ML19351E297
| ML19351E297 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 09/21/1970 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E296 | List: |
| References | |
| NUDOCS 8011280042 | |
| Download: ML19351E297 (9) | |
Text
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O 50 29 Tic ~gtdatory File Cy.
c3= a e.ur M2[-2E '7d YANKEE NUCLEAR POWER STATION
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j OPERATION REPORT NO. 116 For the Month of August 1970
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l Submitted by YANKEE ATOMIC ELECTRIC COMPANY i
Westboro Massachusetts September 21, 1970 l
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'This report' covers the operation of the Yankee Atomic Electric Company at Rove, Massachusetts for. the month of August,1970.
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.At the start of the period, plant load was 178.5 MWe, One-
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scheduled; plant shutdown occurred during the' period for the purpose of effecting repairs to_the Nos._1 and 3 steam generators. The turbine generator was separated from the high line on August 21 at 2314 hours0.0268 days <br />0.643 hours <br />0.00383 weeks <br />8.80477e-4 months <br /> and the plant was placed in a cold shutdown condition which continued through the_ remainder of the report period. During the period August
'l - 21, the pr'.cary to secondary leak rate had increased from 526 to 1077 gallons per dsy.
On August 23 and 2h, the inlet and outlet manway covers and seal velded_diaphrag=s were removed frem steam generators No. 1 and No. 3.
The secondary side of the No. 1 steam generator was pressurized to 750 psis for tube leak detection, revealing one obvious leaker and four weep type leakers. One leaking tute was found in the No. 3 steam generator at a pressure of 200 psig, the magnitude of which_ prohibited further pressure increase. Six tubes were plugged utilizing explosive welding of a thimble type plug to the tube internal surface. Subsequent hydrostatic testing of the No. 3 steam generator showed one additional leaking tube.
Such testing of No. 1 steam generator revealed no additional leakers, but due to an error in tube identification, one of the original leakers had not been plugged. Also in No. 1 steam generator a crack developed in one of the currently installed thimble plugs, caused by a misaligned explosive charge. The two leaking tubes were plugged using the explosive velding tech.ique; and the thimble plug was successfully repaired through the in-s
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I corporation of an alternate backup procedure calling for plugging and
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conventional selding of the thimble end of the plug.
Further leak testing to 750 psig of the secondary side showed all repairs to be sound with no additional leaking tubes.
Radiation levels in the outlet and inlet water boxes at 18" from the tube sheet were 10 r/hr and 15 r/hr in the No. 1 steam generator; and 11.5 r/hr and 19 5 r/hr in the No. 3 steam generator. During the period August 26-28,r.ev diaphragms were seal welded in the manvays, and the manway covers were installed on both steam generators. Pressurizing the primary side to 500 psig indicated no leakage at the diaphragms from either No. 1 or No. 3 steam generator.
Plant heatup was commenced and the reactor was brought critical on August 30.
At a main coolant pressure of 1500.psig a leak developed through the seal welded diaphragm in the inlet water box of No. 1 steam generator. The No. 1 main coolant loop was isolated; cooled down; and drained, while the reactor and loops 2, 3 and 4 were maintained in a hot standby condition.' Successful repair of the leaking diaphragm was completed, and loop No. 1 was valved into the reactor system on August 31 at 2150 hours0.0249 days <br />0.597 hours <br />0.00355 weeks <br />8.18075e-4 months <br />. At the'end of the period the main coolant system was normalized and the turbine generator was ready for phasing to the high_line.
The sixth Core VIII vapor container air leakage surveillar.ce period was terminated August 21, coincident with reactor shutdown. Leakage
'T during the period was normal.
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Two shipments of new fuel for Core IX, each consisting of 12 I
assemblies, were deliv; red on site during the report period. All new fuel for Core IX is now on-site.
i Plant Abnormal Occurrences l
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There were no plant abnormal occurrences 62 ring the :eport period.
Plant Load Reductions i
f August 1 (2135-2320):
Load reduction to 1h0 MWe due to electrical storm.
I August 8 (1650-1840):
August 17 (0655-08h5):
i August 20 (0350-0620):
August 21 (0255-Oh30):
August 21 (0615-0825):
1 Plant Shutdowns:
Shutdown No. 111-8-70:
8-21-70, commenced scheduled plant shutdown fcr j
Nos. 1 and 3 steam generator leak repairs. Outage j
still current at end of report period.
Plant Maintenante The following is a list of major maintenance items performed by the plant staff during the cold shutdown maintenance period.
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1.
The turbine generator exciter commutator was stoned.
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The No. 2 heater drain tank pump and pump motor were dismantled for i
inspection and maintenance. The motor required installation of a new l
bearing; and bushing of its bottom bell. A new sleeve was installed on the pump shaft; and three pump bearings were replaced.
3.
A lubrication oil change was performed for all three condensate pumps.
4.
The turbine No. h control valve was removed for inspection of its inner cylinder noznle chamber. No abnormal conditions were detected.
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5 The main coolant bleed line vari-orifice valve was removed and a new valve body was installed incorporating the existing valve bonnet and internal components.
6.
Repairs were completed of a leak in the main coolant high pressure sample cooler discharge line.
7 A new turbine turning gear we.s installed.
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The flexible section of the stem leakoff line for the No. 3 loop Tc (O) drain valve was replaced.
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Numerous primary and secondary system valves were inspected and repacked.
Instrumentation and Control The following is s list of major instrumentation and control maintenance items performed by the plant staff during the cold shutdown maintenance period.
1.
Installation was completed of a new noise detection and intercom system for the vapor container.
2.
The vapor container relative humidity detectors were replaced.
3.
All temperature channels were recalibrated.
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The safety injection flow transmitter was recalibrated.
5.
A newly assembled, spare triaxial cable vapor container penetration was installed.
Reactor Plant Perfornance The following parameters were determined by means of incore
\\g) instrumentation:
555.5 t'Wt; 516.9 F Tavg; Control Rod Groups A,B,C, and D @ 90 ;
O ppm boron.
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F 2.0 H
1 Minimum DNER 3.71 l
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Maximum Outlet temperature 593.5 F.
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Secondary Plant Performance Feedwater heater terminal differences were as follows:
5.6 F No. 2 No. 1 9.9 F No. 3 55F
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The condenser performance was as follows:
172.8 MWe; 2.40" Hg. B.P.;
574.0 MWt; 62.74 F C.W. in; TTD = 23.82 F; cleanliness factor = 67.157 Ov)
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Chemistry During the period August 1-21, the main coolant average ammonia concentration and pH were 12.9 ppm and 9.k1, ret.pectively. On August 22 the main coolant was borated to a 5% shutdown concentration and averaged 10h0 ppm with an average pH of 6.3h during the shutdown maintenance period.
Boron dilution preparatory to reactor startup had reduced the concentration to 199 ppm at the end of the report period.
l crud level were 8.h6 x 10 gation the average gross beta-gamma activity and During power ope ue/ml and 0.05 ppm, respectively. During the i
August 21-y1 shutdown period the gross beta-gamma activity averaged l
- 5. 32 x 10 ue /ml.
The main coolant tritium concentration decreased from 1.48 ue/ml f
at the beginning of the period to 8.13 x 10-1 uc/ml at the time of shutdown.
l Further dilution preparatory to reactor startup reduced the tritium con-centration to 2.h9 x 10-1 uc/ml at the end of the report period.
I During power operation the average iodine 131 specific activity l
vas 3.26 x 10-5 uc/ml and the iodine 131/133 atomic ratio was 0.71, indi-
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cating the absence of detectable fuel defects.
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A representative crud sample for the conth, collected on August 19, had the following radiochemical analyses: dpm/mg crud
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l Cr-51 Mn-Sh Fe-59 6
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1.65 x 10' h.h1 x 10 5.90 x 10 Co-58 Co-60 Ag-110M 6
5 h.12 x 10' 5.Sh x 10 1.22 x 10 A main coolant gas sanple for the month, collected on August 11, had the following radiochemical analyses: ue/cc gas l
I Xe-133 Xe-135 Ar-41
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4.79 x 10 1.03 x 10 1.07 x 10 Health and Safety Waste disposal liquid releases totalled 80,h50 gallons containing i
0.0hh me of gross beta-gamma activity and 90.05 curies of tritium. Gaseous i
releases during the period totalled 1.7h3 curies of gross beta-gamma activity and 5.40 me of tritium. Secondary plant vater discharged totalled 303,h0h l
gallcns containing h.h30 me of gross beta-ganma activity and 73.83 curies of tritium.
1 In addition to the above releases 3.935 curies of tritium as a vapor was discharged to the environs during the period.
-9 Radiation exposure doses for Yankee plant personnel and 8
N.E.P.S.Co. personnel as measured by film badge, for the month of August, 1970 were:
Yankee Plant Personnel:
Average accumulated exposure dose:
413 mrem t
l Maximum accumulated exposure dose:
990 mrem
- N.E.P.S.Co. Personnel:
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Avarage accumulated exposure dose:
337 mrem Maximum accumulated exposure dose:
830 mrem i
i Orerations i
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Attached 1.5 a su= mary of plant operating statistics and a plot of daily average lead for the month of August, 1970.
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N.E.P.S.Co. personnel on-site only during August 21-31 shutdown period.
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YANKEE ATOMIC ELECTRIC COMPAtiY - OPEFATING GUMMARY August.1970 ELECTillCAL mot 3TH YEAR TO DATE Gross Generation KWH 86,633,000 945,376,600 11,151,035,100 Sta. Service (While Gen. Incl. Losses)
KWH 5,h22,849 56,628,20h 726,633,068 Net Output KWH 81,210,151 888,7h8,396 10.h34,h02,032 Station Service j
6.26 5.99 6.51 Sta. Service (While Not Gen. Incl. Losses) KWH 619,596 2,158,079 31,066,008 Ave. Gen. For Month (744)
KW 116,hh2 Ave. Gen. Running (503.23)
KW 172,154 g-PLANT PERFORMANCE Net Plant Efficiency 28.42 29.34 28.49 Net Plant Heat Rate btu /KWH 12,008 11,632 11,979 i
Plant Capacity Factor 64.02 86.58 75.52 P
Reactor Plant Availability 73.85 91.92 84.40 NUCLEAR Fjo!!Tl CORE VIII TOTAI Hours critical HRS Sh9.h2 7,787 8h 7.
17.62 Times Scrammed 1
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Core Average LMD/MrU 573.13 8,83h.58 g
Region Average FND/MTU l
A (INNER) 569.21 8,237.75 28,163.65 B (MIDDLE) 646.92 10,10J,63 22,133.Th C (OUTER) 499
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7,607.36 7,607.36 D (ZIPCALOY)
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