ML20213E222
| ML20213E222 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 07/29/1982 |
| From: | Johnston W Office of Nuclear Reactor Regulation |
| To: | Tedesco R Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-0534, CON-WNP-534 NUDOCS 8208180197 | |
| Download: ML20213E222 (5) | |
Text
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9 JUL 2 91992 Docketto.Sb-397 I*ENORA!!DUM FOR: Robert L. Tedesco, Assistant Director for Licensing Division of Licensing FRO:!:
111111am V. Johnston, Assistant Director for Materials & Qualificaticr.s Engineering
~ Division of Engineering SUDJECT:
CDC 51 COMPLIAf:CE - UES1?INGTO'l PUBLIC POUER SUPPLY SYSTEll l!UCLEAR FROJECT i;0. 2 Plant fiamo: HPPSS i:uclear Project lio. 2 (UMP 2)
Suppliers: General Electric: Durns & Roe Licensing Stage:.0L Docke: Gumber: 50-397 Pesponsible Branch & Project Ilanager: L3; R. Auluck Revicuer:
J. Halapatz Requested Completion Date: Open De::cription of Task: SER Input Re GDC 51 Cceplicnce Peview Status: Cc:rplete The flaterials Engineering Dranch SER input related to compliance with CDC 51 of the UMP 2 reactor containment pressure boundary materials is presented in tl'.c attachment to this cenorandua.
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Willian V. Johnston, Assistant Directcr L e20G1e0.197 82072 V for itatorials & Gualification Engineering e ADOCK M 00039;-
Division of Engineering
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ATTACHMENT MATERIALS APPLICATION SECTION MATERIALS ENGINEERING BRANCH DOCKET NO. 50-397 i
6.2.7 Fracture Prevention of Containment Pressure Boundary Our safety evaluation review assessed the ferritic materials in the WNP 2 containment. system that constitute the containment pressure boundary to determine if the material fracture toughness is in compliance with the requirements of General Design Criterion 51, " Fracture Prevention of Containment Pressure Boundary". '
GDC 51 requires that under operating, maintenance, testing and postulated accident conditions, (1) the ferritic materials of the containment pressure boundary behave in nonbrittle manner and (2) the probability of rapidly propagating fracture is minimized.
The WNP 2 containment system includes a ferritic steel
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primary containment vessel and head enclosed by a reinforced concrete shield structure.
The ferritic I
materials of containment pressure boundary which were considered in our assessment are those which have been applied in the fabrication of the containment vessel and head, equipment hatch, personnel lock, penetrations and fluid system components including the valves required to isolate the system.
These components are l
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.e the parts of the containment system which are not backed by concrete and must sustain loads during the performance of the containment function under the condition cited i
by GDC 51.
The WNP 2 containment pressure boundary is comprised of ASME Code Class 1, Class 2 and Class MC components.
In late 1979, we revi.ewed the fracture
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toughness requirements of the ferrftic materials of Class MC, Class 1 and Class 2 components which typically constitute the containment pressure boundary.
Based on this ieview, we determined that the fracture tcughness l
requirements contained in ASME Coce editions and addenda f
typical of those used in the design of the WNP 2 containment 2
-may not ensure compliance with GDC 51 for all areas of the
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containment pressure boundary.
We initiatec a program to review fracture tcughness requirements for containment pressure boundary materials for the purpose of defining I
those fract'ure-toughness criteria that most appropriately j
address the requirements of GDC 51.
Prior to completion t
of.this study, we. elected to apply in our licensing review of ferritic containment pressure boundary materials the criteria for Class 2 components identified in the Summer i
1977 Addenda of Section III of the Code.
Because the fracture toughness criteria that have been applied in construction typically differ in Code classificaticn and i
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3-Code editica and addenda, we have chosen the criteria in theSummer1977AddentaofSectionIIfoftheCodeto provide a uniform review, consistent with the safety function of the containment pressure boundary materials.
Therefore, we have reviewed the Class 1, Class 2, and Class MC components of the WNP 2 < containment pressure boundary accordingtothefracturetoughneshrequirementsofthe i
Summer 1977 Addenda of Section III for Class 2 components.
Considered in our review are components of the containment system which are load bearing and provide a pressure boundary in the perforcance of the containment function under cperating, mainterance, testing and postulated accideht conditions as addressed in GDC 51.
These cceponents are the containment vessel and head, equipment hitch, person.nel airlock, penetrations and elements of the main steam and c.ain feedwater systems.
l Our assessment of the fracture toughness of the ferritic l
j materials of these ccaponents is based on fracture i
toughness test data provided by the applicant, tneir l
metallurgical characteri;ation and fracture toughness data i
" resented in NUREG-C577, "Fontential for Low Fracture l
Toughness and Lacellar Tearing of PWR Staa:n Generator and Reactor Coolant Pump Supports", USNRC, 0:tober 1979 and l
ASME Ccde Section III, Summer 1979 Addenda, Sucsection NC.
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. The metallurgical characterization of these materials, with respect to their fracture toughness, was developed from a review of how these materials were fabricated and what thermal history they experienced during fabrication.
The metallurgical characterization of these materials, when correlated with the dated presented in NUREG 0577 and the Summer 1977 Addenda of the ASME Code Section III, provided the technical basis for our evaluation of compliance with the Coile requirements.
Based on our review of the available fracture toughness data and material fabrication histories, and the use of correlations between metallurgical characteristics and material fracture toughness, we conclude that the ferritic materials in the WNP 2 containment pressure boundary meet the fracture toughness requirement that are specified for Class 2 components by the Summer 1977 Addenda of Section II of the ASME Code.
Compliance with these Code requirements provides reasonable assurance that the WNP 2 reactor containment pressure boundary caterials will behave in a nonbrittle manner, that tne prcbability of rapidly propagating fracture will be minimized and that the requirements of GDC 51 are satisfied.
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