IR 05000327/1993020
| ML20045H908 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/06/1993 |
| From: | Blake J, Coley J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20045H901 | List: |
| References | |
| 50-327-93-20, 50-328-93-20, NUDOCS 9307220102 | |
| Download: ML20045H908 (9) | |
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UNITED STATES o
NUCLEAR REGULATORY COMMissl0N
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HEGION H
j 101 MARIETTA STREET, N.W.
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AT LANTA, GEORGI A 30323
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Report Nos.:
50-327/93-20 and 50-328/93-20 Licensee:
Tennessee Valley Authority -
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6N 38A Lookout Place 1101 Market Street Chattanooga, Tn, 37402-2801 Docket Nos.:
50-327 and 50-328 License Nos.: DPR-77 and DPR-79
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Facility Name:
Sequoyah 1 and 2 Inspection Conducted: June 7 - 11, 1993 Inspector: k.,c7.
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" 3K L. Coley, J R g \\\\
' Date Signed Approved By:
M J
J. Blake, Chief Date Signed aterials and Processes Section Engineering Branch Division of Reactor Safety
SUMMARY
Scope:
This routine announced inspection was conducted on site to review the licensee's monitoring programs for detection and prevention of degradation caused by microbiological 1y induced corrosion (MIC), erosion due to cavitation, sediment, and macroscopic biological fouling organisms such as blue mussels, American oysters, and Asiatic clams in raw cooling water systems.
.i Results:
In the areas inspected, no violation or deviation was identified. As a result
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of recent problems with erosion corrosion on high pressure systems, the licensee had established a task group in March, 1993, to review the low pressure raw cooling water systems and to verify by inspection, the integrity of this piping prior to startup of both Units. The inspector reviewed the programs and preventive measures in place, to determine whether the methods
used to verify system integrity and the logic used for selection of inspection points would in fact achieve the goals set by the licenree. Two weaknesses were identified by the inspector and subsequently corrected by the licensee.
They consisted of: (1) Failure of the licensee to have operations personnel 9307220102 930707?
PDR ADOCK 05000327 G
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review the inspection population to ensure that essential and/or non-isolable piping and components would be bounded by the sample selected; (2) With the exception of the containment penetrations, no essential raw cooling water piping or components were selected for verification of degradation in the containment building. To correct the concerns addressed by the inspector, system engineers for the fire protection and essential. raw cooling water systems subsequently reviewed the population to be examined and 12 additional sites were selected for inspection.
During radiographic inspections performed by the licensee, extensive MIC was-discovered in several welds in the stainless steel portion of the essential raw cooling water system. The licensee was evaluating these welds and expanding the inspection population in order to identify other areas of MIC degradation in this system.
These inspections have the potential to impact Unit 2 startup.
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REPORT DETAILS
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1.
Persons Contacted
Licensee Employees
- J. Baumstark, Operations Manager L
- M. Cooper, Restart Manager
- R. Driscoll, Site Quality Manager
- R. Fenech, Vice President, Sequoyah
- C. Fulwider, Site Engineering
- J. Hamilton, Technical Programs and Performance
- K. Meade, Licensing Engineer
- G. Pitzl, Corporate Engineer
- J. Proffitt, Compliance Engineer
- M. Skarzinski, Technical Programs and Performance
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- R. Thompson, Compliance Licensing Manager
- T-. Ward, Engineering and Modifications Manager
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Other licensee and contractor employees contacted during this inspection included engineers, quality assurance, and administrative personnel.
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NRC Employees
- W. Holland, Senior Resident Inspector
- A. Long, Resident Inspector
- S. Shaeffer, Resident Inspector
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- Attended Exit Interview Acronyms and initialisms used throughout this report are listed in the last paragraph.
2.
Review of Licensee Programs for Detection and Prevention of Cavitation Erosion, Microbiologically Induced Corrosion, Sediment Buildup, and Macroscopic Biological Fouling Organisms (such as blue mussels, American oysters, and Asiatic clams) in Raw Cooling Water Systems Units 1 and 2
(49001)
As a result of questions raised by an NRC inspector about seven licensee identified leaks in the fire protection system piping during a preceding inspection (Region II Report Nos. 50-327,328/93-18). The integrity of all raw cooling water system piping including the fire protection system was examined during this inspection.
Upon arriving at the Sequoyah facility the inspector discovered that on March f,1993, the licensee had similar questions regarding these systems and had established a corporate led task group to review the low pressut e raw cooling water systems and to verify by inspection the integrity of this piping before start up on either unit. At the present time the task group is focusing their inspection efforts on Unit 2 and
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piping common to both units. The concern systems included the essential raw cooling water (ERCW), the raw cooling water (RCW), the condenser cooling water (CCW), and the high pressure fire protection (HPFP)
systems.
The following documents and drawings were reviewed by the inspector
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during the assessment of the licensee's programs-
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Procedure Identifier Document Title and/or Subject
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Not Applicable Service Water Corrosion Task Force Project Instruction
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Not Applicable Service Water, Borated Water, and Protective Coatings Suitability
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Assessment For Restart Project Plan
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Technical Instruction Nondestructive Testing of Stainless
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TI-109 Steel Butt-welds to Assess Damage Resulting From Microbiological 1y -
Induced Corrosion (MIC)
Civil Design Standard Structural Evaluation of DS-CI.2.8 Microbiologically Influenced Corrosion Degradation in Piping Civil Design Standard Structural Evaluation of Single DS-C].2.5 Phase Erosion-Corrosion Thinning
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in Piping SQNP-CI-93.02 Application of Design Criteria and Design Standards For The Evaluation of Pipe Wall Degradation Periodic Instruction Essential Raw Cooling Water-(ERCW)
0-PI-DXX-000-704.A and Component Cooling Water (CCS)
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Semi-annual Degradation Monitoring Program-Train A i
Periodic Instruction Essential Raw Cooling Water (ERCW)
0-PI-DXX-000-704.2 and Component Cooling Water (CCS)
Annual Degradation Monitoring Program - Train B Periodic Instruction Essential Raw Cooling Water (ERCW)
0-PI-DXX-000-704.B and Component Cooling Water (CCS)
Semi-Annual Degradation Monitoring Program-Train B l
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Continuation of Documents Reviewed Periodic Instruction Essential Raw Cooling Water (ERCW)
0-PI-DXX-000-704.1 and Component Cooling Water (CCS)
Annual Degradation Monitoring Program-Train A
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SQNP-PM-2223 Visual Inspection of Designated -
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SQNP-PM-2222 Visual Inspection of Designated Welds
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SQNP-PM-2241-Visual Inspection of Designated Welds
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SQNP-PM-3083 Monthly Walkdowns of Identified Leakers in ERCW Stainless Steel
Butt-welded Piping SQNP-PM-3082 Monthly Walkdowns of Identified
Leakers in ERCW Stainless Steel Butt-welded Piping SQNP-PM-2221 Visual Inspection of Designated i
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SQNP-SI-566 Flow Verification Test of ERCW
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System 0-SI-SFT-026-002.0 Auxiliary Building Fire Protection
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System Hydraulic Performance Verification Not Applicable TVA's Responses Dtd.
January 26, 1990, October 24, 1990 and July 29,1992 to Generic letter 89-13," Service Water Problems Affecting Safety-Related Equipment"
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Drawinas Reviewed CCD NO: 2-47W845-3 Flow Diagram for ERCW CCD N0: 1-47W845-3 Flow Diagram'for ERCW CCD N0: 1,2-47W845-2 Flow Diagram for ERCW
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CCD NO: 1,2-47W845-2 Flow Diagram for ERCW CCD NO: 1,2-47W845-5 Flow Diagram for ERCW CCD N0: 1,2-47W845-6 Fla, Diagram for ERCW CCD N0: 1,2-47W850-1 Flow Diagram for HPFP & RCW CCD N0: 1,2-47W850-2 Flow Diagram for HPFP & RCW
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CCD NO: 1,2-47W850-7 Flow Diagram for Fire Protection-CCD NO: 1,2-47W850-9 Flow Diagram for Fire Protection I
CCD NO: 1,2-47W850-18 Flow Diagram for HPFP CCD NO: 1,2-47W844-1 Flow Diagram for RCW
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CCD N0: 1,2-47W844-2 Flow Diagram for RCW CCD N0: 1,2-47W844-3 Flow Diagram for RCW CCD NO: 1,2-47W844-4 Flow Diagram for RCW CCD NO: 1,2-47W832-1 Flow Diagram for RCW & Fire Protection Systems CCD NO: 1,2-47W857-1 Flow Diagram for Cont'enser Tube
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Cleaning System CCD NO: 1,2-47W850-10 Flow Diagram for Fire Protection CCD N0: 1,2-47W850-6 Flow Diagram for Fire Protection Procedures Not Reviewed But Existence Verified SQNP-SI-234 Operability Test of Deluge Valves SQNP-SI-171 Chemical Flush of Raw Cooling Water Systems
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As a result of the above reviews; walkdowns and reviews of the systems inspection population; and discussions held with Quality Assurance, Nuclear Engineering, Design Engineering, the Corrosion Task Group, and System Engineers, the inspector concluded that, for startup, the operational condition of these raw cooling water systems can be assured.
To maintain this level of confidence, the task group leader stated that, the existing inspection program will be supplemented with inspection sites to be monitored on each raw cooling water system (only the essential raw cooling water system was examined previously) based on the data obtained during the enhanced baseline inspections being presently conducted by the corporate task group.
During the inspector's audit of the inspection population, two
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weaknesses were identified by the inspector to the task group. They consisted of the following: (1) Failure of the task group to have operations / system engineers review the inspection population to ensure that piping essential for operation had been bounded by the inspection population selected; (2) A review of the ERCW inspection population revealed that with the exception of the containment penetrations no _ERCW piping had been selected for inspection in the containment building. To address this concern system engineers for the fire protection and essential raw cooling water systems identified piping that was essential for plant operation.
From this select sample the task group determined that an additional 12 inspection sites would be required to ensure the integrity of this piping.
In addition to the examinations conducted by the corporate task group or those already being performed on the ERCW system, the licensee had the following methods in place to prevent system degradation from biofouling, <adiment buildup, and MIC.
Continuous injection of a biocide into SQN's ERCW supply piping
(however injection pumps have only been reliable 70% of the time).
A program has been developed to perform periodic inspections (18-
month frequency) of the ERCW intake structure for biological fouling mechanisms, sediment, and corrosion.
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The HPFP and the RCW piping are treated and flushed with
hypochlorite bi-annually.
Flow verification tests are performed annually on the HPFP and
ERCW systems.
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An annual flow verification test procedure for the RCW system has
been written and is scheduled to be performed during the week of June 14-18, 1993.
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Preventive maintenance, operability test on HPFP Deluge Valves
(performed every 18 months), strainer inspections of HPFP systems (performed every 12 months), and weekly walkdowns by system engineers of portions of their systems.
PCN No. 607 is currently in progress to change the high pressure
fire protection system from a raw water system, to a closed, treated water system. A prerequisite to making the system a treated water system, is to address the existing MIC problems in the system.
This PCN is in the early stages of design, the DCN is currently scheduled for completion in July of 1994 and construction work is scheduled to-complete on September 30, 1995.
In summary, ultrasonic.and visual inspections on Unit 2 piping and piping common to both Units are nearing completion. However, radiographic examinations of 20 ERCW welds has discovered extensive MIC in several stainless steel welds. The licensee is planning to expand their ERCW population to included approximately 20'more radiographic inspection sites.
The licensee is also removing the weld with the most extensive MIC for metallurgical analysis. Metallurgical examination and results from expansion inspections may impact Unit 2 restart.
MIC is also occurring in carbon steel; however, structural integrity has been demonstrated in the areas examined.
Examinations conducted by the licensee has also discovered that MIC is prevalent within the first several feet of piping dead legs off flowing headers in carbon steel, in lieu of further down the low flow piping as first thought. This is apparently due to the nutrients provided in the water from the higher velocity header piping flow.
However, most of this piping would be non-isolable from the header if failure occurred.
In addition to MIC, cavitation problems are being identified and dispositioned by plant personnel.
Within the areas examined, no violation or deviation was identified.
3.
Exit Interview The inspection scope and results were summarized on June 11, 1993, with those persons indicated in paragraph 1.
The inspector described the areas inspected and discussed in detail the inspection results.
Proprietary information is not contained in this report.
Dissenting comments were not received from the licensee.
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Acronyms and Initialisms
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Component Cooling Water CCS
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Condenser Cooling Water DCN Design Change Notice
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DS Design Standard
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Date ERCW -
Essential Raw Cooling Water
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HPFD High Pressure Fire Protection
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MIC Microbiologically Induced Corrosion
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Numbers NRC
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Nuclear Regulatory Commission PCN
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Preliminary Change Notice PI
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Periodic Instruction PM
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Preventive Maintenance RCW
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_ Raw Cooling Water
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Surveillance Instruction SI
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SQNP -
Sequoyah Nuclear Plant TI
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Technical Instruction TVA
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Tennessee Valley Authority
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