ML19351E122

Operation Rept 87 for Mar 1968

ML19351E122
Person / Time
Site:	Yankee Rowe
Issue date:	04/24/1968
From:	YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML19351E121	List: ML19351E120 ML19351E122
References
NUDOCS 8011250631
Download: ML19351E122 (8)

Text

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^rm::i ; 77, g7 YANKEE NUCLEAR PCWER STATION OPERATION REPORT NO. 87 For the month of MARCH 1968 O

Subnitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts April 2h, 1968

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j 7 tis report covers tne Operation of the Yankee Aormic Electric Company plant at 3cve, Massachusetts, for the month of March, 1969.

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Cn March 23 at 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> the plant was taken cff the lint for i

the Core VI-VII refueling and maintenance shutdcyn; plant lead was 116 MWe.

I The total electric gcneraticn for Core VI was 1,659,986,200 DTn; reactor availability and the overall plant operating facter including stretch;ut cperation but exclusive of refuel:ng shutdown time vere 94.11 5 and 86.60 %,

respectively.

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l At the beginning of the repcrting pericd the plant was in stretchaut operation and systems were being prepared for the Core VI-VII refueling cutage.

Ammonia feed to the main ecolant system was secured cn March 15; residual e

ammonia was removed by mixec ced (H, Ch.-s) puri f_ic at i on.

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c r reactivity lcsc vas experienced Sc to the time cf shutdovr es a result of the change in ecclant chemistry conditions.

The reactivity Icss was approximately l

tvice the reactivity gain that was realized following system ammaniation in November, 1967. Thic effe:t supports the theory of al v reactiv::y gains i

since July, 1967 (see Operati:n Repcrt No. 8k).

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Steam line safety valves frcm the fcur steam generatcrs were t"sted l

cn March 7, S.

Ten of twelve valves cperated at the set pressurer; vo valves i

i required slight adjustrant.

On March 21 e continucus dilution of the main ccclant was perfcrmel to reduce the system tritium inventory.

The 8C,CCC gallon dilution decreased l

the ecclant tritium concentration frcm 1.1 ucf $1 tc 0.C8 tc/ml.

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h A succecsful teet of the turbine generator averspeed trip was performea prior to reac'ar shutd:vn.

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t Folicving plant shutdcvn, system cocidown was initiated and

'ne main ^;rlan-was bcrated.

During cocldown the tartine generatcr excit er ccmmutator was honed in place Plant cooldown and the vapor container purge were cenpleted on March 2L; the International Atemic Energy Agency f

seals were removed from the missile chield by an inspector frcm that organization.

i During the last week of the period, vo-k was centered on the l

stripping of equipment from the reactor head and removal of reactor head I

studs.

Considerable difficulty was encountered in rencving the studs l

located in the northern area of the vessel. The removal problems could have been caused by boron and rust deposits on the thread surfaces. These materials l

Vere present in the general head and flange area as a result of a leak at the j

mechanical seal in the north in-core instrumentation thimble that occurred during the plant startup following the Core V 'il refueling shutdown (see Operation Report No. 71).

i Modifications to the fuel chute transfer carriage were completed and the spent fuel pit was filled with demincralized water. At the end of the report period all preparations hsd been completed for the removal of the head from the reactor vessel, l

Rcutine vibration testing of the fcur main coolant pumps was performed. The high f:equency vibrations from the No.1 pump were sufficiently different from the other three pumps that inspection was varranted.

The iio. 1 pump was removed from its volute on March 30.

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'The pressurizer surveillance portion of the Core VI-VII inspection program' vas performed during.the period. The 17.5 to 19.5 foot level and t,-upperheadareaswerevisuallyinspectedandphotcgraphed.

Dye penetrant tests were then done and the areas were rephctographed. The area in the l

northeast quadrant of the upper head was ultrascnically tested and radicgraphed l

Ultransonic testing was performed at the north-east-sourth area of the vecsel i

at a distance of 17.5 to 19.5 feet below the manvay flange. Depch micrometer measurements were'made in the two toat sample cavities.

Twenty four stainless steel clad new fuel assemblies were received on site; this completes the Core VII loading requirement for this type of fuel element. On site assembly of two Zirealoy clad f>el elements was completed.

ij' Plant load reductions during the period vers as follows:

I March 6 (1205-1315):

load reduced to 100 MWe for conthly throttle valve exercise.

March 7 (1015-1kl5):

lead reduced to 100 MWe for steam line safety valve testing.

March 8 (0830-1035):

load reduced to 110 MWe for steam line safety valve testing.

March 14 (11h5-1327):

.lcad reduced to 105 MWe, Two tubes were pluBEed in the main ccndenser east side water box.

h March 19 (1145-1309):

load reduced to 105 MWe, Two tubes were plugged in the main condenser vest side water box.

Plant Shutdowns:

Shutdown No:

93-6-8 3/23/68 Scheduled Core VI-VII i

refueling shutdown.

Plant Maintenance, i

i The following is a list of pertinent plant maintenance performed l

by the plant staff during the month of March, 1968.

1.

Floor plates, spacers, racks, upender and elevator were reinstalled in the-

-l spent fuel pit.

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2.. The component cooling vater sample point was relocated to the sample hood; l-the original sample point was capped to prevent pcssible spiilage to the floor.

3.

The No. 2 boiler feed pump and motor vere inspected.

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Charging pump No. 1 was repacked after approximately 2700 heura of continuous operation.

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The spent fuel pit manipulator tool boom was reinstalled following a co= plate l

-inspection.

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An "A" frame'and base vere fabricated to facilitate TV inspection of reactor internals.

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. Instrumentation and Control The following is a list of pertinent instrumentation and control maintenance items performed by the plant staff during the month of March, 1968..

1.

A new Gaitronics station was installed in the decontamination building.

2.

The TCNR and TIBiR channels were recalibrated to reflect the decreasing coolant temperature associated with plant stretchout operation.

3 A video tape recorder was tested and a light was fabricated for the TV camera.

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Vibration readings were taken on the circulating water and reactor main coolant pumps.

5 Source range channels were recalibrated following the shutdown.

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Flux wire tubes and thermocouple connections were removed from the rer.ctor head.

Chemistry Main coolant ammonia concentration averaged 12.1 ppm until March 15 at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> when the ammonia feed was secured. Radiolytic decomposition 1

decreased the ammonia concentration to 1 98 ppm.

On March 18 at 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> a mixed bed ion exchanger was placed in service and the ammonia concentration was reduced to negligible levels.

Main coolant tritium concentrations decreased from 1.31 pc/ml to 1.14 pc/ml due to the decreasing power le el.

On March 21 an 80,000 gallon dilution of the main coolant system was initiated which reduced the main coolant tritium concentration to 0.08 pc/ml.

Following reactor shutdown on March 23, the main coolant system was borated to a concentration of 2225 ppm; a borated mixed bed ion exchanger was placed in service for coolant purification durir.g refueling.

The average main lant gross beta-gamma specific activity and crud

-2 level were 6.33 x lo pc/mi and 0.23 ppm respectively; as a result of tritium dilution these levels were reduced to 1.90 x 10-5 uc/ml and 0.41 ppm respectively.

The iodine-131 specific activity was 2.0 x 10 uc/ml; the iodine 131/133 atomic ratio was 0.80.

A representative crud sample for the month, collected on March h, had the following radiochemical analyses: dpm/mg crud Hf-181 Mn-Sh

• -59 6 Cr-51 6 5

6 6.03 x 10 1.h3 x 10 h.06 x 10 2.52 x 10 Co-58 Co 60 Ag-110Mk

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2.95 x-10 1.35 x 10 3.37 x 10 l

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A main coolant gas sample collected on March 12 had the following l

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- ' radiochemical analyses: ue/cc gas Xe-133 Xe-135 Ar k1 h.91 x 10 8.39 x 1,,-3 2.33 x 10

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-2 Health and Safety Warte disposal liquid releases totaling Sk,270 gallons contained 72.h5 uc of gross beta-gamma activity and 96,12 curies of tritium. Gaseous releases during this period ' vere 32.68 me cuf gross beta-gamma activity, i

Secondary plant watec discharged was 217,825 gallons and contained a total of 5.06 uc cf gross beta-garaa activity and 282.6 me of trivium.

An additional 4.01 curies of tritium vapor vas purged frcm the vapor container to the primary vent stack during the period March 2h to i

March 31.

Airborne tritium concentration in the vapor container at the I

time of reactor shutdown was 1.5 x 10-5 pc/ce. After six hours cf contair. ment purge the tritium level was 9,2 x 10-7 ue/ce. Unusually lov vapor container j

humidity precluded further atmosphere sampling until March 27 when the t-itium l

concentration was 1.0 x 10 7 uc/cc. During the remaining period conteiraent airborne tritium levels varied between 9.3 x 10-0 pc/cc and 6.5 x 10-0 ve/ce.

l During the pressurizer inspection program 'he radiation level-at the vessel manvry was 300 mr/hr, five feet below the manway the level was 500 mr/hr, at the ten foot and nineteen foot depths the levels were 1 r/hr 4

and 1.5 r/hr, respectively; measurements were made with the vessel water level twenty feet below the 2angay flange.

Radiation levels from the No.1 main coolant pump that was removed

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for inspection were censistent with those found in the past; the measurements two inches and three feet from the impellar were 2 - 5 r/hr and 500 mr/hr.

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i Radiatica expcsure doses as measured by fibn badge f or the month of March, 1968, were:

Yankee Personnel l

Average accumulated exposure dose:

350 mrem I

Maximum accu =ulated exposure dese:

12LO mrem N.E.P.S,Co. Perscanel Average secumulated exposure dose:

619 mrem i

l Maximum accun i exposure dose:

1123 mrem i

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Operations-l Attached is a summary of plant opera ing statistics a?.d a plot of daily l

l average load for the month of March, 1968.

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o YANKEE ATOMIC ELECTRIC COMPANY -- OPERATING SU)tERY MARCH 1968 EIETRICAL 10 NTH YEtR TO D&TE Gross Generation WH 69,763,800 283,560,000 7,994,hkk,600 Sta. Service (While Gen. Incl. Losses)

WH 5,352,719 19,751,333 532.h18,266 Net Output WH 64,h11,081 263,808,667 7,462,026,334 Station Servi.ce T.67 6.97 6.66 Sta. Service (While Not Gen. Incl. Iosses)

WH 190,653 190,653 24,996,180 Ave. Gen. For Month W

93,769 Ave. Gen. Running W

127,656 PIANT PERFORMANCE Net Plant. Efficiency 27.01 27.88 28.37 Not Plant Heat Rate Bru/WH 12,635 12,241 12,029 Plant Operating Factor 53.42 72.21 T3.h8 Reactor Plant Availability T3.56 90.99 83.64 NUCLEAR PoirTH CORE VI TOTAL Houis Critical HRS 547.25 11,381.Th 55,10 7. h2 Times Scrammed 0

3 55 Durnup Core Average MD/MPU h78.21 12,h18.76 Region Average WD/MTU A (INN R) 472.693 12,h93.587 29,266.08 B (MIDDLE) 568.135 14,8ho.0h2 22,515.33 C (OUTR) 388.886 9,987.432 9,987.h3

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