ML20217J951
| ML20217J951 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 03/31/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217J948 | List: |
| References | |
| NUDOCS 9804070085 | |
| Download: ML20217J951 (2) | |
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p UNITED STATES
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NUCLEAR REGULATORY COMMISSION t
WASHINGTON. D.C. 30806-0001
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i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 220 TO FACILITY OPERATING LICEiNSE NO DPR49
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IES UTILITIES INC.
CENTRAL IOWA POWER COOPERATIVE CORN BELT POWER COOPERATIVE DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331
1.0 INTRODUCTION
i By letter dated February 3,1998, the licensee submitted a request for changes to the Duane Arnold Energy Center (DAEC) Technical Specification (TS). The amendment would change the operability requirement fer the Standby Liquid Control (SLC) system to Run/ Power Operations and Startup. This proposed revision to DAEC TS is consistent with NUREG 1433, Revision 1. " Standard Technical Specifications, General Electric Plants, BWR/4," and the DAEC's proposed conversion to the improved Standard Technical Specifications submittal dated October 30,1996.
2.0 EVALUATION The SLC system is manually initiated from the main control room, as directed by the emergency operating procedures, if the operator believes the reactor cannot be shut down, or kept shut down, with the control rods. The SLC system is used in the event that enough control rods cannot be inserted to accomplish shutdown and cooldown in the normal manner. The SLC system injects borated water into the reactor core to add negative reactivity to compensate for all of the various reactivity effects that could occur during plant operations. To meet this objective, it is necessary to inject a quantity of boron, which produces a concentration of 600 ppm of natural boron, into the reactor coolant at 70'F. To allow for potential leakage and imperfect mixing in the reactor system, j
an amount of boron equal to 25% of the amount cited above is added.
The SLC system provides backup capability for reactivity control independent of normal reactivity control provisions provided by the control rods. When the mode switch is in Run/ Power Operation and Startup, shutdown capability is required. When the mode switch is in Shutdown, control rods are not able to be withdrawn since a control rod block is applied, This provides adequate controls to ensur.a that the reactor remains subcritical.
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2-With the mode switch in Refuel, only a single control rod can be withdrawn from a core cell containing fuel assemblies. For demonstration of adequate Shutdown Margin (SDM),
LCO 3.1.1, " Reactivity margin", ensures that the reactor will not become critical.
Therefore, the staff has determined that the SLC system is not required to be operable when the mode switch is in Shutdown or Refuel.
3.0 SIATE CONSULTATION in accordance with the Commission's regulations, the Iowa State official was notified of the proposed issuance of the amendment.= The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment change 0 a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent 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 amendment involves no significant hazards consideration and there has been no public comment on such finding (63 FR 9872). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(g). Pursuant to 10 CFR 51.22(b), no environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that: (1) there is k
reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
- Principal Contributors: P. Ray Date: March 31, 1998
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