ML20210B941

Proposed Tech Specs Revising SLMCPR to Support Operation with GE-12 Fuel with 10x10 Pin Array

ML20210B941
Person / Time
Site:	Duane Arnold
Issue date:	07/16/1999
From:	IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:
Shared Package
ML20137X881	List: ML20210B941 NG-99-0956, Application for Amend to License DPR-49,revising SLMCPR to Support Operation with GE-12 Fuel with 10x10 Pin Array. Proprietary & non-proprietary Info Re Cycle Specific SLMCPR for DAEC Cycle 17,encl.Proprietary Info Withheld
References
NUDOCS 9907230281
Download: ML20210B941 (4)

Text

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SLs 2.0 2.0 SAFETY LIMITS (SLs) 2.1 SLs 2.1.1 Reactor Core SLs 2.1.1.1 Fuel Cladding Integrity - With the reactor steam dome pressure < 785 psig or core flow < 10% rated core flow:

THERMAL POWER shall be s 25% RTP.

2.1.1.2 HCPR - With the reactor steam dome pressure = 785 psig and core flow a 10% rated core flow: g,gg 1 be a hl.for two recirculation loop operation MCPR h gga or a 1.

for single recirculation loop operation.

2.1.1.3 Reactor Vessel Water Level - Reactor vessel water level shall be greater than 15 inches above the top of active irradiated fuel.

2.1.2 Reactor Coolant System Pressure SL Reactor steam dome pressure shall be s 1335 psig.

2.2 SL Violations With any SL violation, the following actions shall be completed within 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s:

2.2.1 Restore compliance with all SLs: and 2.2.2 Fully insert all insertable control rods.

l gg72ggggg gg[,gggt p

PDR DAEC 2.0-1 Amendment 223 L

r Reactor Core SLs B 2.1.1 BASES APPLICABLE 2.1.1.1 Fuel Claddina Intearity (continued)

SAFETY ANALYSES 3.5 psi.

Thus, the bundle flow with a 4.5 psi driving 3

head will be > 28 x 10 lb/hr. Full scale ATLAS test data taken at pressures from 14.7 psia to 800 psia indicate that the fuel assembly critical power at this flow is approximately 3.35 MWt.

With the design peaking factors. this corresponds to a THERMAL POWER >

50% RTP.

Thus, a THERMAL POWER limit of 25% RTP for reactor pressure < 785 psig is conservative.

2.1.1.2 MCPR The fuel cladding integrity SL is set such that no significant fuel damage is calculated to occur if the limit is not violated.

Since the parameters that result in fuel damage are not directly observable during reactor operation, the thermal and hydraulic conditions that result in the onset of transition boiling have been used to mark the beginning of the region in which fuel damage could occur.

Although it is recognized that the onset of transition boiling would not result in damage to BWR fuel rods, the critical power at which transition boiling is calculated to occur has been adopted as a convenient limit.

However, the uncertainties in monitoring the core operating state and in the procedures used to calculate the critical power result in an uncertainty in the value of the critical power.

Therefore, the fuel cladding integrity SL is defined as the critical power ratio in the limiting fuel assembly for which more than 99.9% of the fuel rods in the core are expected to avoid transition boiling. considering the power distribution within the core and all uncertainties.

The MCPR SL is determined using a statistical model that combines all the uncertainties in operating parameters and the proceoures used to calculate critical power.

The probability of the occurrence of boiling transition is determined using the approved General Electric Critical Power correlations.

Datails of the fuel cladding integrity rFc>r $LO,%e.SLMCPR SL calculation are given in Reference 2.

Reference 2 also

• Y"g,, %ccoud includes a tabulation of the uncertainties used in the determination of the MCPR SL and of the nominal values of (for %e, W"N the parameters used in the MCPR SL statistical analysis.

awcerke d MS'-

rDuring SLO. t SL MCPR must increased by'.01 to account3 for the inct sed uncertaint in the core fl and Traversing

-Core Probe (T P) readings.

J t

(continued)

DAEC B 2.0-3 Amendment 223

TSCR-021 A to NG-99-0956 Page1ofI SAFETY ASSESSMENT By letter dated July 16,1999, IES Utilities Inc. submitted a request for revision of the Technical Specifications for the Duane Arnold Energy Center (DAEC). The proposed amendment revises the Safety Limit Minimum Critical Power Ratio (SLMCPR). This change will support operation with a new fuel design, GE-12 with a 10x10 pin array, beginning with Cycle 17.

Evaluation:

The Updated Final Safety Analysis Report (UFSAR) Safety Design Bases,(Section 4.4, Thermal-Hydraulic Design) states that the thermal-hydraulic design of the core shall establish the safety limits for use in evaluating the safety margin relating the consequences of fuel barrier failure to public safety.

As discussed in the Technical Specification 2.1.1.2 BASES, the fuel cladding integrity Safety Limit (SL)is set such that no significant fuel damage is calculated to occur if the limit is not violated. The fuel cladding integrity SL is defined as the critical power ratio in the limiting fuel assembly for which more than 99.9% of the fuel rods in the core are expected to avoid transition boiling, considering the power distribution within the core and all uncertainties. This is consistent with Section 4.4 of the Standard Review Plan, NUREG 0800.

For Single 1.oop Operation (SLO), the SLMCPR is greater to account for the increased uncertainties. provides the SLMCPR to support operation with GE-12 fuel. The calculations, which consider the impact on SLMCPR of the combined GE-12 and GE-10 core, show that an increase in SLMCPR is necessary. All applicable conditions of the cycle specific SLMCPR process and method as specified in the NRC's approval of Amendment 25 to GESTAR-Il have been satisfied.

The fuel to be used in the reactor at the start of Cycle 17 is comprised of the following:

120 bundles of GE-10 (8x8) burned one cycle e

120 bundles of GE-10 (8x8) bumed two cycles j

48 new bundles of GE-12 (10x10) Design GE12-P10DSB370-14GZ-100T-150-T e

80 new bundles of GE-12 (10x10) Design GE12-P10DSB371-12G7-100T-150-T e

These new bundle designs comply with the NRC's requirements in their approval of Amendment 22 to GESTAR-II.

Therefore, we have concluded that the proposed revision to the DAEC Technical Specifications is acceptable.

TSCR-021 A to NG-99-0956 Pageiof1 ENVIRONMENTAL CONSIDERATION 10 CFR Section 51.22(c)(9) identifies certain licensing and regulatory actions which are eligible for categorical exclusion from the requirement to perform an environmental assessment. A proposed amendment to an operating license for a facility requires no environmental assessment if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant hazards consideration; (2) result in a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; and (3) result in a significant increase in individual or cumulative occupational radiation expcaure. IES Utilities Inc. has reviewed this request and determined that the proposed amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9). Pursuant to 10 CFR Section 51.22(b),

no environmental impact statement or environmental assessment needs to be prepared in connection with the issuance of the amendment. The basis for this determination follows:

Basis The change meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9) for the following reasons:

1.

As demonstrated in Attachment I to this letter, the proposed amendment does not involve a significant hazards consideration.

2.

There is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite. The way in which the fuel assemblies will be operated is not being changed by this revision to the Safety Limit Minimum Critical Power Ratio (SLMCPR). The SLMCPR values are designed to ensure that fuel damage from transition boiling does not occur in at least 99.9% of the fuel rods as a result of the limiting postulated accident and there are no new accidents being introduced.

3.

There is no significant increase in individual or cumulative occupational radiation exposure. The SLMCPR values are designed to ensure that fuel damage from transition boiling does not occur in at least 99.9% of the fuel rods as a result of the limiting postulated accident and there are no new accidents being introduced.

There are no changes in reactor operation that would increase the dose rate.