IR 05000324/1985037

Insp Repts 50-324/85-37 & 50-325/85-37 on 851104-08.No Violation or Deviation Noted.Major Areas Inspected:Plant Chemistry

ML20139A268
Person / Time
Site:	Brunswick
Issue date:	11/29/1985
From:	Cline W, Ross W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20137Z981	List: IR 05000324/1985037 ML20137Z975
References
50-324-85-37, 50-325-85-37, NUDOCS 8512110480
Download: ML20139A268 (7)

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UNITO STATES ,

/pn nargDo NUCLEAR REGULATCRY COMMISSION

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%*****/ NOV 29 BB5 Report Nos.: 50-325/85-37 and 50-324/85-37 Licensee: -Carolina Power and Light Company P. O. Box 1551

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Raleigh, NC 27602 Docket Nos.: 50-325 and 50-324 License Nos.: DPR-71 and DPR-62 Facility Name: Brunswick 1 and 2 Inspection Conducte : November 4-8, 1985

, Inspector:

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0 ate Signe Approved by: -

. E" CTine, Section Chief

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Protection Branch Division of Radiation Safety and Safeguards SUMMARY .,

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Scope: This routine, unannounced inspection entailed 37 inspector-hours onsite in the area of. plant chemistr Results: No violations or deviations were identifie ,

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) REPORT DETAILS

.q, 15 Persons Contacted s

Licensee Employees

• C. R.'Dietz,, General Manager

• A. G. Cheatham, Manager, Environmental Radiological Control (E&RC)

• C E. Robertson, Chemistry Supervisor, E&RC T. Caldwell, Systems Engineer

• J. Davis, Prefect Specialist, E&RC W. Nurnberger', Chemistry Foreman, E&RC

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L. Sellers, Radwaste Supervisor, Operations A S. Smith, Systems Engineer f

Other licensee employees contacted included chemistry staff personne NRC Resident Inspector

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W. Ruland

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" Attended exit interview

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/ Exit Interview The' inspection scope and findings were summarized on November 8, 1985, with p those persons indf cated in Paragraph 1 above. The inspector described the j- areas inspected and discussed in detail the inspection finding No

>> dissenting comments were received from the licensee. The licensee did not identify as proprietary .any of the materials provided to or reviewed by the inspector during this inspectio . Licensee Action on' Previous Enforcement Matters This subject was not addressed in the inspectio If 4 Unresolved Items Unresolved items were not identified during this inspectio . Plant Chemistry (79501 and 79502)

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In a recents action the NRC Office of Inspection and Enforcement has

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6] developed two new Inspectjon Procedures to verify that the design of a nuclear power plant provides conditions that ensure long-term integrity of

, , the reactor coolant pressure boundary and to establish the extent to which a a licensee is able to - control plant chemistry so that corrosion and occupational . radiation exposure are minimized. The objectives of these new procedures were partially fulfilled during a previous inspection of the

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Brunswick plant (see Inspection Report Nos. 50-325/84-23 and 50-324/84-23, August 30,1984). This followup inspection consisted of a review of plant operating experience since the previous inspection and an assessment of the protection that had been provided through chemi stry surveillance and contro Plant Operation At the time of this inspection Unit I was restarting, in its third fuel cycle, after an eight month outage during which major maintenance and repairs were performed, including repair of intergranular stress corrosion cracks (IGSCC) in the recirculating water lines. Unit 2 was in the last month of its seventh fuel cycle that began in October 198 An outage of approximately seven months is planned for Unit 2 to allow similar major repairs to be mad During their periods of operation since the last inspection, in July 1984, both units experienced a number of problems that resulted in unstable operation or shutdown None of these problems were attributed to control of chemistr However, besides the IGSCC degradation of the recirculating lines the licensee has also observed stress corrosion cracks in the low pressure

, _ turbine wheels and has replaced one rotor in Unit 1 and plans to replace one in Unit 2 as soon as a replacement is availabl Once Unit 2 began operating in a stable condition during the past year (~ April 1985) the licensee was able to maintain both chemistry control and diagnostic parameters within the limits recommended by the BWR Owners Group (BWROG) for corrosion control. This favorable condition is attributed to the integrity of the condenser and other components of the reactor coolant system (i .e. , no inleakage of air or condenser cooling water) as well as to the capability of the dual condensate cleanup system to remove impurities from the condensate makeup as well as to filter out solid oxidation products of-iron that form on the inner surfaces of both the low pressure and high pressure components of the reactor coolant system during plant outages. The licensee has been able to maintain a high level of cleanliness within the reactor coolant system as shown by the fact that the filter /demineralizers usually have been precoated _ only once per three or four weeks and calculations indicate the deep-bed demineralizers will not be depleted for several (two to six) years under normal condition The licensee is attempting to improve the quality of makeup water by switching from well water to domestic (county) water as the input to the water treatment plant and, thereby, eliminating fouling of the cation and anion resin beds. Also, the limiting conductivity of the product of the water treatment plant has been decreased from 1.0 umho/cm to 0.1 umho/cm, thereby ensuring that the product water is essentially free of all potentially corrosive species. This product water is still being stored in the Condensate Storage Tank (CST) where it is exposed to air, thereby saturating the water with dissolved oxygen. During the last outage for Unit 1 the design of the reactor coolant cycle was modified so that suction for control-rod-drive (CRD)

water no longer is taken from the CST but rather from the discharge of l

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the condensate cleanup syste Consequently, the quality of the CRD

- water, that eventually mixes with the reactor coolant, has been improved and ' ensures that the reactor coolant will not be degrade However, in Unit 2 CRD water is still taken directly from the CST without benefit of further polishing or air removal. By preventing ingress . of impurities into the feedwater the licensee has been maintaining essentially the purity of demineralized water, i.e.,

conductivity of 0.054 umho/cm and silica less than 1 ppb. This purity -

translates into high quality reactor coolant, i.e., conductivity of 0.16 to 0.28 umhos/cm, chloride <5 ppb, silica 50-200 ppb. The licensee's capability to provide continual cleaning of the reactor water, by means of the Reactor Water Cleanup System (RWCU) has been variable. The inspector observed that the RWCU, when operable, was able to produce water with a conductivity of 0.07-0.08 umho/c However, the effluent of the RWCU periodically has been contaminated with " fines" from the filter /demineralizer resin columns. These small resin fragments leak through the DeLaval septums and are subsequently thermally degraded into acidic sulfate species that can form corrosive environments that enhance IGSCC. All of the septums in Unit I were replaced during the recent outage in an effort to reduce resin leakag The inspector was also informed that a different design of seotum is under investigation and may be substituted for the DeLaval tube . Summary The inspector's audit of analyses performed on the reactor coolant revealed that whenever Unit 2 was operating in a stable condition, the chemistry variables that are controlled to prevent IGSCC were within the limits recommended by the BWROG, unless there was resin leakage in the RWCU. When the power level was fluctuating the conductivity of the reactor water often exceeded the 0.3 umho/cm limit established by the-BWROG and, therefore, was less conducive to corrosion contro The licensee does not attempt to control the concentration of oxygen in the-reactor water, other than by maintaining the oxygen content of the condensate and feedwater as low as achievable (20-30 ppb) by means of condenser vacuum and the- dearation achieved in the high' pressure

- feedwater heaters. The licensee has made no commitment to initiating hydrogen water chemistry control of dissolved oxygen in the reactor coolant. Unit 2 operated under stable conditions' for a record (for i Brunswick) period between April and August 1985; however, there were

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-several periods before- and afterwards when chemistry control was not

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optimum because of power changes and periodic power outage The inspector was informed that no evidence of chemical inc. .ced degradation of fuel elements had been observed in either Brunswick f -unit.

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' Chemistry Program As during _ the previous inspection, the inspector used the water chemistry guidelines that have been _ prepared by the BWR Owners Groups -

-(BWROG) as a yardstick to evaluate the scope and adequacy of the

. licensee's water. chemistry program. From discussions with plant management and chemistry supervisory personnel the inspector established that the licensee was . familiar with both the philosophical and technical recommendations developed by the BWROG;_ however, there

- was no indication. that any of the specific guidelines had been

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incorporated into management directives or plant. procedures. _Although the BWROG guidelines have not yet been endorsed by the NRC, as have the guidelines developed by the_ industry for PWRs, the guidelines represent the consensus of current understanding of stress corrosion cracking and

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fuel degradation in BWRs~and their prevention. Consequently, throughout this. inspection, emphasis was placed on those parts of the licensee's - 1 water chemistry program that did not _ appear to be consistent with the BWROG . guideline Two_ areas specifically were of concern. First, the inspector perceived a need;for a formal commitment by corporate and plant management to corrosion control and a policy for controllin'g water chemistry

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to prevent corrosion. Second, there is a need to make the chemistry and operating procedures more specific and consistent-relative-to allowable limits - for ~ chemistry control - parameters during all modes of plant operation as well as to the actions to be taken when.these limits are

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exceede The inspector was informed that -new- directives are -being -

developed by ' the corporate chemistry staff that will address these areas of concer The inspector evaluated the licensee's capability to_ maintain-appropriate water chemistry conditions in ~ the two _ Brunswick units u through the following means: auditing chemistry control data that had been acquired for Unit 2 during its current- fuel cycle; interviewing cognizant pers'onnel- in .the Chemistry 'and Radwaste staffs; observing activities performed .in the chemistry laboratory; and reviewing the

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licensee's program for quality control 'and quality assessment of data-required . by Procedures E&RC-1001 Sampling' and Analysis Schedule for

.Padioactive and Non-Radioactive Non-Technical Specifications Related Chemistry and E&RC-1700. Verification of Analytical Performanc !The. licensee's Chemistry staff. remained essentially unchanged since the

previous inspection. This . stable condition .was considered to be favorable because.the licensee has initiated a formal training program, both at the corporate training center and onsite, for upgrading the training of. all chemistry technicians _ and specialists. Most analyses

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required by Procedure E&RC-1001 (as well as under Procedure E&RC-1000 for analyses. required by Technical-Specifications) are performed on

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grab samples. . Conductivity measurements are the principal exception .The licensee has acquired state-of-the-art analytical instrumentation and ' is training all chemistry technicians so that each will be

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qualified on all radio-chemical as well as non-radiochemical procedures and instruments. A computerized program has been developed for tracking the training and qualification of each member.of the chemistry staf The chemistry specialists are being used effectively in support of the training activities' as well as for resolving specific problem The inspector reviewed the chemistry quality control program and data acquired through routine calibrations and in-house verification procedure Control charts are maintained for each instrumental procedure and are revised monthly on the basis of standard analyses performed by many of the 23 Chemistry Technicians. The licensee also participates in two inter-laboratory control programs. The CP&L corporate chemistry laboratory submits ' blind' samples to all power plant laboratories, however, the inspector believes that this program would be _ of greater value if the samples were prepared to be more representative of those encountered at Bruwnswick. In addition, the licensee has recently initiated a cross-check program with a commercial laboratory. ' An audit of the results of all of these quality control program revealed that a high level of assurance is being achieved for

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all key chemistry variables as well as for many diagnostic parameters such as sulfate and copper ions that exist in trace chemical levels in the reactor coolan The Chemistry Staff exhibited a high level of understanding of the potential mechanisms for corrosion in a BWR as well as a comprehension of the~ theory and techniques associated with state-of-the-art analytical instrumentatio All activities were being performed in a professional manne The inspector emphasized the need to maintain an exceptionally clean laboratory environment while performing analyses of

< - essentially pure water as well as to prevent spread of radioactive L

contaminatio Summary During this part of the inspection, no violations or deviations were identified. The licensee's surveillance and control program, as

- defined in current procedures, is considered to provide an acceptable-levd cf protection against IGSCC. The inspector believes, however, that this program does not incorporate two concepts that are considered by the NRC to be central to the current philosophy and guidelines for chemistry control ~ that have been developed by the BWROG: (1) plant procedures should define allowable limits for chemical variables and progressively more stringent. corrective actions that must be taken for out-of-specification chemistry conditions; and (2) written corporate goals and policies relating to water chemistry control and station operation should be developed and should show an understanding of the

' action level' concept and its possible impact as well as its possible benefits to the utilit It is the inspector's experience that utility commitment to these two concepts has provided the basis for the improvement in chemistry control that has been observed at nuclear plants in Region II during the last two years.

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.. y Closeout of Inspector Followup Items (IFI)

The following two IFIs were addressed during this inspection, and, on the basis of the information summarized below, both IFIs are hereby close IFI ' 84-23-01 Implementation of Technical Specification 3.3.5.6 - Chloride Intrusion Monito The inspector established that the licensee is meeting the requirement of Technical Specification 3.3.5.6 to have chloride intrusion monitors in the condenser hotwell outlet headers, in the condensate pump discharge, and in the inlets to both the condensate filter /demineralizer.and the deep-bed demineralizer. In order to achieve greater reliability for chloride in different ranges (0-1 ppb, 0-10 ppb, and 0-100 ppb) conductivity meters have been substituted for in-line chloride detector In the absence of other

. impurities the measured conductivity can be converted to chloride concentration; however, the licensee uses the conductivity measurement as a direct method of monitoring the intrusion of all ionic impurities into the hotwell. The four conductivity meters on the condenser hotwell display in the. Control Room and afford the first indication of condenser cooling water inleakag IFI 84-23-02 Role of Ionic Impurities in the Cracking of Valve G31-F042 in Unit 2

.The licensee provided the inspector with additional information related to the earlier identification of IGSCC indications in a valve downstream of the filter demineralizers in the RWCU system. The basic cause of failure was hypersensitization of the 304 stainless steel valve seat when stellite was placed over the seat by application of local weldin The licensee believes that the valve would have probably failed without the aggravating effects of deposition of " fines" from the ion-exchange resins in the RWC No investigation was performed to determine if localized chemistry excursions would have accelerated the -deteriorction. The inspector does not consider that further research on this matter is warranted.