IR 05000302/1987008
| ML20205N387 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 03/23/1987 |
| From: | Kahle J, Ross W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20205N354 | List: |
| References | |
| 50-302-87-08, 50-302-87-8, NUDOCS 8704030015 | |
| Download: ML20205N387 (11) | |
Text
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UNITED STATES
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'o NUCLEAR REGULATORY COMMISSION
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ATLANTA, GEORCI A 30323
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Report No.: 50-302/87-08 Licensee: Florida Power Corporation 3201 34th Street, South St. Petersburg, FL 33733 Docket No.: 50-302
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License No.: DPR-72 Facility Name: Crystal: River 3 Inspection Conducted: March 2-6,;1987 Inspect :
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Date Signed
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Approved by:
b. bib [6dNr 3/17/27 J. 8.,K le, Section Chief Date Signed Divis of Radiation Safety and Safeguards 4.
SUMMARY Scope:
This special unannounced inspection involved plant water chemistry and protection of the primary and secondary coolant systems from corrosion.
Results: No violations or deviations were identified.
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8704030015 870323 PDH ADOCK 05000302 G
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REPORT DETAILS 1.
Persons Contacted Licensee Employees
- B. J. Hickle, Manager Nuclear Plant Operations
- S. L. Robinson, Acting Superintendent, Nuclear Chemistry and Radiological Protection
- J. L. Roberts, Nuclear Chemistry Manager J. Cooper, Nuclear Technical Support Superintendent B. Crane, Engineer, Plant Enginaaring R. Fuller, Environmental Enc'
, Steam Generator Task Force J. Holton, Engineer, Inservice Inspection Engineering D. Jones, Nuclear Shift Supervisor W. Neuman, Engineer, Inservice inspection Engineering J. Payne, Nuclear Chemistry Supervisor
- R Pinner, Nuclear Chemistry Supervisor K. Staton, Nuclear Chemistry Training Coordinator D. Worley, Nuclear Chemist, Steam Generator Task Force NRC Resident Inspector
- T. Stetka
- Attended exit interview 2.
Exit Interview The inspection scope and findings were summarized on March 6, 1987, with those persons indicated in Paragraph 1 above. The inspector described the areas inspected and summarized the results.
No dissenting comments were received from the licensee.
The licensee did not identify as proprietary any of the material provided to or reviewed by the inspector during this inspection.
3.
Licensee Action on Previous Enforcement Matters j
This subject was not addressed in the inspection.
4.
Plant Chemistry (79701)
As a result of its continuing concern for steam generator integrity, the NRC staff has issued recommended actions and review guidelines that are directed toward the resolution of unresolved safety issues regarding this subject (see Generic Letter 85-02 dated April '17,1985),
One of the recommended actions relates to the control of secondary water chemistry and is stated as follows:
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" Licensees and applicants should have a secondary water chemistry program i
(SWCP) to minimize steam generator tube degradation.
The specific plant program should incorporate the secondary water chemistry guidelines in the Steam Generator Owners Group (SG0G) and Electric Power Research Institute (EPRI) Special Report EPRI-NP-2704, "PWR Secondary Water Chemistry Guidelines," October 1982, and should address measures taken to minimize steam _ generator corrosion, including materials selection, chemistry limits, and control methods.
In addition, the specific plan procedures should include progressively more stringent corrective actions for out-of-specification water chemistry conditions. These corrective actions should include power reductions and shutdown, as appropriate, when excessively corrosive conditions exist.
Specific functional individuals should be identified as having the responsibility / authority to interpret plant water chemistry information and initiate appropriate plant actions to adjust chemistry, as necessary.
The reference guidelir.es were prepared by.the Steam Generator Owners Group Water Chemistry Guidelines Committee and represented a consensus opinion of a significant portion of the industry.for state-of-the-art secondary water chemistry control."
Reference Section 2.5 of NUREG-0844 The licensee responded to this Generic Letter by letter dated July 9, 1985.
In parallel actions,.the NRC office of Inspection and Enforcement developed new Inspection Procedures to verify that the design of a nuclear
power plant provides long term integrity of the reactor coolant prrssure
boundary.
Also, these procedures were designed to verify a licensee's capability to control the chemistry of plant process water in a manner that minimizes corrosion and occupational radiation exposure.
The objectives of these procedures were partially fulfilled.during previous inspections (see Inspection Report Nos. 50-302/84-08 dated April 17, 1984,
-l and 50-302/85-10 dated April 4, 1985).
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The inspector-used the current inspection to update the assessments of
plant design and the licensee's water chemistry program that had been made
at the end of Fuel Cycle 4 in March 1985.
In the interim period Crystal River Unit 3 (CR-3) had been shut down for several extended periods.
Consequently, although CR-3 operated continually for approximately 150 i
days in 1986 and for approximately 40 days so far in 1987, the current Fuel Cycle 5 will extend to September 1987. During the last two years the licensee had given considerable attention to the detrimental effect on power level that had resulted from the presence of iron-copper oxide sludge in the once-through-steam-generators (OTSGs), especially in the tube / tube support plate broached openings. Also, the licensee has revised
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its water chemistry program to include the guidelines recomended by the
SG0G.
f. current assessment of the capability of the licensee to prevent
degradation of the primary and especially, the secondary coolant systems is sumarized below.
In addition to evaluating factors related to steam
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generator tube deterioration and/or failure, the' inspector gave. increased l
attention to potential for general corrosion and thinning of carbon steel
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pipe - as identified by IE Notice 86-106.
a.
Plant Design
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In its response to Generic Letter 85-02 the licensee provided brief-
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descriptions of the major components of the secondary water system i
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protection of the OTSGs from ingress of corrodants.
The response
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also ir:dicated the concern of CR-3 management over the fouling.of the
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OTSG that had caused this unit to be load limited and discussed the
steps that were being taken to (1) remove the fouling material, (2)
to reduce future carryover of contaminants, and (3) to improve the design and operation of the secondary side components to minimize further fouling.
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Through discussion with cognizant' plant personnel and through review
of pertinent documents and record; the inspector reassessed the licensca's activities related to improving the effectiveness of the
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secondary cooling system.
j The copper-nickel (70%-30%) condenser tubes.had continued to be the
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most troublesome components of the secondary water system and -the cause of frequent inleakage of saline condenser cooling water into
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the hotwell. During the last refueling outage, in 1985, all tubes in three of the four water boxes had been inspected by ultrasonic means
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and all tubes with indications of thinning in. excess of 80%
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i through-wall depth had been plugged. Also, the condenser tube sheets j
had been recoated with epoxy to prevent. leaks at tube-tube sheet
junctions. However, several tube leaks occurred during the period of June-November 1986 when the plant was operating in an otherwise
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stable condition.
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The licensee, through its Steam Generator Task Force / Secondary -
Systems Operations and Plant Review Team, had given high priority to resolving condenser tube failures.
An Amertap tube-cleaning system was installed during the 1985 refueling' outage in an effort to maintain the tube surfaces, in contact with the condenser cooling
water, free-of organic and inorganic cotrodants.
The inspector was-informed that the addition of sacrificial iron to the waterboxes of
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the condenser (either ~as cast iron screens or hyrous ferrous oxide
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film) appeared to diminish corrosive attack of both the copper-nickel tubes.as.well as carbon steel components of the intake water boxes and Amertap system.
The mechanisms associated with the pitting of
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the tubes were thought to be microbiologically influenced as well as i
to be exacerbated by the high chloride content of the condenser
coolant.
Consequently, the licensee had initiated a study of the possible advantages of retubing the condenser with a more corrosive resistant metal such as titanium.
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The licensee had also initiated an ongoing surveillance program to i
detect sources of air inleakage into the turbine / condenser.
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consequence several leaks had-been discovered and repaired, and the total air inleakage had been reduced to 16-18 cubic feet per minute (CFM).
This leak rate remained twice as high as the designed limit
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of approximately 9 CFM, and will require that the surveillance efforts be continued.
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b.
Water Makeup System i
The inspector was informed of two actions that had been taken to
increase the purity of the water used for condensate makeup'and for providing high purity water for the emergency feedwater pumps.
Because of the relatively high concentration of dissolved oxygen in the water stored in the condensate storage tank (CST), the licensee continued to add Amerzone (hydrazine) to this water so as to auoment
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the degas capability of the condenser and condensate deaerator. The
oxygen content of the makeup water; was ' thereby reduced to l
approximately 10 ppb.
Because of the high content of dissolved solids in the CST water,
another tank was being constructed to provide highur quality water to the suction of the emergency feedwater pumps.
Although this system would be used only in emergencies then the main feedwater system was
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not available, the availability of a supply of high quality emergency feedwater would decrease the probability that additional solids or
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corrosive chemicals would be injected into the OTSGs.
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c.
Condensate Polishers
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The licensee was continuing to provide full-flow cleanup to the
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condensate water by means of the deep-bed demineralizers. The resin
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beds were also still being discarded when depleted in order not to
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contaminate the feedwater with regiment chemicals (e.g., sulfate and hydroxide ions).
Since the last inspection the licensee had
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increased the upper limit for controlling the pH 'of the feedwater
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from 9.2 to 9.5 in an effort to reduce the amount of iron oxide ~
sludge transported to OTSGs from' carbon steel pipes in the secondary system. This change was accomplished by increasing the concentration
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of ammonia injected into the feedwater. As a consequence, the cation
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resins in the condensate polishing system became saturated with
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aninonia more quickly, and thereby, provided le::s protection against inleakage of sodium ions from a condenser tube leak.
An audit of
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j control data obtained during 1986 revealed that, in.the absence of
condenser leaks, the polishers provided an acceptable. level of
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condensate cleanup for a considerably longer period than observed
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during previous inspections.
Again, the principal obstacle to pH
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control was the frequency with which the resin beds had to: be
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replaced because sodium leaked through the saturated cation resins whenever a condenser tube leak occurred.
d.
MoistureSeparator(MSR) Tubes
The inspector was informed that, during the next refueling outage the
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copper alloy MSR tubes.will be replaced with stainless steel tubes in an effort to reduce the amount of copper that has been transferred to-
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the OTSGs through corrosion of these tubes.
Although the inspector did not con:' der the MSR tubes to be a major source of copper in the OTSGs (the MSR drains always flow back -to the hotwell and are subsequently cleaned by the condensate polishers), the elimination of any copper-containing components in the secondary water system is considered to reduce the potential for copper influenced stress corrosion and/or pitting of alloy-600 (Inconel) OTSG tubes.
e.
OTSGs At the end of the last fuel cycle (Cycle 4) the maximum attainable
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power level of CR-3 had been 92% of licensed power because of i
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limitation on feedwater flow caused by iron-copper oxide blockage of
OTSG tube / tube support plate broached holes.
Consequently, during the refueling outage after Cycle 4 the licensee attempted to remove these blockages by means of " water slap" technique.
This technique had been successful to the extent that the maximum attainable power level had been increased to 97% of design during startup of Cycle 5.
Slightly higher levels have been attained after each extended outage in 1985 and 1986; however, the plant was operating at 97% power
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during this inspection period.
J As the result of studies by the OTSG Task Force, plans were being made to repeat the water slap procedure (as modified during the last two years) during the next refueling outage.. In addition, the OTSGs will be lanced to remove solids from the lower tube sheets and tube support plates, and, if necessary, from the uppermost tube support plates.
i Licensee representatives stated that the OTSG Task Force - was investigating the feasibility of removing sludge by chemical' methods.
the removal of " hideout return" in the presence or absence of massive
amounts of iron-copper oxide sludge on the lower tube sheet and tube support plates was also discussed with licensee representatives.
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Summary In its fifth fuel cycle CR-3 had been power limited (but to a smaller extent than in the fuel cycle) by the. presence of iron-copper oxide sludge in the branched tube / tube support plate holes.
In addition,
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an unknown amount of sludge had been observed on the lower tube sheet and lower tube support plates. This sludge had been transported from both high and low pressure carbon steel pipes as a result of general oxidation of these pipes.
The existence of sludge deposits conceals regions of the OTSGs where localized corrosion could occur (e.g.,
crevices) and where such corrosive ions as chloride and sulfate, that
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are found in " hideout return," may be concentrating.
The licensee had established a task force to address the formation, transport, and deposition of iron-copper oxides.
As the result of the feedwater pipe failure described in IE Notice 86-106 (see Section 6 of this report) increased attention was also being given to the condition of the carbon steel pipes that are the sources of the iron oxide that eventually ends up in the OTSG.
The licensee also has recognized the difficulties in water chemistry control that can and have been attributed to inleakage of saline
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condenser cooling water following condenser tube leaks. Considerable attention had been given to maintaining the integrity of condenser
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tubes, and some progress had been made inasmuch as the plant had not
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been shutdown in 1986 because of excessive inleakage of condenser cooling water -- although several tube leaks did occur.
I The licensee recognizes that continued use of copper-nickel condenser tubes increases the probability that tube leaks will continue. Also the copper tubes prevent the pH of the secondary coolant from being elevated greater than 9.5 to reduce the. corrosion of carbon steel pipes.
Therefore, the licensee is limited to a pH range of 8.9-9.5 to minimize the formation of both iron and copper oxides.
The inspe tor was informed that while studies have been made related to the replacement of the copper-nickel condenser tubes, no decision had been reached.
No violations or deviations were identified.
5.
Water Chemistry Program In its response to Generic Letter 85-02 the licensee addressed the
recommendation related to secondary water chemistry by sunnarizing the actions that were being taken to achieve acceptable levels of chemistry control.
Previous inspections showed that the licensee was committed to maintain "the best possible controls to prevent ingress of impurities into
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the OTSGs."
Since the last inspection in this area, the Chemistry and Radiation Protection Department had issued a new Compliance Procedure (CP-138, Secondary Water Chemistry Guidelines) that included the concept of a three-level protection program based on SG0G criteria.
These action levels and associated action statements were based on the increasing vulnerability to sei;ous degradation of steam generators (i.e., the primary coolant pressure boundary) as the level of specified chemical
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variables increased in various parts of the secondary coolant system. The.
limits of these parameters that were set in Procedure CP-138 and subsequently in specific chemistry procedures, were consistent with those
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recommended by the SG0G. Likewise, the actions to be taken when an action i
level was exceeded also met or exceeded those recomended by SG0G.
From discussions with supervisory personnel in both the Chemistry and Operations Departments the inspector verified that the bases and
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objectives of the SG0G criteria were understood. As discussed later, the Chemistry Department was taking actions in other parts of its chemistry program to ensure: that the higher level of chemistry control could -be i
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_ accomplished.
Members of the Operations Department had received training -
in the bases for the action levels and action statements and the relationship between Operations and Chemistry that would be required in
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the future.
Inasmuch as the actions discussed above were taken as responses to Procedure CP-138, the inspector could not establish to what extent these actions had been approved by corporate or plant management. -Likewise, in the absence ~ of written corporate or plant policy and/or directives, the
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inspector was uncertain as to the extent corporate and plant management
had endorsed the philosophical and management recommendations that were
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considered by the SG0G as being necessary to successfully implement the technical guidelines, especially the concepts of action statements and
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priority maintenance for chemistry control equipment.
The inspector j
encouraged the licensee to clarify this issue.
The SG0G Guidelines provide very stringent conditions for chemical surveillance and control.
Consequently, the inspector reassessed the i
capability of the CR-3 Chemistry Department to meet these requirements.
As summarized below, this phase of the inspection involved a review of four aspects of the chemistry program:
staffing, training, quality
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i control, and instrumentation.
a.
Staffing
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Several changes had been made in staffing the Chemistry Department l
since the last inspection:
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(1) The staff Chemist had been transferred to the OTSG Task Force.
Although this chemist continued to provide some support to the Chemistry Department, there was no longer a -degreed chemist on the chemistry staff.
(2) A third laboratory supervisor had been added to the staff to provide supervision in the areas of primary and secondary j'
chemistry as well as radiological effluents during a ten-hour back shift four days per week.
This supervisor had also been given responsibilities for the Chemistry Department's quality
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control program.
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(3) Three contract chemistry technicians had been added to the normal staff of 18 technicians and three supervisors.
These temporary personnel were needed as replacements for a Chief
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Technician who had been transferred to the Training Department on a permanent basis and another who was assisting this new Chemistry Training Coordinator on a temporary assignment.
(4) Three Chief Technicians had been assigned to support functions as assistants to the three laboratory supervisors.
After the transfer of the Staff Chemist these Chief Technicians provided the manpower needed for non-routine problems as well as performing their dedicated responsibilities.
b.
Training Approximately 50% of the chemistry technicians had been on the chemistry staff for less than three years.
Essentially all of their training, as well as the training of the more experienced technicians, had been accomplished through on-the-job training.
In 1986 the licensee developed a Nuclear Chemistry Technician Training i
Program that will require 340 hours0.00394 days <br />0.0944 hours <br />5.621693e-4 weeks <br />1.2937e-4 months <br /> of classroom / laboratory instruction over a two-year period.
In addition, 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> of instruction will be provided in subjects not directly related to chemistry.
The inspector briefly reviewed the ten areas that are to be covered and considered the scope of the courses to provide a good basis for the overall nuclear analytical chemistry training program.
In addition. the inspector was informed that the licensee hopes to initiate an agreement with local colleges to provide fonnal evening courses in curricula that would lead to an associate-degree in science, and thus, afford the chemistry technician an opportunity to expand their overall knowledge of chemistry.
c.
Quality Control The action levels that are recommended in the SG0G Guidelines have i
been based on extensive information related to corrosion of steam generator tubes and components that was collected between 1977 and 1983 by EPRI and the nuclear power industry.
The licensee has
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adopted these very low (parts per billion or ppb) limits for
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specified control and diagnostic chemistry parameters that have been established by the SG0G for protection against corrosion.
As a consequence, the chemistry control program was being upgraded to ensure the reliability and credibility of chemistry data for trace amounts of impurities in the primary and secondary coolants.
As mentioned earlier, a new laboratory supervisor had been given the responsibility for revising the chemistry quality program.
Increased i
emphasis was being placed on analyses performed by new techniques, such as ion chromatography and inline instruments.
In addition to using in-house standards for calibrations and " unknowns" the licensee had also contracted with two vendors to provide standard solutions
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for cross-checking purposes. The inspector questioned the usefulness of the vendor's standards because the-concentrations of the chemical
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j species were much higher than the concentrations normally observed.in-plant water systems.
The inspector reviewed control charts that had
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been developed during the current fuel cycle and discussed-the need for increased effort to ensure that all chemistry control data met the reliability standards required by the SG0G guideline,
d.
Instrumentation
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Through an inspection of the secondary water laboratory and
discussions with chemistry personnel, it.was apparent that the
Chemistry Department was well equipped ~ to perform the trace element i
analyses needed to diagnose and control chemistry parameters in the
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primary and secondary coolant systems.
As discussed in previous inspection reports, sample lines from key points in.the secondary j.
system have been run to the secondary chemistry laboratory. By means of "hard pipe" connections and/or a patch panel these lines have been i
a connected to inline instrumentation for such parameters as chloride, sodium, cation conductivity, pH, dissolved oxygen, and hydrazine.
The licensee had also installed two new ion chromatographs so that
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these, and other, chemical variables could be analyzed from grab
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samples or monitored continually as an inline system.
Another ion chromatograph and an atomic absorption spectrophotometer are located in the primary chemistry laboratory.
Thus, the Chemistry Department was considered to have the state-of-the-art capabilities to measure
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potentially corrosive chemical species at the concentration levels
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needed to assure that the primary coolant pressure boundary is not
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degraded.
Through its endorsement of the SG0G Guidelines the licensee was considered to have enhanced its capability to protect the OTSGs and other plant components against corrosion..
'However, effective
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implementation of the guidelines will be dependent on the support provided by corporate and plant management as well as by cooperation
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and support from all departments in-CR-3.
The licensee had taken
positive actions to upgrade the overall effectiveness of the water i
chemistry program.
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No violations or deviations were identified.
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6.
IE Information Notice 86-106:
Feedwater Line Break l
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During this inspection the inspector discussed with members of plant management and plant staff this Notice that was issued on December 16, 1986, in response to a feedwater line break at the Surry Power Station
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Unit 2.
Supplement 1 to this Notice was issued on February 13, 1987. and included additional information related to the cause of the pipe failure.
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l The licensee had responded to this Notice by forming a task force to l
investigate the potential for a similar accident at CR-3 and to take the
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necessary actions to prevent this type of accident.
The licensee's activities were being monitored by the NRC Senior Resident Inspector and an Inspector Followup Item (50-302/86-38-14) had been opened.
Because of the relevancy of this Notice to the overall subjects of corrosion and water chemistry the licensee briefed both the Senior Resident Inspector and the Regional Inspector on the progress of the short term activities of the task force, e.g., identification of likely areas for wall thinning and ultrasonic testing of these pipe areas. To date no evidence of thinning had beer found.
The licensee was also developing a long-term program for continued monitoring of selected sections of carbon steel pipes that might be vulnerable to erosion / corrosion.
In discussions with members of the OTSG Task Force the inspector stressed i
the need to better understand the role of chemistry in the thinning of carbon steel pipe in single phase (water) systems as well as in systems where the carbon steel components are in contact with steam or water-steam mixtures.
No violations or deviations were identified.
7.
Inspector Followup Item 50-301/84-08-01, Steam Generator Sludge Deposits During this inspection the inspector verified that the licensee had established and implemented procedures during the last refueling outage to remove the iron-copper oxide sludge from various locations in the OTSG.
In addition, the inspector reviewed an updated (February 20,1987) summary of activities underway through the Integrated 0TSG Integrity Program to eliminate the transport of solids to the OTSG and future plans to remove the solids that are currently in these steam generators.
The inspector also verified that the licensee had identified the composition of tha sludge in the OTSG.
This information was considered to be sufficient to closecut IFI 50-301/84-08-01.
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