ML20029B222
| ML20029B222 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 02/28/1991 |
| From: | Feigenbaum T PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NYN-91036, NUDOCS 9103060244 | |
| Download: ML20029B222 (6) | |
Text
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e New. Hampshire Y
khh Ted C. Feigenbovm President and CMet be,cutwe Officer NYN-91036 February 28, 1991 United States Nuclear Regulatory Commission Washington, D.C.
20555 Attention:
Document Control Desk
Reference:
Facility Opereting License No. NPF 86, Docket No. 50 443
Subject:
Secondery Chemistry Annual Report Gentlemen:
Enclosed is the Scabrook Station Secondary Chemistry Annual Report. This report, submitted in accordance with Branch Technical Position MTED 5.3, summarires and evaluates the 1990 condensate, feedwater, and steam generator water chemistry operating experience and reports the total time secondary water chemistry parameters were out of specification.
Should you have any questions regarding this report, please contact Mr. James M.
Peschel, Regulatory Compliance Manager, at (603) 474 9521, extension 3772.
Very truly yours.
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New Hampshire Yankee Division of Public Service Company of New Hampshire
'o 05G105 P.O. Box 300
- Seabrook, NH 03874 + Telephone (603) 474 9521 t
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United States Nuclear Regulatory Commission February 28, 1991 Attention:
Docutaent Control Desk Page two ec: '
Mr. Thomas T. Martin Regional Administrator United States. Nuclear Regulatory Commission 1
Region l' 475 Allendale Road King of Prussla, PA 1906 i
Mr. Gordon E Edison, Sr. Project Manager Project Directorate 13 Division of Reactor Projects U.S. Nuclear Reguatory Comtnission Washington, DC 20555 Mr. Noel Dudley-NRC Senior Resident inspector P.O. Box 1149 Seabrook, NII" 03874 i
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New Hampshire Yankee
- February 28, 1991.
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ENCLOGRi? TO NYN 91036 i
SECONOARY CHEMISTRY ANNUAL REPORT h
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SECONDARY CHEMISTRY ANNUAL REPORT The Secondary Chemistry Annual Report summarizes and evaluates the condensate, feedwater and steam generator _ chemistry, as well as documenting total out of specification hours on these systems. The report is divided into three sections: Wet Lay Up, Power Ascension Testing, and Full Power Operation, l.
Wet Lay Up A.
Pre Startun The steam generators were in wet lay up from January 1 to February 3,1990.
During this period the condensate and feedwater systems were in stand by condition with hydrazine and ammonia, waiting to support the Power Ascenslon Test Program (PATP). Between January 10 30, 1990 the steam generators were without nitrogen overpressure and recirculation due to work on the Main Steam isolaticn Valves (MSIV) and the Emergency Feedwater (EFW) System.
A vacuum was drawn in the condenser on January 28, 1990 at which point the p
steam generators w;;; uner partial vacuum. On February 3,1990 draindown j
of the steam generators was commenced and they were drained and refilled by i-February 6,1990 prior to a.cension into Mode 4.
B.
May Turbine Outane Steam generator draindown commenced on May 1, 1990 without nitrogen blanketing. By May 5,1990 all steam generators were back in wet lay up, but without a nitrogen blanket due to the turbine outage work. Lack of ni rogen t
continued through May 15, 1990 and the steam generators were drained and refilled between May.18 20,1990.
C.
November Feedwater Reculator Valve Outagg, The steam. generators were placed in wel lay up without a nitrogen blanket on L
November 12, 1990 to support a maintenance outage following a reactor trip, The_ steam generators were drained and refilled on November 15, 1990.
The total hours the_- steam generator were out _ of specification for wet ' lay up per the Westinghouse Secondary Chemistry Manual are:
Month No Nitronen No Recirculation f.Agig.
January 219.5 497 EFW and Main Steam Testing Turbine Outage May 336 November 87 63 Feedwater Regulator -
l Valve and Reactors Coolant Pump Outage 1
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.11.
Power Ascension Testing Between February 6 August 12, 1990 with the exception of the May outage, the plant was preparing for or in the PATP. During this period two types of chemistry excursions occurred.
The first was a condenser tube leak on April 28, 1990. The "!P steam generator chlorides peaked at 395 ppb. The 'C' waterbox was drained shortly after confirmation of the leak.
Blowdown was maximized and condensate discharged to minimize transport forward and concentration into the steam generators. The steam generators were fed from the Condensate Storage Tank within about 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of the identified leak. - The estimated leak size was approximately 500 ml/hr. It was determined that mechanical failure of a baffle resulted in two phase impingement on a group of titanium tubes. One tube was determined to be the lenker and approximately 20 other tubes were plugged for potential failure due to erosion.
The othur excursion was a result of tectyl being removed from the internal surfeces of the condensate, feedwater and heater drains systems. Cation conductivities and sulfates would cycle high as new sections of systems were cut in, or when power increases were in progress. Westinghouse co, curred that the increased levels of these contaminants were due to tectyl washout and decomposition. The steam generator blowdown cation conductivity reached a peak 11.5 pnho/cm and sulfates peaked at 239 ppb, on May 30, 1990 while at 20% power. Each power change subsequent to this -also would yield spikes in cation conductivity and sulfates, but as full power operation was approached these transients were of shorter duration and lower intensity.
Concomitant with steam generator elevated cation conductivity was main steam catica conductivity, increasing trends in the parameter were simultaneous with power increases. Conductivity would downtrend at constant power levels with blowdown -in service for both main steam and steam generator blowdown. The total hours outside the operating guidelines for main steam were:
Abnormal Limit on Steam ( > 0.2 pnho/cm) 2818 hours0.0326 days <br />0.783 hours <br />0.00466 weeks <br />0.00107 months <br /> Purity (GE Steam Turbine Generator Manual) 260 hours0.00301 days <br />0.0722 hours <br />4.298942e-4 weeks <br />9.893e-5 months <br /> Emergency Limit on Steam ( > 0.5 pmho/cm)
Purity (GE Steam Turbine Generator Manaul)
The main steam system was above the 3 ppb limit for sodium for a total of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in April 1990 while the plant was in Mode 2 with minimal steam flow. No other values above he minimum detectable were recorded for the remainder of the year.
The other major secondary system parameter which displayed power related trending l
was condensate pump discharge. oxygen. Prior to the synchronization with the grid at approximately 15% power, condensate pump oxygen would hold steady at 30 50 i,
j ppb. The feedwater oxygen specification of < 5 ppb was maintained by hydrazine control. Subsequent to synchronization, condensate dissolved oxygen would rapidly l
trend downwards. This is an operational concern that depends on sealing and main l
steam flow to the turbine and appears to be correctable only by minimizing the time l
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speut in this translent state, Time spent in-Action Level I was minimal and did not exceed the one week limit which would initiate g,oing to Action Level 11.
Individual secondary chemistry parameters summed over all of the steam generators were out of specification for a total of 17,396 hours0.00458 days <br />0.11 hours <br />6.547619e-4 weeks <br />1.50678e-4 months <br /> during the Power Ascension Test Program.
~l11.
Full Power Operation The evaluation of secondary chemistry for this operational mode is from mid August through the end of the year. The total out of specification hours for the steam generators were recorded for the following parameters:
164 hours0.0019 days <br />0.0456 hours <br />2.71164e-4 weeks <br />6.2402e-5 months <br /> Cation Conductivity
( > 0.8 pnho/cm) 97 hours0.00112 days <br />0.0269 hours <br />1.603836e-4 weeks <br />3.69085e-5 months <br /> Sulfates
( > 20 ppb) 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Chlorides
( > 20 ppb)
With the exception of three specific instances, these and other steam generator parameters displayed a downward trend with no out-of specification hours in October and December.
A chloride.and cation conductivity excursion into Action Level 11 followed intrusion of 1,2 Dichloropropane into the secondary system from vendor demineralization units on September 19, 1990. Power was reduced to less than 30% within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, and power escalation resumed approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> later when all parameters were back within specification.
On November 2,1990, during a start-up from. 8% power, cation conductivity and sulfates increr, sed following synchronization to the grid, and at the 30% hold point were downtrending; This resulted in a total of 44 and 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />, respectively, at action Level 1.
A third excursion occurred during plant start up following the forced outage due to the feedwater regulator valve modification and the reactor coolant pump seal replacement. This accounted for approximately 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br /> in Action Level 1 due to sulfates and cation conductivity, Following this excursion maintaining blowdown at 70 gpm showed decreasing cation conductivity trends and brought chlorides and sulfates to levels of approximately 13 and 3-6 ppb-respectively.
During the period of full power operation in 1990 the condensate and feedwater chemistry continued to improve, with dissolved oxygen routinely at 4 7 ppb and 12 ppb respectively.
Cation conductivity in both systems dropped to 0.10 and 0.14 gnho/cm during this time period.
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