IR 05000348/1985019

Insp Repts 50-348/85-19 & 50-364/85-19 on 850408-12.No Violation or Deviation Noted.Major Areas Inspected:Plant Chemistry & Inservice Insp of Pumps & Valves

ML20127F769
Person / Time
Site:	Farley
Issue date:	04/22/1985
From:	Blake J, Ross W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20127F756	List: IR 05000348/1985019 ML20127F754
References
50-348-85-19, 50-364-85-19, NUDOCS 8505200591
Download: ML20127F769 (7)

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UNITE 3 STATES

_ [Sniergb o NUCLEAR REGULATCRY COMMISSION y #

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Ij 101 MARIETTA STREET, r ATLANTA. GEORGI A 30323 s., ...../

Report ~Nos.: 50-348/85-19 and 50-364/85-19 Licensee: Alabama Power. Company 600 North 18th Street Birmingham, AL 35291 <

Docket Nos.: 50-348 and 50-364 License Nos.: NPF-2 and NPF-8 Facility Name: Farley Units 1 and 2 Inspection Conducted: pril 8 - 12, 1985 Inspector: h # ## fs" W. J. Ross ' ' '

Date Signed Approved by:

J. J B ike, Section Chief 2zI'r-Date Signed _

En n ring Branch D vis on of Reactor Safety SUMMARY Scope: This routine, unannounced inspection entailed 40 inspector-hours on site in the areas of plant chemistry and inservice inspection of pumps and valve Results: No violations or deviations were identifie I'

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REPORT DETAILS

. Persons Contacted Licensee Employees

• J. D. Woodard, Plant Manager

• D. N. Morey, Assistant Plant Manager-Operations

• C. D.' Nesbitt, Technical Superintendent ,

• W. R. Bayne, Chemistry and Environmental Supervisor R. T. Wood, Plant Chemist .

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T. Livingston, Chemistry Foreman ' *

J. Upchurch, Shift Supervisor W. Van Landingham, Inservice Testing Supervisor Other licensee employees contacted included chemistry technician NRC Resident Inspectors

• H. Bradford

• B. R. Bonser

• Attended exit interview Exit Interview The inspection scope and findings were summarized on April 12, 1985, with those persons indicated in paragraph 1 above. The inspector described the ,

areas inspected and discussed in dotati the inspection finding No *

dissenting comments were received from the license The licensee did not identify as proprietary any of the material provided to or reviewed by the inspector during this inspectio ,

, Licensee Action on Previous Enforcement Matters This subject was not addressed in the inspectio . Unresolved Items Unresolved items were not identified during the inspectio . Plant Chemistry (92706)

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cycle and the licensee's water chemistry program in preventing degradation i of the reactor coolant pressure boundary and low pressure turbine rotor ;

1 This followup of an earlier inspection (Inspection Report Nos. 50-348 and i j 364/84-09, March 26-30,1984) consisted of a reassessment of plant design '

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and operation during the past year and a review of the chemistry control achieved by the licensee during this perio Reassessment of Plant Design and Operation This inspection coincided with the beginning of the sixth refueling outage for Unit 1. This unit had operated at power for approximately 320 days without a shutdown during its sixth . fuel cycle. Likewise, Unit 2 had a successful third fuel cycle with only one significant outage (two weeks during September 1984) before its shutdown for refueling during January and February 1985. The September outage was caused by a leaking steam generator tube. While the plant was shut-down, two other steam generator tubes were also plugged because eddy current tests had indicated serious (70% and 80%) wall thinnin ' '

Through an audit of plant records and discussions with plant personnel the inspector established that a high level of control of secondary water chemistry control had been maintained during the past year. To a large degree, this control was made possible by the design and opera-tion of the secondary water systems as discussed belo (1) Integrity of the Condenser Hotwell During 1984 inleakage of air into the hotwell was maintained at <1 SCFM in Unit 1 and <2 SCFM in Unit 2. The licensee attributed this very high integrity condenser to a continual'of the low pressure surveillance turbines program and maintenance and the directed at such leak susceptible components as steam glands, rupture disks, pump seals, and the crossover steam lines between the turbines and moisture separator reheaters (MSRs). As a consequence, there has been little. difficulty in maintaining the dissolved oxygen concentration in the hotwell water at <5 pp '

The integrity of the ma,in condensers against inleakage of condenser cooling water was also kept at a high level. Trends of the cation conductivity of the hotwell water showed that contaminants were decreased, soon after startup in the last fuel cycles, to the extent that values for cation conductivity of < umho/cm were obtained. This purification process was continued, through the use of steam generator blowdown, throughout the fuel cycle so that cation conductivities of <0.2 umhc/cm were achieved during the second half of the twelve-month fuel cycl The licensee has experienced condenser tube failures in the past, as the result of mechanical failure or impingement by loose metal objects; however, the titanium tubes and integrally grooved tube sheets have resisted all forms of chemical attac (2) Condensate Makeup System Further review of chemistry control and diagnostic data accumulated during the past year indicates that there had been

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very little ingress of corrosive contaminants into the conden-sate /feedwater through makeup water. The licensee informed the inspector that no serious problems had been encountered with the two water treatment plants during the past year. However, there are indications that part of the cation conductivity of water in the secondary cycle can be attributed to leakage of non-ionic organic compounds through the water treatment plant and subsequent thermal degradation of these compounds to low molecular weight ionic species, such as formic and acetic acid (3) Chemical Control Boric acid is added to the feedwater of Unit 1, along with AVT chemicals (hydrazine and ammonia), to counteract hideout of chloride when the steam generator water is at operating temperature (~550 F). Boric acid is maintained at a concentration of 5 pp:n in the blowdown. The licensee has established that the cation conductivity of 1 ppm boric acid is approximately 0.03 umho/cm; consequently, the normally higher cation conductivity in Unit 1 blowdown is attributed to boric aci Also, approximately ten percent of the boric acid is carried over to the hotwell in the steam and adds to the cation conductivity of the hotwell water, which would otherwise approach the purity of demineralized wate (4) Transport of Corrosion Products to Steam Generators During the last refueling outages for both units, the licensee sludge lanced the steam generators and removed several hundred pounds of oxides of iron and copper (and lesser amounts of nickel and zine) that represent corrosion products derived from the carbon steel pipe in the secondary cycle and copper-nickel tubes in the feedwater heaters and MSR. In the absence of a condensate cleanup system the licensee is handicapped in preventing the transport of these large quantities of solids to the steam generator Once in the steam generators, the solids are not removed efficiently by blowdown, and, thus, form an environment that is conducive to localized corrosion. The licensee has taken the following steps to reduce the detrimental effect of these corrosion product During the current refueling outage feedwater heaters IA and B, 2A and B, 5A and B, and 6A and B are being replaced with new heaters that have stainless steel tubes. Consequently, since feedwater heaters 3A and B and 4A and B, as well as the MSRs, were replaced during the fifth refueling outage, there no longer are copper-containing components in the secondary cycle (half of the feedwater heaters in Unit 2 still have copper-nickel alloy tubes).

By this action, and centinued sludge lancing, the licensee hopes to remove all copper-containing material from the steam generators

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and to prevent the types of corrosion, such as denting, that are enhanced by copper metal and/or oxid The licensee is.also taking advantage of existing filters in:the secondary cycle of Unit 1 to remove solids during the 'startup cleanup of the. condensate lines of this unit. Although most of the corrosion products that are transferred to.the steam generator

'during plant startup are thought to come from the high energy water and steam lines, (as opposed to the condensate /feedwater lines) this action will reduce the overall transport of solid The inspector was informed that each of the new feedwater heaters underwent an alkaline flush and was subsequently rinsed and laye up dry to minimize oxidation of inner surfaces before being **

installe During the current Unit 1 outage steam generator 2B has been opened .to make modifications on the anti-vibration bars that are associated with the tube bundle. ' While. the steam generator is open both the feedwater downcomer region and the tube bundle are-

.being hosed down with demineralized water in an effort to maximize the removal of sludge. The inspector was informed that there were indications that there was sludge on the upper tube support plates and the tubes themselves as well as in lower regions of the steam generato .

(5)' Hideout of Corrosive Chemicals in Steam Generators Analyses of the liquid phase removed with metal oxides during sludge lancing have revealed the presence of parts per million (ppm) amounts of chloride and lesser amounts of sulfate, silica, sodium, calcium, and magnesium. These species are common to all cooling water and makeup water sources and probably represent buildup over the operating life of the plant from small sources of inleakage of condenser cooling water or leakage through the water -

treatment plant.

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The licensee has performed an in-depth study of the ' hideout' of these trace, but potentially corrosive, species in an effort to minimize their detrimental effect on the components of the steam generato This study also showed that fluoride is being dissolved from weld flux residues (probably as ammonium fluoride)

and further increases the potential for stress corrosion cracking in the steam generators. As the result of this study the license has begun monitoring the changes in solubility of all potentially corrosive impurities (i.e., hideou+. and hideout return) whenever a unit is started up or shut down. During the refueling shutdown for Unit 2 in January 1985, the licensee found that hideout return of sulfate, silica, and calcium increased to several hundred ppm (300-900 ppm) as the steam generator water was cooled. The steam generators were subsequently flushed with domineralized water

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until the concentration of each species had been reduced to 40 ppb. However, when Unit 2 was restarted in March 1985 even graater of silica. (~2500 ppm), as well as significant amounts (50-250 ppm) amounts of sulfate were found in blowdown samples.as the unit fluctuated in modes of operation for the first two weeks of the new fuel cycl These results indicate to the inspector that during the opera-tional history of the two units undesirably large amounts of such potentially corrosive species as sulfate, fluoride, chloride, and silica have been transported to the steam generators. Further, the amount of these species that remain after sludge lancing also remains undesirably high. The inspector - believes that the licensee is obtaining a much better understanding of how trace amounts of cations, anions, and silica are retained in the steam generator and how they can be removed by periodically maximizing hideout return conditions - with and without boric acid soak (6) Turbines During this inspection the licensee was replacing the rotor of the Unit I high pressure turbine with a rotor of improved design. The inspector made a brief visual inspection of the old rotor but could not observe any degradation of blades or disk The licensee informed the inspector that evidence of steam erosion had been observed in the turbine shroud and was being reviewed for significanc The low pressure turbiner of Unit I were being serviced during this inspection; however, the rotors were not being inspecte b. Control of Secondary Water Chemistry During the past year the licensee has completed the revision of the Farley water chemistry program to endorse the technical and administrative recommendations proposed by the Steam Generator 40wners Group (SG0G) and the Electric Power Research Institure (EPRI). The inspector reviewed the licensee's Chemistry Data Logs and graphical trends of analytical results to establish the degree to which high

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quality steam generator water had been maintained during the past yea These data showed that during post-refueling startup, one to three weeks are required to reduce chemistry control parameters (cation conductivity, sodium, chloride, and sulfate) below the limits specified for extended power operation. In order to expedite system cleanup, especially in high energy steam and drain lines, the operational limits are relaxed by a factor of five untti the unit exceeds a power level of 35%.

Further analysis of the graphical trends showed that the cation conductivity of water in both the hotwell and blowdown continued to decrease throughout the fuel cycle except when the blowdown rate was decreased or when there was a power transient. During most of the fuel

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6-cycle' the~ concentrations of sodium,. fluoride, sulfate, and chloride were below limits detectable by state-of-the-art analytical chemistry ,

instrumentation and silica was normally <5 ppb. These data indicate that inleakage was minimal and, during power operation, these contami-

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nants are either occluded within the sludge or-precipitated with the metal oxides as such insoluble species as calcium sulfate or magnesium silicat Inspector Followup Item 50-348/84-09-01, Boric Acid Treatment of Steam Generators in Unit 1 (Closed)

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-Based on additional information provided by the licensee during.this inspection and similar information acquired at other plants, the inspector',s concerns relevant to the use of boric acid in the secondary '

cycle have been resolved. Although the presence of 5 ppm boric' acid in the steam generator depresses the pH to 7-8 there are no operational data .that indicate increased corrosion of -iron components at these relatively low pH valve '

6. Inservice Testing of Pumps and Valves (92706)

The inspector continued an assessment of the licensee's program for testing l pumps and valves per the requirements of Section XI of the ASME. Boiler and Pressure ' Vessel Code. This review had been initiated earlier (Inspection Report . Nos. 50-348 and 364/83-02). During the ' current inspection the licensee's Valve Status List was audited and no deficiencies in tabulation were identified. The test data in this list also showed no trends that would indicate degradation of valves and no stroke times were outside allowable limits. The inspector observed that a number of valves had maximum allowable stroke times considerably longer (a factor of >10) than the actual stroke time. The licensee agreed to review the basis for these reference values to determine if more practical values could be set to  ;

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increase protection against gradual degradatio The inspector also reviewed the licensee's procedures for. testing the  ;

accumulator discharge check valves (Procedure FNP-2-STP-40.0) and discussed- ,'

with the licensee alternative methods for assuring that these valves will open if safety injection is needed.

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