ML16285A321

ROP PI Frequently Asked Questions (Faqs): 13-05

ML16285A321
Person / Time
Site:	Oyster Creek
Issue date:	10/12/2016
From:	Mary Anderson NRC/NRR/DIRS/IPAB
To:
Anderson M,NRR/DIRS,301-415-8744
References
Download: ML16285A321 (5)

Text

NRC Final Response FAQ 13-05 Oyster Creek Downpower Plant: Oyster Creek Nuclear Generating Station Date of Event: 09/28/2012 Submittal Date:

Licensee

Contact:

Dennis M Moore Tel/Email: 609-971-4281 dennis.moore@exeloncorp.com NRC

Contact:

Jeffrey Kulp Tel/Email: 609-971-4978 Performance Indicator: UNPLANNED POWER CHANGES PER 7,000 CRITICAL HOURS (IE03)

Site-Specific FAQ (Appendix D)? No FAQ requested to become effective: when approved.

Question Section NEI 99-02 Guidance needing interpretation (include page and line citation):

Page 13 25 Unplanned changes in reactor power are changes in reactor power that are initiated less than 72 26 hours following the discovery of an off-normal condition, and that result in, or require a change 27 in power level of greater than 20% of full power to resolve. Unplanned changes in reactor power 28 also include uncontrolled excursions of greater than 20% of full power that occur in response to 29 changes in reactor or plant conditions and are not an expected part of a planned evolution or test.

Page 14 10 Equipment problems encountered during a planned power reduction greater than 20% that alone 11 may have required a power reduction of 20% or more to repair are not counted as part of this 12 indicator if they are repaired during the planned power reduction. However, if during the 13 implementation of a planned power reduction, power is reduced by more than 20% of full power 14 beyond the planned reduction, then an unplanned power change has occurred.

Event or circumstances requiring guidance interpretation:

On September 28,, 2012 at 1802- Oyster Creek Nuclear Generating Station (OCNGS) experienced an increase in leakage from a previously identified (<72 hours) salt water leak into the condenser bay from a hole in circulating water piping. The timeline of power changes and event details are as follows:

1855 - Control Room Operators commenced lowering power to allow isolating and draining of the 1A North Condenser waterbox to mitigate the leakage of water into the condenser bay.

1914 - GenManager Ticket Number 1022326 was created to track the emergent downpower to 85%. The ticket begin time was 1901 with an end time of 2259 (the ticket was created, as such, with the intention of merging the repair with the upcoming planned downpower to 73%).

1927 - The power reduction was complete with Reactor Power at 85%.

1943 - The 1A North Condenser waterbox was isolated reducing the leakage to approximately half of the initial leakage.

2110 - Operations commenced draining 1A North waterbox 2147 - Operations completed a pre-job brief for lowering reactor power to 73% for End of Cycle Rod Maneuvers March 17, 2014

NRC Final Response FAQ 13-05 Oyster Creek Downpower 2305 - Control Room Operators commenced lowering power from 85% to 73% for End of Cycle Control Rod conditioning maneuver (This is the beginning of a planned, >72 hours in advance, downpower to lower power to 73% from 9/28, 2300 until 9/29, 0700 )

9/29, 0015 - Control Room Operators completed lowering power to 73%.

9/29, 0033 - Control Room Operators commenced raising power for End of Cycle Control Rod conditioning 9/29, 0041 - The initial repair to the 1A North Condenser waterbox piping was complete reducing the leakage from the waterbox to approximately 1 gpm.

9/29, 0116 - A decision was made to hold the power ascension (with power at 80%) to further assess the salt water leak prior to returning to 100% power 09/29, 0217 - Operations completed a pre-job brief for lowering power to 70% to aid in completing additional circulating water piping repair to reduce or eliminate leakage. (70% was chosen to provide more repair options) 09/29, 0302 - Control Room Operators commenced lowering power from 80% to 70% to Repair leak Circ Water Leak 09/29, 0335 - Control Room Operators completed lowering power to 70%

09/29, 0335 to 09/29, 1539 - OCNGS took action, as required, to aid in repairing the circulating water leak.

09/29, 1539 - Circulating water repairs are complete and Control Room Operators commenced raising reactor power from 70% to 100%

09/29, 1843 - Reactor power was returned to 100%

As noted above, Oyster Creek lowered power emergently (<72 hours) due to a salt water leak- with an initial power reduction to 85% (<20% reduction). Power was then lowered to 73% at 0015 in accordance with a planned (>72 hours) power maneuver. After completion of the planned power maneuver, during power ascension (at approximately 80%) a decision was made to lower power to 70% power to facilitate additional repairs to the circulating water system to attempt to eliminate leakage. 70% power was chosen to allow securing of a circulating water pump to increase repair options. (It is important to note that the repair could have been made at a power level above 70%.)

If licensee and NRC resident/region do not agree on the facts and circumstances explain:

NRC Resident Comments The description of the event and subsequent plant response is accurate as presented.

The NRC resident inspection staff does not agree that the guidance provided in NEI 99-02 excludes the duration of a downpower from consideration when determining whether a downpower should count against this performance indicator. NEI 99-02 revision 6, page 14, lines 10-14 state:

Equipment problems encountered during a planned power reduction greater than 20% that alone may have required a power reduction of 20% or more to repair are not counted as part of this indicator if they are repaired during the planned power reduction. However, if during the implementation of a planned power reduction, power is reduced by more than 20% of full power beyond the planned reduction, then an unplanned power change has occurred.

March 17, 2014

NRC Final Response FAQ 13-05 Oyster Creek Downpower The NRC resident inspection staff determined that this downpower should count for the following reasons:

• The initial downpower was due to address an off-normal condition (the leak on the circulating water piping) and occurred approximately 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> before scheduled power reduction for control rod conditioning.

• The licensee reduced power by a total of 30% to perform the repair and resolve the equipment problem.

• The equipment problem was not repaired during the planned power reduction.

Licensee Position An emergent downpower to 85% was initiated to address circulating water piping leak. The emergent downpower was scheduled to coincide with a planned downpower to 73% for End of Cycle Rod Maneuvers (rod pattern adjustments). Repairs commenced during the emergent downpower and continued into the planned power reduction significantly reducing the leakage (to approximately 1 gpm). The emergent downpower was < 20 and therefore outside the scope of the performance indicator.

During power ascension from the planned power reduction for rod pattern adjustments, a decision was made to halt the power ascension at 80%, reduce power to 70%, and perform additional repairs to further reduce or eliminate leakage from the circulating water piping repair prior to returning to 100%

power.

• The power reduction to 70% was outside of the preplanned evolution which ended at 0033 on 9/29/12

• The power reduction to 70% was < 20% below the previous power level of 80%

• A power reduction to 70% was not required for the additional repairs

• Power level had not been restored to 100% following completion of the planned power reduction.

Potentially relevant existing FAQ numbers: None Response Section Proposed Resolution of FAQ The emergent and preplanned power reduction should be evaluated as two power reductions as opposed to one continuous power reduction to 73%. The power reduction from 80 to 70 should not be counted as an unplanned power reduction since it was not >20% from the preplanned or the previous power level.

If appropriate, provide proposed rewording of guidance for inclusion in next revision.

March 17, 2014

NRC Final Response FAQ13*05 Oyster Creek Downpower - Reactor Power vs Time Low=-r d Pow r Low:.r d comm. m d LOW Hd pow r oomp t=d du: to ;1 3in pu t of : r pow:.r du: to n:=d to OircUl:tin.i th OircUl t*ini p nn d(>i2 du: to continu: W H.r pip:

W: t=-r sysu.m hour s) r od comp tionof OircUl:tin.i r p ir 00 (ur.p r.n d) p tt:.r n r odp tt:.rn w:w pip: r i:s.:dpow:.r

djustm .nt  : djustm .nt r p ir NRC Response The licensee is requesting interpretation of NEI 99-02 guidance as applied to their particular donwpower event. The current guidance in NEI 99-02, Rev. 7 was incorporated by FAQ 469 (Sept.

2009) that changed the definition of unplanned power changes to the following:

NEI 99-02 Rev.7, Page 13 26 Unplanned changes in reactor power, for the purposes of this indicator, are is a changes in 27 reactor power that (1) are was initiated less than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the discovery of an off-28 normal condition that required or resulted in a power change, and that result in, or require a 29 change in power level of greater than 20% of full power to resolve, and (2) has not been 30 excluded from counting per the guidance below. Unplanned changes in reactor power also 31 include uncontrolled excursions of greater than 20% of full power that occur in response to 32 changes in reactor or plant conditions and are not an expected part of a planned evolution or test.

March 17, 2014

NRC Final Response FAQ13*05 Oyster Creek Downpower The licensee concludes that the event should be excluded from counting as an Unplanned Power Change per 7,000 Critical Hours per the following guidance:

NEI 99-02, Rev. 7, Page 15 15 Equipment problems encountered during a planned power reduction greater than 20% that alone 16 may have required a power reduction of 20% or more to repair are not counted as part of this 17 indicator if they are repaired during the planned power reduction.

The NRC staff concludes that this event meets the first part of the definition of unplanned changes in reactor power since the down power was initiated less than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the discovery of a circulating water leak and resulted in a total power reduction of 30% (100% to 70%) of full power to fully resolve.

The staff also concludes that the exclusion (NEI 99-02, Rev. 7, page 15, lines 15-17) does not apply based on the specific circumstances of the event, particularly because the equipment problem drove operators to lower power earlier than originally planned. The staffs conclusion is that this event meets the guidance in NEI 99-02, Rev. 7, as an Unplanned Power Change per 7,000 Critical Hours performance indicator occurrence.

The staff believes that the exclusion as written doesnt have sufficient detail on when an equipment problem should be counted toward the PI. The guidance (NEI 99-02, Rev. 7, page 15, lines 15-17) is difficult to apply because the intent is ambiguous (i.e., why is credit being granted when otherwise the occurrence by itself would count against the PI). The staff recommends modifying the guidance to provide a clear understanding of the basis for applying the guidance.

This FAQ is effective immediately after approval.

March 17, 2014