ML20126F995
| ML20126F995 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/14/1985 |
| From: | Koester G KANSAS GAS & ELECTRIC CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| GL-85-02, GL-85-2, KMLNRC-85-158, NUDOCS 8506180034 | |
| Download: ML20126F995 (9) | |
Text
KANSAS GAS AND ELECTRIC COMPANY T>E ELECT 54C COMPANY OLENN L MOESTER vict persacrNT muctran June 14, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 KMLNRC 85-158 Re:
Docket No. STN 50-482 Ref: NRC Letter from HLThompson to all PWR Licensees of Operating Reactors, Applicants for Operating Licenses, and Holders of Construction Permits, and Ft. St. Vrain, Staff Recommended Actions Stemming from NRC Integrated Program for the Resolution of Unresolved Safety Issues Regarding Steam Generator Tube Integrity (Generic Letter 85-02)
Subj: Response to Generic Letter 85-02
Dear Mr. Denton:
The attachments to this letter provide Kansas Gas and Electric Company's (KG&E) response to the subject Generic Letter.
If you have any questions concerning this subject, please contact me or Mr. Otto Maynard of my staff.
Yours very truly, pLK:bb tAttach xc:PO'Connor (2), w/a JCummins, w/a I
B506100034 8 0 82 PDR ADOCK 0 PDR a
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201 N. Market - Wichits, Kansas - mar Address: RO. Box 208 I Wichita, Kansas 67201 - Telephone: Area Code (316) 261-6451 l
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'S RESPONSE TO GENERIC LETTER 65-02:
STEAM GENERATOR TUBE INTEGRITY 1.a PREVENTION AND DETECTION OF LOOSE PARTS (INSPECTIONS)
Visual inspections to identify loose parts or foreign objects on the tubesheet and to identify any external damage to peripheral tubes just above the tube sheet will be performed after any secondary side modifications of repairs to the steam generator internals and when eddy current indications are found in the free span portion of the peripheral tubes, unless it can be determined that the indication did not result from damage by a loose part or foreign object.
A step by step procedure will be developed prior to any inspections.
A visual inspection is not presently planned at the first outage for eddy current testing due to a previous inspection for loose parts performed by Aptech Engineering Services, Inc.
This inspection was performed after upper plenum modifications were completed and prior to start-up activities.
The required visual inspections will be performed using fiber optic techniques with remote monitor and recorded on a video tape cassette, or a system with equivalent capabilities.
Access for the optical fiber will be through the hand holes.
A tube index tape secured in the periphery at the hand holcs or a system with equivalent capabilities, will be used for determining tube diameter if tube damage is observed.
If any foreign objects are observed, during visual inspection, the location of the object will be documented.
A report will document the type of object, size, weight, location found, material, origin (if known), date found, found by, and any other pertinent information.
Upon completion of the inspections, the inspection report and any foreign objects retrieved will be submitted to maintenance.
1.b PREVENTION AND DETECTION OF LOOSE PARTS (QUALITY ASSURANCE)
Administrative controls have been established expressly for the purpose of assuring steam' generator tube integrity.
Procedures and instructions which control work being performed in or adjacent to an open steam generator or in systems feeding the.
steam generator invoke measures which provide for:
1) detailed accountability for all tools, equipment and materials used; 2) exclusion of foreign objects which are not required to perform the work; 3) securing of foreign objects such as eye glasses, dosimetry, etc.;
4) accountability of parts and pieces removed as a result of the the work and activity; and 5) maintenance and/or restoration of required cleanliness level.
Details of these measures are provided in station administrative procedures.
Responsibility for implementation of these requirements rests with the group performing the work.
Additionally, Quality Branch procedures and instructions related to steam generator foreign object exclusion provide for:
Initial verification of the establishment of foreign object exclusion controls prior to opening of the affected system / component.
Surveillance and monitoring of work activities to assure effective implementation of the above work control measures; Final verification of foreign object exclusion and cleanliness adequacy prior to closure of optning.
The above mentioned administrative, work, and quality procedures meet the requirements of Regulatory Guides 1.37 and 1.39 as committed to in Appendix 3A of the Wolf Creek FSAR.
2.a INSERVICE INSPECTION PROGRAM (FULL LENGTH TUBE INSPECTION)
The Wolf Creek Generating Station (WCGS) Technical Specifications define a Steam Generator Tube Inservice Inspection as an inspection of the Steam Generator Tubes from the point of entry (hot leg side) completely around the U-bend to the top support of the cold leg side.
The Wolf Creek Technical Specification definition is consistent with the Standard Technical l
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l Specifications and Regulatory Guide 1.83.
Westinghouse Steam Generator Technology division is contracted to perform the Steam Generator Tube Inservice Inspections at WCGS and will perform a 100% inspection of the entire length of the tubes in the Steam Generator on the number of tubes determined by the Technical Specifications.
This provides an inspection of the tube length beyond that required by the Technical Specifications for WCGS.
After the initial 3% sample, supplemental sample inspections will be conducted if degradation of tubes is noted.
This is detailed in Enclosure 2.
2.b INSERVICE INSPECTION PROGRAM (INSPECTION INTERVAL)
WCGS Technical Specifications adheres to the same eddy current inspection frequency as provided in Section 4.4.5.3 of the Standard Technical Specification.
3.a SECONDARY WATER CHEMISTRY PROGRAM Administrative procedure establishes the guidelines for the development and implementation of a Steam Generator Protection Program (SGPP).
The purpose of the SGPP is to emphasize adherence to chemistry limits and corrective action requirements which will prolong the lifetime and minimize damage to the steam generators and other secondary system components.
This directive requires adherence to.the WCGS' Secondary Water Chemistry Program except during an emergency situation as directed by the Director of Nuclear' Operations or the Vice President Nuclear.
The WCGS Secondary Water Chemistry Program is based on SGOG/EPRI "PWR Secondary Water Chemistry Guidelines", Revision 1.
A' procedure is established to minimize steam generator corrosion, chemistry limits, and control methods.
The secondary chemistry control procedure also includes l
progressively more stringent actions for out-of-specification 2
water chemistry conditions.
The following outlines these actions:
Action Level 1
?
I Objective:
To promptly identify and correct the cause of an out-of-normal value without power reduction.
i Actions:
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(a)
Return parameter to within normal value range within one week following confirmation of excurt. ion.
(b)- If parameter.is not within normal value range within one week following confirmation of-excursion go to Level 2 for those parameters having Action Level 2 values.
(c)
If Action Level 2 is not implemented, a special report should be prepared Which details the reason for the off normal condition, the corrective actions which have been taken to date and the plans for returning the parameter to within normal limits.
This special report should be submitted to the Plant Manager.
Action Level 2 j
Objective:
To minimize corrosion by operating at reduced power while corrective actions are taken.
Power reduction should be to a level which will reduce available steam generator superheat and heat flux while providing sufficient system flow to maintain automatic operation while the source of impurity is corrected.
This reduced power level is typically 30% of full power or less.
Actions:
J (a)
Reduce power to appropriate level (typically 30% or l
1ess) within'four hours of initiation of Action Level 2.
-(b)
Return parameter to within normal value range within 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> or to Action Level 3 for those parameters having Action Level 3 values.
Action Level 3 Objective:
To correct a condition which may result in rapid steam generator corrosion during continued operation.
Plant shutdown will avoid ingress and eliminate further concentration of harmful impurities.
Actions:
(a)
Shutdown within six hours and take appropriate action I
(repair, bleed and feod, etc.) until normal values are reached.
The judgement on maintaining the steam 4
generator in a hot condition or progressing to cold shutdown should be based on the corrosion concern t
imposed by the specific impurity and the most rapid
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means to effect cleanup.
Accordingly in the secondary chemistry control procedure, the responsibilities for chemistry control are delineated as follows:
It is the responsibility of the Shift Supervisor, upon being advised by the Site Chemist, to ensure that the secondary j-water chemistry is maintained within specifications.
It will be the responsibility of the Site Chemist that any changes to the secondary chemistry control procedure are carefully evaluated to ensure that they are incorporated into
^
the WCGS Chemistry Specification Manual.
Exceptions to the secondary chemist control procedure shall be made only during emergency conditions when concurrence to continue generating power has been granted by the Director Nuclear Operations or the Vice President-Nuclear.
In addition, the WCGS Chemistry group-has established procedures for secondary chemistry control to address surveillance, training, reporting chemistry data to operations, documentation, out-of-specification condition quality control program for chemistry instrumentation, and verification of analytical performance.
3.b CONDENSER INSERVICE INSPECTION PROGRAM i
The condenser at WCGS was uniquely designed for SNUPPS.
Special
. consideration in the design was given to minimize plant down time due to contamination of the condensate by circulating water i
j inleakage. Unique features include isolating incoming condensate contaminants and special tube sheet hole serrations for extra i
sealing effect.
The condenser was also designed for easy tube plugging during normal operation.
The preventative maintenance program on the the condenser and effective water chemistry controls have also been established to ensure reliable condenser performance.
The Managed Maintenance Program controls the periodic maintenance on the condensers.
The condenser is inspected and cleaned on a refueling basis and the tubes are inspected and cleaned every fifth refueling.
Tube leaks are pinpointed with helium leak L
detection or similar equipment and the damaged tubes are plugged or, if necessary, the main condenser tubes will be replaced per manufacture's recommendations.
t Water chemistry is controlled through a secondary water chemistry program which detects abnormal water chemistry in the condensate and feedwater systems.
The circulating water chlorination system minimizes impurities introduced into the condenser tubes.
A microbiological induced corrosion program was established to ensure the effectiveness of the chlorination system.
Due to the unique design of the condenser, the preventative maintenance program established, and adequate water chemistry controls, the effects of leakage can be held to a minimum.
An Inservice Inspection Program for the condenser has not been implemented.
If condenser leakage is of a magnitude that a power reduction corrective action is required on a recurring basis, a program will be implemente6 to determine the cause and to es.tablish measures to prevent recurrence.
4.
PRIMARY TO SECONDARY LEAKAGE LIMITS WCGS Technical Specifications limits for primary to secondary leakage rates match the limits outlined in Standard Technical Specifications.
Administrative procedures are in place to ensure compliance.
5.
COOLANT IODINE ACTIVITY LIMIT WCGS adheres to the Standard Technical Specifications (STS) limits and surveillance requirements for coolant iodine activity.
In addition, WCGS design utilizes High Head High Pressure Safety Injection Pumps rather than Low Head High Pressure Safety Injection Pumps.
Therefore, the concern to restrict iodine limits which are 20% of the STS values is not applicable to WCGS.
As a preventative measure, however, RCP Trip Criteria has been developed and implemented as appropriate in plant emergency j
procedures.
6.
SIFETY INJECTION SIGNAL RESET The design and control logic associated with the safety injection pump suction flow path as identified in NUREG 0844 is not i
applicable to Wolf Creek design.
The Ginna station's design for High Head SI-Pump (HHSIP) suction has the pumps drawing borated water from a boric acid storage tank (BAST) first, then on low level, switching to the Refueling Water Storate Tank (RWST).
The problem occurs when the HHSIPS are aligned on the BAST and a SI reset signal is generated.
This action defeats the automatic.
switchover from BAST, due to low level, to the RWST.
- Hence, operator action is required to ensure the UHSIPs do not lose suction.
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e The Wolf Creek design does not rely on a BAST; instead the HHSIPs (the charging pumps) draw suction from the RWST.
Since there is no changeover from BAST to RWST for Wolf Creek, the problem identified at Ginna is not applicable.
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CATEGORY C-2 STEAM GENERATOR TUBE INSPECTIONS During the first inservice inspection two of the four steam generators will be inspected, as all were inspected during the preservice inspection.
The first inservice inspection will be performed after six effective full power months of operation but within twenty-four calendar months from initial criticality.
During this first inspection, 3% of the total number of tubes contained in all four steam generators are to be inspected.
The tubes inspected will include all nonplugged tubes that previously had detectable wall penetrations greater than 20%.
If a tube will not allow passage of the eddy current probe for the tube inspection, this will be recorded and an adjacent tube will be I
inspected.
During any inspection if the results are that one or more, but not more than 1% of the total tubes inspected are defective, 1.e.,
having an imperfection of such severity that it exceeds the i
plugging limit, or between 5% and 10% of the total tubes inspected are degraded tubes, additional tubes equal in number to two times the number of tubes originally inspected in the steam generator will be inspected.
Additionally, if more than 10% of the total tubes inspected are degraded tubes or more than 1% of the inspected tubes are defective all tubes in the steam generator will be inspected and each other steam generator will I
. have tube-inspections equal in number to two times the number of tubes originally inspected in the affected steam generator.
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