ML20217K870

Provides Plant & Schedule for Closing Reg Guide 1.97 Items Re Adequacy of Neutron Instrumentation Sys During post- Accident Monitoring at Quad Cities Station.Commitments Made by Util,Listed

ML20217K870
Person / Time
Site:	Quad Cities
Issue date:	04/24/1998
From:	Dimmette J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-REGGD-01.097, RTR-REGGD-1.097 SP-98-145, NUDOCS 9805040178
Download: ML20217K870 (6)

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Commonwcahh thon Company l

, Quad CWts Generating Nation

, 22-*10 2With Ascnue North

.- Cordm a, ll. 61212 C IO ,

j rei mon 22 o SVP-98-145 l

April 24,1998 U. S. Nuclear Regulatory Commission i Washington, D. C. 20555 l Attention: Document Control Desk

Subject:

Quad Cities Nuclear Power Station Units 1 and 2 Regulatory Guide 1.97 Closeout l NRC Docket Numbers 50-254 and 50-265 i

Reference:

(a) B. Boger letter to C. Tully (BWROG), NRC Evaluation of BWR Owners' Group Topical Report NEDO-31558, dated January 13,1993.

(b) M. J. Vonk letter to USNRC, Compliance whh Regulatory Guide 1.97, (Neutron Flux Monitor), dated November 12,1993.

l The purpose of this letter is to provide a plan and schedule for closing Regulatory Guide 197 items as they relate to the adequacy of the Neutron Instrumentation System during post-accident monitoring at Quad Cities Station. In response to the requirements in Regulatory Guide 1.97, the BWR Owners Group (BWROG) developed a set of alternate criteria for Neutron Instrumentation which are outlined in GE report NEDO-31558, Requ/rementsfor Post-Accident Neutron Afon/toring System. The NRC Staff approved NEDO-31558 in Reference (a). The NRC required Comed to submit an action plan to ensure existing designs met the sixteen criteria contained in NEDO-31558. Our response was submitted in Reference (b).

In Reference (b), Comed closed the majority of the requirements in NEDO-31558; however, four items were deferred pending further evaluation. Two of the four items are now considered closed based on additional BWROG guidance. The Attachment provides a description of all four items including a plan and schedule for the remaining open items.

The following commitments are being made by this letter:

l. GE has prepared a report that evaluates the containment response during an Anticipated Transient Without Scram (ATWS) event (using Dresden as the limiting plant). This information will be used to evaluate the performance of the Local Power Range Monitor (LPRM) system (cables and connectors) during an ATWS event to ensure the operators have Average Power Range Monitor (APRM) indication (reactor power) for a one-hour duration.

This action will be completed by December I,1998.

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4805040178 980424 goa .oocsosoog4 J

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, USNRC SVP_-98-145 2 April 24,1998 2 Quad Cities station component classification engineering procedure requires augmented quality designation for non-safety related ATWS equipment consistent with GL 85-06. This criteria will be applied to Neutron Monitoring System (NMS) monitoring equipment to support ATWS events. The NMS equipment that is currently classified as non-safety related j will be reviewed for their function in an ATWS event. Augmented quality requirements '

consistent with GL 85-06 will be assigned to these components. This action will be completed by December 1,1998. j l

i Ifyou have any questions coneeming this letter, please contact Mr. Charles Petersou, Regulatory I Affairs Manager, at (309) 654-2241, extension 3609.

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Re ectfully, l l

< f s-) t 1

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(pHnWAAb l

/Joel P Dimmette, Jr, Site Vice President ' I Quad Cities Station Attachment A: Reg. Guide 1.97 Neutron Instrumentation Requirements Closecut Plan cc: A. D. Beach, Regional Administrator, R.egion Ill l R. M. Pulsifer, Project Manager, NRR

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l- C. G. Miller, Senior Resident Inspector, Quad Cities W. D. Leech, MidAmerican Energy Company j D. C. Tubbs, MidAmerican Energy Company l F. A. Spangenberg, Regulatory Affairs Manager, Dresden INPO Records Center Office of Nuclear Facility Safety, IDNS DCD License (both electronic and hard copies)

M. E. Wagner, Licensing, Comed

ATTACilMENT A

., SVP-98-145 REG. GUIDE 1.97 NEUTRON INSTRUMENTATION CLOSEOUT PLAN REQUIREMENTS PAGE 1 OF 4

1. NEDO-31558 Item 2: Instrument Accuracy (12% ICLOSEDI Original Commitment In the response to NEDO-31558, Quad Cities committed to perfonn an APRM loop error analysis.

If the error analysis could not support the specified loop accuracy, operating practices would be adjusted appropriately. This action has not been completed; however, justification consistent with the BWROG position on this topic is provided below.

Revised Commitment I

NEDO-31558, Requirement 5.2.2, specifies an accuracy requirement of 2% of rated power. This requirement is more restrictive than Reg. Guide 1.97, which is silent on instrumentation accuracy.

Contrary to our original conunitment, Quad Cities has not completed an engineering analysis to determine the total loop inaccuracies for the APRM system. However, Quad Cities has determined that the APRM system will NOT meet the NEDO accuracy requirement of 2% of rated power.

This judgment is based on evaluations performed for other stations with similar design features, i and based on the effects of the anticipated off-normal core conditions following an ATWS event (control rod pattern, xenon, etc.). Quad Cities has evaluated the impact of not conforming to NEDO-31558 Requirement 5.2.'2 and concludes the deviation is acceptable. Thejustification for this conclusion is provided below and is consistent with the BWROG position on this subject.

The steady-state APRM system measurement setting is goserned primarily by the plant Technical Specifications. A wecitly surveillance ensures the APRM system is calibrated to within 2% of core

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thermal power using the reactor heat balance calculation. The plant heat balance is the most accurate method of determining reactor core thermal power and is generally accurate to within 2-l 3%. During an ATWS condition, the APRM measurement uncertainties are compounded by the off-normal core conditions (xenon and control rod pattern). Therefore, the total APRM power measurement uncertainties are expected ta be in excess of 2% during an ATWS event.

Quad Cities uses the Emergency Procedure Guidelines (EPGs) to achieve shutdown during an ATWS event. When the ATWS condition potentially threatens containment, shutdown is' accomplished by injecting boron via the Standby Liquid Control system. The decision to inject boron is independent of the APRM indications and is predicated on degrading containnet condition Irising suppression pool temperature). Therefore, an APRM system uncertainty beyond that spew al in NEDO-31558 is acceptable and does not compromise plant safety. Therefore, Quad Cities considers this item closed.

Closure Date Quad Cities considers this item closed. No further action is required.

l ATTACHMENT A . f

... SVP-98-14S 1

j. REG. GUIDE 1.97 NEUTRON INSTRUMENTATION i f CLOSEOUT PLAN REQUIREMENTS PAGE 2 OF 4 l

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2. NEDO-31558 Item 4: EO Rpguirements - Operate in an ATWS Environment IOPEN!

l Original Commitment in the response to NEDO-31558, Quad Cities committed to evaluate the impact of a postulated ATWS on the LPRM components following the BWROG review of equipment qualification requirements for an ATWS environment. This item remains open.

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Revised Commitment For the purposes of post-accident monitoring, the NEDO-31558 requires the APRM/LPRM system to remain functional dming an ATWS event for a one-hour period. In general, this is not an issue with BWRs because an ATWS event does not produce conditions more severe than the l

design basis LOCA esent. However, for plants equipped with safety relief valves that vent directly to the containment atmosphere, the containment environment may degrade significantly during an  ;

ATWS. GE has prepared a report that evaluates the containment response during an ATWS event (using Dresden as the limiting plant). This information will be used to evaluate the performance of

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j the LPRM system (cables and connectors) during an ATWS event to ensure the operators have l

APRM indication (reactor power) for a one-hour duration. (NTS 2541239803501) j i

Closure Date This action will be completed by December 1,1998.

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3. NEDO-31558 Item 8: Power Supplies - Uninterruptible and Reliable ICLOSED] l i

Original Commitment l l 1 In the response to NEDO-31558, Quad Cities deferred a response to this issue because it was

under resiew by the BWROG. Quad Cities committed to provide a response when the BWROG l

! evaluation was completed.

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Revised Commitment i .NEDO-31558, Requirement 5.2.8, specifies that the power supply for the APRM system is reliable i and uninterruptible. A review of the APRM system at Quad Cities concludes that the power

! source is reliable but NOT uninterniptible. Quad Cities has evaluated the impact of not I conforming to NEDO-31558 Requirement 5.2.8 and concludes the deviation is acceptable. The justification for this conclusion is provided below and is consistent with the BWROG position on this subject

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ATTACHMENT A  !

- SVP-98-145 REG. GUIDE 1.97 NEUTRON INSTRUMENTATION {

CLOSEOUT PLAN REQUIREMENTS PAGE 3 OF 4 l j

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The APRM system at Quad Cities is comprised of two divisions with independent power supplies.

in each division, there are three separate APRM channels. Each APRM division is powered from  !

one of two redundant reactor protection system (RPS) motor-generator sets. The motor-generator (MG) sets are, in-turn, pov.ered from safety-related power supplies. An alternate (backup) power l

supply is also available and can be aligned in the event the normal power supply is lost. All j electrical power fceds to RPS are protected by Electrical Protection Assemblies (EPAs) which i monitor the quality of power to prevent inadvertent application of out-of-tolerance voltage and 1 trequency to the RPS.  !

Although the power supply to the APRMs would be interrupted during a loss of offsite power event, power would be easily restored via operator action (procedurally controlled) once the Emergency Diesel Generators (EDGs) restored power to the safety-related buses. In addition to the EDGs, the Station Blackout Diesels (SBO) could be aligned to restore power to RPS, if required.

Loss of the most direct indication of reactor power during the short period required to re-energize RPS would not preclude the operators' ability to determine power level. Many alternate  !

indications can be used to determine power output (examples include the plant Safety Parameter l Display System, turbine generator output (if not tripped), containment heat load input, and relief l

valve or turbine bypass valve positions). In addition, the key decision to ir. ject boron via the standby liquid control system is not compromised by a loss of APRM indication. The decision to

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inject boron to shutdown the reactor during an ATWS is independent of the APRM indications and is predicated on degrading containment conditions (rising suppression pool temperature).

Note that the APRM recorders at Quad Cities are powered from an uninterruptible power supply.

l Therefore, the recorders meet the uninterruptible requirements of NEDO-31558, criteria 5.2.8.

.: I, Therefore Quad Cities concludes the deviation from NEDO-31558, criteria 5.2.8, is acceptable  !

and does not compromise plant safety. This is consistent with a BWROG owners group position l l on this topic. Therefore. Quad Cities considers this item closed.

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- Closure Date A i

Quad Cities considers this item closed. No further action is required.  !

4. NEDO-31558 Item 10: Limited OA Requirements (GL 85-06) IOPEN1 Original Commitment In the response to NEDO-31558, Quad Cities committed to identif . locate all non-safety NMS components in the Master Equipment List (MEL) and assign augmeued quality standards to these items consistent with Generic Letter 85-06. This acticu has not been completed.

ATTACHMENT A l c- SVP-98-145 REG. GUIDE 1.97 NEUTRON INSTRUMENTATION CLOSEOUT PLAN REQUIREMENTS PAGE 4 OF 4 I

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Revised Commitment Quad Cities station component classification engineering procedure requires augmented quality i designation for non-safety related ATWS equipment consistent with GL 85-06. This criteria will )

be applied to NMS monitoring equipment to support ATWS events. The NMS equipment that is currently classified as non-safety related will be reviewed for their function in an ATWS event.

Augmented quality requirements consistent with GL 85-06 will be assigned to these components (NTS 2541239803502).

Closture Date This item will be completed by December 1,1998.

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