ML20114C648
| ML20114C648 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 08/25/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20114C647 | List: |
| References | |
| NUDOCS 9209030044 | |
| Download: ML20114C648 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ED ATED TO AMENDMENT NO.187 TO FACillTY OPERATING LICENSE NO. DPR-49 IOWA ELECTRIC LIGHT AND POWER COMPANY R4 TRAL 10WA POWER COOPERATIVE LORN BELT POWER COOPERATIVE QULANE ARNOLD ENERGY CENTER l
DOCKET NO. 50-3.3_1 1.0 JNTRODUCT[0B By letter dated February 18, 1992, Iowa Electric Light and Power Company (the licensee) proposed changes to the Technical Specifications for Facility Operating License No. UPR-49 for the Duane Arnold Energy Center (DAEC).
The proposed changes incorporate revised setpoints for isolation of the High Pressure Coolant injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems on a high sti.am flow condition.
2.0 EVALUATION Boiling Water Reactor (BWR) HPCI and RCIC Systems include instrumentation that measures differential pressure a., e means of detecting high steam flow to the turbine, which may be indicative of a break in system piping.
System isolation occurs if the flow exceeds 300% of rated steam flow.
This value is a historically accepted industry standard which is below the choke flow limit and abcVe the values for steam ficw which could occur during system startup transients. Testing at several BWRs showed that the method originally used to convert 300% of rated flow to a differeatial pressure value may not be conservative with respect to the analytic limit, i.e., the result may exceed 300%. As a result, General Electric suggested that BWR licensees recalculate the affected setpoints.
The licensee has determined that the current setpoints for the HPCI and RCIC high steam flow isolation are conservative with respect to the analytic limits.
Further study has concluded that the isolation setpoints should be increased to provide additional margin above the values of steam flow expected during system startup transients. This change will reduce the likelihood of an inadvertent isolation during system startup, thereby improving overall system reliability.
This increase in setpoint will still ensure that the analytic limit is not exceeded when all errors are taken into consideration as discussed in the plant's setpoint methodology.
The following are the proposed cnanges to the DAEC Technical Specifications for the trip level settings of the HPCI Turbine Steam Line High Flow and RCIC Turbine High Flow Trip functions.
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On Page 3.2-13, the setpoints for the HPCI and RCIC High Steam Flow Isolation-have been revised.
The "5" notation is being incorporated to ensure conservative adjustment of the associated setpoints.
The reference _ to a setpoint tolerance for the RCIC High Steam Flos isolation has been deleted.
The reference to Note 3 in the HPCI trip level setting is being duplicated for each instrument to ensure that it is applied to both instruments.
(2)
On page 3.2-40, the Bases for Section 3.2/4.2 are being revised to reflect the change to the HPCI and RCIC High Steam Flow Isolation setpoints.
The word "which" in the third paragraph is being added.
The proposed setpoints are conservative with respect to the 300% flow analytic limit.
Increasing the setpoints to the proposed values will provide additional margin above the transient flow rates that can occur during system startup.
The changes will h?lp prevent unwanted system isolations and increase the probability that HPCI and RCIC will be available to perform their design functions.
These changes to the Technical Specifications Table 3.2-B and Bases are, therefore, acceptable.
3.0 STATE 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.
3 4.0 -[MIRONMENTAL CONSIDERATIONS This amendment involves.a change to a requirement with respect to the instal-lation or use of a facility component located within the restricted area as defined ~in 10 CFR Part 20.
The staff has determined that the amendment involves 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 this amendment involves'no significant hazards consideration and there has been no public comment on such finding.(57 FR 9446). Accordingly, this amendment-
. meets the-eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared ir, connection with the issuance of this amendment.
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.3 5.0 CONCLV11QU 1he staff has 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, (2) such activities will be conducted ir. compliance with the Commission's regulations, and (3).the issuance of the amendment will not be inimical to the common i
defense and security or to.the health and safety of the public.
f Principal Contributor:
C Y. Shiraki Date: August 25, 1992 5
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