ML20244C855
| ML20244C855 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/07/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20244C848 | List: |
| References | |
| NUDOCS 8906150175 | |
| Download: ML20244C855 (3) | |
Text
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'pp nrou Jg UNITED STATES
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. NUCLEAR REGULATORY COMMISSION 5
f WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 39 TO FACILITY OPERATING LICENSE NO. DPR-80 AND AMENDMENT NO. 38 TO FACILITY OPERATING LICENSE NO. DPR-82 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET NO. 50-275 AND 50-323
1.0 INTRODUCTION
By letter dated March 29, 1989 (Reference LAR 89-04), Pacific Gas and Electric Company (PG&E or the licensee) requested amendments to the combined Technical Specifications (TS) appended to Facility Operating License Nos. DPR-80 and DPR-82 for the Diablo Canyon Power Plant (DCPP),
Unit Nos. I and 2, respectively. The amendments change the TS to require that at least 23 feet cf water be maintained above the top of irradiated fuel assemblies within the vessel during movement of rod cluster control assemblies.
2.0 EVALUATION The previous TS required that at least 23 feet of water must be maintained above the top of the reactor vessel flange.
These amendments change that requirement only during movement of rod cluster control assemblies, and not during movement of fuel assemblies. The amendments revise TS 3/4.9.10, " Water Level-Reactor Vessel," and the associated Bases.
Specifically, TS 3.9.10 is subdivided into TS 3.9.10,,1 and TS 3.9.10.2 to address different operational situations. TS 3.9.10.1 requires at least 23 feet of water above the reactor pressure vessel flange for movement of fuel assemblies within containment. TS 3.9.10.2 allows rod cluster control assembly (RCCA) movement within the reactor pressure vessel with at least 23 feet of water over the top of the irradiated fuel assemblies. Also, a statement is added to the TS 3.9.10.1 action statement to specify that the provisions of TS 3.0.3 are not applicable.
TS 4.9.10 is also subdivided into TS 4.9.10.1 and TS 4.9.10.2 to require surveillance of the refueling water level for movement of fuel assemblies and for mwement of control rods, respectively. Also, the TS Bases are changed to reflect the above changes in the TS.
The NRC staff has reviewed the licensee's proposed TS change and finds it acceptable, based on the following:
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l Regulatory Position C.I.c of NRC Regulatory Guide l.25, " Assumptions Used for Evaluating the Potential. Radiological Consequences of a Fuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors,". recommends that 23 feet of water be maintained above the location of any damage'to irradiated fuel that could occur in a postulated fuel handling accident. The primary purpose of this recommendation is to ensure that sufficient water depth is available to remove 99 percent of the lu percent iodine gap activity that is assumed to be released in a fuel handling accident. The highest elevation at which such a release could occur would be at the level of-the reactor vessel flange, where a release could result from an irradiated fuel assembly striking the reactor vessel tlange while the assembly is being loaded into or unloaded from the reactor vessel.
Based on this, TS 3/4.9.10 currently' requires that 23 feet.of water be maintained above the reactor vessel flange during all refuelina operations.
However, during uncoupling of the control rod drive shafts, the upper reactor vessel internals are still in place and the tuel assemblies will remain seated in the reactor pressure vessel, and fuel damage cannot I
occur above the top of the fuel. With the fuel assemblies seated in the pressure vessel, 23 feet of water above the top of the. fuel will ensure that sufficient water depth 1s available to remove 99 percent of the assumed 10 percent iodine gap activity released in the event of fuel damage. Based on this, the revised TS requires that 23 feet of water be maintained above the reactor vessel flange when fuel is being moved, and that 23 feet of water be maintained above the fuel in the vessel when only the control rods are being moved. Therefore, the revised TS will continue to provice assurance that the plant meets the recommendations of Regulatory Guide 1.25 in the. event of a fuel handling accident.
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Based on the above, the staff finds acceptable the proposed amendments authorizing revision of the TS to require that at least 23 feet of water be maintained above the top of irradiated fuel assemblies within the vessel during movement of rod cluster control assemblies.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes in the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20, and changes in surveillance requirements. We have determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
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4.0. CONCLUSION We have concluded, based on the considerations discussed above, that:'
(1) there is reasonable assurance that the health and safety of the-public will-not be endangered by operation in the proposed ma'nner, and
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-(2) such activities will be conducted in compliance with the-j Commission's regulations and (3) the issuance of these amendments will.
not be inimical to the common defense and security or the health and safety of the public.
l Principal Contributor:
Harry Rood Dated:. June 7.1989 l
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