IR 05000250/1988023
| ML17345A453 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 09/23/1988 |
| From: | Bernhard R, Jape F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML17345A452 | List: |
| References | |
| 50-250-88-23, 50-251-88-23, NUDOCS 8810120396 | |
| Download: ML17345A453 (12) | |
Text
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dr ~ L.liv7'.. G.OnQlrh QC323 Report Nos.:
50-250/88-23 and 50-251/88-23 Licensee:
Florida Power and Light Company 9250 West Fl agl er Street Miami, FL 33102 Docket Nos.:
50-250 and 50-251 License Nos.:
DPR-31 and DPR-41 Facility Name:
Turkey Point 3 and
Inspection Conducted:
August: 15-19, 1988 Inspector:-
R. Bernhard Approved by:
F. Jape, Chief Test Programs Section Engineering Branch Division of Reactor Safety Date Signed Date Signed SUMMARY Scope:
This routine, announced inspectio n was conducted in the areas of the Intake Cooling Water ( ICW) and Component Cooling Water (CCW) systems.
The systems were evaluated with respect to their design functions.
Interviews were conducted with the system engineer, a general system walkdown was performed of accessible components, operations and maintenance procedures reviewed, and the history of the systems problems reviewed.
Discussions were held to determine future plans to insure system operability.
Results:
In the areas inspected, violations or deviations were not identified.
Due to the nature of past problems',
the licensee has implemented a
program of heat exchanger efficiency testing for the CCW heat exchangers for operability verification.
The testing and evaluation program for this purpose is well developed.
The amount for margin to the system design limits is low enough that frequent cleaning of the CCW heat exchangers is required.
A final solution to the frequent cleaning is not yet ready for implementation.
A review of the Justification for Continued Operations (JCO)
the plant is operating under revealed some weaknesses.
The basis for the JCO was flow testing performed in 1985 and 1986 on the ICW pumps, instead of design flows specified by the FSAR.
No allowance was made for pump degradation, and pump testing performed to meet ASME Section XI requirements was not used to determine if degradation was taking place.
This issue is an unresolved item, as data to determine pump performance since the plant started operating under the JCO was not PaR O~9>><<~~8 88) pg ~
ADQcp pc~Qapgs PNU
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available in a
form that could be evaluated during the inspection (reference Paragraph 4.0).
Plant performance for the area inspected would be rated average.
management commitment to assuring quality results seems high, but enough time has not elapsed since the arrival of the new management team io determine if the commi tment will be converted into programs solvi'ng the root causes of the ICW and CCW issues at Turkey Point.
Response to NRC initiatives was good in the areas inspecte *$$$
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REPORT DETAILS Persons Contacted License Employees
"J.
W. Anderson, Supervisor, Quality Assurance/Regulatory Compliance
- W.
Bladow, Quality Assurance Superintendent
"J.
Brooks, Quality Control
"J.
E. Cross, Plant Manager
"D.
Hasse, SEG Chairman
- S.
Hale, Engineering Manager
"R.
Hart, Acting Regulation and Compliance Supervisor
"D.
W. Jones, Technical Supervisor
"E.
Lyons, Compliance Engineering
"R.
G.
Mende, Operation Supervisor
- J.
S.
Odom, Jr., Site Vice President Other licensee employees contacted during this inspection included engineers, operators, mechanics, security force members, and administrative personnel.
NRC Resident Inspectors
"R. Butcher, Senior Resident Inspector
"G. Schnebli, Resident Inspector T. McElhinney, Resident Inspector
"Attended exit interview System Description The heat removal systems for safety-related components at Turkey Point are the CCW and ICW systems.
The CCW system is a closed cycle system with chemical corrosion inhibitors added to the water.
Heat is transferred from the loads into CCW through each system's neat exchangers and then to ICW through the CCW heat exchangers.
ICW uses a large cooling reservoir as a heat sink.
The system takes it suction from the reservoir through the plant's intake canals Traveling screens prevent debris from the canal from entering the pumps.
The three pumps are driven from busses with emergency 'ower available during loss of normal power.
The pumps discharge into a
common header which discharges into two system headers.
Isolation valves are available to isolate the two headers from each other.
The major system loads are the two Turbine Plant Cooling Water (TPCW) heat exchangers and the three CCW heat exchangers.
The CCW heat exchangers have a
common discharge.
The water discharges to the plant discharge canal which returns to the reservoi > 'LE t ~
The CCW system is composed of three CCW pumps, three CCW heat exchangers, a
head tank, and the heat exchangers servicing the loads.
There are two separate trains, each servicing a different division of safety related loads and nonsafeiy-related loads.
The safety-related loads include the Residual Heat Removal (RHR) heat exchangers, the Containment Spray and Safety Injection pumps bearings and seals, and the Containment Coolers.
Review of Past Programs The plant was originally designed to have an open cooling system for ICW and Circulating Water.
The reservoir was constructed as a result of a
court order.
The reservoir has been extensively studied.
Makeup water is provided via infiltration from the surrounding water table.
Salt and calcium carbonate concentrations are stable.
The reservoir is built on prorous limestone, which is composed of calcium carbonate.
The canal levels of calcium carbonate stay near saturation.
Temperature of the reservoir is affected by outside temperature, solar radiation absorption, and with a
hour delay, station output.
Reductions in station electrical-output would not effect water temperature in the intake canal for almost two days.
The details on the reservoir, its thermal cycle, salinity and calcium carbonate concentrations are all included in studies performed for the licensee in the 1970s.
Calcium carbonate deposition problems were impacting main condenser performance.
One major report (reference d.{1))
discussed various control methods to improve thermal efficiency of the condensers.
The problem closely parallels the current findings with the CCW heat exchangers.
The solutions evaluated included chemical addition to inhibit formation of the calcium carbonate scale, and mechanical removal using hydrolaysing or CONCO scrapers.
All of these methods are currently used or under consideration for the CCW heat exchangers.
Amertap cleaning was als'o discussed.
Amertap has been installed on the CCW heat exchangers.
The report indicates that-mechanical cleaning can miss carbonate scale that has formed in the pits in the tube walls.
Buiidup of scale in the pits leads to local corrosion cells and a decrease in cleaning efficiency.
At the time of this inspection, there were indications that the effectiveness of CONCO scrapers was decreasing.
Past studies performed for the condensers considered the process of degradation of performance and possible solutions to calcium carbonate deposition.
The lessons learned can be applied to CCW heat exchangers.
Review of the Current Program The inspector reviewed the documents listed in Paragraph 5.
In addition, the accessible components of ICW and CCW were walked down to determine system configuration and general condition of component ~
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f p IO
The inspector observed many local instruments in need of repair or calibration.
These instruments did not perform safety functions, but could supply operators with indication of component perfoma'nce.
Notable amoung these instruments were the local temperature gauges for ICW and CCW.
The system engineer indicated current plans called for removal of many of the instruments in lieu of their repair.
Locally installed instrumentation can provide indications of potential problems if adequately maintained.
Potential benefits o<
this instrumentation should be considered prior to deciding removal is the best course of action.
The operating CCW pump had noises resembling cavitation noise coming from the bowl.
The system engineer indicated a
records review performed prior to the inspection indicated the noises were noted during startup of the plant and had not effected system operations over the years since tnen.
The inspector verified positive pressures were indicated at the pump suction.
A later walkdown of the system head tank showed instrumentation was available to monitor tank level, insuring system pressure would be main-tained.
The condition of the observed major equipment was good.
The resident inspectors had conducted system walkdowns earlier.
Their results are documented in Inspection Reports 87-51 (CCW) and 88-07 (ICW).
The procedures for testing the CCW heat exchanges were reviewed.
The procedure is detailed and well written.
Computer routines used for calculation of results are verified prior to their use.
Sensitivity studies conducted during the inspection by the licensee indicate the technique of using a single portable temperature measurement device for all temperatures acts.
to control the variable which could cause the greatest uncertainty in the calculations.
The calculations are much more sensitive to errors in temperature differences between the inlet and outlet to the heat exchangers tnan they are to flows. Allowances are made for tube plugging.
The procedure and evaluation techniques determine if the total heat removal capacity extrapolated to accident conditions is satisfactory and predict how long until cleaning is required.
Data is trended to insure conservatism of assumptions.
The inspector was not able to observe efficiency testing during the inspection, but did observe cleaning with CONCO scrapers.
The JCO for CCW was reviewed to insure all assumptions.
made were valid.
Two weaknesses were noted.
The JCO calculated an allowable response time for operator action for isolating ICW flow to the Turbine Plant Cooling Heat exchangers of five minutes.
The calculations assumed a
CCW temperature of 90'F.
Actual CCW temperatures during the inspection were about 102'F.
The action time for operations to respond would be almost halved.
This will need to be reevaluated.
The plant had shown it could isolate the flow in one minu.e.
.Another weakness was that the pump performance assumed in the JCO was one obtained through testing of actual pump performance, with no stated degrada-tion.
Linkage between the JCO and tests of the pumps for ASME Section XI was not made.
The inspector asked for an evaluation of system operability
based upon the actual pump performance versus that.assumed in the JCO for all times since the JCO was in effect.
The evaluation was not available by the end of the inspection.
An Unresolved item (URI) 88-23-01, ICW Pump Flow Adequacy Determination, will be opened to track. this matter.
The FSAR states an ICW pump performance requirement that is higher than obtained by the curr'ent system pumps.
The pumps, when newly rebuilt, are marginally above the requirements in the FSAR.
The JCO assumed lower performance than that in the FSAR and shows adequate heat removal can be obtained, but the design basis document and FSAR should reflect minimum performance standards.
The inspector reviewed the Continuous Tube Cleaning Sys em Test plan and visited the TAPROGGE tester used to simulate CCW heat, exchangers.
Test rigs for chemical treatment were also examined.
The final result of the studies are expected in December of 1988.
The system engineer said that CCW heat exchanger replacement is planned.
First, the exchangers will be replaced with new units identical to the current exchangers to improve performance with smoother tube surfaces.
Later, newly designed larger heat exchangers will be installed as a more permanent solution.
Other initiatives at the site included a vertical slice audit being performed by the gA group on ICW. This audit is similar to an NRC Safety System Junctional Inspection.
Interviews with the team members revealed the audit to be an indepth look at all aspects of the system, from design through operations.
Results of the audit will be available to utilities management soon.
The inspector reviewed plant operating procedures.
Current procedures (OP-019) limit iCW pump operations to greater than 3200 gpm.
Typical values for similar pumps at other sites are 70io'f the maximum efficiency point or about 10,000 gpm for pumps of thi s size.
Current system design would make it diffi'cult to operate pumps at these flows, but the procedure caution should be evaluated for accuracy.
One ICW weakness observed was that with current configuration and operating practices, the system strainers are susceptible to simultaneous fouling from grasses in the iptake water.
This potential common mode failure should be analysed to determine if ways can be found to prevent or minimize the effects of the fouling.
ICW pumps perfor'mance may be adequate, but fouled strainers could reduce system flows to unacceptable levels.
References a.
UFSAR, Revision 5, 7/87 (1)
Section 6.2,. Safety Injection System (2)
Section 6.3, Emergency Containment Cooling and Filtering system
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b.
(3)
Section 6.4, Containment Spray System (4)
Secti.on 9.3, Auxiliary Coolant Systems
~
(5)
Section 9.6, Facili'ty Systems Design Basis Documents (1)
Intake Cooling Mater System, 5610-019-DB-001, Revision E
(2)
Cooling Water System, 5610-030-DB-001, Revision D
(3)
Residual Heat Removal System, 5610-050-DB-001, Revision E
(4)
Emergency Containment Coolers, 5610-055-DB-001, Revision E
(5)
Containment Sunray System, 5610-.068-DB-001, Revision E
Procedures (1)
Component Cooling Water System, 3-0P-030, 5/31/88 (2) Intake Cooling Water System, 3-0P-019, 6/30/88 (3)
Component Cooling Water System, Periodic Tes of Pumps, OP-3104. 1, 7/11/88 (4)
Intake Cooling Water Pump Inservice Test 3-OSP-029. 1, 12/22/87 (5)
Component Cooling Water Heat Exchangers Performance Test, 3-0SP-030.4, 6/23/88 (6)
Component Cooling Water Heat Exchangers Performance Monitoring, TP-440, 7/29/88 (7)
Intake Cooling Water System Flow Test - Unit 3, Special Test 86-04, 3/8/86 (8)
Intake Cooling Water System Flow Test, Special Test 86-15, 4/28/86 (9)
Component Cooling Water System, Residual Heat Removal Heat Exchanger Throttling Valve Adjustment Test, Test 86-05 Other Documents ( 1)
Calcium Carbonate Scaling in the Condenser of the Turkey Point Plant, Ray L. Lyerly and Associates, February, 1978 (2)
Compo'nent Cooling Mater System Flow Balancing Safety Assessment Submittal, 7/20/86 (3)
Justification for Continued Operation for ICM System Design, Turkey Point 3 and 4, JPE-LR-87-45, Revision 1, 12/15/87 (4)
Continuous Tube Cleaning (CTC)
System Test Plan, Revision 0,
7/18/88 6.
Exit Interview
The inspection scope and results were summarized on August 19, 1988, with those persons indicated in Paragraph 1.
The inspector described the areas inspected and di scussed in'etail the the inspection results listed below.
Although reviewed during this inspection, proprietary information is not contained in this report.
Dissenting comments were no received from the licensee.'RI 88-23-01, ICW Pump Flow Adequacy Determination (Reference Paeagraph 4.0)