
Component cooling pump No. 2 ACB was found to have a broken are chute necessitating its replacement.
- 12. The main batteries were tested and water was added as required.
Chemistry On March 30 ammonium hydroxide feed to the main coolant was terminated and by April 1 the main coolant NH concentration had decayed 3
to 0.7 ppm. For approximately one week there1fter the NH3 concentration slowly decayed until it reached a somewhat stable value of 0.3 ppm. Over the period described above the main coolant pH decreased from 9.5 to 8.5 On April y c new hydrogen-hydroxyl cycled mixed bed demineralizer was placed into service. The remaining NH3 was removed from the main g(,)
coolant and the pH decreased to neutral.
On April 15 the pH of the Main Coolant System was again increased to 9 5 through the addition of 300 grams of potassium hydroxide. As a result of this chemical addition, the potassium ion concentration was 2 ppm.
On April 17 the potassium concentration was increased to h.o ppm.
On April 29 the concentration was increased to h.3 with a main coolant pH of 10.2.
Periodic potassium makeup was required during the month as main coolant dilution occurred. Some inaccuracies were recorded.ns attempts were 1
made to correlate feed rate and main coolant dilution.
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The main coolant oxygen concentration remained below the point of I
detection throughout the reporting period.
Early in the reporting period the average main coolant specific activity ranged between 5 7 and 7 3 x 10-L On April 17 the main coolant specificactivitywasmeasuredat15x10gc/ml.
pc/ml; the increase in activity aL/
being attributed to the presence of the K-h2 nuclide.
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Upon the return to neutral pH the main coolant crud level decreased
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to 0.12 ppm. As the main coolant pH was increased to 9 5 a corresponding increase;in the crud concentration to ~ 1.h ppm was recordsd.
The' main coolant, I-131 specific activity was measured at 3 0 'x 10-3 pc/ml and the I-131/I-133 atomic ratio was 5.1.
A typical main-coolant gas analysis made during the period indicated:
A
- h1 1.8 x 10-1 Ie - 133 8.1 x 10-1 Ie - 135 8.2 x 10-2 A typical main coolant crud analysis made during the period indicated:
1 Cr - 51 2.8 x 10 dpm/mg Mn - 5h 2.6 x 1 dpm/mg Fe - 59 8.9 x 10 dpm/mg Co - 58 1.6 x 1 dpm/mg Co - 60 15x1 dpm/mg Only minute traces of hafnium have been found in the crud samples taken to date being essentially below the detection point of p. ant equipment.
Reactor Plant Performance The second phase of the special test procedure to allow natural decay of the main coolant NH3 concentration began on March 30. At the beginning of the test the NT concent. ration was measured at 10 ppm 3
decaying initially to 0 3 ppm. Approximately 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> following the termination of NH3 feed, a slow reactivity loss amounting to 0 37 x 10-h 6 /hr began.. The total reactivity loss associated with the NH3 removal to 0 3 ppm was approximately ' 25 x 10-h 6' to which was observed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the be inning of the test. During the next h8 hours a slight j -
reactivity gain 3.h x 10-h AG ) was observed following which a higher than normal burnup rate was observed.
On April 9 a new mixed bed ion exchanger was placed in service
- to remove the 0 3 ppm NH3 still remaining in the main coolant system.
Reducing the concentration to zero resulted in a reactivity loss equal to approximately 21 x 10-h 6 (D The loss occurred over a period'of 2h hoursandwasfollowedbyashortperiodofnormalburnupuntg1theion exchanger was removed from service. A slight gain (2.3 x'10- 6 p ) was measured over a h8 hour period following the removal of the ion exchanger from service.
On April 15 potassium in the. form of KOH was added to the main coolant system. ~ Shortly after the initial injection a steady reactivity gain was observed occurring at'a maximum rate of 5.75 x 10-h 6 p/hr.
Over a 16 hour1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> period a total corrected (xenon and burnup) gain of
~.h hl.5'x 10-4 A p was observed.
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'On April 17 the main coolant system potassium concentration was increased to h ppm resulting in an approximate reactivity gain of h.6 x 10-h 64 For the balance of the raporting period the burnup rate was seen to be slightly higher than normal. On April 29, following an-increase of main coolant pH to 10.2, the burnup curve showed a tendency to flatten out. The point burnup at the end of the reporting period was approximately 3.h5 x 10-h 6 p lower than the extended NH3 burnup curve.
The following were determined by means of in-core instrumentation measurements at a power level of h8h Nt with all rods banked at 87 6/8".
2.5 Fq
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6H h.1 QDNBR -
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Hot Channel Outlet = 573 F The core lifetime extension program remained in effect throughout the reporting period. With the four turbine control valves at the full open position, reductions in main steam temperat;re and pressure accompany the decrease in main coolant average temperature, thereby resulting in reduced steam flow and a corresponding decrease in plant electrical output.
Reactivity additions are achieved through gradual reductions in the main coolant average temperature and reactor power level.
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Turbine Plant Performance While compadngplant calorimetric data vs. plant coastdown, it was noted that for the given plant conditions of We, Wt and circulating water temperatures, ' the condenser back pressure was 0.25" Hg higher than expected.
Coincidently with the bacle pressure increase, the secondary plant feedwater oxygen content increased. Air leakage into the condenser has, therefore, been suspected.
On April 22 a condenser performance test was made, the results indicating a 10% reduction in the cleanlinecs factor.
Freon testing of suspected joints is, therefore, planned in an attempt to locate the source of air leakage into the condenser.
A typical feedwater heater terminal difference measurement made during the period indicated:
@ 158 We 1 50" Hg, 520 *t 0
13.5 F No. 1
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12 50F No. 2 6.7 F No. 3
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Instrumentation'and Control O
o=rs=8 the = ta teet er the vePor Ce=ta1=er etr 1eezese = #1ter1=8 system was conducted. The test proved the makeup air rate to be an accurate monitor of leakage rate.
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The following is 'a' list of the major maintenance items carried
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out by the plant.Insutrumentation and Control group during April.
1.
Performed a gas calibration on the incinerator stack detector, the air ejector effluent detector, and the primary vent stack gas detector.
2.
Replaced the pump on the Vapor Container air particulate monitor.
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- 3. - Recalibrated the T NR main coolant temperature channels as e
required during the month to follow changes in the range of main coolant temperature variations.
h.
Completed the design of a sequencing circuit for use on turbine trips.' (See Operation' Report No. 39, page 6).
5 Completed the revision of the primary plant and nuclear instrumentation check-off list to include the instrumentation changer, to date.
Health and Safety During the month of April 196h,10 druns of routine radioactive wastes containing a total activity of 158.3 mc were prepared. No drums were shipped fron the site.
Liquid wastes-containing a total activity of 0.13 me were discharged during April. Gaseous wastes containing'an estimated 160 me due to radio-activity sampling were discharged during the same period.
During the month a hafnium control rod damaged during the past refueling was returned to the manufacturer for repairs. Rad contamination levels of the rod were 90 mr/hr and 105 apn/ftgation and Upon return to site, all rubbing straps on the control rod were reground to increase their respective end chamfers. Grinding was accomplished in the PCA Storage Building. An air sample taken during grinding indicated a concentration of 1 x 10-11 31c/cc.
The building exhaust fan was in operation, and all concerned wore respirators and face shields.
During Vapor Container entrance for maintenance of the in-core instrumentation system, the air-borne activity level in the Vapor Container was measured at 7 x 10-10 yie/ce, Routine cleanup of the yard decontamination pac reduced radiation and contamination levels from 20 to 0.5 rIr/hr in the moas,.and h000 to 1500 dpm/ft2 respectively.
Radiation surveys performed during machining of the three Core I drive shafts indicated radiation levels 'of m10 mr/hr contact at the cap end, and 60, 150 and 2h0 mr/hr respectively contact with the dashpot' ends.
h Contamination levels were generally 10 to 105 dpm/ linear. foot.
Decontamination on a test basis of a section of one shaft reduced the -levels from 3 x 105 to 2 x 103.dpm/ linear foot.
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V-In late April a spent resin capsule was removed from the ion exchange pit and backflushed to permit resin rnmoval and reuse of the capsule. Maximum contact radiation levele ore and af ter resin removal g
were 350 mr/hr and 3 mr/hr. Contamination. levels before apd after resin removal and subsequent capsule decontamination were 5 x 104 dpm/ft2 and 2
600 dpm/ft,
Personnel exposure for Yankee plant personnel as measured by film badge for the month of April 196h were:
Average for all station personnel-100 mr
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$60 mr Maximum individual exposure
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Newly Issued Emergency Instructions During the month the following revised Emergency Instructions were issued:
$0$Bh Primary Plant Cold Water Accident 505B12 Primary Plant Neutron Shield Tank Leak 505B13 Primary Flaat Excessive Radioactivity IcVel 505B18 Primary Plant Failure of Charging and Volun.2 Control System Plant Operations-Atts.ched is a summary of plant operation statistics for the month of April 196h and a plot of daily average plant load for the same period.
The average burnup of Core III measured in RfD/mtU has been more O
e1eer17 aers ea te i=e2>ae previe== *=r==9 re 11=ea 67 c re 1
ee d see while operating in prev...ous cores. The attached diagram indicates the regions as assigned for identification purposes. The inner region contains new 3.h% enriched fuel. The middle region contains spent 3.h% enriched Core II fuel. The outer region contains new h.1% enriched fuel.
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D TANGE ATOMIC ELECTRIC COMPANY -- OPERATING
SUMMARY
APRIL 196h ELETRICAL ENTH TEAR TO DATE Gross Generation NH 14,125,900 505,217,100 3,210,777,000 sta. Service (While Gen. Incl. Losses)
WH 7,215,700 30,573,661 228,3h5,696 Not Generation NH 106,910,200 h7h,6h3,h39 2,982,h31,30h Station Service 6 32 6.05 7.11 Sta. Service (While Not Gen. Incl. Iosses)
NH 0
19h,200 18,239,h51 Ave. Gen. For Month
'(719 HRS)
W 158,700 Ave. Gen.
D=ani ng (719 HRS)
W 158,700 PIANT PERFORMUICE Not Plant Efficiency 28.hh 28.87 Net Plant Heat Rate Btu /WH 12,000 11 821 Ibs. Steam / Net KWH E.31 1$.00 Circulating Water Inlet Temp.
Marimmyn F
h2 Paninnam F
3h N
Plant Operating Factor 87.1h 9h.h0 68.32 NUCLEAR ENTH CORE III TO DATE Times Critical 0
18 325 Hours Critical HRS 719,o ho23,72 gg,566.83 Timen Scrassued 0
5 h3 htr valent Reactor Hours @ C00 Nt HRS 626.55 3059.09 16,556.9h Average Burnup of Core WD/mtU Control Rod Position at Month 3x1 Equilibrium at $20 Nt 503.2 F Tavg.
Group 1 Rods out-inches 8" 6/8
- Region Group 2 87 6/8 Group 3 87 6/8 Inner 1007 7 6230.9 Group h 87 6/8 PJ.ddle 876.6 10,h79.9 Group 5 87 6/8 Outer 601.8 3,386.6 Group 6 87 6/8 Group 7 87 6/8 Boron
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