ML20117N592
| ML20117N592 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 09/17/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20117N591 | List: |
| References | |
| NUDOCS 9609190306 | |
| Download: ML20117N592 (5) | |
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- 8 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 97 TO FACILITY OPERATING LICENSE NO. DPR-22 NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263
1.0 INTRODUCTION
By letter dated June 22, 1995, as supplemented August 10, 1995, and March 26, 1996, the Northern States Power Company (the licensee) requested an amendment to the Technical Specifications (TS) appended to Facility Operating License No. DPR-22 for the Monticello Nuclear Generating Plant.
The amendment would modify the requirements for avoidance and protection from thermal hydraulic instabilities to be consistent with the Boiling Water Reactor Owners Group (BWROG) long-term solution Option I-D described in the Licensing Topical Report NED0-31960, "BWR Owners Group Long-Term Stability Solutions Licensing Methodology," June 1991, and NED0-31960, Supplement 1, dated March 1992.
NED0-31960 and Supplement 1 to NED0-31960 were endorsed by the NRC staff in a j
letter to L. A. England (BWROG) dated July 12, 1993. The proposed amendment also adds the fuel cycle dependent stability power and flow limits in the Core Operating Limits Report (COLR) and corrects a typographical error in TS 6.7.A.7.b The licensee's amendment request satisfied a prior commitment to the NRC. The licensee had committed to submit a plant-specific topical reDort demonstrating applicability of solution Option I-D as well as an implementation schedule for solution Option I-D in its response to NRC Generic Letter 94-02, "Long-Term Solutions and Upgrade of Interim Operating Recommendation for Thermal-Hydraulic Instabilities in Boiling Water Reactors."
The August 10, 1995, and March 26, 1996, letters provided a nonproprietary version of the topical report GENE-637-043-0295 and clarifying information, respectively. This information was within the scope of the original application and did not change the staff's initial proposed no significant hazards consideration determination. Therefore, renoticing was not warranted.
2.0 [ VALUATION The proposed changes include modifying the requirements for avoidance and protection from thermal-hydraulic instabilities to be consistent with the l
f BWROG long-term solution Option I-D, and adding an exclusion region and its approved supporting methodologies to the COLR. The following describes the proposed changes.
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2 (1)
Bases 2.3.A - Neutron Flux Scram l
Current basis states that the Average Power Range Monitoring (APRM) system 120% scram trip limiting safety setting specified in TS 2.3.A.1 protects against fuel damage for the analyzed abnormal operational transient, and that the use of a flow-referenced scram trip provides additional margin. The proposed change involves modifying a sentence to reflect that the flow-biased r.eutron flux scram (Specification 2.3.A.1) provides protection to the fuel safety limit in the unlikely event of a i
thermal-hydraulic instability.
This change is consistent with the application of the previously approved BWROG long-term solution Option 1-D, and therefore, it is acceptable.
(2)
TS 3.5.F - Recirculation System a.
TS 3.5.F.1.b, c, d, and e and Figure 3.5-1 are deleted to remove limiting condition for operation requirements for monitoring thermal-hydraulic instability during a single-loop operation and to remove the single-loop operation surveillance power / flow curve.
b.
TS 3.5.F.1.a.2 is modified to specify that the MAPLHGR [ maximum average planar linear heat generation rate] limit is modified per TS 3.11.A and is renumbered TS 3.5.F.3.a.2.
c.
The existing TS 3.5.F.1 is renumbered as TS 3.5.F.3.
d.
TS 3.5.F.1 and 3.5.F.2 are added to exclude normal plant operation in the analytically defined exclusion region to be specified in the COLR.
TS 3.5.F.4 is also added to account for the condition with no reactor coolant system recirculation loops in operation.
The proposed addition to the TS requires that the exclusion region is to be avoided and will be immediately exited should inadvertent entry occur, in order to avoid challenges to the safety limit on minimum critical power ratio.
. These changes are consistent with the application of the BWROG long-term solution Option I-D, and therefore, they are acceptable.
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(3)
Surveillance Requirements 4.5.F.2 and 4.5.F.3 are deleted to remove the requirements to obtain baseline neutron flux noise data fu single loop i
operation. These changes are consistent with the application of the l
BWROG long-term solution Option I-D, and therefore, they are acceptable.
(4)
Bases 3.5/4.5.F - Recirculation System The Bases have been revised to reflect the current approach for avoiding and protecting the fuel from thermal-hydraulic instabilities. These changes are consistent with the application of the BWROG long-term solution Option I-D, and inerefore, they are acceptable.
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1 (5)
TS 3.11. A - Average Planar Linear Heat Generation Ratio (APLHGR) i This TS has been revised to clarify the use of the APLHGR correction factors applied during single-loop operation. The current TS only uses 4
one correction factor of 0.85 and the proposed change will also include
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the appropriate flow-and power-dependent correction factors specified i
in the COLR. This change is consistent with the approved topical report NEDC-30492, " Average Power Range Monitor, Rod Block Monitor and Technical Specification Improvement Program for Monticello Nuclear Generating Plant - April 1984," and therefore, it is acceptable.
In addition, the first sentence of TS 3.11.A has been corrected to read "During two recirculation loop ' power' operation...." Although requested in the licensee's application dated January 4,1994, the word
" power" was inadvertently omitted from TS oage 211 issued with Amendment No. 88 on June 30, 1994.
(6)
TS 6.7. A.7 - Core Operating Limits Report (COLR) a.
The proposed change in TS 6.7.A.7.b includes a correction of a typographical error for Siemens Power Corporation report ANF-91-048(P)(A) as ANF-91-0481(P)(A) and an addition of an approved topical report NED0-31960 and NED0-31960, Supplement 1, "BWR Owners' Group Long-Term Stability Solutions Licensing Methodology." These proposed changes are acceptable since they involve appropriate and approved methodologies to be used.
b.
Section 182a of the Atomic Energy Act (Act) requires that applicants for nuclear power plant operating licenses state TS and that the 15 be included as a part of the license.
The Commission's regulatory requirements related to the content of TS are set forth in 10 CFR 50.36.
That regulation requires that the TS include items in five specific categories including:
(1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; and (5) administrative controls.
The regulation also states that the Commission may include such additional TS as it finds appropriate.
TS limiting conditions for operation must be established for each item meeting one or more of the criteria specified in 10 CFR 50.36(c)(2)(ii).
The licensee has requested that the cycle-specific power / flow exclusion region be relocated from TS Figure 3.5-1 to the COLR.
The staff has reviewed the proposed change and has determined that the cycle-specific power / flow exclusion region may be modified by the licensee, without affecting nuclear safety, provided that such changes are determined using the NRC-approved methodologies specified in TS 6.7.A.7.
NRC approval and a license amendment would be required prior to using a methodology other than one approved and specified in TS 6.7.A.7.
Because plant operation will continue to be limited in accordance with the values of the
4 cycle-specific power / flow exclusion region established using NRC-approved methodologies, the staff finds the proposed changes acceptable and consistent with NRC guidance contained in Generic Letter 88-16 on modifying cycle-specific parameters.
The requirement to avoid operations in.the exclusion region will be maintained in the revised TS 3.5.F.1, 3.5.F.2, and 3.5.F.4.
The staff has concluded, therefore, that the relocation of the power / flow
. exclusion region to the COLR is acceptable because its inclusion in technical specifications is not required by 10 CFR 50.36 or other regulations, and it is adequately controlled by existing TS and its inclusion in the TS is not required to avert an immediate threat to public health and safety.
' Based on its review, the staff concludes that the proposed changes, including the application of the BWROG long-term solution Option I-D to the Monticello plant, relocation of the power / flow exclusion region to the COLR, and addition of the approved topical report relating to the I-D methodologies, are consistent with the previously approved generic methodology, and are therefore acceptable.
The staff is planning to perform an inspection of the implementation of these changes. -This inspection will focus on the design record files for the calculations reported in the Table 4.1 of GENE-A00-04021-02 to perform an independent review.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Minnesota State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes 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 and changes surveillance requirements. 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 the amendment involves no significant hazards consideration and there has been no p'blic comment on such finding (60 FR 45181). Accordingly, the 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 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 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 the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
T. Huang Date: September 17, 1996 l
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