ML18033A962
| ML18033A962 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/19/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18033A961 | List: |
| References | |
| NUDOCS 8909260307 | |
| Download: ML18033A962 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMlSSION WASHINGTON, D. C. 20555 ENCLOSURE SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION PROPOSED ALTERNATIVES TO THE BOILER AND PRESSURE VESSEL
- CODE, SECTION XI, "RULES FOR INSERVICE INSPECTION OF NUCI EAR POWER PLANT COMPONENTS - DIVISION 1" TENNESSEE VALLEY AUTHORITY BROWNS FERRY PLANT UNITS 1, 2
AND 3 1,0 INTRODUCTION Section 50.55a, "Codes and Standards,"
of 10 CFR Part 50 requires, in part, that certain safety-related components meet the requirements of Section XI, of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (hereafter "the Code" ).
In order to meet the requirements of this regu-lation, the Tennessee Valley Authority (TVA) has submi tted to the NRC its first ten year interval inservice System Pressure Test (SPT) program.
Regulation 10 CFR 50.55a(a)(3) states that the Director of Nuclear Reactor Regulation may authorize use of alternatives to requirements by licensees upon the licensee demonstrating that the proposed alternative requirements would provide an acceptable level of safety and quality.
This safety evaluation (SE) contains the NRC staff's findings with respect to TVA's request for relief K-13, sub-mitted by TVA's letter dated April 18, 1989.
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~RID I R t
Relief from the hydrostatic test pressure requirements for certain Code Class 2 and 3 non-safety-related instruments of the 1974 Edition, Summer 1975 Addenda of Section XI is requested.
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a.
IWC-5220 pressure
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The system hydrostatic test pressure shall be at least 1.25 times the system design pressure (PD) and conducted at a test temperature not less than 100'F except as may be required to meet the test temperature requirements of IWA-5230.
b.
IWD-5200 System Test Requirements The system test pressure shall be at least 1.10 times the system design pressure.
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- 1.3 Licensee's Basis For Re uestin Relief The plant predates the inservice testing requirements 'of ASME Code Section XI.
System components were designed on the basis of the system design 'pressure.
Some components, in this case non-safety-related instruments, can not accorano-date the test pressures required by the Code.
There exists non-safety-related instruments in some Code Class 2 and 3 systems whose maximum design pressure is equal to the system design pressure.
These instruments are not designed to withstand the overpressurization of a Section XI system pressure test.
The increased
- pressure, although not sufficient to rupture the instruments, is capable of damaging the instruments according to the manufacturers'pecifica-tions.
1.4 Alternative Testin All non-safety-related instruments in Code Class 2 and 3 systems which are not designed to operate at the system pressure test pressures will be isolated by root valves at the base of the instruments from the systems during such tests.
These instruments will be hydrostatically tested at a pressure not to exceed the manufacturer's maximum design pressure, and no less than 94 percent of their maximum design pressure.
The remainder of the systems will be tested to the system pressure required by Section XI of the Code.
2.0 STAFF EYALUATION The NRC staff has reviewed the licensee's request for relief H-13 for the isolation of non-safety-related instruments which are not designed to operate at system pressure test pressures in Code Class 2 and 3 systems during system pressure tests.
The root va'Ives are a part of the pressure boundary which is tested by the system hydrostatic pressure test.
The non-safety-related instru-ments are therefore outside of the tested pressure boundary.
If these instru-ments were subjected to the required hydrostatic test pressure which is above their design pressure, they would be damaged.
The licensee's submittal includes a commitment to incorporate an alternative pressure test of these non-safety-related Code Class 2 and 3 instruments which would demonstrate an acceptable level of quality and safety for these instruments.
- 3. 0 CONCLUSION Based on the staff review of the licensee's request for relief H-13 for Browns Ferry, Units I, 2, and 3, the staff concludes that the licensee's request for relief from certain specific requirements of Section XI of the ASME Code is acceptable.
Any additional program changes, such as revisions or additional relief requests should be submitted for staff review and should not be implemented prior to review and approval by the staff.
The staff has determined that relief may be granted pursuant to 10 CFR 50.55a(a)(3) based on our finding that the proposed alternative testing requirements provide an acceptable level of quality and safety.
Principal Contributor:
D.
E. Smith Dated:
September 19, 1989
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