ML20116J668

Safety Evaluation Supporting Amend 216 to License DPR-49

ML20116J668
Person / Time
Site:	Duane Arnold
Issue date:	08/08/1996
From:	NRC (Affiliation Not Assigned)
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NUDOCS 9608130327
Download: ML20116J668 (6)

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UNITED STATES

.g NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20eeH001

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 216 TO FACILITY OPERATING LICENSE NO. DPR-49 IES UTILITIES INC.

CENTRAL IOWA POWER COOPERATIVE CORN BELT POWER COOPERATIVE DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331

1.0 INTRODUCTION

In a letter dated November 15, 1995, IES Utilities Inc. (IES) proposed changes to the, Technical Specifications (TSs) for the Duane Arnold Energy Center (DAEC).

The proposed changes included revisions to the requirements for the End of Cycle (EOC) Recirculation Pump Trip (RPT) and related editorial changes.

After initial review of the above submittal, the NRC staff expressed concern with respect to the unclear wording in the revised TSs.

In response to NRC staff concerns, the licenspe submitted changes to the original submittal in a letter dated April 9, 1996.

The licensee rephrased the requirements to be more consistent with the Improved Technical Specifications (ITS), NUREG-1433, Revision 1.

2.0 EVALUATION Revisions to Comments Clarifyina Minimum Channels Ooerable Currently, EOC RPT logic is indicated as a single trip function in TS Table 3.2-G, "(ATWS)RPT/ARI and EOC-RPT Instrumentation." This led to confusion with respect to the designation of the minimum operable channels per trip system and with table notes clarifying the system description and requirements.

In response to NRC staff concerns, the licensee revised the table entry from the single trip function, EOC RPT logic, to two separate trip functions: EOC RPT Turbine Stop Valve (TSV) Closure and EOC RPT Turbine Control Valve (TCV) Fast Closure.

In addition, the " Minimum Operable Channels per Trip System" was revised to recognize that there is a need to maintain two channels of each type of input (TSV closure and TCV fast closure) in order to satisfy the existing TS. The revised table representation is consistent with ITS, NUREG-1433, Revision 1.

The staff concludes that these revisions provide a clear indication of the TS requirements and are acceptable.

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i 2 The notes to TS Table 3.2-G were also changed. Note (a), which was originally J

referenced in the " Minimum Operable Channels per Trip System" column header, is now only applicable to the (ATWS)RPT/ARI Logic; therefore, references to 1

Note (a) are relocated to the two trip functions applicable to (ADt5)RPT/ARI Logic.

In the original submittal, the licensee used Note (d), with an associated " Insert," to clarify the E0C RPT trip system logic operability requirements, by describing the minimum operable channels required for the TSV closure and TCV fast closure.

In response to the NRC concerns discussed.

j above, the licensee decided to remove Note (d) and the associated " Insert" altogether to alleviate confusion. Note (d) was replaced with a asw note to delay the required action under certain conditions. This change is reviewed l

in detail later in this SER. Also, Note (e) in TS Table 3.2-G was replaced with a note stating that both EOC RPT systems are required to be aperable when the plant is in Mode I with reactor power greater than or equal to 30% rated thermal power. Note (e) clarifies the operability requirements for the E0C i

RPT systems and is consistent with ITS, NUREG-1433, Revision 1.

Except for j

revised Note (d), the above editorial and technical changes are acceptable to the staff. The acceptability of the revised Note (d) is discussed further 1

below.

1 Action 81 in TS Table 3.2-G was modified to reflect the existence of the i

proposed Operating Limit Minimum Critical Power Ratio (OLMCPR) penalty. The l

penalty is added onto the OLMCPR when the reactor is operating with the E0C l

RPT bypassed to ensure that the SLMCPR criterion is satisfied. The licensee proposes to put the OLMCPR into the Core Operating Limits Report (COLR) because its value will be cycle specific. The OLMCPR concept provides the

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same level of protection as the EOC RPT and is consistent with ITS, NUREG-1433. Revision 2.

Therefore, the staff finds this change acceptable.

Revisions to A0T and STI for the E00 RpT The licensee proposed to incorporate the extended surveillance test interval (STI) and allowable out-of-service time (A0T) for the E0C RPT instrumentation, in accordance with NRC-approved Licensing Topical Reports (LTRs) previously submitted by the Boiling Water Reactor Owner's Group (BWROG), of which IES is a member. On July 21, 1992, the NRC forwarded its safety evaluation (SE) on the review of General Electric (GE) topical report GENE-770-06-1, *5ases for Changes to STIs and A0Ts for Selected Instrumentation Technical Specifications (TS)." The staff's review of GENE-770-06-1 concluded that the report provides a generally acceptable basis for extending STIs and A0Ts for selected 4

actuation instrumentation, including the E0C RPT instrumentation, for BWR4 and BWR6 plants.

The instrumentation included in this report is either the same or similar instrumentation to that analyzed in previous analyses for reactor-protection system (RPS), emergency core cooling system (ECCS), and isolation actuation instrumentation. The primary difference is the safety function performed by the different actuation instrumentation. The E0C RPT has common instrumentation with the RPS, but provides a different function than the RPS.

This safety evaluation verifies that the TS changes to the A0T and STI proposed by the licensee for the E0C RPT and their associated justifications are bounded by the analyses provided in the approved topical report and that i

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_3-the licensee has met all conditions stipulated by the staff in their SER approving the topical report.

To implement the extended STIs and A0Ts for the selected instrumentation, the staff's SER for GENE-770-06-1 requires that the licensee do the following: 1) confirm the appilcability of the generic analyses of GENE-770-06-1 to the plant, and 2) confirm that any increase in instrument drift due to the extended STIs is properly accounted for in the setpoint calculation methodology.

In a previous submittal, the licensee confirmed the applicability of the generic analysis for NEDC 30851-P-A, " Technical Specification Improvement Analysis for BWR RPS," to the DAEC.

In addition, in their telecon dated January 3,1996, the licensee stated that the analysis of GENE-770-06-1 was applicable to DAEC. This is acceptable to the staff.

Instrument setpoint drift is monitored during channel calibration tests only.

The proposed TS revision does not change the frequency of the channel calibration. The proposed change revises the STI of the channel functional test from monthly to quarterly.

Since the channel calibration intervals are not affected by the proposed changes, instrument drift is not a factor and the RPS channel setpoint drift that could be expected under the proposed quarterly STIs for the channel functional test will remain within the existing allowance in the RPS instrument setpoint calculation. This is acceptable to the staff.

Based on the above, the findings of GENE-770-06-1 and the conclusions of the NRC staff's July 21, 1992, SER are applicable to the Duane Arnold Energy Center.

The licensee proposed to increase the channel functional test STI specified in TS Table 4.2-G, "(ATWS)RPT/ARI and E0C-RPT Instrumentation Surveillance Requirements," from monthly (M) to quarterly (Q) for the E0C RPT logic. The revision of the STI as described is consistent with the staff's July 21, 1992, SER and therefore, is acceptable.

The licensee proposed to modify Note (d) of TS Table 3.2-G, "(ATWS)RPT/ARI and EOC-RPT Instrumentation," to clarify the conditions under which delaying a required action is allowed and to reflect an extended A0T of 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

The revised note indicates that a required action may be delayed up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> when an EOC RPT channel is placed in an inoperable status solely for the performance of required surveillance testing, provided that the trip capability for the associated trip function is maintained.

This revised wording is consistent with the ITS, NUREG-1430, Revision 1.

The proposed change to extend the A0T is in accordance with the staff's July 21, 1992, SER and therefore, is acceptable.

Revisions to Acceptance Criteria for E0C RPT Response Time Testina By design, the EOC RPT is assumed to interrupt power to the recirculation pump motor within 175 milliseconds after initiation of either TSV closure or TCV fast closure. The response time test measures only a portion of the complete trip, and the remaining portion is measured as a part of start-up testing.

Also, time measured is dependent on which trip input is being measured.

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. The licensee proposed to revise the response time test acceptance criteria as specified in TS Table 4.2-G, "(ATWS)RPT/ARI and EOC-RPT Instrumentation Surveillance Requirements - End-of-Cycle (EOC) Recirculation Pump Trip System Response Time," for the E0C RPT system and to clarify the method of measuring that response time. The DAEC TS currently indicates a single response time of i

s140 usec for the RPT System Trip Function, which is measured from the initiation of the TCV fast closure or the TSV closure to the actuation of the RPT breaker secondary (auxiliary) contact.

The licensee proposed to change 1

i the single trip function designation, RPT system, to two separate trip functions: RPT System TSV Closure and RPT System TCV Fast Closure. This is 3

consistent with the changes made to TS Table 3.2-G.

By separating the trip i

function in this manner, the licensee can delineate between the differences in j

response times when testing the input produced by the TSVs or TCVs.

Turbine stop valve closure is sensed by a position switch, which is set to 4

initiate E0C RPT logic at 10% valve closed. A brief delay exists between the beginning of valve motion and initiation of the E0C RPT logic.

The licensee proposed a response time of s 120 msec for the TSV closure. The licensee also proposed to add Note (**) to TS Table 4.2-G to clarify that this response time is " measured from the actuation of the TSV position switch to the actuation of j

the RPT breaker secondary (auxiliary) contact." On the other hand, TCV fast closure is sensed by a pressure switch that monitors the hydraulic fluid controlling the valve.

Therefore, there is no measurable delay between valve i

motion and the initiation of the E00 RPT logic. The licensee proposed a l

response time of s 140 msec for the TCV fast closure. The licensee also proposed to add Note (*) to Table 4.2-G to clarify that this response time is

" measured from the energization of the fast acting solenoid to actuation of I

i the RPT breaker secondary (auxiliary) contact."

i The licensee added notes relating to the E0C RPT Logic surveillances.

Note

(***) states that the surveillance is required only during periods when the i

EOC RPT trip function is operable. Also, Note (#) requires that the i

surveillance be performed during the refueling outage prior to the operating cycle during which the E0C RPT will be operable.

These notes are acceptable.

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l The proposed response times account for the differences in instrumentation and are still within the allowable time period.

Therefore, these proposed response times are acceptable to the staff.

The licensee is not changing the testing methodology.

In actuality, the proposed changes to the table are just providing clarifications to reflect the actual testing practices.

Both the l

editorial and technical changes proposed are acceptable to the staff.

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Editorial and Bases Chanaes i

Changes were proposed for Note (##) in TS Table 4.4-1 and two pages of the DAEC TS; page 3.2-34 and 3.2-47.

The change to Note (##) in TS Table 4.1-1 provides an appropriate reference to another table and is, therefore, acceptable.

The change to page 3.2-34 is editorial in nature and is acceptable. Change 3.2-47 modifies the TS bases for the OLMCPR and how it is applied.

This change is also acceptable.

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. J Conclusions The staff has reviewed the Technical Specification changes ~ proposed by IES for the Duane Arnold Energy Center relating to the End-of-Cycle Recirculation Pump Trip. The staff concludes that the proposed changes are acceptable.

3.0 STATE CONSULTATION

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In accordance with the Commission's regulations, the Iowa State official was notified of the proposed issuance of the amendment.

The State official had no comments.

4.0 ENVIRONMENTAL CONSIDERATION

S This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent that may be released offsite, and that there is no significant increase in individual or cumulative

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occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (61 FR 1629). Accordingly, the amendment meets the eligibility criteria for s

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 prepareo in connection with the issuance of the amendment.

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, i

and (3) the issuance of the amendment will not be inimical to the common i

defense and security or to the health and safety of the public.

Principal Contributors:

T. Ulses S. Wittenberg Date:

August 8, 1996 i

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REFERENCES 1.

Letter from John F. Franz (IES) to William T. Russell (NRC) requesting changes to the DAEC TS for the EOC RPT, November 15, 1995.

2.

Letter from John F. Franz (IES) to William T. Russell (NRC) modifying November 15, 1995 submittal regarding EOC RPT, April 9,1996.

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