ML20079L497
| ML20079L497 | |
| Person / Time | |
|---|---|
| Site: | Clinch River |
| Issue date: | 02/14/1983 |
| From: | Longenecker J ENERGY, DEPT. OF, CLINCH RIVER BREEDER REACTOR PLANT |
| To: | Grace J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20079L498 | List: |
| References | |
| HQ:S:83:222, NUDOCS 8302230347 | |
| Download: ML20079L497 (2) | |
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Department of Energy Washington, D.C. 20545 Docket No. 50-537 HQ:S:83:222 FEB 14 DO Dr. J. Nelson Grace, Director CRER Program Office Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Dr. Grace:
REACTOR CLOSURE HEAD CAPABILITY TO MEET MARGIN REQUIREMENTS The Clinch River Breeder Reactor Plant project has completed its assessment of data from tests recently performed to determine the capability of the prototypic. reactor closure head for hypothetical core disruptive accident energetics.
The conclusion is that the closure head can be designed to fulfill the design requirement of a sodium slug impact with 75 megajoules (MJ) of energy.
The conservative design calculation upon which this conclusion is based (see ) will be subject to confirmatory tests and supplementary analysis prior to operating license review (see Enclosure 2).
The present evaluation, in our judgment, provides adequate assurance of design acceptability for our construction permit application.
The most important finding from review of the recent static test data is that the observed failure mode of the head is a kinematic failure rather than a structural failure.
The implications of this finding are fully discussed in l.
The project has reviewed the test data in detail to ensure that the failure mode has been correctly gl>()l identified and is fully understood.
Feasible modifications i
have been developed to eliminate this kinematic failure.
With the head modified, calculations, based largely on 3
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available test data, indicate, with significant margin, the
/
I required energetics accommodation capability.
Other head
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design requirements have also been reviewed, including i
seismic analyses, to verify overall acceptability of the identified modifications.
The overall approach employed by the project to ensure containment integrity is conservative.
For example, summarizes assessments which indicate that i
hDR DO K O 537 A
l /
the reactor containment building integrity is not challenged by large releases of sodium through the reactor vessel clocure head.
Thus, substantial additional margin to prever,t a challenge to the containment building integrity beyond the project's requirement (see: CRBRP-3, Volume 1, i
"SMBDB") is available.
The project is committed to design for and to demonstrate the capability of the reactor vessel head to accommodate the impact of a sodium slug with 75 MJ of kinetic energy.
Accordingly, a detailed modified design will be developed based in the concept in Enclosure 1.
Experimental confirmation of the head capability will be an integral part of the design process.
Both static and dynamic tests will be performed as described in Enclosure 2.
The dynamic test will be designed to obtain a 75 MJ slug impact to a model head reflecting the final design.
This experimental program will thus provide a direct basis for judging the acceptability of the integrity of the reactor vessel closure head and for assessing the loadings on head mounted components.
The adequacy of the head mounted components for those loads will be demonstrated through appropriate analyses during Final Safety Analysis Report review.
Sincerely, Jo n R.
Longen ker Acting Director, Office of Breeder Demonstration Projects
' Office of Nuclear Energy Enclosures cc:
Service List Standard Distribution Licensing Distribution
.