ML18052A275
| ML18052A275 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/29/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18052A274 | List: |
| References | |
| NUDOCS 8602070003 | |
| Download: ML18052A275 (4) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF FROM PERFORMING HYDROSTATIC TESTS INTRODUCTION FOR CLASS 2 SYSTEMS AT 1985-86 OUTAGE CONSUMERS POWER COMPANY PALISADES PLANT DOCKET No. so-255 Paragraph 10 CFR 50.55a(g)(4) requires that throughout the service life of a pressurized water-cooled nuclear power facility, components (including supports) which are classified as ASME Class 1, Class 2 and Class 3 shall meet the requirements set forth in the applicable Section XI Editions and Addenda of the ASME Boiler and Pressure Vessel Code to*the extent practical within the limitations of design, geometry and materials of construction of the components.
In a letter dated November 1, 1985, the Consumers Power Company (CPCo, the 1 icensee) requested relief from performing the Code hydrostatic testing of Class 2 systems at the 1985-86 outage after ten years of plant operation and also after the anticipated repair or replacement of main steam and feedwater systems which are unisolable from the secondary side at the steam generator up to and including the containment isolation valves.
The ten-year hydrostatic test should have been conducted on these systems in 1983, but due to an error in Code interpretation, no hydrostatic tests were performed. A licensee representative, Mr. Thomas Bordine, described the misinterpretation of the requirements in a telephone call as follows:
In accordance with a revision to 10 CFR 50.55a, the licensee's inservice inspection program was revised to incorporate the requirements of the 1977 edition of the ASME Section XI of the code which included requirements for Class 2 systems, such as main steam and feedwater.
Previously, the program did not include Class 2 systems.
The licensee then erroneously computed a 10 year interval for inspection scheduling purposes based on 1977 as the colTftTlencing date for the inspection requirement. However, the regulation requires the 10 year interval to commence at the start of commercial operation, December 31, 1971 in the case of Palisades. With the appropriate contingency allowances for outages, as permitted by the code, the latest refueling outage at which this should have required completion was the 1983 refueling outage.
The licensee's program indicated 1987, 10 years from the date of the requirement.
As a result of this error being found while preparing for the 1985 refueling outage, it was determined that the only tests that could not be completed were the main steam and feedwater systems.
The licensee has reviewed and revised as necessary their inservice inspection program to correct the schedules to prevent reoccurrence of this problem.
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,,.. ' Since this noncompliance was discovered shortly before the current outage, it is considere*d impractical to perform the required test at this outage because of extensive preparation and developmental work required.
- However, the licensee has proposed, in lieu of the required test, to perform the system leakgage test at a pressure higher than the system operating pressure but less than the required Code pressure at this outage.
Further, the licensee has also committed to perform the Code-required hydrostatic test on these systems at the next scheduled outage.
The licensee has requested written relief from the testing requirement that he has determined to be impractical in accordance with paragraph 10 CFR 50.55a (g)(5){iii). The staff has evaluated the information in the referenced letter and has determined that the testing requirement, from which relief is requested, is impractical as discussed in the following paragraphs.
RELIEF REQUESTED The licensee is requesting relief from performing the Code-required hydrostatic test of main steam and feedwater systems (includes secondary side of steam generators) after ten years of plant operation and also after the anticipated repairs and replacement of main steam and feedwater systems at the 1985-86 outage.
The applicable Code isSection XI, 1977 Edition including Addenda through Summer 1978.
CODE REQUIREMENT A hydrostatic test shall be conducted at or near the end of each inspection interval and also subsequent to repairs or modifications by welding which penetrate the pressure boundary on piping.Section XI of the ASME Code requires, in Article IWC-5000, a system hydrostatic test pressure of at least 1.10 times the system pressure Psv for systems with design temperature of 200°F or less, and at least 1.25 times the system pressure P for systems with design temperature.above 200°F. The system pressure P svshall be the lowest pressure setting among the number of safety or reliefs~alves provided for overpressure protection within the boundary of the system to be.tested.
LICENSEE'S BASIS FOR REQUESTING RELIEF It has been discovered that, due to an apparent difference in Code interpretation, no hydrostatic test was performed on the main steam and feedwater systems during the first inspection interval which ended in 1983.
A system leak test at a pressure of approximately 860 psig was performed which was more conservative than the operating pressure of 700 psig required by Section XI.
Since the Code noncompliance was only recently discovered, and in view of the current refueling outage scheduled from November 30, 1985 to February 1, 1986, and the necessary preparations, it is considered highly impractical to perform the required test this outage.
In addition, the following items are submitted regarding the impracticality of performing the test this outage:
- 1.
Currently, no prc>'cedure exists to perform the test. This would have to be drafted, reviewed and approved for use.
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- 3.
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- Main-ste-am system hangers must be pinned and block:ed to allow the piping system to be water solid.
As part of this effort, hanger settings must be recorded to allow return to normal after testing. Procedure must be drafted, reviewed and approved to accomplish this work.
Scaffolding would have to be erected to pin hangers and record settings.
Preplanning for materials or budget must be developed for this activity.
- 4.
Overpres~ure protection must be properly addressed.
Relief valves must be calibrated and installed.
- 5.
Proper valve lineups and routing of discharge and drain piping must be addressed (see #1).
- 6.
Test would require approximately 50,000 gallons of condensate quality water.
- 7.
Main steam relief valves must be removed or gagged.
CPCo currently owns only one gag and a total of 24 are required *. Removing and reinstallation of valves would require approximately 100 man-hours per valve.
- 8.
Repair work on main steam isolation valves (MSIV) will not be complete until mid January.
Hydro cannot take place prior to MSIV,completion.
- 9.
Integrated leak rate testing (ILRT) is scheduled at the end of the outage.
No work will be allowed in containment during that time.
This will be impacted by the hydro if performed.
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Maintenance work may have unisolable portions of system open.
Detailed review of maintenance work is required.
-11. System instrumentation must be evaluated regarding capability to withstand hydro pressure and isolated or removed as applicable.
12 *. Based on above considerations, sufficient time does not exist to evaluate all facets of performing the required test.
- 13.
Budget does not exist to support required action items and manpower requirements to perform the test this outage.
The alternate examination proposed below coupled with previous augmented nondestructive examinations (100% volumetric examination of all welds in main steam and feedwater penetration rooms each 3-1/3-year period and weekly visual inspection) plus routine inservice-inspection examinations, conducted over the first inspection interval, provide a reasonable level of quality and safety equal to or greater than that of the ten-year hydrostatic test.
ALTERNATE EXAMINATION Consumers Power Company will perform a system leak test during the 1985-86 refueling outage at the increased pressure as previously performed (plant in hot standby with systems pressurized to containment isolation valves).
- e. STAFF* EVALUATION AND CONCLUSION
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~o comply with the Code hydrostatic test pressure requirements would entail flooding the steam generators, main steamline and feedwater line, gagging safety and relief valves, providing additional support for the main steamline, and pressurizing the main steam and feedwater systems to 1.25 times the system service pressure.
To ensure that the first Code hydrostatic can be conducted effectively without damaging the structural integrity of systems involved, it would require months of procedural development and preparatory work.
- Besides, the licensee has proposed to perform the system leak test at the 1985-86 outage in lieu of hydrostatic test at a pressure of approximately 860 psig which is lower than the Code-required 1231 psig but higher than the secondary side operating pressure of approximately 700 psig.
In addition, the licensee has committed to perfonn the Code-required hydrostatic test at the next refueling outage. Considering the hardships that the 1 icensee would encounter in implementing the Code requirements at this outage versus the assurance of the systems' structural integrity provided by the licensee's alternate examination and test, augmented and routine inservice inspections, and systems leak tests perfonned during the first ten-year interval, the staff finds the Code require-ments impractical to perform and that imposition of the required test at this outage would not provide a commensurate increase in the plant safety.
The staff, therefore, concludes that relief from the Code requirements may be granted.
Further, the staff requires that the Code hydrostatic test of the main steam and feedwater systems for the first ten-year be perfonned at the next scheduled outage and for the second ten year be conducted at or near the end of the inspection interval, i.e., 1993.
Principal Contributor:
C. Y. Cheng Date:* January 29, 1986