ML19256D218
| ML19256D218 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/09/1967 |
| From: | Deyoung R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Boyd R US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7910170719 | |
| Download: ML19256D218 (3) | |
Text
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R. S. Boyd, Assistant Director for Reactor Projects THRU:
S. Levine, Assistant..tirector for Reactor Technology,"DRL R. C. DeYoung, Chief Containment & Conponent Technolon 3 ranch Division of Reactor Licensin:;
THREE MILE ISLAND - THERMAL SHOCK ON REACTOR VESSEL jo -[
DRL:C&CTB: SSP RT-304 We have reviewed the information submitted by Babcock & Wilcox (Supple =ent No. 2, Pages 11.1-1 through 11.10-1) on the thermal shock on the Three Mile Island reactor vessel, due to the cperation of the emergency core cooling syst.em.
On the basis of S. S. Pavlicki's preliminary evaluation of the brittle fracture analysis submitted by the applicant, we conclude that the transition temperature approach is not quite adequate to treat crack propagation problems in thick plates, while the fracture mechanics analysis submitted does not provide sufficient detail to allow an evaluation. We reememend that you ask B&W to submit a detailed analysis of the thermal shock problem using, fracture mechanics approach.
Attached to this memorandum is a more detailed report on the Three-Mile Island thermal shock problem.
Attachment:
Report ec:
C. G. Long, DRL
- 3. K. Crines, DRL bec:
S. Levine, DRL R. C. DeYouce, DRL S. S. pawlicki, DRL Distribution:
Suppl.
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O T:17EZ MILZ ISLAND T*:ET"AL SdCC" ON "l'ACTCE 'IZESCL
'Je are continuing our ganaral study of the probles involving dabece?.
& '411cox, Combustion Engineering, General Electric, and Uestinghouse. Two modes of a potential failure are being considered: ductile yieldinc and brittle fracture. The latter is being analyzed by sena applicants usin-both the Pellini-Puzak fracture diagram approach and fracture mechanica.
In general, the information subnitted so fcr is insufficient to conclude that the reactor vessel vill naintain its integrity during, a thernal shock induced by operation of the emergency core cooling system.
The inf ormation submitted by the applicant in connection with the Three Mile Island plant is included in Supplement No. 2, pages 11.1-1 through 11.10-1.
For the ductile yielding mede of failure the applicant concluded that yielding may occur in the inner 14.7 per cent of the vessel vall thickness. Our preliminary evaluation indicates that this pcre of ~
anslysis is realistic.
7 r the brittle scle of failure, the applicent used bcth the tran-sition temperature approach (Pellini-Pu ak fracture diagras), and fracture mechanics. The first typa of analysis ahcwed that a crack could propagate only throu~h the inner 43 per cent of the wall thickness if a crac'/
initiation threshold of scro were assumed. The fracture mechanics analysis indicated that the crack prepa;ating energy is belcw that requirad for crack propa;ation when the crack reachas a depth of less than 3 inchas cr 33 per cent of the wall thickness.
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. On the basis of cur preliainary evalur tion of the brittle fracture analysis submitted by the applicant, we conclude that the transition ten-perature approach is not quite adequate to t.tre.it crack prepngccion prob..cns in plates with section thicknesses greater t' tan 2 in.
The detailed ressens for this conclusion are well sumanrized in the report 0 CL-IiSIC-21, " Tech-nology of Steel Pressure Vessels for Water-Coolec :;uclear Reactors, Section 7.6.4 On the other hand, the fracture ccchanics analysis su'mitted a
by the applicant does not provide sufficient detail to cllow an evaluation.
We recomnend that you ask the cesigner to submit a detailed analysis of the thermal shock problem using f racture mechanics approach. Evaluation of this additional information will be completed within the framework of the general study of the thermal shock problem.
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