ML19351E103
| ML19351E103 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 04/24/1964 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E098 | List: |
| References | |
| NUDOCS 8011250604 | |
| Download: ML19351E103 (10) | |
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YANKEE NUCLEAR POWER STATION OPERATION REPORT NO. 39 For the month of MARCH 1%h O
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Subnd.tted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts April 2h,196h
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6 This report covers the operation of the Yankee Atomic Electric
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Company plant at Rcwe, Massaetresette for the month of March 196h.
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At the beginning of the reporting per1od plant electrical output was 18h.We, remaining essentially constant at that point until March 11 when the plant was shut down by a turbine solenoid trip. Both lls-KV oil' circuit breakers opened and the -reactor scrammed. A turbine trip was the only indication registered on the trip sequence and memory
' light panel ~.. Investigation indicated that the turbine solenoid trip was caused by vibration af a moisture separator high 1cvel trip magnetrol
-and that no serious plant conditions existed. A more detailed descrip'.hn of the trip can be found in the Instrumentation and Control section of this report.
l' After the cause of the trip and accompanying reactor scram was ascertained, the reactor was brought critical through programmed rod withdrawal. The' turbine was brought to speed and phasing was accomplished approximately four hours following the trip.
O z1ectrica1 eetvet was raieed te 182 =e re e1=18 esse tia117 constant at that point until March 26. On that date the central loaa dispatching agency notified the plant control room of impending severe wind storms approaching the area. With conditions as they were the shift supervisor elected to reduce plant load to below the one-pump scram load or approximately 150 We gross.
~O wa11e a= 99 8 1oea it e aotea thet no a t=rd1=e co tro1 vetve 1
was stuck in the wide open position. Control was transferred to No. 3 i
valve and it was decided to remove ths plant from the line.
Prior to doing so the servo motor stem was tapped with a hammer whereupon the valve released and.went closed. Similar conditions were experienced with No. 2 control valve. Coincidently with the freeing of the valver, word was received of passage of the severe weather and the plant was therefore
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returned to full power.-
p The cause of the valve sticking has been traced to oil sludge v
lodging around the seal. rings on the valve servo motor piston.. Oil sludge j
was suspected due te the discovery of a water to oil leak in an oil cooler on-March 13 Weekly exercising of the four control valves has been instituted to prevent a similar recurrence.
During the. month two special tests were performed to determine andmeasuretheeffectsofnomaincoolantpurificationflowandNH}nbe removal on. core reactivity. A detailed discussion of these tests c:
found in both the Reactor Plant Performance and Chemistry sections of this report.
On March 10 the gross output of the Yankee reactor passed the three billion kilows.'. hour mark.
The weekly control rod exercise program was. carried out as scheduled as was tne rod withdrawal sequence for wear distribution on
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the rubbing' strap surfaces.
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Plant Shutdowns Shutdown No. 69-3-7
'3/11/6h Arh.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> shutdown resulting
'from a spurious turbine solenoid trip signal.
Reactor Scrams Scram No. h3-3-5 3/11/6h An automatic reactor scram
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from a power level of 600 Mit resulting from a tur'oine trip.
Maintenance Following is a summary of major activities carried out by plant maintenance personnel during March:
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1.
The anti reverse flow device of the pressure maintenance pump of the fire protection system was cleaned.
2.
An ion exchange tank was charged with resin and made ready for service.
3 During the month a program was ' initiated whereby spent ion 3
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exchange columns could be flushed and recharged with fresh resins thus permitting reuse of ion exchange tanks..
Salvaging of two tanks was accomplished in February.
h.
Station. service transformers Nos.-h, 5 and 6 were cleaned and gas pressures were adjusted as required.
5 The spent fuel pit manipulator crane was inspected.
iO-6.
The erare centre 1 rod indicetine ce11 eteck mes inspected end
-tested. High resistance was noted on the connectors thus ac cunting for a substantial portion of the ' operating i ficulties previously experienced with these coils.
7 Three Core I drive shafts have been machined to permit installation of complete Core II type dashpot assemblies.
8.
No. 1 charging pump was repacked.
9.
Reworking of spare valves commenced during the p9riod in anticipation of use at the next' refueling.
- 10. All available h80v air circuit breaker relay trip time-checks,and breaker inspections were completed.
'11.
The wa$te disposal building drum roller was dismantled and cleaned, the gear box was checked and the rollers were' inspected.
- 12. A junction box and conduit has been installed in.the warehouse
'to permit electrical feed to shipping cask trailers.
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.3-jv Chemistry In late February a partially spent mixed bed ion exchanger was placed in service in an attempt to ammoniate the cation portion of the resin bed.
During the. attempted ammoniation a loss in reactor temperature was noted. When the loss approached specified limits, the anion exchanger was placed back in service.' The reactivity loss, seen as a temperature reduction with constant rod position was halted by the return to anion exchange and by March 2 the system had returned to normal. S!-d.lar results were obtained from an identical test performed in early February and were reported in the-Operation Report for that month.
Since the above were performed with partially spent beds that had seen service in Core II, it was decided to duplicate the tests using a nos mixed bed. On March 9 a new mixed bed'lon exchanger was placed in service.. Ammoniation of the cation cycle of the bed was normal and no
.eactivaty effects were noted.
O-Both tests in February, performed with partially spent beds, were accompanied by slight reactivity losses and crud releases from the ion exchanger shortly after they were cut in.
However, the reactivity loss cannot be directly connected to the crud release since in the second test he purification ion exchange discharge was initially directed to waste disposal and, therefore, no apparent crud increase was seen in the main coolant system.
To permit further evaluation the aforementioned test with a new mixed bed was performed in early March. As mentioned previously, no abnormal conditions were noted following the insertion of the new bed to service.
In late March additional testing was initiated to study rH effects on the core reactivity. On March 2h main coolant purification flow was terminated, being followed by elimination of NH3 feed on March 30.
d As this test was carried over into April the results will be reported in a subsequent Operation Report.
A typical main coolant crud analysis made during the period indicated:
Cr - $1 17x1 dpm/mg Mn - $h h.h x 10 dpm/mg Fe - $9 1.0 x 10 dpm/mg Co - 58 2.2 x 1 dpm/mg Co - 60 1.7 x 1 dpm/mg Ag -110 m 6.h x 1 dpm/mg A typical main coolant gas analysis made during the period indicated:
A A - hl 9.1 x 10~3 pc/cc gas d
Xe - 135 5.5 x 10-2 pc/cc gas Ie - 133 h.$ x 10-1 pc/cc gas
-h-Throughout the reporting period the main coolant oxygen concen-73 V
tration remained below the point of detection.
The average main coolant specific activity remained essentially constant at approximately 5-7 x 10-2 Jac/ml throughout the balance of the reporting period. A slight increase to 7 2 x 10-2 pc/ml was noted following the termination of purification of March 2h.
The main coolant crud concentration remained essentially constant at 1.5 ppm. Slight increases were noted as the loop bypass lines were flushed following the scram on March 11. No increases were noted following the termination of purification flow.
During the month the main coolant iodine-131 concentration was 7.9 x 10-h pc/ml. The I-131/I-133 atomic ratio was measured at h.2.
Some variations were recorded in the main coolant NH3 concen-tration since it has been difficult to combine the feed concentration and pumping rate to produce a constant condition. Generally the NH3 concen-
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tration has been held to a range of 7 to 10 ppm. Occasional increases to 13 ppm have been noted.
v Reactor Plant Performance Due to the control red wear distribution program the end of Core III full power life occurred midway through the reporting period. Conditions at
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this point with all rods at 85 2/8 inches, boron
<,1 ppm, and adjusted U
main coolant pH were:
Core Power 600 Wt Core T avg.
$27.5 F Loop T avg.
525.5 F Pressure 2000 psi Xenon Equilibrium 0 600 mt Et hours 1,606,110 EtD/MPU 3220
,,(j WeG h93,737 5 Date and Time March 16 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> Due to the nature of the main coolant chemistry tests, an extensive program of core reactivity follow was carried on during the month. At the leginning of the reporting period a slow reactivity gain was recorded following the removal of a partially spent mixed bed ion exchanger from service.
On March $ core reactivity again approached the normal burnup curve. Until March 30, core reactivity remained essentially stable, in general, fol.'. awing the expected burnup curve. Slight reactivity variances were recorded due to the inability of the ammon9. feed pump to maintain cv :-tant feec' conditions, At the end of the reporting period on March 30, a slow reactivity loss was experienced being r.ttributable to the stoppage of ammonia feed in line with the chemistry test program.
The following were determined by means of in-core instrumentation g()
measurements at a power level of $65 Et with all rods banked at 86 $/8".
2.6 F
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2.3
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6H QDNBR 31
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Hot channel outlet = 585 F
Turbine Plant Performance
<h During the month a performance test of the vacuum priming tank drain system on the circulating water discharge piping was made. The test was initiated to datermine the effectiveness of the modification made during the previous refueling outage and reported in the Operation Report for September and October 1963 At full plant load an intentional tail pipe vacuum loss was initiated by closing the isolation valve between the 12 inch air removal header and 'he vacuum priming tank. Within 20 minutes of valve closing, 12 in. Hg. tail vacuum were lost and the condenser outlet water box temperature increased approximately 50F.
Tail vacuum was restored immediately following the opening of the isolation valve and the consequent return to service of Nos.1 and 2 vacuum pumps. From the results obtained, it has been concluded that the changes made to the air removal system in September 1963 were necessary to make the system perform sdequately. However, total performance assurance of the system will not be available until a duplicate test is performed (o) some tine this summer under the combined conditions of low pond water level and high circulating water intake temperatures.
During the plant shutdown on March 11, a successful boiler feed pump auto restart test was performed. Plant instrumentation has been set such that a boiler feed pump, with its control switch in the " auto" 7s position, that has tripped off on low suction pressure will restart auto-i matically when the suction pressure is restored.
A typical feedwater heater terminal difference measurement made alring the period indicated:
@ 18h rte 1 55" Hg.
600 THt No. 1 11.0 F No. 2 lh.9 F
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No. 3 7.h F U
On Ihrch 13 No. 2 turbine oil cooler was found to have a water to oil leak and was, therefore, removed from service. Within a few days the centrifuge. lad removed the water and turbine oil conaitions were within specifications.
A condenser performance test was conducted during the month. No measureable change in the cleanliness factor was recorded.
Instrumentation and Control On two previous occasions scrams from full power have been caused through the accidental jarring of a moisture separator level magnetrol by personnel working in the crea. Or March 3 the installation of a series-parallel switching arrangement in the moisture separator high level turbine O
trip circuit was completed and tested. When the new switch on the main control board is in the parallel (in) position the turbine will trip on high level in either separator, and when in the series (out) position the A.
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turbine will trip only on coincidence of high level in both moisture V
separators. Should the need arise to perform n intenance in the area of the moisture separators with the plant at power the new circuit will be operated in the out position.
Immediately following the scram on March 11, the cause of the solenoid trip was not readily apparent. All turbine auxiliary systems vere found to be normal and it was, therefore, theorized that a spurious vibration in the high level magnetrol of the moisture separators caused the trip. In an attempt to limit further scrans of this type new vibration-free.
switches have been ordered and will be installed once they are received.
A trip sequence panel for the solenoid trip circuit is now being designed to permit positive pinpointing of scrams originating in the secondary plant.
Until the aforenentioned are put into service, the moisture separator trip circuit will be operated in coincidence.
Health and Safety During the month of March 196h,15 drums of routine radioactive waste and 6 drums of special radioactive waste (expm led resins) containing a total activity of 68 me were prepared. Thirty-eight drums (32 of routine waste, and 6 of special waste consisting of excended ion exchange resins) were shipped from the site during the same period. Total activity of the shipment was 160 me.
Liquid waste containing a total activity of 0.25 me was dis-
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charged fron the site during March. Gaseous waste containing an estimated 80 me due to radiochemistry sampling was discharged during the same period.
Two resin capsules were.emoved from the ion exchange pit and backflushed to permit resin removal. The resin was in turn loaded into
$$ gallon drums for off site dispccal. Radiationandcpntaminagionlevels on the first capsule were 75 mr/hr contact and 2.6 x 104 dpm/f t. Following removal of thg resins, the outside surface of the capsule was decontaminated to 300 dpm/ft. On the second capsule, maximum contact radiation levels
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before and after removal of res[ns were 200 mr/hr and h ar/hr. Contamination 2
2 levels were reduced from 7 x 10'+ dpm/ft to 800 dpm/ft,
v A special radiation and contamination survey of the water treat-nent plant indicated a maximum radiaticn level of 0.07 mr/hr. No contam-ination was detected.
A special radiation and contam1Ation survey of the Information Center building irrlicated a maximum radiatt <. level of 0.06 - 0.08 mr/hr.
No contamination was detected.
A radiation survey of the waste disposal tank farm indicated:
activity dilution decay tank 1200 mr/hr contact bottom; waste holdup tank 1800 mr/hr contact bottom; and gas surge drum 0.5 mr/hr contact bottom.
A survey of the spent fuel pit building showed the following radiationandcontaminationlevgls: general area and manipulator crane 2-5 mr/hr, and 1000-20go dpm/f t ; jacking and cooling pumps area 25-35 mr/hr s'
and 5000-20,000 dpm/ft.
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A survey of the fuel chute dewatering pump showed the following radiatic n levels :. pump shaft of packing gland 13 mr/hr; check valve 20 mr/br; impeller 80 mc/hr. 311 readings contact.
The radioactive combustible vaste. incinerator has been returned to service. The initial burning, following particulate filter and filter houcing modificationsa, showed a stack effluent concentration of 1.9 x 10-10 ue/ce.
Prior to the machining of three Core I control rod drive shafts, m M__mnm radiation' levels measured on the shafts were 20-30 mr/hr contact at the cap end, and 00-250 mr/hr contact at the dashpot end. Contamination levels were 1-2 x 10 dpm/ linear foot.
Personnel exposures for Yankee-plant personnel as measured by film badge for the month of March 196h were:
Average for all station personnel = h6 mr (N
Maximum individual exposure
= 200 mr V
Nevly Issued Energency Instructions During the month the follcwing revised Emergency Instructions were issued:
A
$0$B2 Pring Plant loss of Load Accident U
505Bd Primary Plant Partial Loss of Main Coolant Flow 505B16 Primary Plant Failure of Regenerative Heat Exchanger 505B17 Primary Plant loss of Shutdown Cooling 505B19 Primary Plaat Loss of Component Cooling 505B22 Isolation of Vital Bus Feeder Troubles Plant Operations Attached is a summary of plant operation statistics for the renth of March 196h and a plot of daily average plant load for the same period.
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YANKEE ATOMIC ELTgj{c COMPANY -- uEniTTia SII'2ttRY r
MARCli 1%h EI.ECTRICAL METH YEAR TO DATE Gross Generation W11 133,1h9,900 391,091,200 3,0 %,651,100 Sta. Service (Wldle Gen. Incl. Iosses)
IDfH 7,995,228 23,357,961 221,129,996
'Not Generation KWII 12$,15h,672 367,733,239 2,875,$21,10h Station Service 6.00 5 97 7.]h Sta. Service (While Not Cen. Irel. IovsN)
WH 26,700 19h,200 18,239,h51 Ave. Gen. For htth (7h!s IRS)
W 178 %$
3 Ave. Gen. Ihmn3 ng (739.52 "RS)
KW 180,0h9 HANT PERFORMANCE Net Plant Erficiency 28.95 28.99 Net Plant Heat Rate BLu/NH 11,788 11,772 Ibs. Steam / Net KWH Ih.05
- 13. 93 Circulating Water Inlet Temp.
Maximm
,F 37 a,
Minirmam 0F 33 Plant Operating Factor 96.85 96.79 67.77 N9CLlAR M) NTH CORE III TO DATE Times Critical 1
18 325 Hours critical IRS 7ho.65 330's.72 2h,8h7.83 Times Scrassued 1
h3 Et uivalent Reactor Hours C 600 Wt, HRS 720.$3 Ph32.5h 15,930 39 l
Average Burnup of Core WD/mtU C46.72 Control Rod Position at Month 3xi Equilibrium at $60 : lit $15 F Tavg.
Group 1 Rods out-inches 86 $/6 Group 2 86 $/8 Group 3 86 $/8 Group h 86 $/8 Group $
86 $/8 kap 6
% $/8 Group 7 86 $/8 Boron <. 1
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