ML20135F499
| ML20135F499 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 03/07/1997 |
| From: | Hughey W ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GNRO-97-00021, GNRO-97-21, TAC-M96177, NUDOCS 9703120435 | |
| Download: ML20135F499 (7) | |
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Enttrgy Operations,Inc.
Ih Po. Box 756 Pcrt G.bson, MS 39150 Tel 601437-6470 W. K. Hughey Director lutlear Safety & Regulatory l
March 07, 1997
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U.S. Nuclear Regulatory Commission Mail Station P1-37 Washington, D.C.
20555 Attention:
Document Control Desk
Subject:
Grand Gulf Nuclear Station Docket No. 50-416 License No. NPF-29 Responses to NRC Questions Requested in a NRC letter dated January 29, 1997, related to Proposed Exemption to the Criticality Monitoring Requirements in 10CFR70.24 (a)
Reference:
NRC Letter to Grand Gulf Nuclear Station, Request for Additional Information Related to a Proposed Exemption to the Criticality Monitoring Requirements in 10 CFR 70.24 (a)
(TAC NO. M 96177) dated January 29, 1997, (GNRI-97/00013)
GNRO-97/00021 i
Gentlemen:
As requested in the NRC reference letter, we are providing a written response to NRC questions concerning the Proposed Exemption to the Criticality Monitoring Requirements in 10CFR70.24 (a).
Yours truly WKH/MJL
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attachment:
Responses to NRC Questions Requested in O\\
NRC letter dated January 29, 1997 cc:
(See Next Page) 1
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9703120435 970307 PDR ADOCK 05000416
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t March 07, 1997 GNRO-97/00021
-Page 2 of 2 cc:
NRC Senior Resident Inspector (w/a)
Mr. R. B. McGehee (w/a)
Mr. N. S. Reynolds (w/a)
Mr. H. L. Thomas. (w/o) i Mr. J. W. Yelverton (w/a) i Mr. L. J. Callan (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region IV d
611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 i
Mr. J. N. Donohew, Project Manager (w/2) f Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission i
' 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 i
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Attachment to GNRO-97/00021 l
Responses to NRC Questions Requested in NRC letter dated January 29,1997 4
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Atttchment to GNRO-97/00021 Page 1 of 4 4
NRC Question la.
Provide a list of the areas at Grand Gulf, Unit 1 which contain criticality monitors that conform to 10CFR70.24(a), the activities conducted in these areas with special nuclear material (SNM), and the amount of SNM that could be in these areas.
Describe the controls, if any, which limit the SNM in these areas.
Answer 208' AUXILIARY BUILDING j
SNM-related activities performed:
Unloading of fuel from Reactor Assembly (RA) containers.
Inspection and channeling of new fuel.
e Placement of new fuel bundles in the spent fuel pool or new fuel vault.
Placement of spent fuel in storage.
Packaging of spent fuel for shipment (future).
Transfer of new or spent fuel through the horizontal transfer system.
New or irradiated fuel refurbishment.
Irradiated fuel sipping or inspection.
Storage of used in-core neutron detectors.
Storage of damaged fuel assemblies or pins.
208' CTMT BUILDING SNM-related activities performed:
Irradiated fuel sipping or inspection.
Transfer of new/ irradiated fuel to/from reactor / storage racks / horizontal transfer system.
- In-core fuel shuffle.
The total quantity of fuel allowed in these two areas is limited by the Operating License to that needed for reactor operation and which can be safely stored per FSAR assumptions. (There are additional practical and criticality control limitations discussed below.)
Restrictions on enrichment are discussed in Question 3.
Small quantities (<1 gram) of SNM contained in neutron detectors are also present on the floor during transfer activities.
NRC Question 1b.
Describe the controls, if any, which limit the SNM in these areas.
Answer:
Floor loading restrictions (Reference 1) and practical considerations limit the amount of new fuel that can be present in the inspection area at any given time to <32 assemblies.
No more than three new fuel assemblies may be outside of approved packaging at any time, and spacing limitations apply.
The reactor and fuel storage areas are limited by available space.
The spent fuel pool and upper containment pools combined are currently limited to approximately 4400 useable fuel storage locations. The new fuel vault
. contains 300 locations.
The reactor core contains 800 assembly locations.
Fuel may only be stored in the reactor vessel, approved storage racks, or shipping containers.
References:
1.
EER 90/196, 2.
17-S-02-100, Criticality Rules
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UFSAR Section 12.3.4.1, Table 12.3-3 (Area Radiation Monitoring) 4.
Technical Specification 4.3, Fuel Storage
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3 AttcchmInt to GNRO-97/00021 Page 2 of 4 5
l NRC Question 2.
i Describe the procedural controls and/or physical constraints which exist to j
preclude inadvertent removal of unirradiated fuel from Nuclear Regulatory i
' Commission-(NRC)-approved packaging in areas where criticality monitors are not provided.
i Answer:
Handling of fresh fuel at GGNS is strictly governed by administrative and j
_ departmental procedures.
Procedures 17-S-02-110, New Fuel Processing,.and 17-S-02-100, Criticality Rules, specify procedural and physical controls to ensure that fuel is not inadvertently removed from the NRC-approved reactor assembly (RA) containers in which it is shipped from the fuel vendor. The fuel is shipped two assemblies to a RA container with up to 18 RA containers (w/overpack) on.a shipping truck trailer.
Trailers are temporarily stored in designated areas prior to unloading. Outside packaging is securely j
bolted with tamper seals. No more than three truck trailers with <96 i
assemblies may be in the temporary storage areas at any given time! Fire j
inspections are performed once/ shift.
Fuel containers must be continually t.
attended by Security until they are inside the " primary building" (turbine building). After that time, they must be checked at.least every 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> by i
Security personnel (GGNS Security Plan procedure 11-S-71-2).
Individual RA containers may not be opened until they are positioned in the fuel inspection area of the auxiliary building-(208' elevation) where criticality monitors are present. Cautions are provided to ensure that the RA' container covers are not inadvertently used for lifting. Only one loaded RA container is lifted at a time. Cranes and lifting equipment are appropriately certified.
RA containers may not be stacked more than three high.
Empty containers are clearly marked.
-Storage of fresh fuel inside the New Fuel Vault (NFV) is allowed.
There are no criticality monitors in the NEV, however several measures are implemented to ensure inadvertent criticality is precluded.
(See Question 4.)
References:
1.
17-S-02-110, New Fuel Processing 2.
17-S-02-100, Criticality Rules 3.
11-S-71-2, GGNS Security Plan Procedure
Attachmrnt to GNRO-97/00021 Page 3 of 4 l
NRC Question 3.
Discuss the maximum U-235 fuel enrichment (or k-infinity) of fuel analyzed for storage in the fresh fuel racks at Grand Gulf, Unit 1, and the effects of accidental flooding or low-density optimum moderation conditions on l
potential criticality in storage.
Discuss the maximum enrichment which is accounted for in the NRC-approved packaging.
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Answer:
The design basis criticality margin requirement for new fuel storage racks is based on a hot, in-core peak k-infinity value of 1.31 as described in
-GESTAR II, Section 3.5 (Reference 1).
For each new fuel type, the l
applicability of this bounding value is confirmed during the licensing process as described in Amendment 22 of Reference 1 GESTAR II.
The design basis configuration assumes that the rack is fully inundated with unborated water (Reference 3).
Optimum moderation is not addressed in the analysis, but is assumed to be mitigated by compliance with SIL 152
[ Reference 2].
The current maximum enrichment approved for shipping from the fuel fabrication facility is 4.9 wt%(weight percent). This limit is based on the fuel vendor's fabrication facility enrichment limit, not container limits.
The use of higher enrichments will include any necessary evaluation and approval by the NRC of the shipping containers as described in 10CFR71.
References:
1.
NEDE-24011-P-A, " General Electric Standard Application for Reactor i
Fuel", latest approved version 2.
SIL 152, " Criticality Margins for Storage of New Fuel", March 31, 1976 3.
Technical Specification 4.3.1.2, Fuel Storage, Criticality bGU: Question 4.
Discuss the administrative controls mentioned in Section 9.1.1.3.1 of the 4
Updated Final Safety Analysis Report that are used to prohibit the j
introduction of sources of optimum moderation to the stored fresh fuel.
j Answer:
Procedure 17-S-02-100 stipulates that only pressurized water type fire extinguishers are to be used around fuel (no foam). When fuel is in the new fuel vault, only streaming type fire hose nozzles are allowed in the fuel handling areas.
In addition, fuel in the NFV must be covered by a fire retardant cover capable of preventing introduction of optimum moderation, and the vault must be covered by a metal cover when fuel handling activities are concluded. No fuel may be put in the NFV if there is water in the vault.
No items other than fuel may be stored in the NFV.
If a fire occurs in an area where fuel is stored on the refuel floor (other than pool), a fire retardant cover shall be placed over the fuel.
tence:
.7-S-02-100, Criticality Rules
Attachment to GNRO-97/00021 Paga 4 of 4
.NRC. Question 5.
Discuss how this exemption would remain valid if a future fuel enrichment increase was contemplated for Grand Gulf Unit 1.
The Technical' Specifications for Unit 1 do not limit the enrichment of the fuel at the site.
Answers-Since-all fuel accepted on site must meet the design basis criticality margin requirements, all bases for this exemption will remain valid.
References:
See Question 3.
NRC Question 6.
~ Discuss.that radiation, monitoring remains available to meet the requirements of GDC 63 for fuel storage areas.
Answer:
All fuel storage areas are monitored and will continue to be monitored per GDC 63.
Exemption to the radiation monitoring required by GDC 63 was not requested in the exemption request letter dated July 16, 1996 (Grand Gulf to-NRC letter GNRO-96/00082).
References:
1.
UFSAR Chapter 12, Section 12.3.4.1 2.