ML16138A596
| ML16138A596 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/06/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16138A597 | List: |
| References | |
| NUDOCS 8708130219 | |
| Download: ML16138A596 (3) | |
Text
0 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 160 TO FACILITY OPERATING LICENSE NO. DPR-38 AMENDMENT NO. 160 TO FACILITY OPERATING LICENSE NO. DPR-47 AMENDMENT NO. 157 TO FACILITY OPERATING LICENSE NO. DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS 1, 2, and 3 DOCKET NOS. 50-269, 50-270 AND 50-287 INTRODUCTION By application dated November 19, 1985 as supplemented on June 16, 1986, February 18, 1987 and June 5, 1987, Duke Power Company (the licensee) proposed changes to the Technical Specifications (TSs) of Facility Operating Licenses Nos. DPR-38, DPR-47 and DPR-55 for the Oconee Nuclear Station, Units 1, 2 and
- 3. These amendments would consist of changes to the Station's comion TSs to allow the use of the multielement (three-fuel-assembly) spent fuel casks in the Oconee Unit 3 spent fuel pool.
The proposed amendments increase the region of Oconee Unit 3 spent fuel racks within the spent fuel pool with limits on the spent fuel cask movement from 31 to 33'rows. No change is needed for the Oconee Units 1 and 2 TSs on the combined spent fuel pool.
The proposed changes are needed to allow the licensee to use the multielement spent fuel casks to transfer fuel from Oconee to its McGuire Nuclear Station.
The June 5, 1987 submittal provided information on the shipment of fuel and did not alter the scope of the application noticed in the FederalReg ister on March 12, 1987, or affect the staff's initial no significant harid determination..____
DISCUSSION To retain spent fuel storage capacity at Oconee, the licensee is presently transferring Oconee spent fuel to its McGuire Nuclear Station in single fuel assembly spent fuel casks. By letter dated July 26, 1985, the staff issued Amendment No. 44 to Facility Operating License NPF-9 and Amendment No. 25 to NPF-17 for the McGuire Nuclear Station, Units 1 and 2 to receive, possess and store irradiated fuel assemblies from Oconee. To expedite these spent fuel transfers, the licensee plans to use the multielement spent fuel casks (TN-8L or TN-8) which will result o
e he multielementt casks ben sdi teOoe pesfenlrer and heavier multielement casks being used in the Oconee spent fuel pools.
8708130219 870806 PDR ADOCK 05000269
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2 To mitigate the consequences of potential cask drop events, the current TS 3.8.13.b allows the movement of spent fuel casks in the Oconee Unit 3 spent fuel pool only after the first 31 rows of spent fuel located closest to the spent fuel handling area have decayed for at least 70 days. Radiological consequence calculations for a hypothetical worst case cask drop event in volving the heavier multielement spent fuel pool casks indicate that the spent fuel stored in the first 33 rows of the storage racks closest to the cask handling area must have decayed for at least 70 days for the radiation-dose resulting from the accidental cask drop event to be less than the limits under accident conditions set forth in 10 CFR Part 100. Therefore, to allow the use of heavier multielement spent fuel casks in the Oconee Unit 3 spent fuel pool, the licensee proposes to change the number of spent fuel rows in TS 3.8.13.b from 31 rows to 33 rows.
The current accident analysis for the Oconee Units 1 and 2 spent fuel pool bounds the 'use of the multielement spent fuel casks.
Therefore, TS 3.8.13.a which governs spent fuel cask movement in the Oconee Units 1 and 2 spent fuel pool is not bengchanged.
EVALUATION The multielement fuel casks are larger and heavier than the single element casks previously approved for use. The licensee has provided a summary of the results of an evaluation ofrthe load handling features to be utilized with the multielement casks. These results indicated that existing cask platforms, operating decks and handling and lifting devices are adequate to safely handle the multielement casks. Further, these features are essentially unchanged from those used to handle the single element spent fuel cask and which were previously approved by the staff. The staff, therefore, finds the load handling provisions for the multielement casks to be satisfactory.
The licensee also summarized their evaluations of the consequences of a hypo thetical cask/heavyload drop accident involving the heavier multielement spent fuel casks in the Oconee Unit 3 spent fuel pool.
The worst case failure is considered to be a hoist cable break when the cask is positioned over the fuel pool wall and the cask has an eccentric drop into the wall.
In this case, the yoke and load block would be deflected onto the spent fuel resulting in damage to the fuel assemblies. There are 148 fuel storage positions under the projected cask, yoke, and block impact area. These storage racks buckle and deflect into adjacent racks until the total energy of the falling cask is absorbed. In total, 518 fuel storage racks can potentially incur a loss of integrity from impact during a cask drop accident.,
The radiological consequences of the cask drop accident will be mitigated by limiting the age of fuel stored in the first 33 rows. No cask movement will be allowed if fuel in these locations has decayed less than 70 days. The worst radiological consequences experienced would result from 100 percent of the activity contained in the fission gases trapped in gaps in the fuel stored in the locations being released into the pool water. The licensee has calculated an exclusion area boundary dose, taking no credit for.
ventilation system filtration, of 0.1 rem whole body and 23 rem to the thyroid. The staff has performed an independent calculation and determined a dose to the thyroid of approximately 50 rem. These doses are a small fraction of the 10 CFR Part 100 limits.
-3 The staff has reviewed the licenseecs summary analysis concerning the Tostulated multielement cask drop acci dent and the resulting consequences.
The staff finds that the lccensees analysis is reasonable and satisfac only demonstrates that a cask drop will not result in unacceptable consequences. Based on the above, the staff concludes that the proposed change to Oconee, Unit 3 Technical Specification 3.8.13.b to impose limits on spent fuel decay in the first 33 storage rack rows is acceptable since the licensee has demonstrated that offsite doses resulting from damage to spent fuel from a postulated drop of the multielement spent fuel cask are below a small fraction of the 10 CFR Part 100 limits.
ENVIRONMENTAL CONSIDERATION Pursuant to 10 CFR 51.32, the Commission has determined that the issuance of this amendment will have no significant impact on the environment (52 FR 29098).
CONCLUSION The Commission made a proposed determination that the amendments involve no significant hazards consideration whic wspbihdnteFdraRe ister (52 FR 7682) on March 12, 1987, and consulted with the state Federl Rgistera.
No public comments were received, and the state of South Carolina did not have any comments.
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 manner, and (2) such activities will be conducted in compliance with the Commission's regulations and'the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: R. Ferguson M. Wohl H. Pastis J. Minns Dated: August 6, 1987