Referencing 4/14/78 Letter-Modifications to NRC Guidance "Review and Acceptance of Spent Fuel Pool Storage and Handling Applications" (Generic Letter 79-04)
GL79004
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D. C. 20565
January 18, 1979
To All Power Reactor Licensees
Gentlemen:
Our letter of April 14, 1978, provided NRC Guidance entitled, "Review and
Acceptance of Spent Fuel Storage and Handling Applications." Enclosed are
modifications to this document for your information and use. These involve
pages IV-5 and IV-6 of the document and comprise modified rationale and
corrections.
Sincerely,
Brian K. Grimes, Assistant Director
for Engineering and Projects
Division of Operating Reactors
Enclosure:
Pages IV-5 and IV-6
cc w/enclosure:
Service List
7903080173
.
In order to determine the flexibility of the pool wall it is acceptable
for the licensee to use equivalent mass and stiffness properties
obtained from calculations similar to those described in "Introduction
to Structural Dynamics" by J. M. Biggs published by McGraw Hill Book
Company. Should the fundamental frequency of the pool wall model be
higher than or equal to 33 Hertz, it may be assumed that the response
of the pool wall and the corresponding lateral support to the new rack
system are identical to those of the base slab, for which appropriate
floor response spectra or ground response spectra may already exist.
(6) Structural Acceptance Criteria
When AISC Code procedures are adopted, the structural acceptance
criteria are those given in Section 3.8.4.II.5 of the Standard Review
Plan for steel and concrete structures. For stainless steel the
acceptance criteria expressed as a percentage of yield stress should
satisfy Section 3.8.4.II.5 of the Standard Review Plan. When subsection
NF, Section III, of the ASME B&PV Code is used for the racks, the
structural acceptance criteria are those given in the Table below. When
buckling loads are considered in the design, the structural acceptance
criteria shall be limited by the requirements of Appendix XVII-2110(b)
of the ASME Boiler and Pressure Vessel Code.
For impact loading the ductility ratios utilized to absorb kinetic
energy in the tensile, flexural, compressive, and shearing modes should
be quantified. When considering the effects of seismic loads, factors
of safety against gross sliding and overturning of racks and rack
modules under all probable service conditions shall be in accordance
with the Section 3.8.5.II-5 of the Standard Review Plan. This position
on factors of safety against sliding and tilting need not be met
provided any one of the following conditions is met:
(a) it can be shown by detailed nonlinear dynamic analyses that the
amplitudes of sliding motion are minimal, and impact between
adjacent rack modules or between a rack module and the pool walls
is prevented provided that the factors of safety against tilting
are within the values permitted by Section 3.8.5.II.5 of the
Standard Review Plan.
(b) it can be shown that any sliding and tilting motion will be
contained within suitable geometric constraints such as thermal
clearances, and that any impact due to the clearances is
incorporated.
(7) Materials, Quality Control, and Special Construction Techniques:
The materials, quality control procedures, and any special con-
struction techniques should be described. The sequence of installation
of the new fuel racks, and a description of the precautions to be taken
to prevent damage to the stored fuel during
IV-5
.
TABLE
Load Combination
Elastic Analysis Acceptance Limit
D + L Normal limits of NF 3231.1a
D + L + E Normal limits of NF 3231.1a
D + L + To Lesser of 2Sy or Su stress range
D + L + To + E Lesser of 2Sy or Su stress range
D + L + Ta + E Lesser of 2Sy or Su stress range
D + L + Ta + E1 Faulted condition limits of
NF 3231.1c
Limit Analysis
1.7 (D + L) Limits of XVII-4000 of Appendix XVII
of ASME Code Section III
1.7 (D + L + E)
1.3 (D + L + To)
1.3 (D + L + E + To)
1.1 (D + L + Ta + E)
Notes: 1. The abbreviations in the table above are those used in
Section 3.8.4 of the Standard Review Plan where each term is
defined except for Ta which is defined as the highest
temperature associated with the postulated abnormal design
conditions.
2. Deformation limits specified by the Design Specification
limits shall be satisfied, and such deformation limits should
preclude damage to the fuel assemblies.
3. The provisions of NF 3231.1 shall be amended by the
requirements of the paragraphs c.2, 3, and 4 of the
Regulatory Guide 1.124 entitled "Design Limits and Load
Combinations for Class 1 Linear-Type Component Supports."
IV-6
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