ML19351E008
| ML19351E008 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 12/28/1965 |
| From: | Minnick L YANKEE ATOMIC ELECTRIC CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19351E010 | List: |
| References | |
| NUDOCS 8011250405 | |
| Download: ML19351E008 (1) | |
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.a Eile Cop 2 YANKEE ATOMIC ELECTRIC COMPANY d'"// 'J Da GA.
441 STUART STREET, BOSTON 16, MASSACHUSETTa 77 119 d.
December 28, 1965 diYh
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U. S. Ator:ic Energy Commission D
d 73 Washington, D. C.
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y Attention: Division of Reactor licensing
Dear Sirs:
We are enclosing herewith for your use and information twenty five copies of Operation Report No. 59 covering operations at the plant for the month of November 1965 c1
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Very truly yours, D
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t L. E. Minnick Assistant Vice President LEM:la Enc 1s. (u t k p b
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Because the turbine auxiliary governor could have caused the
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' V load transient, a test gage was connected to its oil line.. The oil set pressure of the auxiliary governor was found at 28 psig, it was reset to the recommended set pressure of h5 psig.
i Due to the immediate critical need for power, load was held at 155 We until Friday, November 26. At that time, with the aid of represantatives of the manufacturer, attempts were made to induce the noise and vibration in the turbine. The load was raised to -licensed power of about 185 We without any abnormalties. Further efforts were unsuccessful in. causing any noise or vibration. The unit was taken off the line for inspection of the control oil system and a modified start-of-life physics test program. The plant was reduced to minimum load and attempts were made to trip the turbine from the main control board without success. The turbine was tripped from the turbine pedestal by the hand lever. Investigation showed that the solenoid coil of the
..O throttle valve trip has burned out and was inoperative. The solenoid coil was replaced and a monitor light was installed in the circuit to preclude a reoccurrence of the problem.
The servo mechanisms of #3 and #h control valves and the auxiliary governor were ' disassembled and examined closely. No mechanical defects were found, but it was felt that' foreign matter found in #3 and O
- h servo mechanisms and auxiliary governor orifice had caused a hydraul-
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ically induced noise and vibration problem.
A vapor container inspection made during this period revealed a small leak in the newly installed sample line..The leak was isolated and repaired. The new, motor operated sample valve, SA-MN-513 could not be operated due to an~ internal mechanical problem, which will be repaired at a later date.
The unit was rolled off at 0800 on November 29 and load raised O
to 1s0 We. The 1oad was increeeed to 183 We en November 30 without any difficulty.
Plant Shutodwns Shutdown No. 79-h-8 8/9/65 Scheduled Core IV - Core V refueling shutdown. Total outage time - 2238 hours0.0259 days <br />0.622 hours <br />0.0037 weeks <br />8.51559e-4 months <br />.
Shutdown No. 80-5-1 11/26/65
_ Scheduled 68 hour7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> outage i
for turbine repair and physics testing.
4 plant Maintenance 4
Following is a summary of major activities carried out by the plant maintenance staff:
'l.
Installed a trip circuit to Sherman Station which functions on stuck breaker operation.
-h-Q 2.
The B phase lightning arrestor on the high voltage side of the main transformer was replaced.
3.
Installed a shield tank cavity drain flush connection.
h.
Repaired a pinhole leak in a socket weld in the discharge line of the No. 3 charging pump.
I 5.- Ground in and installed valves and seats in the new cylinder block for the No. 3 charging pump.
6.
Replaced the bearings in the No.1 boiler feed pump motor.
7 Fabricated a glass-ported resin detector station and strainer for the purification system and installed same.
O 8-1e= exch se c 9 =1e i= re iti 2==a 3 ere rer1 cea with reclaimed capsules and new resins.
Position 2 now
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contains a mixed bed unit on H+, B03 cycle.
Position 3 now contains a cation bed. A bypass was installed around Position 6, which is used exclusively for safety injection water clean-up.
9.
The cask from the Naval Research Bureau was lowered into g
i the spent fuel pit, loaded with a basket containing four Q
high flux and one low flux specimen capsules, removed from the pit and decontaminated.
10.
Preparations started on the replacement of parts of the yard area crane which will increase its safety factor to 5 when handling the 10 element spent fuel shipping cask.
~ Chemistry
- The main coolant gross activity (less tritium) increased from h.1 x 10-h c/ml to 2.9 x 10-3 pc/ml after core loading. At plant startup, p
the activity _ increased to 2.h x 10-1 pc/ml; and then decreased to 8.0 x 10-2 ytc/ml with subsequent plant operation.
As a result of fuel. chute operation, the concentration of boron in the spent fuel pit water increased to 20h ppm at the conclusion of refueling.
In going from cold, borated, oxygenated shutdown condition to i
hot chemical shim operating condition.the main coolant changed as follows:
11/5/65 11/11/65 dissolved oxygen - ppm saturated
.20 pH 5.5 h.6 I
conductivity - Jthmo 33.3 11 3 3d gross -activity (less tritium)
- Jtc/ml 2.5 x 10-3 2.h x 10-1 boron - ppm 22h5 13h0 crud
-ppm, 0 50 8
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i After a few days of operation the main coolant gross activity and crud level were measured at 8.7 x 10-2 pc/ml and 0.21 ppm respectively, while the main coolant oxygen level was less than 50 ppb, and remained in that range for the remainder of the period.
Analyses of samples from the pressurizer drain line were as follows:
oxygen - ppa 30
.15 i
pH 5.3 5.0 I
conductivity umhos 35 33 gross activity (less tritium) - pc/ml 1.8 x 10-1 8.3 x 10-2 i
boron - ppm 10140 1055 An analysis of the pressurizer vapor indicated a gas concen-t tration of 210 cc/ liter of condensate with two capillary vents in operation.
4 The gas analysis was as follows:
1 0 oxygen 0.08 N2 lb.5 H2 I
05*h On November 15,1%5, the iodine 131 specific activity was 4
1.1 x 10-5 and the I-131/I-133 ratio was 0.h8 6 Equilibrium conditions were: iodine 131 specific activity, 9.h x 10- pc/ml and I-131/I-133 b
ratio, 0.67 This would indicate that there are no significant fuel defects in Core V at this time.
The secondary condensate-makeup water system tritium concen-tration is 2.2 x 10-3 pc/ml. The gro steam generator blowdown is 3.h x 10-9s beta-gama activity in the #3 pc/ml. It does not appear that j
there has been any appreciable change in the 2 gallon per day leak rate in this generator.
O min c-1-t trm- -nc-trasien wac -asured at 2a r m1.
a A coolant radiochemical gas analysis was as follows:
l A - h1 2.5 x 10- pc/cc gas Ie - 133 3 3 x 10 pc/cc gaa i
Ie - 135
- 17. x 10-3 pc/cc gas 1
A coolant crud samole had the following radiochemical analyses
& - 5h 1.8 x dpvag Cr - 51 1 9'x 1 dpa/mg Hf - 181 1.6 x-1 dpa/ag Fe - 59 6.0 x dpvag Co - 58 6.3 x dpvmg Co --60 1.1 x dpvag
- - _ _.,, _...- --, ~, -, -...- -
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> A Reactor Plant Performance The Core V startup physics program consisted of the following:
1.
cold and hot control rod drops 2.
boron worth measurements 3
moderator temperature coefficient variation with boron concentration and variation with main coolant average temperature h.
power coefficient measurement 5
selected differential rod worth comparing the Inconel clad Ag-In-Cd rods with the stainless clad rod f
The cold control rod drops had been successfully completed l
before the test program had to be. temporarily suspended due to the need for power generation. The test program was completed over the weekend i.
beginning with November 26. The results of the cold rod drops compared favorably with Core IV cold drops. Msasured drop times from breaker opening to rod entering the dashpot varied from 1.22 sec. to 1.83 sec.
with the average being 1,59 sec. This compares with Core IV numbers j
between 158 to 1.88 sec. with an average of 172 sec. These numbers
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include about.29 sec. which is required from breaker opening before rod begins to fall.
0 The hot drops, performed at $15 F, 2000 psi with all four main coolant pumps operating, also compared favorably with Core IV results except for the first drop on one rod which was about 1 sec. slow. Normal Core V results ranged from 130 sec. to 153 sec. with an average of 1.hh sec. Comparable Core IV results ranged the same from 1.30 sec. to 1 53 sec. with the average being 1.h2 sec.
Over the range of boron concentration from 1300 ppm to 1800 ppm the value gf the boron coefficient of reactivity was measured to be
-5 8 x lo-> S F/ ppm. The moderator-temperature coefficient measured over the same range of boron concentrations was -13 x 10-h O / / F, 0
0 at m $20 F.
The moderator temperature coefficient was also measured during peak xenon after shutdown over a range of temperature from 5100F to 5250F. The value measured was -1.8 x 10-h h8/oF.
Power coefficient data was taken while the turbine was being exercised. The data was taken only as time permitted and did not interfere with turbine work. The data was spotty and complicated by an involved xenon picture. The xenon changes -are still being calculated and the power coefficient calculations remain to be ' are q
Differential rod worth measurements were J.ade on Group A.
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. This four rod group was eplit in two to compare the worth of h
the two Inconel clad rods with the worth of the two stainless clad rods.
Differential worth zeasurements were made at four points between 25" and 68" of withdrawal. The results were in very close agreement and indicate that the worth of the stainless clad rods is equivalent to the worth of the Inconel clad rods. In the region measured, the average worth of each pair of rods is about h.5 x 10-5/_18/ in.
The in-core instrumentation system was operated after plant start-up and during power increases to insure that conditions in the hot channels did not exceed limitations. Conservative calculations indicate that no limits are being approached, but the presence of two zircaloy clad fuel assemblies in the core complicate the calculations.
Exact calculations of the conditions in the hot channel of the zircaloy assen-blies have not been completed at this time. These hot channel conditions will be reported upon completion of these calculations. The conditions in the hottest channel of a SS clad assembly, which is core position 0-3, are at $h0 Wt F
2.2 6H
=
Fq 2.7
=
3.2 Min. DNBR
=
580 F Temp. outlet of hot channel
=
O Turbine Plant Performance Calorimetric data was collected at 125 We and at 160 We to check the We - W t relationship. Results indicate that no measureable changes have occurred as a result of any maintenance performed during the past shutdown. Terminal difference reasurements were also made at 125 We and 160 We, these results are:
O 125 We, condenser back pressure 1.13" Hg, throttle press. $h0 psi F.W. Heater #1 8.60F F.W. Heater #2 9.1 F F.W. Heater #3 6.hoF 160 We, condenser back pressure 1.60" Hg, throttle press. h70 psi F.W. Heater #1 9.h F F.W. Heater #2 12.hoF F.W. Heater #3 5 50F The cleanliness factor measured on the condenser at 125 We and 1.15" Hg backpressure was 655 Instrumentation and Control 1.
Replaced the G-M tubes in the steam generater leak detectors O
and the primary vent stack monitor. Repaired the primary
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vent stack detector assembly.
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('v) 2.
Replaced three coaxial jumper cables, and two coaxial cables back to the pull box, and cleaned five connectors in neutron detector thimble #3.
3 Calibrated the steam generator wide rarge level indicators.
h.
Checked the primary plant scram set points.
5 Repaired the gamma guard on the No. 1 manipulator crane.
6.
Recalibrated the T avg. system.
7 Completed the pre-startup instrumentation check-off.
8.
Checked the calibration of the narrow range main coolant temperature channels.
9 Completed the installation of the new vapor container temperature indicator system.
10.
Performed scheduled preventative maintenance on the two off site air particulate radiation monitoring systems.
11.
Repaired several portable survey meters.
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Health and Safety b
During the month of November 1965 the following solid radioactive wastes were shipped off site for disposal:
1.
112 drums containing a total activity of 807 me.
2.
Two, 5 ton casks, total activity of 1.9 curies. First cask (v~'N contained 50 filter cartridges, two sections of a low flux specimen basket, and a piece of steel 1/8" dia.
x 3/8" long. Second cask contained a filter drum.
3 NRL cask containing h Wh flux and one low flux specimens (11h0 curies).
181,180 gallons of liquid waste containing a gross beta-gamma activity of 0.56 me and h3 7 curies of tritium were discharged during November. Gaseous waste from chemistry sampling containing a total activity of 7.6 me and vapor container purge via the primary vent stack containing 953 me were discharged during the same period.
After the shield tank cavity was drained, and before the head was installed, the general radiation level at the bottom of the cavity was 100-200 mr/hr. After the head was set in place, the general radiation levels were 15-100 mr/hr. The cavity walls were washed with a p\\
factor of 10 from ul0gtion and rinsed.to 105 dpm/Ft,
stsndard detergent sol Contamination was reduced a
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This1 report covers the operation of the Yankee Atomic Electric g
Company plant at Rowe,~ Massachusetts for the month of November 1%5 At the start of the period.the. scheduled refueling shutdown
.was in its final stages. The 2h control rod. pressure housings on the vessel head were flushed in an attempt to reduce radietion levels in the area. This. operation was not successful.
Lack of success we attributed primarily to the dried out condition of the crud, and it was also found
.that the spray nozzles were not long enough to assure complete success
'in any event.
The shield tank cavity was dratned and rinsti early on November 1.
By 1700. hours on November 1, the reactor head was in pitee on the vessel and the shield tank cavity surfaces were cleaned with a detergent solution and rinsed. During this operation, one previously unaccounted Charpy'V-notch specimen was located in the cavity which brought the number recovered to seventeen. This leaves five still unaccounted for.
All four steam generators were hydrostatically tested on the steam side with no adverse conditions being noted.
Work continued on the reactor vessel head; installing and tensioning the studs, installaing air ducting, installing cabling and installing flux wire tubes and thermocouples.
The cracks in the cladding of the pressurizer vessel (mentioned O
in previous report) received clossr attention after the refueling water level and pressurizer level was lowered. Cracks were found below the normal operating water level as well as those previously reported above -
the water level in the steam phase. Cladding was ground through to the base metal at the location of three separate cracks. In each case the crack terminated in the stainless cladding without penetration into the base metal. Extensive photographs were taken and maps and notes were made of'all questionable areas.
O rue v vor ce t taer c1o e4 e= ne e der 7 1a grea r tiea for the hydrostatic test of the main coolant system. The 1.i.rst attempt at the hydrostatic test was November 8.
At 3000F and 100 psi, the pressurizer manway gasket leaked. The pressure was reduced to 250 psi, and the bolts were retorqued. The pressure was increased to 2h00 psi for a successful test. All loops were cut in and main coolant pumps started to heat the main coolant system to' h500F for pressurizer safety valve and solenoid relief valve testing. The low set (2h85 psig) valve opened and reseated properly. The solenoid relief valve opened and closed sharply without leakage. The high set valve opened at 2550 psig and chattered violently and closed at 1800 psig with considerable leakage.
Plant cooldown was started in order to relap the leaking safety valve. Cooldown was suspended at 3000F for cold control rod drop time tests. All control red drops were successful cooldown continued. At 1718 hour0.0199 days <br />0.477 hours <br />0.00284 weeks <br />6.53699e-4 months <br />sj the plant experienced a total lose of AC power as most of.
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northeast United States lost power. The emergency Diesel generator was
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started and unnecessary plant equipment was removed from service.
Power was regained 37 minutes later when the Harriaman hydro station upstream from the plant was restarted and-the Z-126 'line to that station energized.
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Normal conditions were restored at 21h0 when the Y-177 line to the Cabst hydro station was energized.
The cooldown was completed and work began on the faulty safety valve at 19h0 hours. While repairs were in progress, plant startup was given top priority so that Yankee might assist in supplying power to make up for damaged electrical generating equipment in the blackout area.
About midnight, repairs were completed and plant heatup was started.
At 1007 hours0.0117 days <br />0.28 hours <br />0.00167 weeks <br />3.831635e-4 months <br />, on November 10, the turbine was rolled off. An inadvertent overspeed trip delayed the startup, but the unit was phased to the system at 1153 hours0.0133 days <br />0.32 hours <br />0.00191 weeks <br />4.387165e-4 months <br />. The load reached 125 We at 1710 and was held at that level until November lh, when, at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />, the load was increased to 160 We. During plant startup, both bearings on the #1 boiler feed pump motor were wiped, and, until they were repaired, the maximum load attainable was 160 We, O
. After pump motor repair, a load increase to the licensed level of 600 Wt was scheduled. On November 17, as the first step, T avg. was to be increased tc $270F while holding load constant. At 521 F, a very loud low pitched hua emanated from the H.P. turbine and control valves.
The hum was accompanied by a noticeable increase in floor vibration near the H.P. turbine ac.d was similar to control valve vibration problems experienced earler in plant life and supposedly corrected.
Turbine bearing vibration, thrust bearing position, spindle position and
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bearing temperature were all normal. T avg. was lowered to 51h F.
'j Generator load had to be reduced to 105 We before the noise and
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vibration were suppressed.
Load was then brought back to 150 We.
A second attempt was made to increase load by increasing T avg.
and allowing load to increase with T avg. Main coolant temperature reached 5260F and load was 160 We. From this level, load was increased to 170 We, when the noise and vibration again began.
Load and T avg.
were reduced, with the noise and vibration stopping at 105 We, Load O
w e then increased to 162 - e-tater i= the d F, the noise and vidration started once more. Load was reduced to 120 We to stop the noise, and promptly raised to 155 We and held overnight.
On November 18, with a turbine service man present, a third attempt was made to increase load.
The approach was made by lowering T avg. and opening control valves to maintain load. At 510 F and 165 We, all four control valves were wide open and backseated. T avg. was then increased with load increasing with T avg. At 52h.5 F and 18h We, the noise was very light and sporadic. After nearly an hour at this level, the plant underwent its most severe load transient to date when all four control valves went to the full closed position for three to nine seconds and then reopened. Simultaneous to, or immediately preceding this transient, the turbine noise increased and became continuous, but did not reach the magnitude experienced on the 17th.
Generator output dropped from 18h We to 0.
It remained at 0 for about three seconds, peaked at 198 ?We, and then stabilized at 180 We.
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The operator immediately reduced load to 155 We. During the transient, reactor T avg. reached $3hoF and pressurizer pressure peaked at 2270 psig.
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Two radiation surveys were taken inside the pressurizer.along 4
'its central axis, one with it drained and, one with the water at the 70" point. The results were:
Location drained 70" level (mr/hr)
' center of manway 70 h5 i
58 down~
160 90 10' 300 200 15' h00 270 20' 1200 h50 23 ',
2200 1500 25' 2600 27' 7000 i
The higher levels recorded with the pressurizer drained are due p
to the immersion heaters, which are located in the bottom of the pressurizer, V
being exposed.
Surveys were taken of the control rod drive pressure housings before and after their internal flushing. All housings were flushed except 17,_19, 21 and 23. No overall reduction of radiation levels results from the flushing. The " hot spot" levels remained between h-12 r/hr on various housings after the flush attempt. It is believed O
that the spray nozzles were too short for complete flushing and that the i
dried out crud couldn't be mobilized for effective wash out. Future (d
flushing operations will be carried out immediately following head removal.
After draining the shield tank cavity, a radiation survey of the drain line from loop 1, through the pipe tunnel, to the ion exchange pit showed levels ~ of h0-375 mr/hr in loop -1, 350 mr/hr to 8 r/hr generally, with a " hot spot" of 200 r/hr in the pipe tunnel, and F
1-35 mr/hr from the tunnel to the ion exchange pit. Many attempts were made at flushing this line. In general, the attempts were successful with the fellowing readings being'inada afts; the final?fhnks" levels increased:to 100 mr/hr to 2 5 r/hr loop 1
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levels reduced *.to h0 to h50 mr/hr, hot spot pips tunnel of 25 r/hr maximum line to ion exchange pit - level reduced to 0.5 - 1 5 mr/hr
- A radiation survey of the Primary Auxiliary Building valve room taken on November 16, 1965 showed the following:
Iocation dose rate (mr/hr) entrance to valve room 25
_ general area 25 (Q'
. pressurizer S.V._ discharge line 1000 shutdown cooling safety valve 3500
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pipe tunnel-.- general' area 30-ho pipe tunnel - contact bleed line 50-100
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The gamma guard, about 28 from the bleed line, indicated 50 mr/hr.
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'ritium concentrations in the vapor container atmosphere were 4
l measured at 7 x 10-6 pc/cc at the end of the reporting period.
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Yankee plant personnel radiation exposures as measured by
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film badge for the month of November 1%5 were:
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Yankee Personnel i
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Average Id40 j
j Mad mum individual exposure 1120 f
N.E. Pbwer Service Company Personnel i
f Average
$60 t
j Maximum individual exposure 1030 1
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