ML13207A142

Pilgrim, Response to Request for Additional Information for the Overall Integrated Plan in Response to the Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation

ML13207A142
Person / Time
Site:	Pilgrim
Issue date:	07/19/2013
From:	Dent J A Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13207A142 (15)

Text

u% Entergy Entergy Nuclear Operations, Inc.Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 John A. Dent, Jr.Site Vice President July 19, 2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852

SUBJECT:

Response to Request for Additional Information for the Overall Integrated Plan in Response to the Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation Pilgrim Nuclear Power Station Docket No. 50-293 License No. DPR-35

REFERENCES:

1. NRC Order Number EA-12-051, "Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation", dated March 12, 2012 (PNPS Letter 1.12.015)2. Entergy letter to NRC, "Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051), dated February 28, 2013 (PNPS Letter 2.13.014)3. NRC letter to Entergy, "Request for Additional Information for the Overall Integrated Plan for Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)", dated June 20, 2013, (PNPS Letter 1.13.031)PNPS LETTER 2.13.057

Dear Sir or Madam:

On March 12, 2012, the NRC issued an Order (Reference

1) to Entergy Nuclear Operations, Inc. (Entergy).

Reference 1 required submission of an Overall Integrated Plan which was provided via Reference

2. By Reference 3, the NRC issued Request for Additional Information (RAI) due within 30 days. The enclosed attachment provides the responses to these RAIs for Pilgrim Nuclear Power Station. The RAI responses provided in the attachment are based on the current preliminary design information/

vendor input which is subject to change as the design is finalized.

PNPS Letter 2.13.057 Page 2 of 3 This letter contains no new regulatory commitments.

Should you have any questions concerning the content of this letter, please contact Mr. Joseph R. Lynch at (508) 830-8403.I declare under penalty of perjury that the foregoing is true and correct. Executed on July 19, 2013.Sincerely, Site Vice President JAD/rmb

Attachment:

Pilgrim Nuclear Power Station Spent Fuel Pool Instrumentation Order Request for Additional Information (RAI) Responses Figure 1: Pilgrim Nuclear Power Station Spent Fuel Pool Levels and References Figure 2: Pilgrim Nuclear Power Station Spent Fuel Pool Level Probe Assembly cc: Mr. William M. Dean Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 2100 Renaissance Boulevard, Suite 100 King of Prussia, PA 19406-1415 U. S. Nuclear Regulatory Commission Director, Office of Nuclear Reactor Regulation One White Flint North 11555 Rockville Pike Washington, DC 20555-0001 Mr. Richard V. Guzman, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop O-8C2A Washington, DC 20555 Mr. John Giarrusso Jr.Planning, Preparedness

& Nuclear Section Chief Mass. Emergency Management Agency 400 Worcester Road Framingham, MA 01702 PNPS Letter 2.13.057 Page 3 of 3 U. S. Nuclear Regulatory Commission Attn: Robert J. Fretz Jr.OWFN, Mailstop # 4A15A 11555 Rockville Pike Rockville, MD 20852-2378 U. S. Nuclear Regulatory Commission Attn: Robert L. Dennig OWFN, Mailstop # 10E1 11555 Rockville Pike Rockville, MD 20852-2378 U. S. Nuclear Regulatory Commission Attn: Ms. Lisa M. Regner OWFN, Mailstop # 11 F1 11555 Rockville Pike Rockville, MD 20852-2378 U. S. Nuclear Regulatory Commission Attn: Mr. Blake A. Purnell OWFN, Mailstop # 12D20 11555 Rockville Pike Rockville, MD 20852-2378 U. S. Nuclear Regulatory Commission Attn: Mr. Steven R. Jones OWFN, Mailstop # 10A1 11555 Rockville Pike Rockville, MD 20852-2378 NRC Resident Inspector Pilgrim Nuclear Power Station Attachment to PNPS Letter 2.13.057 PILGRIM NUCLEAR POWER STATION SPENT FUEL POOL INSTRUMENTATION ORDER REQUEST FOR ADDITIONAL INFORMATION (RAI) RESPONSES Attachment to PNPS Letter 2.13.057 Page 1 of 11 PNPS Spent Fuel Pool Instrumentation Order RAI Responses RAI-1.a) Please provide a clearly labeled sketch depicting the elevation view of the proposed typical mounting arrangement for the portions of instrument channel consisting of permanent measurement channel equipment (e.g., fixed level sensors and/or stilling wells, and mounting brackets).

Indicate on this sketch the datum values representing Level 1, Level 2, and Level 3 as well as the top of the fuel. Indicate on this sketch the portion of the level sensor measurement range that is sensitive to measurement of the fuel pool level, with respect to the Level 1, Level 2, and Level 3 datum points.The requested information is provided in Figure 1. The figure indicates Levels 1, 2, and 3 as well as the approximate location of the proposed mounting bracket incorporating the Seismic Category I attachment.

The sensor is a perforated tubular coaxial waveguide that provides continuous level measurement axially and is sensitive over its entire length. This sketch applies to both the primary and backup channels.The spent fuel pool (SFP) level lower instrument span or probe bottom extends down to at least three inches below the upper limit of the range of Level 3 to account for channel accuracy or instrument loop uncertainty.

Therefore, the SFP level probe bottom/span extends down to at least elevation 93 feet 6 inches (see Figure 1). The SFP level upper instrument span, at a minimum, includes normal water level high alarm. Note that Level 3 is shown in accordance with Nuclear Energy Institute (NEI) 12-02 Revision 1 guidance relative to the top of the rack; the top of the fuel is not shown.RAI-1.b) The OIP states, "Other hardware stored in the SFP will be evaluated to ensure that it does not adversely interact with the SFP instrument probes during a seismic event." Given the potential for varied dose rates from other materials stored in the SFP, describe how level 2 will be adjusted to other than the elevation provided in section 2 above.NEI 12-02 gives two options to determine Level 2. The first option defines Level 2 as ten feet above the highest point of any fuel rack, based on the guidance in Regulatory Guide 1.13, Revision 2. The second option states that Level 2 is based on the need to provide adequate radiation shielding to maintain personnel radiological dose levels within acceptable limits while performing local operations in the vicinity of the pool. The evaluation of the level needed to provide personnel protection should consider the scope of the local operations, including installation of portable FLEX components, along with the emergency conditions that may apply at the time of operator actions.Level 2 has been adjusted to account for materials stored in the SFP by specifying Level 2 at the Technical Specification minimum limit (refer to Figure 1).RAI-2.a) Please provide the design criteria that will be used to estimate the total loading on the mounting device(s), including static weight loads and dynamic loads. Describe the methodology that will be used to estimate the total loading, inclusive of design basis maximum seismic loads and the hydrodynamic loads that could result from pool sloshing or other effects that could accompany such seismic forces.

Attachment to PNPS Letter 2.13.057 Page 2 of 11 The loading on the probe mount and probe body includes both seismic and hydrodynamic loading using seismic response spectra that bounds the Pilgrim design basis maximum seismic loads applicable to the installation location(s).

The static weight load is also accounted for in the modeling described below but is insignificant in comparison to seismic and hydrodynamic loads. Analytic modeling is being performed by the instrument vendor using Institute of Electrical and Electronic Engineers IEEE 344-2004 methodology.

The simple unibody structure of the probe assembly make it a candidate for analytic modeling and the dimensions of the probe and complex hydrodynamic loading terms in any case preclude meaningful physical testing.A detailed computational SFP hydrodynamic model has been developed for the instrument vendor by Numerical Applications, Inc., author of the GOTHIC computational fluid dynamics code. The computational model accounts for multi-dimensional fluid motion, pool sloshing, and loss of water from the pool.Seismic loading response of the probe and mount is separately modeled using finite element modeling software.

The GOTHIC-derived fluid motion profile in the pool at the installation site and resultant distributed hydrodynamic loading terms are added to the calculated seismic loading terms in the finite element model to provide a conservative estimate of the combined seismic and hydrodynamic loading terms for the probe and probe mount, specific to the chosen installation location for the probe.RAI-2.b) Please provide a description of the manner in which the level sensor (and stilling well, if appropriate) will be attached to the refueling floor and/or other support structures for each planned point of attachment of the probe assembly.Indicate in a drawing the portions of the level sensor that will serve as points of attachment for mechanical/mounting or electrical connections.

The proximal portion of the level probe is designed to be attached near its upper end (refer to Figure 2) to a Seismic Category I mounting bracket configured to suit the requirements of a particular SFP. The bracket may be bolted and/or welded to the SFP deck and/or SFP liner/wall according to the requirements of the particular installation per Seismic Category I requirements.

RAI-2.c) Please provide a description of the manner by which the mechanical connections will attach the level instrument to permanent spent fuel pool structures so as to support the level sensor assembly.See RAI-2.b response above.

Attachment to PNPS Letter 2.13.057 Page 3 of 11 RAI-2.d) Please address how other hardware stored in the SFP will not create adverse interaction with the fixed instrument location(s)

An evaluation of non-special nuclear material inventory located in the SFP will be performed during the Spent Fuel Pool Instrumentation (SFPI) modification process. Non-special nuclear material access to the SFP is governed by Procedure 1.16.1, Spent Fuel Pool Non-SNM Inventory Control. This procedure will be used to prevent any instrument interference from non-special nuclear materials.

Special nuclear materials are stored in SFP racks, under administrative controls of Entergy Procedure EN-NF-200; Special Nuclear Materials Controls.RAI-3.a) Please provide a description of the specific method or combination of methods you intend to apply to demonstrate the reliability of the permanently installed equipment under Beyond-Design-Basis (BDB) ambient temperature, humidity, shock, vibration, and radiation conditions.

As stated in NEI 12-02, "Components in the area of the SFP will be designed for the temperature, humidity, and radiation levels expected during normal, event, and post-event conditions...." Components in other areas are planned to be designed for their corresponding maximum conditions.

The discussion below describes the testing and qualification intended to demonstrate equipment reliability as needed for the expected conditions associated with the SFP level channel active components (signal processor and probe assembly including vendor-supplied hard-line coaxial cable pigtail).

Class 1E nuclear-qualified interconnecting coaxial cable is planned to be utilized between the vendor-supplied probe coaxial cable pigtail and the signal processor

/ display located in the Control Room Annex adjacent to the Main Control Room door (an area that is classified as a mild environment).

Temperature:

Signal processor:

Designed for mild environment installation.

Physical testing in an environmental chamber to demonstrate normal operation at the operating temperatures specified for the instrument.

Probe assembly:

Qualification by materials properties and use history of substantially similar probe designs in steam generator applications at significantly higher temperatures and pressures and saturated steam environments.

Humidity: Signal processor:

Designed for mild environment installation.

Physical testing in an environmental chamber to demonstrate normal operation at the operating humidity specified for the instrument.

Probe assembly:

Qualification by materials properties and use history as noted above.Shock: Signal processor:

Physical testing to commercial and/or military standards using shake-table and drop testing.Probe assembly:

Finite element analysis in conjunction with seismic modeling described above.

Attachment to PNPS Letter 2.13.057 Page 4 of 11 Vibration:

Signal processor:

Physical testing to applicable commercial and/or military standards using shake-table and drop testing.Probe assembly:

The probe assembly and bracket together form a simple static unibody structure with intrinsic vibration resistance that is additionally subject to substantial damping due to the surrounding water medium. This is planned to be modeled-using finite element modeling in conjunction with seismic modeling described above.Radiation:

Signal processor:

The signal processor is installed in a mild environment with radiation levels similar to background radiation, with the acknowledgement that the radiation limit for the signal processor is similar to other commercial-grade complementary-metal-oxide-semiconductor (CMOS)-based electronics.

Radiation testing is not planned. It should be noted that the instrument performs self-diagnostics before measurements are obtained and the electronics are easily accessible for periodic replacement.

Probe assembly:

Materials properties qualification is used.RAI-3.b) Please provide a description of the testing and/or analyses that will be conducted to provide assurance that the equipment will perform reliably under the worst-case credible design basis loading at the location where the equipment will be mounted. Include a discussion of this seismic reliability demonstration as it applies to (1) the level sensor mounted in the spent fuel pool area, and (2) any control boxes, electronics, or read-out and re-transmitting devices that will be employed to convey the level information from the level sensor to the plant operators or emergency responders.

Signal processor (electronics):

Triaxial shake-table testing is planned to be performed by the vendor to envelope seismic category 1 safe shutdown earthquake (SSE)conditions or Pilgrim design basis maximum seismic loads (relative to the location where the equipment is mounted) using IEEE 344-2004 methodology.

Probe assembly (level sensor): Seismic and hydrodynamic finite element analysis is performed by the vendor using relevant IEEE 344-2004 methodology (using enveloping seismic category 1 SSE conditions or Pilgrim design basis maximum seismic loads relative to the location where the equipment is mounted), as described in the RAI-3.a response above.RAI-3.c) Please provide a description of the specific method or combination of methods that will be used to confirm the reliability of the permanently installed equipment following seismic conditions to maintain its required accuracy.With respect to the probe assembly, combined seismic and hydrodynamic analysis will be used to demonstrate that the probe waveguide's geometric dimensions do not change significantly as a result of the seismic conditions.

In the absence of alteration to the geometric configuration of the probe waveguide there is no mechanism for seismic excitation of the probe assembly to alter system accuracy.The accuracy of system electronics will be demonstrated following seismic excitation as part of the seismic testing protocol.

Attachment to PNPS Letter 2.13.057 Page 5 of 11 RAI-4.a) Please provide a description of how the two channels of the proposed level measurement system meet this requirement so that the potential for a common cause event to adversely affect both channels is minimized to the extent practicable.

The primary instrument (Channel A) will be in the southwest corner of the SFP and the backup instrument (Channel B) will be in the northwest corner of the SFP. Locating the new instruments in the corners of the SFP takes advantage of missile and debris protection inherent in the corners. Channel A and B displays will be located in the Control Room Annex adjacent to the Main Control Room door.The conceptual design provides two independent level instruments in the SFP with cabling routed to two display/processors mounted in the Main Control Room Annex by the door to the Main Control Room. The Control Room Annex is classified as a mild environment.

Power for each channel is provided from independent 120VAC, 60 Hz sources. Backup power is provided by a battery capable of providing continuous display operation for at least three days. The battery will be provided with the display/processor.

The design prevents failure of a single channel from causing the alternate channel to fail.Channel separation and independence are maintained consistent with existing design basis requirements.

RAI-4.b) Please provide further information on how each level measurement system, consisting of level sensor electronics, cabling, and readout devices will be designed and installed to address independence through the application and selection of independent power sources, independence of signals sent to the location(s) of the readout devices, and the independence of the displays.The design provides two identical non-safety related wide-range level instruments which feed two independent trains of non-safety cable and indicators to provide a highly reliable remote display of SFP water level in the Control Room Annex. Physical separation of the two channels will be accomplished by separately routing cable and conduit as much as practical.

The use of conduit on the refueling floor will provide additional protection from damage due to debris during a BDB event.Each display/processor will have a battery installed in the display enclosure which is capable of providing power for at least three days.See RAI-4.a response above.RAI-5) Please provide the design criteria that will be applied to size the backup battery in a manner that ensures, with margin, that the channel will be available to run reliably and continuously following the onset of the BDB event for the minimum duration needed, consistent with the plant mitigation strategies for beyond-design-basis external events (Order EA-12-049).

The sample rate estimates have been developed by the vendor using conservative instrument power requirements and measured battery capacity with draw-downs during and following exposure of the batteries to their maximum operating temperature for up to seven days. The instrument configuration is planned to be established for an automated Attachment to PNPS Letter 2.13.057 Page 6 of 11 sample rate when under battery power consistent with seven days continuous operation.

Permanent installed battery capacity for seven days continuous operation is planned consistent with NEI 12-02 duration without reliance on or crediting of potentially more rapid FLEX Program power restoration.

Batteries are readily replaceable via spare stock without the need for recalibration to maintain accuracy of the instrument.

These measures ensure adequate power capacity and margin.RAI-6.a) Please provide an estimate of the expected instrument channel accuracy performance (e.g., in % of span) under both (a) normal spent fuel pool level conditions (approximately Level I or higher) and (b) at the BDB conditions (i.e., radiation, temperature, humidity, post-seismic, and post-shock conditions) that would be present if the SFP level were at the Level 2 and Level 3 datum points.The instrument channel level accuracy will be specified as less than +/- 3.0 inches for all expected conditions.

The expected instrument channel accuracy performance would be approximately

+/-1% of span (based on the sensitive range of the detector)RAI-6.b) Please provide a description of the methodology that will be used for determining the maximum allowed deviation from the instrument channel design accuracy that will be employed under normal operating conditions as an acceptance criterion for a calibration procedure to flag to operators and to technicians that the channel requires adjustment to within the normal condition design accuracy.In general relative to normal operating conditions, any applicable calibration procedure tolerances (or acceptance criterion) are planned to be established based on manufacturer's stated/recommended reference accuracy (or design accuracy).

The methodology used is planned to be captured in plant procedures and/or programs.RAI-7.a) Please provide a description of the capability and provisions the proposed level sensing equipment will have to enable periodic testing and calibration, including how this capability enables the equipment to be tested in-situ.The level instrument automatically monitors the integrity of its level measurement system using in-situ capability.

Deviation of measured test parameters from manufactured or as-installed configuration beyond a configurable threshold prompts operator intervention.

Periodic calibration checks of the signal processor electronics to extrinsic National Institute of Standards and Technology (NIST)-traceable standards can be achieved through the use of standard measurement and test equipment.

The probe itself is a perforated tubular coaxial waveguide with defined geometry and is not calibrated.

It is planned to be periodically inspected electromagnetically using time-domain reflectometry (TDR) at the probe hardline cable connector to demonstrate that the probe assembly meets manufactured specification and visually to demonstrate that there has been no mechanical deformation or fouling.RAI-7.b) Please provide a description of how such testing and calibration will enable the conduct of regular channel checks of each independent channel against the other, and against any other permanently-installed spent fuel pool level instrumentation.

Attachment to PNPS Letter 2.13.057 Page 7 of 11 Each instrument electronically logs a record of measurement values over time in non-volatile memory that is compared to demonstrate constancy, including any changes in pool level, such as that associated with the normal evaporative loss/refilling cycle.The channel level measurements can be directly compared to each other (i.e., regular cross-channel comparisons).

The two displays are installed in close proximity to each other, thus simplifying cross-channel checks. Direct measurements of SFP level may be used for diagnostic purposes if cross-channel comparisons are anomalous.

RAI-7.c) Please provide a description of how functional checks will be performed, the frequency at which they will be conducted with a discussion on the measures taken to detect when the instrumentation is operable but degraded, and how these surveillances will be incorporated into the plant surveillance program.Performance tests (functional checks) are automated and/or semi-automated (requiring limited operator interaction) and are performed through the instrument menu software and initiated by the operator.

There are a number of other internal system tests that are performed by system software on an essentially continuous basis without user intervention but which can also be performed on an on-demand basis with diagnostic output to the display for the operator to review. Other tests such as menu button tests, level alarm, and alarm relay tests are only initiated manually by the operator.Performance checks are described in detail in the Vendor Operator's Manual, and the applicable information is planned to be contained in plant operating procedures.

Performance tests are planned to be performed periodically as recommended by the equipment vendor, for instance quarterly but no less often than the calibration interval of two years.Channel functional tests per operations procedures with limits established in consideration of vendor equipment specifications are planned to be performed at appropriate frequencies established equivalent to or more frequently than existing spent fuel pool instrumentation.

Manual calibration tests are as described above in RAI-7.a and 7.b.Manual calibration and operator performance checks are planned to be performed in a periodic scheduled fashion with additional maintenance on an as-needed basis when flagged by the system's automated diagnostic testing features.Channel calibration tests per maintenance procedures with limits established in consideration of vendor equipment specifications are planned to be performed at frequencies established in consideration of vendor recommendations.

RAI-7.d) Please provide a description of the preventative maintenance tasks required to be performed during normal operation, and the planned maximum surveillance interval that is necessary to ensure that the channels are fully conditioned to accurately and reliably perform their functions when needed.Periodic (e.g., quarterly or monthly) review of the system level history and log files and routine attention to any warning message on the system display is recommended by the vendor. Formal calibration checks are recommended by the vendor on a two-year interval to demonstrate calibration to external NIST-traceable standards.

Formal calibration check surveillance interval and timing would be established consistent with applicable guidance [i.e., NEI 12-02 Section 4.3; on a refueling outage interval basis and Attachment to PNPS Letter 2.13.057 Page 8 of 11 within 60 days of a planned refueling].

Items such as system batteries are planned to be assessed under the Preventive Maintenance (PM) Program for establishment of replacement frequency.

Surveillance/PM timing/performance are planned to be controlled via tasks in the PM Program.RAI-8) Please provide a description of the standards, guidelines and/or criteria that will be utilized to develop procedures for inspection, maintenance, repair, operation, abnormal response, and administrative controls associated with the Spent Fuel Pool level instrumentation, as well as storage and installation of portable instruments.

Vendor recommended inspection, maintenance, and repair procedures for the liquid level measurement system have been developed through the vendor's 30-year experience developing and manufacturing liquid level measurement and cable testing instrumentation.

These are for the most part specific to the system's proprietary electronics, subject to relevant industry standards for electronics fabrication and inspection and vendor's quality management system.Where relevant, standards for naval shipboard liquid level indicating equipment have been used to develop procedures for operation, abnormal response, and administrative controls.Portable instrumentation is not utilized.

Both primary and backup SFPI channels incorporate permanent hard-wired installation.

The specific procedures to be used to capture the required activities described in this RAI response have not yet been developed but are planned to be developed in accordance with the vendor recommendations and Entergy processes and procedures.

RAI-9.a) Please provide further information describing the maintenance and testing program the licensee will establish and implement to ensure that regular testing and calibration is performed and verified by inspection and audit to demonstrate conformance with design and system readiness requirements.

Include a description of your plans for ensuring that necessary channel checks, functional tests, periodic calibration, and maintenance will be conducted for the level measurement system and its supporting equipment.

See RAI-6, 7, and 8 responses above for related descriptions of associated maintenance and testing program details. SFPI channel/equipment maintenance/preventative maintenance and testing program requirements to ensure design and system readiness are planned to be established in accordance with Entergy's processes and procedures and in consideration of vendor recommendations to ensure that appropriate regular testing, channel checks, functional tests, periodic calibration, and maintenance is performed.

Subject maintenance and testing program requirements are planned to be developed during the SFPI modification design process.RAI-9.b) Please provide a description of how the guidance in NEI 12-02 Section 4.3 regarding compensatory actions for one or both non-functioning channels will be addressed.

Attachment to PNPS Letter 2.13.057 Page 9 of 11 Both primary and backup SFPI channels incorporate permanent installation (with no reliance on portable, post-event installation) of relatively simple and robust augmented quality equipment.

Permanent installation coupled with stocking of adequate spare parts reasonably diminishes the likelihood that a single channel (and greatly diminishes the likelihood that both channels) is (are) out-of-service for an extended period of time.Planned compensatory actions for unlikely extended out-of-service events are summarized as follows: Compensatory Action if Required Restoration

1. Channel(s)

Action not completed within Out-of-Service Required Restoration Action Specified Time 1 Restore channel to functional status Immediately initiate action within 90 days (or if channel restoration in accordance with Note not expected within 90 days, then below.proceed to Compensatory Action).2 Initiate action within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to restore Immediately initiate action one channel to functional status. in accordance with Note Restore one channel to functional below.status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.Note: Present a report to the On-Site Safety Review Committee within the following 14 days. The report shall outline the planned alternate method of monitoring, the cause of the non-functionality, and the plans and schedule for restoring the instrumentation channel(s) to functional status.RAI-9.c) Please provide a description of what compensatory actions are planned in the event that one of the instrument channels cannot be restored to functional status within 90 days.See RAI-9.b response above.

Attachment to PNPS Letter 2.13.057 Page 10 of 11 E MOUNTING BRACKET OPERATING FLOOR LEVEL NORMAL POOL LEVEL SIPHON BREAK LEVEL LOW ALARM LEVEL TS 314.10.C BLADES STORED OVER SIDE FPC PUMPS TRIP SENSOR FUEL RACK LEVEL + 1 FOOT BOTTOM OF GATE FUEL RACK LEVEL BOTTOM OF POOL LEVEL SFPI LEVEL 2 POOL LEVELS AND REFERENCE ELEVATION 117'-0" 116-6" 116'-0" SFPI LEVEL1 ---- -115'111V-3"-108'ES REFERENCE M-39, Rev.1 Reactor Building -Area 1 & 3 -Plan above el. 117'-4y C-109, Rev.4 Spent Fuel Storage, Dryer, and Separator Pools Sections Top Min. Sensitive Range, 6" Above Normal Pool Level M23, Rev.8 Equipment Locations, C179, Rev.4 -Spent Fuel Pool Sections & Details Drawing M3459 Revision El -Fuel Pool Cooling and Demineralizing System Spent Fuel Storage Pool Clean-Up Diffuser Lines & Reactor Basin Fill Lines 19.5 inches decreasing from Skimmer Surge Tank bottom (M22-5-7BC, Rev.4)M263 sh.1 99A, Rev.2 (1 foot below over flow)TS 314.10.C, Water Level -Spent Fuel Pool (NEI 12-02 LEVEL 2)(Reference SE-2818)Top of Blades FPCP Trip is on Low-Low level in the Skimmer Surge Tank at elevation 102'-5". Fuel Pool overflow is at the weir plates elevation 115T-7.625" (C179, Rev.4). Siphon break is at elevation 115'-8" (M3459, Rev. 1) and is the higher level, therefore, assigned as Level 1.Bottom of Blades Level 3 Bottom Min. Sensitive Range, 3" below LEVEL 3 Upper Limit C180, Rev.4 Reactor Building -Spent Fuel pool C1398, Rev.0, Rack Construction

-Spent Fuel Storage Rack 102'-5" I SFPI LEVEL 3 94'93'-9" 93'-6" 93'-3.75" 92'-9" 78'-3" Drawing C173 Rev.t FIGURE 1 Pilgrim Nuclear Power Station Spent Fuel Pool Levels & References

-Reactor Building -Spent Fuel Pool General Arrangement Attachment to PNPS Letter 2.13.057 Page 11 of 11-17Y Mounting Bracket MOUNT Top FIGURE 2 Pilgrim Nuclear Power Station Spent Fuel Level Probe Assembly