ML20247H642
| ML20247H642 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 07/24/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247H625 | List: |
| References | |
| NUDOCS 8907310085 | |
| Download: ML20247H642 (4) | |
Text
f **Cu i
o,%
UNITED STATES NUCLEAR REGULATORY COMMISSION O
WASHINGTON, D C. 20555
- e,*/
1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO A REQUEST FOR RELIEF FROM HYDROSTATIC TEST REQUIREMENTS t
OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT NO. I l
DOCKET NO. 50-285 1.
BACKGROUND Technical Specifications for the Fort Calhoun Station state that ASME Code Class 1, 2, and 3 components of the fa;:111ty shall be subjected to the examina-tion and testing requirements of applicable editions and addenda of Section XI of the ASME Boiler and Pressure Vessel Code. By letter dated January 18, 1989, the Omaha Public Power District (licensee) indirectly requested relief from the hydrostatic testing requirements of the 1980 Edition throuc' Ei. iter 1980 Addenda of Section XI of the Code following a modification of a' portion of the Raw Water System at the Fort Calhoun Station.
the licensee had determined that the hydrostatic testing requirements ofPursuantto Section XI were impractical to perform at Fort Calhoun Station and provided information in support of its determination. Pursuantto10CFR50.55a(g)(6)(1),
this information is evaluated herein to determine if the necessary-findings can be made to grant the requested relief.
i i
II. RELIEF REQUEST. REQUIREMENTS, AND SUPPORTING INFORMATION f
A.
REQUEST - Relief is requested from performing the hydrostatic test requirements of USAS B31.7 Class I piping in the Raw Water System following a modification.
B.
_ REQUIREMENTS (1980 EDITION, WINTER 1980 ADDE [Q After repairs by welding on the pressure retaining boundary, a 1
system hydrostatic test shall be performed. For ASME Code Class 3 l
systems and components, the hydrostatic test pressure shall be at -
least 1.10 tines the system pressure P for systems with Design Temperature of 200'F or less. ThesysUmpressureP shall be thel i
lowest pressure setting among the number of safety oPrelief valves l
l-l l
8907310085 890724 i
PDR ADDCK 05000285 P
pyy 3
I
x
~
i provided for overpressure protection within the boundary of the system to be tested. For systems (or portions of systems) not provided with safety or relief valves, the system design pressure P shall be subsituted for P d
sv*
Repairs shall be performed in ac u dance with the Construction Code of the component or system. Later editions of the Construction Code or of Section III, either in the entirety or portions thereof, may be used.
C.
LICENSEE'S BASES FOR RELIEF REQUEST The piping codes were under development during the Fort Calhoun Station original design. The RW system was originally designed to USAS B31.7, Class I, 1968 draft, as specified in OPPD Power Piping and liechanical Contract No. 763. This system would be classified today as Safety Clr a 3 in accordance with ANSI /ANS 51.1-1983 and l
Quality Group C
- accordance with Regulatory Guide 1.26, Rev. 3, February 1976.
The original Class I code classification of the RW system is considered to be significantly over-specified based on ANSI /ANS 51.1 and Regulatory Guide 1.26 guidance. Additionally, RW is low energy and low temperature cooling water systems consistent with Cless III designations. An appropriate code classification based on current regulatory guidance would be USAS B31.7, Class III, 1969.
A portion of the Raw Water system was modified during the 1988 refueling outage to provide a larger cooling water supply to the Control Rocm HVAC system. The modification resulted in welds at two (2) locations where the existing Raw Water S without resorting to extraordinary measures.ystem cannot be isolated The welds are 21 inch butt welded pipe caps. One pipe cap is on the 16 inch Raw Water inlet piping and the other is on the 16 inch Raw Water outlet piping.
There are a number of large butterfly valves interconnecting the Component Coolirig Water (CCW) system and the RW systera. Hydrostatic testing of the Raw Water Systera would require, as a minimum, the following:
1.
A potential would exist for Raw Water to enter the Component Cooling Water System during the hydrostatic test.
1
'. 2.
Raw Water supply side hydro would require two Raw Water system outages to remove, blank, and re-install a number of butterfly valves.
3.
Raw Water return side has no isolation valve between the new pipe cap and the river, only a large check valve.
For these reasons, it is not practical to hydrostatically test the RW system changes made by modification MR-TC-81-51 in accordance with USAS B31.7, Class III leak test requirements.
D.
LICENSEE'S PROPOSED ALTERNATIVE Substitution of USAS B31.7, Class III leak test requirements is proposed. The leak testing requirements of USAS B31.7, Class III, 1969 allows 100% radiography of all welded joints of the RW piping modifications to be substituted for a hydrostatic leak test as a means of providing an acceptable method of demonstrating system pressure boundary integrity.
Piping associated with this modification is ASME Section III material, which is equivalent to the material requirements of USAS 831.7, Class I.
In lieu of a hydrostatic leak test,100% radiography of CCW and RW system welded joints associated with modification HR-FC-81-51 has been accomplished in accordance with ASME III, Class 1, 1983 Edition, Summer of 1984 Addendum.
(This code was reconciled to the original USAS B31.7 construction code).
The system is considered operable with no reduction in margin of safety.
E.
STAFF EVALUATION The modification performed on the Raw Water System at Fort Calhoun l
resulted in two 2i inch butt welded pipe caps that were not isolable from the system.
In order to perform the Code hydrostatic test, a major portion of the system would have to be pressurized to the test t
pressure and held at that pressure.
The butterfly boundary valves I
in the system do not provide the seal necessary to achieve and maintain the test pressure, thereby making the hydrostatic test impractical to perform.
In lieu of the required hydrostatic test, the licensee proposed as an alternative 1001 radiography of the welds.
The staff finds the alternative acceptable in determining the structural integrity of the welds. We therefore, conclude that relief from the hydrostatic test requirements may be granted and that granting the relief will i
not compromise the health and safety of the public.
i Dated:
July 24,1989 l
}
Principal Contributor:
G. Johnson j
l l
l l
__ m
m /.,,
7 Document Name:
FC LTR/445582 g
Requestor's ID:
JONES Author's Name:
ABournia Document Comments:
TER NUREG-0737, ITEM II.D.1 CONCURRENCES:
P. Noonan
- concu /i f's
/
C A. Bournia - concu & sign F. Hebdon
- cortcur DISPATCH /Secy This document will be deleted.
l l
l w____-__..