ML20237G223
| ML20237G223 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/26/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237G211 | List: |
| References | |
| NUDOCS 8709020156 | |
| Download: ML20237G223 (2) | |
Text
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i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 49 TO FACILITY OPERATING LICENSE NO. DPR-22 NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263
1.0 INTRODUCTION
By application dated February 4,1987, Northern States Power Company (NSP) l proposed changes to the Technical Specifications (TS) for the Monticello Nuclear Generating Plant.
The proposed changes are to the Rod Block Monitor (RBM) setpoints given in TS Table 3.2.3.
The justification for the change is based on General Electric (GE) calculations extending for Monticello the range l
of initial Minimum Critical Powar Ratio (MCPR) conditions considered for the l
Rod Withdrawal Error (RWE) at power event and the corresponding RBM setpoints required for appropriate protection.
l 2.0 DISCUSSION AND EVALUATION l
In 1984, NSP elected to implement the GE-supplied ARTS (Average Power Range l
l Monitor, Rod Block Monitor and Technical Specification) improvement program for Monticello.
This program includes changes to the RBM system which provides the required protection for the RWE at power event.
The ARTS program, and in particular the RBM system, was described in a GE topical report for Monticello (Ref. 1) which was a part of the Monticello ARTS j
s ub.ni ttal.
It describes the new RBN approach and methodology and the results of calculations which were done to determine the setpoints for the system.
These descriptions, methods and results were approved along with the remainder of the program in the staff review of ARTS for Monticello.
l The Monticello RBM (analytical, allowable and nominal) setpoints presented in Reference 1 were calculated with the assumption that the full power operating limit MCPR (OLMCPR) and thus the initial condition for the RWE were 1.2.0.
These calculated setpoints (including, where relevant, the instrumentation uncertainty components) along with other parameters relevant to the RBM l
operation were presented in Table 4-5 to include setpoints for OLMCPR of 1.25, 1.30 and 1.35.
Other parameter values of Table 4-5 remain the same as in the original report.
This expanded table is included in the NSP submittal.
The j
setpoints are higher for the larger OLMCPR values since there is a larger i
margin to the safety limit MCPR for the RWE event.
These additional setpoints have been developed using previously approved methodology and the results are reasonable and acceptable.
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R Since for Monticello the rated OLMCPR are generally above 1.30 (1.36 for the current cycle), NSP has proposed to modify the RBM TS giving the setpoints; i.e., Table 3.2.3, Items 4.a.1, 2 and 3, and the corresponding Bases 3.2.
The change is based on the OLMCPR of 1.30 and this is stated in the revised Bases 3.2.
The low, intermediate and high (power level region) trip setpoints are changed to 120, 115 and 110, respectively.
These setpoints are conservative for the chosen MCPR.
(Table 4-5 nominal setpoint values are 121.1, 116.1 and 111.3 for operation with the RBM filter.) These are reasonable TS changes, based on approved GE methods and results, and they are acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a' requirement with respect to the installation 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
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significant change in the types, of any effluents that may be released
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l offsite and that there is no significant increase in individual or I
cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment involves no significant l
hazards consideration and there has been no public comment on such finding.
l Accordingly, this amendment meets the eligibility criteria for categorical i
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 l
in connection with the issuance of this amendment.
4.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, I
that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner; l
and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be l
I inimical to the common defense and security or to the health and safety l
of the public.
- 5. 0 REFERENCES 1.
NEDC-30492-P, April 1984, " Average Power Range Monitor, Rod Block Moritor, and Technical Specification Improvement (ARTS) Program for Monticello."
1 Principal Contributor:
H. Richings Dated: August 26, 1987 i
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