NRC-96-0134, Application for Amend to License NPF-43,modifying TS Section 3.1.4.3,Table 3.3.6-1 & Table 4.3.6-1 Re Rod Block Monitor Applicability

Application for Amend to License NPF-43,modifying TS Section 3.1.4.3,Table 3.3.6-1 & Table 4.3.6-1 Re Rod Block Monitor Applicability

ML20135E714
Person / Time
Site:	Fermi
Issue date:	12/02/1996
From:	Gipson D DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20135E717	List: ML20135E719 NRC-96-0134, Application for Amend to License NPF-43,modifying TS Section 3.1.4.3,Table 3.3.6-1 & Table 4.3.6-1 Re Rod Block Monitor Applicability
References
CON-NRC-96-0134, CON-NRC-96-134 AL-95-05, AL-95-5, TAC-M77676, NUDOCS 9612110452
Download: ML20135E714 (9)

Text

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, Douglis R. Gipson Seneof Vice Prendent Nuclear Generation Fermi 2 6400 North Dine Hghway Newport, Michigan 48166 (313158&f249 December 2,1996 NRC-96-0134 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555

References:

1) Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43

2) NRC Letter: Amendment No. 69 to Facility Operating License No. NPF-43: (TAC No. 77676) dated May 15,1991

3) Detroit Edison Letter to NRC," Transmittal of Cycle 6 Core Operating Limits Report", NRC 96-0131, dated November 12, 1996

4) NRC Administrative Letter No. 95-05," Revisions to Staff Guidance for Implementing NRC Policy on Notices of Enforcement Discretion," dated November 7,1995

Subject:

Proposed Technical Specification Change (License Amendment)-

Rod Block Monitor Applicability Pursuant to 10CFR50.90, Detroit Edison hereby proposes to amend Operating j

License NPF-43 for the Fermi 2 plant by modifying Technical Specification (TS)

Section 3.1.4.3, Table 3.3.6-1, and Table 4.3.6-1.

l This application proposes to change the APPLICABILITY requirements for the Rod ,

Block Monitor (RBM) to require that the RBM be OPERABLE when reactor thermal f t power is greater than or equal to 30% of rated THERMAL POWER. This change is /'

l more restrictive than the current Technical Specification requirements and restores this section to the identical wording that existed for this Limiting Condition for Operation (LCO) prior to Amendment No. 69, Reference 2.

9612110452 961202 PDR ADOCK 05000341 P PDR

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USNRC NRC-96-0134 Page 2 Amendment No. 69 provided the Technical Specification changes necessary for operation in an expanded region of the power-flow map referred to as the Maximum Extended Operating Domain (MEOD). It included a group of" Average Power Range Monitoring (APRM)/ Rod Block Monitor (RBM) Technical Specification (ARTS) improvements. One aspect of Amendment No. 69 involved changes to the i applicability of RBM operability requirement specified in TS Section 3.1.4.3, Table 3.3.6-1, and Table 4.3.6-1. The changes established power level /MCPR values for j which the operability of the RBM was not required.  :

The basis for the RBM specification changes made by Reference 2 was that the delta- l CPR resulting from the Rod Withdrawal Error (RWE) transient would be used to l establish appropriate RBM Rod Block setpoints. With the setpoints established in ,

this manner, the MCPR Safety Limit would not be jeopardized in the event of an RWE transient. Furthermore, prior to the introduction of GE 11 and later fuel designs, compliance with the MCPR Safety Limit was believed to be adequate to ensure fuel cladding integrity; i.e. other fuel limits were bounded by this analysis. GE 11 fuel was first used in the Fermi 2 core in Cycle 4, however, because of the specific  ;

core design in Cycles 4 and 5 the RBM Technical Specification continued to be adequate. When the RWE analysis for Cycle 6 was completed, however, it was  :

determined that mechanical overpower (MOP) limits could be exceeded for an RWE if credit was not taken for the RBM. The MOP analysis checks for compliance with 1% circumferential plastic strain restrictions.

To ensure that all fuel limits would be met during Cycle 6 for an RWE at power, Detroit Edison placed additional RBM operability restrictions in the Core Operating Limits Report (COLR). These restrictions were placed in Section 5.2 of the Cycle 6 COLR, Revision 0 which was provided to the NRC by Reference 3. Measures were also taken to ensure that operators were made aware of and understand these additional restrictions on RBM operability. These measures included issuing a Technical Specification Clarification (TSC) in accordance with Fermi 2 administrative procedures and conducting on-shift training oflicensed operators. The TSC is distributed to all controlled copies of the Technical Specifications and ensures that these copies include an appropriate cross reference to the additional restrictions now being imposed through the COLR.

Detroit Edison believes that the additional controls described above are adequate to ensure that the Rod Block Monitor will be OPERABLE and thus provide the necessary protection against an RWE at power. These measures and the RBM ensure that adequate protection is provided for all fuel clad integrity limits.

The actions taken by Detroit Edison and conclusions regarding the need for this TS change are also consistent with NRC Administrative Letter 95-05, Reference 4. This document provides the following guidance for such situations: "...when a licensee l

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NRC-96-0134 Page 3

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finds itself in non-compliance with a regulation, immediate action such as shutting  !

down the plant is not explicitly required, unless otherwise specified by NRC  !

requirements. However, it is important that the licensee performs prompt safety .  !

assessments of the noncompliance with regulations and make a determination of what ,

should be the safe operational status of the plant." l i

Detroit Edison does not consider the issuance of the TS amendment requested by this . I letter to be a restraint to either: (1) startup from the current refueling outage, or (2)  !

operation at power levels above 30% of rated (the power level above which the RBM l

. is needed). From a safety perspective, Detroit Edison firmly believes that adequate l protection of fuel cladding integrity is ensured by the RBM, by measures described ' )

above to ensure operability of the RBM, and by actions taken to ensure operator j awareness of the additional Cycle 6 restrictions.. .!

The description and evaluation of the specific changes are included in Attachment I to -I this letter. Attachrnent 2 shows the proposed Technical Specification revisions and j Attachment 3 contains the retyped Technical Specification pages. I r

r Detroit Edison has evaluated the proposed Technical Specification change against the ]

criteria of 10CFR50.92 and determined that No Significant Hazards Consideration is )

involved. The Fermi 2 Onsite Review Organization has approved and the Nuclear Safety Review Group has reviewed the proposed Technical Specification and concurs with the enclosed determinations. In accordance with 10CFR50.91, Detroit Edison is providing a copy of this letter to the State of Michigan.

If you have any questions, please contact Mr. Roben Newkirk at (313) 586-4211.

Sincerely, Q) cc: A. B. Beach M. J. Jordan A. J. Kugler A. Vegel l

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l I, DOUGLAS R. GIPSON, do hereby affirm that the foregoing statements are based j on facts and circumstances which are true and accurate to the best of my knowledge l and belief.

DOUGLAS R.81PSON Senior Vice President 1

l On this day of /[Ldbxl/L ,19% before me personally appeared Douglas R. Gipson, being first duly sworn and says that he executed the foregoing as his free act and deed.

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Notary Public ROSAllE A. ARMETTA NOTARYPUBLIC MONROECOUNTY,Mi MYCOMMISS10N EXPlRES10t 1/99 l

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Attachment I to NRC-96-0134 Page1 ATTACHMENT 1 DESCRIFFION AND EVALUATION OF PROPOSED TECHNICAL SPECIFICATION CIIANGE ROD HLOCK MONITOR OPERAHILITY REQUIREMENTS

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. Attachment l'to NRC-96-0134 Page 2 INTRODUCTION The purpose of this proposed amendment is to modify Technical Specification Section 3.1.4.3, Table 3.3.6-1, and Table 4.3.6-1 to change the APPLICABILITY requirements for the Rod Block Monitor (RBM). This proposed change will require that the RBM be OPERABLE when reactor thermal power is greater than or equal to ,

30% of rated THERMAL POWER. This change is more restrictive than the current '

Technical Specification requirements and restores the specifications to the identical wording that existed for RBM operability prior to Amendment No. 69, Reference 2.

EVALUATION i l Detroit Edison installed the GE APRM Rod Block Technical Specification (ARTS) l improvements to the Rod Block Monitor System (RBM) dering Fermi 2's second l refueling outage (RFO2). The analytical basis for the ARTS RBM System was

! documented in Section 15 of GE Nuclear Energy Document NEDC-31843P.

" Maximum Extended Operating Domain Analysis for Detroit Edison Company Enrico Fermi Energy Center Unit 2," July 1990. This document was submitted as Enclosure 4 to Detroit Edison's letter no. NRC-90-0125, dated August 20,1990 which requested the necessary changes to the Technical Specifications to implement the' l

' ARTS RBM System. These Technical Specification (TS) changes were approved as Amendment 69 to the Fermi 2 Operating License.

I i l These changes included a revision to the Rod Block Monitor Applicability section in . i TS 3.1.4.3, Table 3.3.6-1, and Table 4.3.6-1. Prior to the ARTS modification, the i RBM System was required to be OPERABLE in OPERATIONAL CONDITION 1, when THERMAL POWER is greater than or equal to 30% of RATED THERMAL POWER. The Applicability section was revised by Amendment No. 69 to read  ;

" OPERATIONAL CONDITION 1 with (a) THERMAL POWER greater than or 1 equal to 30% of RATED THERMAL POWER and less than 90% of RATED THERMAL POWER and the MINIMUM CRITICAL POWER RATIO (MCPR) less l than 1.71, or (b) THERMAL POWER greater than or equal to 90% of RATED THERMAL POWER and the MCPR less than 1.40."

l The design basis of the RBM System is to mitigate the consequences of the Rod Withdrawal Error (RWE) event at power. At the time when the ARTS RBM was installed at Fermi 2, the focus of the RWE analysis performed by GE was to determine the change in Minimum Critical Power Ratio during a RWE transient.

Compliance with the MCPR Safety Limit was believed to be adequate to assure fuel  !

! cladding integrity during an RWE event. The delta-CPR resulting from the RWE transient was used to establish appropriate RBM Rod Block setpoints to assure that

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in the event of a RWE transient, the MCPR Safety Limit (SLMCPR) would not be jeopardized, thereby precluding transition boiling and potential fuel failure. When

Attachment I to t

NRC-96-0134 Page 3 l

core conditions, defined by the thermal power and actual operating MCPR , are such  !

that a RWE event cannot possibly violate the Safety Limit MCPR (Initial MCPR - l RWE delta-CPR > SLMCPR), the RBM System was not required to be operable. A i l

generic RWE analysis documented in NEDC-31843P determined the values ofinitial MCPR and margin to the MCPR Safety Limit that was needed to assure that the j complete withdrawal of any single rod would not violate the Safety Limit MCPR.

The results of this analysis then formed the basis of the revised RBM TS Applicability i section.  ;

With the introduction of gel 1 and newer fuel designs, GE discovered that the analysis to determine the change in MCPR during a RWE was no longer adequate by l l itself to assure fuel cladding integrity. Consequently, their Technical Design Procedures were revised to require evaluation of thermal overpower (TOP) and mechanical overpower (MOP) response of the core during a RWE The TOP analysis l checks for compliance with fuel centerline melt restrictions, and the MOP analysis checks for compliance with 1% circumferential plastic strain restrictions.

Operation with the ARTS RBM Technical Specifications began in Cycle 3. The RWE analysis is performed each cycle using the NRC approved methods described in i GESTAR II. This analysis showed for Cycle 3, and each subsequent cycle prior to Cycle 6, that the MOP and TOP performance requirements would be met without taking credit for a RBM control rod withdrawal block. Thus, the current RBM l Technical Specifications were adequate to assure fuel cladding integrity in the event of a RWE event. However, for Cycle 6 it was necessary to take credit for the 1I1.0% rod block High Trip Setpoint (HTSP) Analytical Limit (without RBM filter) l in this analysis in order to meet the MOP performance requirements during portions l of Cycle 6. Analysis of the mechanical overpower results with no rod withdrawal block indicated a maximum of 13% over the applicable acceptance criteria.

Detroit Edison, therefore, included a requirement in the Core Operating Limits

Report for Cycle 6 to ensure that at least one RBM channel was OPERABLE when

! moving control rods with thermal power greater than or equal to 30% of rated

! THERMAL POWER in order to ensure that mechanical overpower limits are met.

These restrictions were placed in Section 5.2 of the Cycle 6 COLR, Revision 0, which was provided to the NRC by Reference 3. Measures were also taken to ensure that l operators were made aware of and understand these additional restrictions on RBM operability. These measures included issuing a Technical Specification Clarification (TSC) in accordance with Fermi 2 administrative procedures and conducting on-shift training oflicensed operators. The TSC is distributed to all controlled copies of the Technical Specifications and ensures that these copies include an appropriate cross l reference to the additional restrictions now being imposed through the COLR.

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Attachment I to NRC-96-0134  :

Page 4 Detroit Edison has thus already taken the actions necessary to ensure the safe j

operation of the plant. This change is being requested in order to ensure that the l RBM operability requirements in the Technical Specifications will be adequate in the future without reliance on additional cycle specific requirements being included in the COLR.  !

SIGNIFICANT HAZARDS CONSIDERATION 1

Detroit Edison has evaluated these proposed Technical Specification changes in i accordance with the criteria specified by 10 CFR 50.92 and has determined that the proposed changes do not involve a significant hazards consideration. The criteria and the bases for the determination are presented below. ,

1. Does the change involve a significant increase in the probability or consequences of an accident previously evaluated?  ;

The proposed changes provide requirements that are more restrictive than the existing requirements for operation of the facility. There changes provide assurance that the Rod Block Monitor system is operable when necessary to prevent or mitigate transients that could potentially threaten the integrity of the fuel cladding. There will be no adverse impact on the probability of any accident previously evaluated since the change provides additional assurance that fuel thermal and mechanical design bases will be satisfied and has no effect on any accident initiating mechanism. The additional restrictive conditions on plant operation also ensure that the consequences of anticipated operational occurrences are no more severe than the most limiting conditions using the current Technical Specifications. Therefore, these changes do not involve any increase in the probability or consequences of an accident previously evaluated.

2. Does the change create the possibility of a new or different kind of accident from any accident previously evaluated?

The proposed changes will not involve any physical changes to plant systems, structures, or components (SSC). The changes in Rod Block Monitor operability requirements are consistent with the current safety analysis assumptions. These requirements provide assurance that the Rod Block Monitor will be operable if necessary to terminate a rod withdrawal error so that fuel thermal and mechanical design limits are satisfied. The change does not cause a physical change to the plant or introduce a new mode of operation. Therefore, the proposed amendment will not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does this change involve a significant reduction in a margin of safety?

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Attachment 1 to NRC-96-0134 Page 5 l

l l These changes maintain current assumptions within the safety analyses and l licensing basis. The changes provide assurance that the Rod Block Monitor l will be operable to terminate a rod withdrawal error so that fuel thermal and

! mechanical design limits are satisfied. Therefore, these changes do not involve l a reduction in a margin of safety.

ENVIRONMENTAL IMPACT l

Detroit Edison has reviewed the proposed Technical Specification changes against the criteria of 10CFR51.22 for environmental considerations. The proposed changes do l not involve a significant hazards consideration, nor significantly change the types or 1 increase the amounts of effluents that may be released offsite, nor increase individual or cumulative occupational radiation exposures. Based on the foregoing, Detroit Edison concludes that the proposed Technical Specifications meet the criteria given in  ;

l 10CFR51.22(c)(9) for a categorical exclusion fom the requirements for an l l

Environmental Impact Statement. - )

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CONCLUSION Based on the evaluations above: (1) there is reasonabic 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 regulations, and the proposed amendment will not be inimical to the common defense and security or the health and safety of the public.

l Detroit Edison requests that the proposed license amendment be effective within 60 days of approval by the Commission.

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