ML20138H684
| ML20138H684 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/29/1997 |
| From: | Hughey W ENTERGY OPERATIONS, INC. |
| To: | Paperiello C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GNRO-97-00035, GNRO-97-35, NUDOCS 9705070249 | |
| Download: ML20138H684 (7) | |
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I Oy Entergy operations, Inc.
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PO. Box 756 Port G Oson. MS 39150 Tel 601437 6470 W.K.Hughey Drector NucAv Stery & Rego'aty/
April 29,1997 4
U.S. Nuclear Regulatory Commission Director, Office of Nuclear Material Safety and Safeguards Washington, D.C. 20555 Attention:
Mr. Carl J. Paperiello
Subject:
Grand Gulf Nuclear Station Docket No. 50-416 1.icense No. NPF-29 10CFR70.24 Exemption, Supplement 1 to GNRO-96/00082
Reference:
- 1) Letter to NRC from Grand Gulf Requesting Exemption 10CFR 70.24(a), to GNRO-96/00082, dated July 15,1996
Dear Mr. Paperiello:
GNRO-97/00035 By this letter, Entergy Operations, Inc. is supplementing a request for an exemption from
' the requirements of 10CFR 70.24(a), " Criticality Accident Requirements" for Grand Gulf Nuclear Station (GGNS). Tne original exemption was requested by reference 1) above.
The supplement was determined to be necessary after discussions with NRC reviewers.
Criticality monitors are located in the area of the new fuel vault (NFV) (208 ft. elevation of the Auxiliary Building (AB)), howev tr no criticality monitors are physically located in the NFV. The NFV can only be accessed by removing steel covers on the 208 ft. elevation of the AB. Once the unirradiated fuel is lowered into the NFV, the criticality monitors located on the 208 ft. elevation of the AB are shielded by concrete and steel and cannot monitor the new fuel stored in the NFV. Therefore, this supplement is required to request an exemption from 10CFR 70.24(a) to have criticality monitors in the NFV. It should be noted that during handling of new fuel on the 208 ft. elevation of the AB, numerous criticality controls are in effect.
During tile NRC review of the exemption request in reference 1) the reviewer noted that in our referenced exemption we had not committed to keeping our quantity of special nuclear material (SNM), in the form of incore detectors, below Regulatory Guide 10.3 limits. Grand Gulf will not exceed the quantities of special nuclear material (SNM) listed in the guidance in Section 1.1 of Regulatory Guide 10.3," Guide for the Preparation of Applications for Special Nuclear Material Licenses of Less than Critical Mass Quantities" of SNM contained in incore detectors. The quantities of SNM specified to be enough for a critical mass in NRC Regulatory Guide 10.3 are 350 grams of U-235,200 grams U-233, and 200 grams of Pu-239. Grand Gulf will stay below these values for SNM in tho form of incore detectors while 8
0,'1 in storage.
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GNRO-97/00035 Page 2 of 3 l
j The basis for this request is similar to the previously provided basis for an exemption to 10CFR 70.24(a) (granted in the July 15,1981 Special Nuclear Material (SNM) License No.
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1882 for this facility). This letter requests a regranting of part of the previously approved exemption to 10CFR 70.24(a), and an exemption is requested to the criticality accident j
monitoring requirements of 10CFR 70.24(a) for the NFV as referenced in Updated Final Safety Analysis Repert Section 9.1.1.
The basis for satisfying the good cause requirements outlined in 10CFR 70.24(d) is provided in the attached exemption request and justification. The requested exemption is authorized by law, will not endanger life or property or the common defense and security, and is otherwise in the public interest.
Yours truly, ferv WKH/MJL attachment:
Supplement 1 to 10CFR 70.24 Exemption Request and Justification cc:
(See Next Page)
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i GNRO-97/00035 Page 3 of 3 cc:
GGNS Senior Resident (w/a)
Mr. R. B. McGehee (w/a)
Mr. N. S. Reynolds (w/a)
Mr. H. L. Thomas (w/o)
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Mr. J. W. Yelverton (w/a) i Mr. E. W. Merschoff (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 i
Mr. J. N. Donohew, Project Manager (w/2) l Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission l
Mail Stop 13H3 Washington, D.C. 20555 Dr. E. F. Thompson (w/a)
State Health Officer State Board of Health P. O. Box 1700 Jackson, Mississippi 39205 9
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1 ATTACHMENT 1 i
i SUPPLEMENT 1
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10CFR70.24 EXEMPTION REQUEST and JUSTIFICATION I
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f 10CFR70.24 EXEMPTION REQUEST and JUSTIFICATION 1
i EXEMPTION REQUESTED:
i An exemption is requested from the criticality accident monitoring requirements of 10CFR 70.24(a) specifically for the new fuel storage vault (NFV) as referenced in the Updated Final Safety Analysis Report (UFSAR) Section 9.1.1. The exemption would also apply during loading and unloading of the
- NFV, This exemption is necessary to clarify the requirements of the Operating Licolse for GGNS, which in general invokes 10CFR 70 as a whole. The exemption specified above will in no way affect the health and safety of the public.
GOOD CAUSE JUSTIFICATION:
10CFR 70.24(d) anticipates that licensees may request relief from these requirements and allows liccnsees to apply for.n exemption, in whole or in part, if good cause is shown. Grand Gulf believes that good cause exists for following reasons:
The need for criticality monitoring in the NFV is precluded by its design and by the administrative controls in place for handling of the unirradiated fuel. As discussed in the Grand Gulf Technical Specifications, Section 4.3.1.2, the new fuel storage racks are designed and shall be maintained with k.,r <0.95 if fully flooded with unborated water, which includes an allowance for uncertainties as described in Section 9.1.1 of the UFSAR. A nominal fuel assembly center to center storage spacing of 6.535 inches within rows and 11.875 inches between rows in the new fuel storage racks is also maintained.
UFSAR Section 9.1.1 discusses in detail the Safety Design Bases, Facility Description, and a Safety Evaluation on the Criticality Control aspects of the NFV. The relevant portions are included below and are the basis for this request:
Safety De' sign Bases - Structural (Sections 9.1.1.1.1.1, 9.1.1.2, and 9,1,1.3.2) -The new fuel storage racks containing a full complement of fuel assemblies are designed to withstand all credible static and dynamic loadings to prevent damage to the structure of the racks, and therefore the contained fuel, and to minimize distortion of the racks arrangement. The racks are designed to protect the fuel assemblies from excessive physical damage which may mitigate the release of radioactive materials in excess of 10CFR 20 requirements under normal or abnormal conditions. The racks are constructed in accordance with the Quality Assurance Requirements of 10CFR 50, Appendix B. The new fuel storage racks are categorized as safety Class 2 and seismic Category 1. The building containing the new fuel storage vault (auxiliary building) is a seismic Category I structure and is designed to Regulatory Guides 1.13 and 1.29 which precludes any deleterious effects on fuel storage (fuel rack) integrity due to natural phenomena such as earthquakes, tornadoes, hurricanes, tornado missiles, and floods.
The new f I storage facility is designed in accordance with General Design Criteria 61,62, and 63 i
j GOOD CAUSE JUSTlFICATION (cont.):
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The new fuel storage vault contains 30 sets of castings which may contain up to 10 fuel assemblies; therefore a maximum of 300 fuel assemblies may be stored in the fuel vault.
2 There are three tiers of castings which are positioned by fixed box beams. This holds the fuel assemblies in a vertical posi :,n supported at the lower and upper tie plate with additional 1
lateral support at the center of gravity of the fuel assembly. The lower casting supports the t
weight of the fuel assembly and restricts the lateral movement; the center and top casting restricts lateral movement only of the fuel assembly. The floor of the new fuel storage vault is -
sloped to a drain located at the low point. This drain removes any water that may be l
accidentally and unknowingly introduced into the vault. The drain is part of the equipment -
t drain subsystem of the liquid radwaste system.
Criticality Control (Section 9.1.1.3.1) - The arrangement of fuel assemblies in the fuel storage racks results in k,n below 0.95 in a dry condition or completely flooded with water 3
which has a density of 1 g/cc. To meet the requirements of General Design Criterion 62, l
geometrically-safe configurations of fuel stored in the new fuel array are employed to assure i
that k.nwill not exceed 0.95 if fuel is stored in the dry condition or if the abnormal condition of flooding (water with a density of 1 g/cc) occurs. In the dry condition, k.n is maintained _<0.95 due to undermoderation. In the flooded condition, the geometry of the fuel storage array assures the k., will remain <0.95 due to overmoderation.
Administrative controls are used to prohibit the introduction of sources of optimum moderation in the fuel storage areas and to ensure the use of solid noncombustible covers over the fuel j
whenever possible.'
i No limitation is placed on the size of the new fuel storage array from a criticality standpoint I
l since all calculations are performed on an infinite basis. Confirmatory analyses are performed for new fuel designs to demonstrate that the 0.95 acceptance criterion continues to be satisfied.
Criticality monitoring is not necessary during loading and unloading of the NFV. There is a short period of time for which a new fuel bundle being handled would not be monitored for criticality. The short period is when the bundle moves into the vault from the 208 ft elevation AB to its stored position in the NFV To preclude criticality during this time, handling procedures only allow one bundle to be loaded / unloaded into the NFV at a time. Also, fuel spacing rules are in effect which include prohibiting no more than four bundles outside of shipping containers and edge-to-edge spacing of 12 inches or
' more from all other fuel. Fuel will be also be stored such that water will drain freely from assemblies.
Based on these controls we feel that criticality monitoring is not required for the short period of time that new fuel passes between the 208 ft. AB elevation and the stored position in the NFV,
' These controls include the use of streaming nozzles on fire hoses, pressurized water portable fire extinguishers, and covering, with a fire retardant cover, of new fuel stored in the NFV. If a fire should occur during loading and unloading of the NFV, it will be covered immediately with a fire retardant cover New fuel stored in the NFV must be covered with a l
fire retardant cover that would preclude criticality due to inundation by low density water, fog or spray from a fire hose.
Metal NFV hatch covers must be placed over the entrance to the vault after conclusion of all fuel inspection and handling activities involving new fuel vault (
Reference:
Procedure 17-S-02-100, Rev.100, Criticality Rules).
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COST:
' Compliance with 10CFR 70.24 would result in a considerab!e expenditure of resources to install, maintain, and operate a criticality accident monitoring system for storage and handling of the items listed in the exemption. We believe these resources could be put to better use in other areas to improve the operation of Grand Gulf Nuclear Station.
RISK TO PUBLIC HEALTH AND SAFETY:
Due to the design and administrative controls in place that prevent criticality for handling and storage of new fuelin the NFV, public health and safety considerations are preserved.
CONCLUSION:
Based on the above request and justification evaluation, Entergy Operations, Inc. has concluded that operation in accordance with the proposed exemption to 10CFR 70.24(a) is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security l
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