ML20236D915
| ML20236D915 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/21/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236D906 | List: |
| References | |
| NUDOCS 8707310127 | |
| Download: ML20236D915 (3) | |
Text
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l
'o, UNITED ST ATES
',g NUCLEAR REGULATORY COMMISSION g
,.p WASHINGTON, D. C. 20555 l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 9 TO FACILITY OPERATING L1JENSE NO. NPF-43 DETROIT EDISON COMPANY AND WOLVERINE POWER SUPPLY COOPERATIVE, INCORPORATED FERMI-2 j
DOCKET NO. 50-341
- 1. 0 INTRODUCTION By letter dated March 9,1987, Detroit Edison Company (the licensee) proposed two changes to the Technical Specifications (TS) for Fermi-2.
The primary change proposed is to the " ACTION" in TS 3.2.2, changing the time to adjust trip setpoint values when they do not meet specified limits, from two to six hours.
Also proposed is an administrative change removing a typographical error in TS Table 3.3.6-2.
2.0 EVALUATION TS 3.2.2 provides a formulation for the average power range monitor (APRM) limiting condition for operation (LCO) setpoints for high flux scram and rod j
block trips.
These setpoints are a function of recirculation loop flow rate and local power density peaking factor (expressed as the factor T, the ratio of the Fraction of Rated Thermal Power divided by the Maximum Fraction of Limiting Power Density).
If the setpoint limits are exceeded, TS 3.2.2 action presently requires the initiation of corrective action within 15 minutes and the adjustment of the setpoints (or the APRM gain) to meet the LC0 statement within two hours, or else the reduction of power to less than 25 percent within the next four hours.
The licensee proposes that the two hours be increased to six hours for Fermi-2.
(The required immediate (15 minutes) action would be operator determination that the peaking factor would be improved by the changing xenon and rod pattern within the time frame, as discussed below.)
The problem of exceeding the setpoint limits arises primarily during lower power operation during startup when local power density peaking factors may be larger than those permitted for full power operation.
(At full power, the peaking factor is limited by the TS linear heat gent.ation rate LC0 of 13.4 kw/ft, and T must be equal to or greater than 1.0.
At lower power, this LC0 is still in effect but permits large peaking factors and T may be less than 1.0.)
The larger peaking factor is generally the result of temporary control rod patterns which exist before achieving the target higher power patterns, and the xenon level and distribution which are not yet at equilibrium values.
Allowing longer times for the setpoint change action allows progress toward the target rod pattern and provides increased xenon, both of which improve the peaking factor and tend to make the setpoint change unnecessary.
8707310127 B70721 PDR ADOCK 05000341 p
2 The flow biased'APRM rod block and scram trips provide only additional margin to the safety analysis since the Fermi-2 (and other BWRs) relevant safety analyses (e.g., the Final Safety Analysis Report) are primarily based on the fixed (120 percent power) scram.
The extension to six hours for the setdown action has been reviewed and approved for a number of operating reactors, e.g., Browns Ferry 1, 2, and 3 (Ref.2 & 3) and as initial TSs for several i
recently licensed reactors, e.g., Limerick 1 and Hope Creek.
The primary I
basis for these approvals has been the secondary role played by the flow biased APRM trips (see References 2 and 3).
This review has concluded that the proposed change to the TS 3.2.2 action time l
is the same as the change (or original specification) approved in previous f
reviews and that the secondary nature of the affected trips and improvement in j
peaking factor to be expected for continued operation in the startup mode j
provide a reasonable and acceptable basis for approval of the change.
j The licensee alto proposes a change to the TS Table 3.3.6-2, removing from
{
the Rod Biock Monitor upscale trip formulation two asterisks referring to a j
footnote.
The presence of the asterisks was an error.
This footnote is correctly applied to the APRM Flow Biased Neutron Flux-High trip and was not intended for the Rod Block Monitor.
Its removal is acceptable.
The licensee proposes to add "APRM" to the footnote to clarify the intent of the specification.
This too is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes to requirements with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20.
We have 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.
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 nor environmental assessment need be prepared in connection with the issuance of this amendment.
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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 manner, and (2) such activities will be conducted in compliance with the Commission's regula-tions, and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
5.0 REFERENCES
1.
Letter (and enclosure) from F. Agosti, DECO, to the NRC, dated March 9, 1987, " Proposed TS Change - ARPM Setpoints (3/4.2.2)..."
2.
Letter (and enclosure) from T. Ippolito, NRC, to H. Parris, TVA, dated September 15, 1981, Amendment No. 76 and Safety Evaluation for Browns Ferry Unit 1.
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3.
Letter (and enclosure) from R. Clark, NRC, to H. Parris, TVA, dated August 17, 1984, Amendment Nos. 104 and 77 and Safety Evaluation for Browns Ferry Units 2 and 3.
Principal Contributor:
H. Richings, NRR Dated: July 21, 1987
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