ML20127H200

Application for Amend to License DPR-22 to Authorize Use of Partial Drilled Model for Plant

ML20127H200
Person / Time
Site:	Monticello
Issue date:	08/10/1978
From:	Wachter L NORTHERN STATES POWER CO.
To:
Shared Package
ML20127H193	List: ML20127H188 ML20127H200 ML20127H217 ML20127H244
References
NUDOCS 9211180434
Download: ML20127H200 (5)

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UNITED STATES NUCLEAR REGULATORY CuttiiSSION NORTilERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 REQUEST FOR AMENIX1ENT TO OPERATING LICENSE NO. DPR-22 (Supplement 1 to License Amendment Request Dated March 21, 1978)

Northern States Power Company, a Minnesota corporation, d requests authorization for changes to the Technical Specifications as shown on the attachments labeled Exhibit A Exhibit B, and Exhibit C. Exhibit A describes the proposed changes along with reasons for -the change, Exhibit B _ is a set of Technical Specification pages incorporating the proposed changes. Exhibit C is a safety evaluation supporting the changes.

This request contains no restricted or other defense information.

NORTilERN STATES POWER CalPANY By dj[ ~

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1. 1. L J Wachtcr Vice President, Power Production &

System Operation on this 10th day _of August ,-1978 ,_before me a notary public in and for said County, personally appeared L J Wachter, Vice President, - Power Production & System Operation, and first being duly _

sworn acknowledged that he is authorized to execute this document in be-half of Northern States Power Company, that he knows che contents thereof and that to the best of his knowledge, information and belief, the state-

' ments made in it 'are true and that it is not interposed for delay, a /T kl f) 0) . i

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"g DENtSE E. HALVORSON ! ,

, ; i NOTARY PUBUC

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I HENNEPIN COUNTY My ComrMasson Empires Oct 10,1961)f

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9211180434.780810 PDR ADOCK 05000263 P PDR r.

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, EXHIBIT A

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MONTIC ELll) NUCLEAR GENERATING PIANT Docket No. 50-263 License No. DPR-22 SUPPLDENT NO. 1 TO LICENSE AMENDMENT REQUEST DATED MARCH 21, 1978 PROPOSED CHANGES TO TECHNICAL SPECIFICATIONS Pursuant to 10CFR50, the holders of Provisional Operating License DPR-22 hereby propose the following changes to the Appendix A Technical Specifications.

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1. List of Figures and List of Tables PROPOSED CHANGES Delete Figures 2.1-1, 2.3.1, 2.3.2, 3.11.1-u through d and 3.11.2 from Pages vii and viii. Add Table 3.11.1 to Page ix. These proposed changes are incorporated in Exhibit B.

REASON FOR CHANGES The information from the deleted figures is proposed to be incorpo-rated ' in either the newly created Table or in the Specifications.

SAFETY EVALUATION These changes are only in format and require no safety evaluation.

2. Power Density Definition PROPOSED CHANCES Delete the definition of " Peaking Factor" on Page 3. Add the definition fo r "!!aximum Fraction of ' Limiting _ Power Density (MFLPD)"

on Page 2. Re-letter the definition on those pages as shown to maintain the alphabetical order.

_ REASON FOR CHANGES The concept of peaking factor, as .- defined , is only meaningful for a core of a single fuel design. The Monticello reactor uses a number of compatible fuel types. The - parame ter of interest '. is .

the relationship between the local power density and ' the design -

limit. The concep t of peaking factor compares the local surface heat flux to the core average surf ace heat flux. This involves the heat transfer area which is dependent on the fuel type (Number of fuel pins per assembly, cladding diameter, etc.). The concept of MFLPD is more appropriate for a core of multiple fuel types..

SAFETY EVALUATION These changes do not affect the safety of the plant, since it simply introduces a new set of units for core monitoring.

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3. Fuel Cladding Integrity Safety Limits and Limiting Safety Systems

Settings.

I PROPOSED CHANGES Change the MCPR safety limits from 1 06 to 1.07 as shown on Page 6 in Exhibit B.

i Change the APRM flux scram and rod block trip settings as shown in e

Exaibit B, Pages 6, 7 and 8, including the neces sa ry editorial changes on Page 9 to accommodate the overflow information.

Eliminate Figures 2.3.1 and 2.3.2 on Pages 11 and 12.

i Make the changes to the Bases shown in Exhibit B, Pages 13, 14, 19, 20 and 21.

i l REASON FOR CHANGES The MCPR safety limit change is made necessary by the use of retrofit fuel as discussed in the Safety Evaluation.

4 The APRM flux scram in rod block trip settings are proposed to be changed for three reasons: Firs t , they implement the definition of

MFLPD in place of peaking factor as discussed in item 2 above.

Second, they place the linear equations in the Specification rather

, than in a Figure for easier reference. Third, the settings are stated in terms of reactor power rather than a heat flux equation which is unique to a fuel type.

Figures 2.3.1 and 2.3.2 are proposed to be deleted because the Specification discussed in the above paragraph incorporates the same inf o rma tion.

The proposed changes to the Bases are to make proper ref erence to the newly proposed safety limit incorporating the concept of MFLPD in place of peaking factor, and to make correct reference to the Specifications which replace figures.

SAFETY EVALUATION 2

The Saf ety ' Evaluation of the new MCPR safety limit is included as Exhibit C and the Topical Report which Exhibit C supplements,

, N ED 0-2 4011. The remaining proposed changes are a matter of editing and using dif ferent units which require no f urther saf ety evaluation.

4. Reactor Fuel Assembly Limiting Condition for Operation.

PROPOSED CHANGES Revise the APLHGR Specification as shown on Page 18CB of Exhibit B to make ref ere nce to Table 3 .11. ~1 rather than Lgures 3.11.1-a through d.

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PROPOSED CHANGES (Continued)

Incorporate the LilGR equation in the Specification as shown on Page 189C of Exhibit B to allow deletion of Figure 3.11 2. Also, the densification penalty at the top of the core has been increased from

.021 to .022.

Change the MCPR to the new values supported by this submi t t al as shown on Page 189D of Exhibit B.

Create a new Table 3 11 1 as shown on Page 189E of Exhibit B, which replaces the existing MAPLHGR figures. This Table adds new fuel types which will be firs t used in Cycle 7 and e11 minutes a fuel type which is not expected to be used in the future.

Re-number Pages 189E,F and G to be 189F, G and H as shown in Exhibit B. Ins e rt the newly proposed MCPR ope ra ting limit as shown and climinate the ref erence to the superseded safety limit.

Delete Figures 3.ll.1-a through d and 3 11.2.

REASONS FOR CHANGES The proposed change to the APlHGR specification is merely a format change which accommodates the use of a Table rather than a Figure.

The straight line interpolation referenced is exactly the way data is presently used in deriving the exisiting APLilGR figures.

The proposed change in LilGR is partially editorial to eliminate a figure. The proposed change in the densification penalty is in accordance with the Safety Evaluation.

The operating MCPR limit is proposed to be changed as a result of the transient analysis discussed in the Safety Evaluation. The limit of 1.32 is based on the most limiting abnormal operational transient for Monticello, the turbine trip without bypass. As discussed in Exhibit C, steady state operation with an improperly loaded f uel assembly could, in the worst possible case with a very conservative analytical model, result in a greater delta CPR than a turbine trip without bypass. The May 12, 1978 NRC Staff Safety Evaluation of Topical Report N EDO-2 40 l l , "Ceneric Reload Fuel-Application" states that the Staff is still reviewing this matter.

When loading f uel in the Monticello reactor, measures are taken to assure that the core is properly loaded, the result being that the plant has never experienced a bundle loading error. We have not seen suf ficient evidence to justify a limit so restrictive that full power operation may not be allowed. We therefore propose that in the interim, while the Staf f is considering the matter, the licensing basis for Monticello be our past experience and that the turbine trip without bypass remain to be considered the limiting abnormal ope ra tional eve nt .

Table 3.11.1 is proposed to be added to simplify the editing when other fuel types are used. It is also more accurate to use the Table rather than reading from a Figure. These numbers are used in a tabular form in the process computer for core monitoring. The Table has been updated to include those fuel types scheduled to be used in the Monticello Cycle 7 core. l

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'g A-4 The Bases pages are simply revised to reflect editorial changes in nu mb e ri ng , in stating the revised opera ting MCPR limit and in deleting the superseded MCPR safety limit.

Figures 3.11.1 a through d are proposed to be deleted because they -

a re replaced by Table 3.11.1 and Specification 3.II.A. Figure l 3.11.2 is proposed to be deleted with Specification 3.ll.B taking 1 its place.

SAFETY E'.'ALUATION i

The Safety Evaluation for these proposed changes is Exhibit C and

the Topical Report which Exhibit C supplements.

5. Design Features - Reactor Fuel

! PROPOSED CHANGES Modify the desc rip tion of the reactor core shown as shown on Page i 190 Exhibit L to delete the numbe r of fuel rods per assembly.

REASON FOR CHANGE The 8x8R fuel has 62 fueled rods which is not within the present scope of Specification 5.2.A. This fuel type has been shown to be fully compa tib le as can be expected for a number of other fuel l designs having dif ferent numbers of f uel rods per assembly.

SAFETY EVALUATION 4

l The Safety Evaluation for this proposed change is Exhibit C and the Topical Report which Exhibit C supplements. Two comments should be made- in addition to Exhibit C regarding the use of 8x8R fuel.

I The generic Topical Report on retrofit fuel, NED0-240ll,- considers

' only s tandard f uel s torage racks. Monticello has been authorized to install a High Density Fuel Storage System (HDFSS) 'which is not i

discussed in the Topical Report. However, the April 14 1978 Staff

Safety Evaluatior authori<.e. tiie installation and use or nurbb at Monticello for any fuel type containing less than 15.2 grams of U-235 in any axial centimeter of the fuel assembly. All fuel types

[ discussed in NEDO-240ll meet the criteria and are therefore accept-1 able for use in the HDFSS.

The transient analysis in Exhibit C assumes no recirculation pump '

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trip initiated from ATWS sensors. A March 1,1978 License Amendment Req ues t for Technical Specifications covering operation of this system is presently before the NRC Staff. It is conservative to assume that the recirculation pump trip is not available with

-respect to over-pressurization events - and operating limit MCPR analyses for Monticello; the refo re , the Exhibit C analyses are i bounding whether the recirculation pump trip is implemented in I Cycle 7 or not.

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