ML20207M043

Safety Evaluation Denying Util 880711 Request for Relief from Hydrostatic Test Requirements of Section XI of ASME Code for Class 2 Portion of Main Steam Lines Between Outboard MSIVs & Turbine Stop Valves

ML20207M043
Person / Time
Site:	Hatch
Issue date:	10/13/1988
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20207M035	List: ML20207M030 ML20207M043
References
NUDOCS 8810180078
Download: ML20207M043 (3)

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' " UNITED STATES

,/ 'k NUCLEAR REGULATORY COMMISSION

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l WASHINGTON, D. C. 20556

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SAFET', EVALUATION BY THE OFFICE OF NUCLEAR [,EACTOR REGULATION REQUEST FOR RELIEF FROM HYDROSTATIC TEST REQUIREMENT EDWIN I. HATCH NUCLEAR PLANT, UNITS 1 AND 2 4

INTRODUCTION 4 By letter dated July 11, 1988, Georgia Power Company (the licensee) requested relief from the hydrostatic pressure test requirement of Section XI of the ASME Boiler and Pressure Vessel Code for the Class 2 portion of the main steam line (!WC-5222). This relief request is for the second ten-year inservice inspection (ISI) interval.

Pursuant to 10 CFR 50.554(g)(5)(iii), if the licensee determines that certain ASME Code examination requirements are impractical, the licensee shall submit information to the Nuclear Regulatory Commission (NRC) in support of that determination. Pursuant to 10 CFR 50.55a(g)(6)(1), the NRC will evaluate the <

determination that Code requirements are impractical. The NRC may grant relief and impose alternative requirements that it determines are authorized by law and will not endanger life or property or the cor.non defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

EVALUATION The second ten-year ISI interval for Hatch Units 1 and 2 began January 1, 1986 and will end January 1,1996. The evaluation of the relief request for the second ten-year ISI interval is based on the requirements of Section XI of '

the ASME Boil. and Pressure Yessel Code, 1980 Edition, including Addenda through Winter 1981 (80W81).

Code Requirement: Section XI, Article IWC-5000 requires that the Class 2 pressure Tetaining components within each system boundary bo subjected to a system hydrostatic pressure test [IWA-5211(d)] for each system or portion of systems and for repaired or replacei components, or altered portions of  ;

systems. The system hydrostatic test shall be conducted in accordance with IWA-5000, as applicable. The fluid contained in the system shall serve as the pressurizing medium. Also, Table IWC-2500-1, Examination Category C-H, requires that the system hydrostatic test he conducted at or near the end of each inspection interval during the same inspection period of each inspection i interval, i

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e The system hydrostatic test pressure shall be at least 1.10 times the system pressure for systems with design temperatures of 200'F or less, and at least 1.25 times the system pressure for systems with design temperatures above 200*F. The system pressure shall be the lowest pressure setting among the safety or relief valves provided for overpressure protection within the boundary of the systems to be tested. For systems (or portions of systems) not provided with safety or relief valves, the system design pressure shall be substituted for the system pressure.

Requested Relief: Relief is requested from the hydrostatic pressure test requirements of IWC-5222(a) for the Class 2 pai t of the main steam line.

Proposed Alternative Examination: Tne licensee proposed to perform a pressure test of the Class 2 main steam line using the Class 1 pressure and temperature listed in Table IWB-5220-1, while simultaneously pressurizing the reactor pressure vessel and the Class 1 and Class 2 piping portions of the system.

Basis for Requesting Relief: The licensee states that the Class 2 part of the main steam line of each unit extends from each of four outboard main steam isolation valves (MSIVs) to the turbine stop valve assembly. The !!SIVs, which are 24-inch, air-operated globe valves, are installed so that the steam pressure assists in the tight closure of the valves. However, when performing the Class 2 hydrostatic test, the valves are pressurized in the reverse direction, Jelow the globe. This prevents the valves from holding th9 test pressure without the installation of special discs. Georgia Power Company considers the use of these discs unwarranted, since the more important Class 1 portion of the main steam system is hydrostatically tested at reduced pressure per IWB-5222.

In a telephone conversation with the staff on August 19, 1988, the licensee

stated that the Code required test pressure is 1398 psig at 70 F for the Class 2 portion of the main steam lines. The Code required test pressure for the Class 1 portion, which is the proposed alternative test pressure for the Class 2 part, is 1085 psig at a temperature greater than 200'F.

The design of the MS!Ys does not permit pressurizing the Class 2 portion of the main steam lines to the Code required t.st pressure without either installing speciel test discs or overpressurizing the Class 1 part. Since the Class 2 design pressure is 1118 psig, the Class 1 part of the main steam line cannot be pressurized to the Code required Class 2 test pressure in order to meet the Class 2 Code requirement.

The licensee stated in the July 11, 1988 submittal that the proposed alternative hyorostatic tests were to be performed during the fall 1988 Unit 1 maintenance /ref u ling outage, which began on September 28, 1988. Since the Hatch plants are still in the first period of the second ten-year ISI interval and since the licensee hos not addressed either repaired or repit.ced components

or altered sortions of systems, this violates the Code requirement which specifies tiot the mdrostatic test be performed at or near the end of each ten-year ISI interval, i

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. CONCLUSION  !

The licensee has provided insufficient technical information to justify the determination that the Section XI ASME Boiler and Pressure Yessel Code requirement is impractical to perform at Hatch Units 1 and 2. We conclude that the elevated hydrostatic pressure test requirement for the Cless 2 portion of the main steam line (IWC-5222) is not impractical and should be performed near the end of the interval in order to ensure structural integrity of the main steam line between the main steam isolation valve and the turbine stop valve assembly.

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