L-12-244, Correction of Errors in the License Renewal Application Environmental Report Severe Accident Mitigation Alternatives Analysis, and License Renewal Application Amendment No. 29

Correction of Errors in the License Renewal Application Environmental Report Severe Accident Mitigation Alternatives Analysis, and License Renewal Application Amendment No. 29

ML12200A024
Person / Time
Site:	Davis Besse
Issue date:	07/16/2012
From:	Dominy J FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-12-244, TAC ME4613
Download: ML12200A024 (117)

Text

FENOC Davis-Besse Nuclear Power Station 5501 N. State Route 2 FirstEnergyNuclear OperatingCompany Oak Harbor,Ohio 43449 July 16, 2012 L-1 2-244 10 CFR 54 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Davis-Besse Nuclear Power Station, Unit No. 1 Docket No. 50-346, License Number NPF-3 Correction of Errors in the Davis-Besse Nuclear Power Station, Unit No. 1, License Renewal Application (TAC No. ME4613) Environmental Report Severe Accident Mitiqation Alternatives Analysis, and License Renewal Application Amendment No. 29 By letter dated August 27, 2010, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML102450565), FirstEnergy Nuclear Operating Company (FENOC) submitted an application pursuant to Title 10 of the Code of Federal Regulations, Part 54 for renewal of Operating License NPF-3 for the Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse). In January 2012, during review of the License Renewal Application (LRA), Environmental Report, Attachment E, Severe Accident Mitigation Alternatives (SAMA) Analysis, four errors were identified that affected the SAMA Analysis. In March 2012, during review of the draft corrected SAMA Analysis and an extent-of-condition review for the four errors, an additional error was identified in the analysis. On January 12 and March 28, 2012, FENOC contacted Ms. Paula Cooper, Nuclear Regulatory Commission (NRC) Environmental Project Manager, to inform NRC of the SAMA Analysis errors and discuss the impacts to the SAMA Analysis review schedule. Following correction of the five errors, the revised (corrected) SAMA Analysis conclusions did not change; specifically, the revised SAMA Analysis did not result in the discovery of any additional cost beneficial SAMAs beyond the one (SAMA AC/DC-03, which adds a portable diesel-driven battery charger to the DC system) identified in the FENOC letter dated June 24, 2011 (ML11180A233).

Attachment 1 provides a description of the five SAMA Analysis errors.

Attachment 2 provides, based on the revised SAMA Analysis, the results of a review for impacts to the responses to NRC requests for additional information (RAIs) for the SAMA Analysis submitted by FENOC letter dated June 24, 2011 (ML11180A233).

Attachment 3 provides, based on the revised SAMA Analysis, the results of a review for impacts to the supplemental responses to NRC supplemental RAIs for the SAMA Analysis submitted by FENOC letter dated September 1,2011 (ML11250A068).

The Enclosure provides Amendment No. 29 to the Davis-Besse LRA.

Davis-Besse Nuclear Power Station, Unit No. 1 L-1 2-244 Page 2 There are no regulatory commitments contained in this letter. If there are any questions or if additional information is required, please contact Mr. Clifford I. Custer, Fleet License Renewal Project Manager, at 724-682-7139.

I declare under penalty of perjury that the foregoing is true and correct. Executed on July K__, 2012.

Sincerely, J C. Dominy DIctor, Site Maintenan Attachments:

1. Description of Errors Identified in the Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse), License Renewal Application, Environmental Report, Attachment E, Severe Accident Mitigation Alternatives Analysis

2. Review for Impacts to Responses to Requests for Additional Information for the Review of the Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse),

License Renewal Application, Environmental Report, Attachment E, Severe Accident Mitigation Alternatives Analysis Submitted by FENOC Letter Dated June 24, 2011 (ML11180A233)

3. Review for Impacts to Responses to Requests for Additional Information for the Review of the Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse),

License Renewal Application, Environmental Report, Attachment E, Severe Accident Mitigation Alternatives Analysis Submitted by FENOC Letter Dated September 1,2011 (ML11250A068)

Enclosure:

Amendment No. 29 to the Davis-Besse License Renewal Application cc: NRC DLR Project Manager NRC DLR Environmental Project Manager NRC Region III Administrator

Davis-Besse Nuclear Power Station, Unit No. 1 L-1 2-244 Page 3 cc: w/o Attachments or Enclosure NRC DLR Director NRR DORL Project Manager NRC Resident Inspector Utility Radiological Safety Board

Attachment 1 L-1 2-244 Description of Errors Identified in the Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse), License Renewal Application, Environmental Report, Attachment E, Severe Accident Mitigation Alternatives Analysis Page 1 of 1 During reviews of the Severe Accident Mitigation Alternatives (SAMA) Analysis, the following five errors were identified:

1. An inaccurate land area conversion factor for acres to hectares was used.

2. Dollar values for Ohio farmland and non-farmland used as inputs to the "MELCOR Accident Consequence Code System" (MACCS2) software used in support of the SAMA Analysis were not appropriate. The land values were selected from Ohio Department of Taxation 'tax assessment' values instead of 'appraised' values. The Ohio tax assessment value is 35 percent of the appraised value.

3. The escalation of decontamination costs used in the SAMA Analysis was not performed per the guidance of Nuclear Energy Institute (NEI) 05-01 "Severe Accident Mitigation Alternatives (SAMA) Analysis Guidance Document,"

November 2005, using the consumer price index.

4. Use of core inventory isotopic 'activity' instead of isotopic 'mass' in the Modular Accident Analysis Program (MAAP) software code runs did not reflect updated industry guidance. MAAP Users Group News Bulletin, "MAAP-FLASH #68" (August 5, 2008), recommended that users of MAAP versions 4.0.5 through 4.0.7 (FENOC is currently using MAAP software version 4.0.6) include plant-specific values for the mass of the relevant fission product elements instead of the isotopic activity of those elements.

5. The wind direction from the Davis-Besse Meteorological Tower was not converted from the 'blowing from' direction to the 'blowing toward' direction for use in the SAMA Analysis calculations. The data from the Davis-Besse Meteorological Tower is received in the 'blowing from' direction. However, the MACCS2 software requires wind direction data inputs to be provided in the 'blowing toward' direction.

The data conversion was not performed properly.

Following correction of the five errors identified above, the revised (corrected) SAMA Analysis conclusions did not change; specifically, the revised SAMA Analysis did not result in the discovery of any additional cost-beneficial SAMAs beyond the one (SAMA AC/DC-03, which adds a portable diesel-driven battery charger to the DC system) identified in the FENOC letter dated June 24, 2011 (ML11180A233). LRA Appendix E, "Applicant's Environmental Report Operating License Renewal Stage," Attachment E, "Severe Accident Mitigation Alternatives Analysis," is revised to incorporate the corrected information in the affected Sections and Tables.

See the Enclosure to this letter for the revision to the Davis-Besse LRA.

Attachment 2 L-12-244 Review for Impacts to Responses to Requests for Additional Information for the Review of the Davis Besse Nuclear Power Station, Unit No. 1 (Davis-Besse),

License Renewal Application, Environmental Report, Attachment E, Severe Accident Mitigation Alternatives Analysis Submitted by FENOC Letter Dated June 24, 2011 (ML11180A233)

Page 1 of 63 FirstEnergy Nuclear Operating Company (FENOC) performed a review, based on the revised SAMA Analysis, for impacts to the responses to Nuclear Regulatory Commission (NRC) requests for additional information (RAIs) for the Severe Accident Mitigation Alternatives (SAMA) Analysis submitted by FENOC letter dated June 24, 2011 (ML11180A233). Based on the changes to the SAMA Analysis, no revision to the FENOC responses provided by the June 24, 2011, letter is necessary for the following SAMA RAIs:

SAMA RAI Responses -

No Revision 1.a 3.b 6.b 1.b 4.a 6.c 1.c 4.b 6.d 1.d 4.c 6.e 1.e 5.a 6.f 1.f 5.b 6.g 2.a 5.d.i 6.h 2.b 5.e 6.i.i 2.c 5.f 7.b 2.d 5.h 7.c 2.e 5.i 3.a 6.a FENOC responses are revised for the remaining SAMA RAIs from the June 24, 2011, letter as provided in the following discussion. The NRC request is shown in bold text followed by the original FENOC response provided by the June 24, 2011, letter. A statement is provided for each SAMA RAI response to identify whether the response is replaced in its entirety or edited. For edited responses, the sentence affected is printed in italics with deleted text lined ou and added text underlined.

L- 12-244 Page 2 of 63 Item 3 Provide the following information with regard to the treatment and inclusion of external events in the SAMA analysis:

Question RAI 3.c ER Section E.3.1.2.4 presents the basis for an external events multiplier of 3 based on a "conservatively" estimated fire CDF of 2.5E-05/yr developed using the FIVE methodology and the assumption that a "realistic" fire CDF is a factor of 3 less than this FIVE-produced fire CDF. The NRC staff disagrees that a fire CDF produced using the FIVE screening methodology is necessarily conservative in light of more recent research and guidance on hot short probabilities (i.e.,

NUREG/CR-6850). The NRC staff particularly notes that the minimal or non-treatment of hot shorts in the IPEEE FIVE analysis may more than offset other conservatisms in the FIVE analysis. Based on this, and the previous RAI, the NRC staff believes the best estimate of the fire CDF for Davis-Besse is 2.9E-05/yr.

In addition, the USGS issued updated seismic hazard curves for much of the U.S.

in 2008. Using this data, the NRC staff estimated a "weakest link model" seismic CDF for Davis-Besse of 6.7E-06/yr (see NRC Information Notice 2010-18 regarding Generic Issue 199). Based on a fire CDF of 2.9E-05/yr, a seismic CDF of 6.7E-06/yr, and an internal events CDF of 9.8E-06/yr, the NRC staff estimates the external events multiplier to be 3.6. In light of this, provide a revised SAMA evaluation using an external events multiplier of 3.6 or alternatively provide justification for an evaluation of a different multiplier based on this updated USGS information.

RESPONSE RAI 3.c

[The response to RAI 3.c is edited as shown in 2 nd paragraph.]

Based on the information provided in the RAI, an updated external events multiplier was calculated for Davis-Besse. The updated external events multiplier includes risk contribution from fire, seismic, and other hazard groups. The risk contribution for the fire and seismic hazard groups was determined by a ratio between the hazard group CDF and the internal events CDF as shown in the equations below. The risk contribution from the other hazard group was conservatively assumed to be equivalent to the internal events contribution. Therefore, the other hazard group multiplier is 1.0.

L-12-244 Page 3 of 63 Fire Hazard Multiplier:

Fire CDF = 2.9x10-5/yr 5

290 1.0x10- /yr Internal Events CDF Seismic Hazard Multiplier:

Seismic CDF 6.7x10-6/yr Internal Events CDF 1.0x10- 5 /yr To determine the multiplier to account for fire, seismic, and other hazard groups, the three individual multipliers were summed, resulting in a multiplier of 4.6. The cost-benefit evaluation was updated using an external event multiplier of 4.6. The updated maximum benefit for Davis-Besse is $,,955i,223 $2,053,481. Based on the updated maximum benefit, one SAMA candidate, AC/DC-03 (add a portable diesel-driven battery charger to the direct current (DC) system) was determined to be cost-beneficial.

ER Section E.3.1.2.4, "External Event Severe Accident Risk," is deleted based on the response to this RAI. ER Section E.4.5, "Total Cost of Severe Accident Risk," is revised to explain the updated external events multiplier. ER Tables E.4-1, E.7-2, E.7-3, E.7-5, and E.8-1 are revised to reflect the revised cost-benefit results.

See the Enclosure to this letter for the revision to the Davis-Besse LRA.

L-12-244 Page 4 of 63 Item 4 Provide the following information concerning the Level 3 analysis:

Question RAI 4.d ER Section E.3.4.6.2 does not identify the population base/year reference for the emergency planning zone (EPZ) evacuation speed. Describe how/whether the EPZ evacuation time was corrected for the year 2040 population (and address the population discrepancy noted in RAI 4.b).

RESPONSE RAI 4.d

[The response to RAI 4.d is edited as shown in the 2 nd paragraph and Table 4.d-1.]

Reference [4] (in Attachment E of the Environmental Report) does not identify a collection date for the data that were used to estimate the evacuation speed in Section E.3.4.6.2. The evacuation information provided in Reference [4] was assumed to be current as of the 2000 census. However, no correction factor was applied to account for the increased population in 2040 in the original analysis.

Assuming that an increase in population is proportional to a decrease in evacuation speed, the evacuation speed was adjusted from 0.58 meters/second to 0.52 meters/second. This adjustment represents a 9.6 percent decrease in the evacuation speed, which was used to offset a 9.6 percent [(1.047)2 = 1.096] increase in population at the end of the two-decade license renewal period. This decrease in evacuation speed was evaluated as a new sensitivity case (Sensitivity Case E3). The results are provided in Table 4.d-1, below, and show no ve*"-!itte-change from the base case, indicating that the results are not sensitive to slow evacuation speeds. The base case results shown in Table 4.d-1 include the updated population (as needed to respond to RAI 4.b); similarly, sensitivity case E3 includes the updated population, to permit an equitable comparison to the base case. ER Section E.3.5.2.4 is revised and new ER Table E.3-33, "Comparisonof Base Case and Case E3," is added to incorporate sensitivity case E3.

See the Enclosure to this letter for the revision to the Davis-Besse LRA.

L-12-244 Page 5 of 63 Table 4.d-1: Comparison of Base Case and Case E3 Internal Events Base E3  % diff.

Whole Body Dose (50) (person-rem/yr) 2 12E+00 2.12E+00 0.0%

Economic Impact (50) ($/yr) .5

3. 59E+03 3.59E+03 I.9E+03 0.0%

Question RAI 4.e In ER Section E.3.5.2.3, for Case Al, identify the heat release energy (e.g. thermal, 1 MW) assumed for both the base and sensitivity cases.

RESPONSE RAI 4.e

[Table 4.e-1 is replaced in its entirety.]

The energy of release for the base case and sensitivity Case Al are provided for each release category in Table 4.e-1, below.

L-12-244 Page 6 of 63 Table 4.e-1 Energy of Release: Base Case and Sensitivity Case Al PLHEAT/Energy of Release (watts)

Release Category Base Case Sensitivity Case Al 1.1 3.87E+07 1.49E+08 1.2 1.45E+07 9.21E+07 1.3 3.87E+07 1.49E+08 1.4 1.45E+07 9.21E+07 2.1 8.91E+06 6.04E+08 2.2 6.68E+06 6.16E+08 3.1 2.22E+06 2.92E+07 3.2 2.61 E+06 1.82E+07 3.3 2.22E+06 1.78E+07 3.4 2.61 E+06 1.82E+07 4.1 9.17E+05 1.66E+07 4.2 2.24E+05 1.66E+07 4.3 6.77E+05 1.66E+07 4.4 2.10E+05 1.66E+07 5.1 3.17E+06 2.48E+07 5.2 1.09E+07 6.31 E+07 5.3 2.83E+06 2.01 E+07 5.4 9.59E+06 5.80E+07 6.1 7.35E+07 3.36E+08' 6.2 1.14E+08 4.64E+08 6.3 6.10E+07 3.87E+08 6.4 1.16E+08 4.90E+08 7.1 3.02E+07 1.79E+08 7.2 2.79E+07 1.67E+08 7.3 2.82E+07 1.68E+08 7.4 2.80E+07 1.66E+08 7.5 2.01E+07 1.34E+08 7.6 2.36E+07 1.22E+08 7.7 1.93E+07 1.32E+08 7.8 2.45E+07 1.29E+08 8.1 8.71E+06 1.61E+08 8.2 9.78E+07 4.11E+08 9.1 2.63E+02 2.08E+03 9.2 3.30E+02 2.14E+03

L-12-244 Page 7 of 63 Item 5 Provide the following with regard to the SAMA identification and screening process:

Question RAI 5.c None of the SAMA candidates identified in Table E.5-4 appear to be plant-specific SAMAs identified from plant-specific risk insights based on the current PRA model. Clarify how the importance lists were used to develop plant-specific SAMA candidates and justify the apparent absence of any plant-specific SAMA candidates. Also, the basic events identified in importance analysis Tables E.5-2 and E.5-3 are not linked to SAMA candidates. Sections E.5.4 and E.5.5 only discuss the SAMA candidates identified to address basic events with high risk reduction worth (RRW) values. Identify, for each basic event having a RRW benefit value (averted cost risk) greater than the minimum cost of a procedure change at Davis-Besse, the specific SAMA(s) that address each event and describe how the SAMA(s) address the basic event. Identify and evaluate SAMAs for basic events not addressed by an existing SAMA (e.g., flooding related basic events and initiators, including WHAF31SE, SHAF21SE, F3AM, and F7L). For any basic event for which no SAMA is identified, provide justification for not identifying a SAMA(s).

RESPONSE RAI 5.c

[The response to RAI 5.c is edited as shown on pages 9 and 10 of 63, and Table 5.c-2 on page 22 of 63. Tables 5.c-1 and 5.c-2 are also revised (multiple locations) to change the steam generator replacement schedule from 2013 to 2014 to align with current FENOC plans and with the discussions in the ER.]

The final list of SAMA candidates was developed from a combination of generic data, industry SAMA analyses and Davis-Besse-specific insights. The following SAMA candidates were added to the generic list based on Davis-Besse PRA-identified insights:

SAMA candidate AC/DC-25 (dedicated DC power for AFW) and AC/DC-26 (alternator/generator for turbine-driven auxiliary feedwater (TDAFW) pump) were designed to extend the life of the TDAFW pumps in a station blackout (SBO) event and improve the likelihood of successful restoration of alternating current (AC) power.

L-12-244 Page 8 of 63

• SAMA candidate AC/DC-27 (increased size of SBO fuel oil tank) was also designed to help mitigate an SBO event.

• SAMA candidate CB-21 (pressure sensors between the two in-series Decay Heat Removal (DHR) System suction valves) was designed to help reduce the likelihood of ISLOCA events.

• SAMA candidate CC-19 (automatic switchover of high pressure injection (HPI) and low pressure injection (LPI) suction from the BWST to the containment sump) was designed to increase the reliability of the switchover during a loss of coolant accident (LOCA) event.

• SAMA candidate CC-20 (modify hardware and procedures to allow using make-up pumps for high pressure recirculation from the containment sump) was designed improve the reliability of high pressure recirculation following the loss of HPI.

• SAMA candidate CC-21 (reduce the BSWT level at which switchover to containment recirculation is initiated) was designed to extend the time available to accomplish BWST refill.

" SAMA candidate CP-1 9 (install a redundant containment fan system) was designed to increase containment heat removal ability. This SAMA candidate was added as a variation to CP-18 to provide a redundant containment cooling function, in the form of containment fan coolers.

• SAMA candidates CW-24 (adding a diversified CCW pump) and CW-25 (providing the capability to cool makeup pumps with fire water on loss of CCW) were designed to mitigate the total loss of CCW cooling.

• SAMA candidate FW-16 (surveillance of manual AFW suction valves) was designed to improve the reliability of alternate sources of AFW water supply.

• SAMA candidate HV-06 (procedure guidance for alternate means of switchgear cooling) was designed to prevent the loss of one train of service water in the event of loss of one HVAC fan for the service water pump room. This SAMA candidate was developed from Davis-Besse IPE insights.

L-12-244 Page 9 of 63 Evaluating Basic Events with Potential Benefit Greater Than the Cost of a Procedure Change The internal events and LERF basic events with an RRW value estimated to be equal to or greater than the cost of a procedure change were evaluated. These basic events were dispositioned by either identifying resulting SAMAs or presenting the reason for no new SAMA candidate. One new SAMA candidate (OT-9R) resulted from this evaluation.

An estimate of the cost-benefit versus RRW was developed for the internal events basic events calculated for the base PRA model. The minimum cost of a procedure change was assumed to be $10,000. In addition, the minimum cost of a hardware modification was estimated to be $100,000. The cost-benefit versus RRW assumed that cost-benefit was directly proportional to the reduction in core damage frequency (CDF). Cost is not perfectly correlated with CDF, due to the fact that different scenarios, even with the same CDF, will result in different distributions of release categories. It is judged, however, that this correlation provides a reasonable estimate of potential benefit along with what is judged to be a low cost for a procedure change, and provides strong confidence that cost-effective SAMA candidates will be captured.

For the total benefit for the hazard group (Bt), the cost-benefit versus RRW used the maximum derived benefit of-$3494,4 $366,693.

The following formula is used for deriving the estimated benefit by hazard group based on RRW:

EB(BE) = Bt1- RR1 W

where, EB(BE) = the estimated benefit based on a basic event Bt = the total benefit for the hazard group (internal events, fire, or seismic)

RRW = the RRW for the basic event from the PSA, by hazard, assuming the basic event failure probability is reduced to zero.

The RRW for the Level 2 PRA basic events may be calculated based on LERF rather than CDF. Additional conservatism is added by treating Level 2 PRA basic event RRW values based on LERF as if they were based on CDF (i.e., the use of Bt significantly overstates their benefit), and the degree of conservatism could be large.

L-12-244 Page 10 of 63 Based on these estimates, an RRW value of 1.03 was calculated to have a maximum cost benefit of $10,000 and an RRW of4*4 1.37 was estimated to have a maximum cost benefit of $100,000. The maximum cost benefit is based on the RRW of the basic event being reduced to 1.0 (basic event modeled as perfect). For all basic events having an RRW value estimated to be at, or above, the value of a procedure change, a disposition was provided either identifying the SAMA candidate(s) addressing that basic event or a description as to why the basic event was not addressed in a SAMA candidate. No basic events had an RRW value equal to, or greater than the estimated cost of a hardware modification. Table 5.c-1, below, lists the basic events with the highest RRW for CDF.

Table 5.c-2, below, tabulates the basic events with the highest RRW for LERF. The estimated benefit for each basic event was derived by taking the RRW for LERF and applying the maximum total benefit used for the CDF basic events. This is very conservative, since the total maximum benefit does not apply only to LERF. For all basic events having an RRW value estimated to be at, or above, the value of a procedure change, a disposition was provided either identifying the SAMA candidate(s) addressing that basic event or a description as to why the basic event was not addressed in a SAMA candidate. No basic events had an RRW value equal to, or greater than the estimated cost of a hardware modification.

Basic events WHAF31SE, SHAF21SE, F3AM, and F7L did not have RRW values with potential benefit equal to, or greater than, the minimum cost of a procedure change.

Basic event F7L, a large circulating water flood in the Turbine Building, did, however, result in an RRW value greater than the minimum cost of a procedure change for the 95 percent uncertainty CDF model. SAMA candidate FL-01 (improve inspection of rubber expansion joints on main condenser) was initially identified to address basic event F7L, and was designed to reduce the frequency of a large circulating water system flooding event due to failure of the circulating water system expansion joints.

Based on the F7L RRW value from the 95 percent uncertainty CDF model and its original screening of "Very Low Benefit," SAMA candidate FL-01 was reevaluated and screened as "Already Implemented," as discussed in the response to RAI 6.k.

The ER is revised (numerous locations) to identify that there are now 168 SAMA candidates that were evaluated instead of the original 167. Also, ER Table E.5-4 is revised to include changes identified in Tables 5.c-1 and 5.c-2, below.

See the Enclosure to this letter for the revision to the Davis-Besse LRA.

L-12-244 Page 11 of 63 Table 5.c Basic Event Level 1 PRA Importance Event Name F-V RRW Description Disposition A SAMA candidate was developed that presents the highest worth PRA human Failure to initiate makeup/HPI cooling after actions to the Davis-Besse operator UHAMUHPE 2.59E-01 1.349 loss o initiate training. SAMA candidate OT-09R was loss of all feedwater added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

SAMA candidate FW-17R evaluates QHAMDFPE 2.45E-01 1.324 Failure to start MDFP after loss of feedwater implementing an automatic start of the motor-driven feed pump (MDFP) on loss of main feedwater (MFW).

SAMA candidate CW-26R evaluates Operators fail to trip RCPs after a total loss of implementing an automatic RCP trip on high QHARCPCE 2.32E-01 1.302 Operatorail tbearing cooling temperature or loss of CCW seal cooling flow to the RCP thermal barrier cooler and loss of seal injection flow.

Numerous SAMA candidates that address LOOP were evaluated:

AC/DC-01, additional battery capacity T3 1.96E-01 1.243 LOOP (initiating event) AC/DC-14, install gas turbine generator AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps AC/DC-27, increase SBO fuel oil tanks size SAMA candidate AC/DC-28R evaluates the EHASBDGE 1.64E-01 1.196 Operators fail to align power from SBO diesel automatic start of the SBO diesel and generator to supply MDFP loading to Bus D2 upon loss of power to Bus D2.

L-12-244 Page 12 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition A SAMA candidate was developed that presents the highest worth PRA human EHASBD1E 1.58E-O1 1.187 Operators fail to start SBO diesel generator actions to the Davis-Besse operator 7and align to bus D1 training. SAMA candidate OT-09R was added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

A SAMA candidate was developed that presents the highest worth PRA human actions to the Davis-Besse operator to align power EDG 1-1 or fromLOOP cani date opera s S M candidate tinng SAMA EHAD2DGE EHD2G 1.53E-O1 153-1 1.181

.11 EDG 1-2 tofail Operators supply MDFP given training. OT-09R was added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

L-12-244 Page 13 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition This is based on a somewhat conservative T1 value of 1.02/yr. Davis-Besse trip occurrence frequency is considered representative of industry values.

SAMA candidates have been evaluated that address various Davis-Besse important scenarios following a reactor/turbine trip.

CC-01, evaluates the installation of an T1 1.35E-01 1.156 Reactor/turbine trip (initiating event) independent active or passive HPI system.

CW-26R, evaluates an automatic RCP trip on high motor bearing temperature or loss of CCW flow to the RCP thermal barrier cooler and loss of seal injection flow.

FW-17R, evaluates an automatic start of the motor driven feedwater pump.

HV-01, evaluates a redundant train for ventilation.

HV-03, evaluates the staging of backup fans in the switchgear room.

SAMA candidate AC/DC-25 provides a dedicated DC system to TDAFW pumps and SAMA candidate AC/DC-26 provides Operators fail to take local manual control of an alternator/generator driven by TDAFW QHAOVF2E 1.22E-01 1.139 TDAFW pump 1-2 speed. pumps.

These SAMA candidates would eliminate the need for local manual control of the TDAFW pumps.

L-12-244 Page 14 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition SAMA candidate CW-26R evaluates 4

Operators fail to trip RCPs following loss of implementing an automatic RCP trip on high ZHARCPCE 1.10E-01 1.124 Operatorail tbearing cooling temperature or loss of CCW seal cooling flow to the RCP thermal barrier cooler and loss of seal injection flow.

A SAMA candidate was developed that presents the highest worth PRA human Failure to recover CCW using spare CCW actions to the Davis-Besse operator WHASPREE 1.07E-01 1.12 trtraining. SAMA candidate OT-09R was train (prior to damage) added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

This estimated benefit of this basic event is below the minimum estimated cost of a hardware modification.

The following SAMA candidates address QMBAFP1 1 7.61 E-02 1.082 AFW Train 1 in maintenance improvements to the reliability of AFW in loss of off-site power scenarios:

AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps XHOS- 7.54E-02 1.082 CCW Pump 1 running, Pump 2 in standby This is a plant configuration probability in CCW1 RUN2STBY the model. It does not contribute to risk.

SAMA candidate AC/DC-14 evaluates EDG0012F 7.12E-02 1.077 EDG 1-2 fails to run adding a gas turbine generator as an I I_additional source of on-site power.

L-12-244 Page 15 of 63 Table 5.c Basic Event Level I PRA Importance (continued)

Event Name F-V RRW Description Disposition Numerous SAMA candidates that address LOOP were evaluated:

AC/DC-01, additional battery capacity AC/DC-14, install gas turbine generator 7OP007BR 7.09E-02 1.076 Failure to restore off-site power AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps AC/DC-27, increase SBO fuel oil tanks size SAMA candidate CW-24 evaluates the TMPP43XF-CCALL 6.79E-02 1.073 All CCW pumps fail to run due to CCF standby CCW pump with a pump diverse

-(initiating event) from the other two CCW pumps.

XHOS- 6.57E-02 1.07 CCW Pump 2 running, Pump 1 in standby This is a plant configuration probability in CCW2RUN1STBY the model. It does not contribute to risk.

Davis-Besse is scheduled to install new steam generatorsin-2403 2014. This modification, with resulting reduction in R 6.37E-02 1.068 SGTR (initiating event) SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

A SAMA candidate was developed that presents the highest worth PRA human actions to the Davis-Besse operator EHAD1ACE 5.90E-02 1.063 Failure to lineup alternate source to D1 training. SAMA candidate OT-09R was added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

L-12-244 Page 16 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition The estimated benefit for this basic event is T2 5.86E-02 1.062 Plant trip due to loss of MFW (initiating event) below the cost of a hardware modification.

No SAMA candidate considered.

Numerous SAMA candidates that address LOOP were evaluated:

AC/DC-01, additional battery capacity NORCVRT3 5.57E02 1.059 Offsite power recovery not possible after a AC/DC-14, install gas turbine generator tornado. AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps AC/DC-27, increase SBO fuel oil tanks size Reactor vessel rupture is a low probability event that that is assumed to result in AV 5.12E-02 1.054 Reactor vessel rupture guaranteed core damage. No applicable SAMA candidates were considered possible to prevent core damage.

The estimated benefit for this basic event is QTP000XA-CC_1_2 5.1 3E-02 1.054 CCF QPO2 of two components:

TAW QTPOO01A & below the cost of a hardware modification.

QTP0002A (TDAFW)

No SAMA candidate considered.

The estimated benefit for this basic event is QTPOO01A 4.90E-02 1.051 AFPIT-1 fails to start below the cost of a hardware modification.

I_ I I No SAMA candidate considered.

L-12-244 Page 17 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition The estimated benefit for this basic event is below the cost of a hardware modification.

The following SAMA candidates address improvements to the reliability of AFW in QMBAFP12 4.67E-02 1.049 AFW Train 2 in maintenance LOOP scenarios:

AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps Numerous SAMA candidates that address LOOP were evaluated:

AC/DC-01, additional battery capacity AC/DC-14, install gas turbine generator ZOP006FR 4.58E-02 1.048 Failure to restore off-site power AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps AC/DC-27, increase SBO fuel oil tanks size SAMA candidate CC-01 evaluates the installation of an independent active or passive HPI system.

S 4.35E-02 1.045 Small LOCA (initiating event) SAMA candidate CC-19 evaluates the implementation of automatic switchover of HPI and LPI suction from the BWST to the to containment sump for LOCAs.

L-12-244 Page 18 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition The estimated benefit for this basic event is T13A-1-3-1EF 4.18E-02 1.044 Loss rung of CCW Train 1 initiating event Pump 1 below the cost of a hardware modification.

running No SAMA candidate considered.

A SAMA candidate was developed that presents the highest worth PRA human actions to the Davis-Besse operator MHARMVTE 4.17E-02 1.043 Operators fail to compensate for loss of room training. SAMA candidate OT-09R was cooling for makeup pumps. added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

A SAMA candidate was developed that presents the highest worth PRA human XHAMUCDE 4.10E-02 1.043 Operators fail to attempt cooldown via actions to the Davis-Besse operator makeup/HP cooling.

43 training. SAMA candidate OT-09R was added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

The estimated benefit for this basic event is T13A-2-3-1E F 3.93E-02 1.041 Loss rung of CCW Train 2 initiating event Pump 2 below the cost of a hardware modification.

running No SAMA candidate considered.

SAMA candidate AC/DC-14 evaluates EMBEDG12 3.85E-02 1.04 EDG Train 2 in maintenance adding a gas turbine generator as an I I__ Iadditional source of on-site power.

L-12-244 Page 19 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition A SAMA candidate was developed that presents the highest worth PRA human actions to the Davis-Besse operator training. SAMA candidate OT-09R.

CHASGDPE 3.63E-02 1.038 Operators fail to cooldown during a SGTR Also, Davis-Besse is scheduled to install new steam generatorsin-204 2014. This modification, with resulting reduction in SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

The estimated benefit for this basic event is FMFWTRIP 3.71 E-02 1.038 MFW/ICS faults following trip below the cost of a hardware modification.

No SAMA candidate considered.

SAMA candidate CB-22R evaluates the use FMM00003 3.52E-02 1.037 Any MSSVs on SG1 fail to reseat of a "gagging device" to close a stuck open MSSV.

SAMA candidate AC/DC-14 evaluates EDG0012A 3.46E-02 1.036 EDG 1-2 fails to start adding a gas turbine generator as an additional source of on-site power.

Davis-Besse is scheduled to install new steam generatorsin--2-43 2014. This modification, with resulting reduction in AASGTR11 3.42E-02 1.035 SGTR occurs on OTSG 1-1 (split fraction) SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

L-12-244 Page 20 of 63 Table 5.c Basic Event Level 1 PRA Importance (continued)

Event Name F-V RRW Description Disposition Davis-Besse is scheduled to install new steam generatorsin-2043 2014. This Failure to close MSIV and isolate steam modification, with resulting reduction in LHAMSIVE 3.34E-02 1.035 generator containing ruptured tube SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

SAMA candidate FW-17R evaluates implementing an automatic start of the motor-driven feed pump (MDFP) on loss of QHAMDF3E 3.34E-02 1.035 Failure to start MDFP prior to depletion of main feedwater (MFW).

BWST during makeup SAMA candidate CC-22R evaluates implementing an automatic refilling of the BWST.

The estimated benefit for this basic event is QTP0002A 3.25E-02 1.034 AFP/T-2 fails to start below the cost of a hardware modification.

No SAMA candidate considered.

SAMA candidate AC/DC-14 evaluates EDG0011 F 3.13E-02 1.032 EDG 1-1 fails to run adding a gas turbine generator as an additional source of on-site power.

This is a PRA model flag. It is not a FCIRCTMP 3.OOE-02 1.031 Circ water temperature not acceptable candidate for a SAMA.

No SAMA candidate considered.

RRW of 1.03 is estimated to have a cost of approximately $10,000. This is assumed to be the minimum cost of a procedure change.

L-12-244 Page 21 of 63 Table 5.c Basic Event LERF Importance Event Name F-V RRW Description Disposition Davis-Besse is scheduled to install new steam generatorsin-2043 2014. This modification, with resulting reduction in R 9.O0E-01 10.048 SGTR (initiating event) SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

A SAMA candidate was developed that presents the highest worth PRA human XHAMUCDE 6.10E-01 2.563 Operators fail to attempt cooldown via actions to the Davis-Besse operator training. SAMA candidate OT-09R was makeup/HPI cooling added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

A SAMA candidate was developed that presents the highest worth PRA human actions to the Davis-Besse operator CHASGDPE 5.40E-01 2.175 Operators fail to cooldown during a SGTR training. SAMA candidate OT-09R was added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

A SAMA candidate was developed that presents the highest worth PRA human Failure to close MSIV and isolate steam actions to the Davis-Besse operator LHAMSIVE 4.97E-01 1.989 gtraining. SAMA candidate OT-09R was generator containing ruptured tube 9 added to the initial list of SAMA candidates, but subsequently found to be already implemented at Davis-Besse.

L-12-244 Page 22 of 63 Table 5.c Basic Event LERF Importance (continued)

Event Name F-V RRW Description Disposition Davis-Besse is scheduled to install new steam generatorsin-2:204 2014. This modification, with resulting reduction in AASGTR11 4.81 E-01 1.926 SGTR occurs on OTSG 1-1 (split fraction) SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

Davis-Besse is scheduled to install new steam generatorsin-224e 2014. This modification, with resulting reduction in AASGTR12 3.93E-01 1.646 SGTR occurs on OTSG 1-2 (split fraction) SGTR frequency, is not reflected in the current PRA model. This plant improvement is assumed to result in a reduction risk importance of SGTR events.

RRW of-l__ 1.37 is estimated to have a cost of approximately $100,000.

This is assumed to be the minimum cost of a hardware modification.

SAMA candidate CB-22R evaluates the use FMM00003 7.90E-02 1.086 Any MSSVs on SG1 fail to reseat of a "gagging device" to close a stuck open MSSV.

SAMA candidate CB-21 evaluates placing pressure measurements between the two VD-IEF 7.54E-02 1.082 ISLOCA due to internal rupture of DHR DHR suction valves in the RCS hot leg allowing early detection of inboard isolation valve leakage.

The estimated benefit for this basic event is FLCO101F 7.31 E-02 1.079 Logic card fails during operation - MSIV 101 below the cost of a hardware modification.

fails to close No SAMA candidate considered.

L-12-244 Page 23 of 63 Table 5.c Basic Event LERF Importance (continued)

Event Name F-V RRW Description Disposition The estimated benefit for this basic event is LPPNISOZ 7.18E-02 1.077 ISLOCA occurs in non-isolable portion of DHR below the cost of a hardware modification.

system No SAMA candidate considered.

SAMA candidate CB-22R evaluates the use FMM00004 6.80E-02 1.073 Any MSSVs on SG2 fail to reseat of a "gagging device" to close a stuck open MSSV.

The estimated benefit for this basic event is FLCO10OF 6.13E-02 1.065 Logic card fails during operation - MSIV 100 below the cost of a hardware modification.

fails to close No SAMA candidate considered.

SAMA candidate FW-17R evaluates Failure to start MDFP as backup to turbine- implementing an automatic start of the motor-driven feed pump (MDFP) on loss of QHAMDFPE 5.96E-02 1.063 driven feedwater pumps for transient, Small main feedwater (MFW).

LOCA or SGTR events The estimated benefit for this basic event is 1_2 5.19E-02 1.055 CCF of two components: EC1Z089N & below the cost of a hardware modification.

EC1Z)XXXN-CC 1E25.1E-2Q10N EC1Z100N No SAMA candidate considered.

The estimated benefit for this basic event is LPSRC2BH 4.93E02 1.052 Press switch PSH RC2B4 fails high - fails below the cost of a hardware modification.

DHR No SAMA candidate considered.

The estimated benefit for this basic event is LPSZ416H 4.93E-02 1.052 Press switch PSH 7531A fails high - fails DHR below the cost of a hardware modification.

I I _ I _ I INo SAMA candidate considered.

L-12-244 Page 24 of 63 Table 5.c Basic Event LERF Importance (continued)

Event Name F-V RRW Description Disposition SAMA candidate CB-21 evaluates placing pressure measurements between the two LMVF012R 4.53E-02 1.047 Internal rupture of DH 12 (annual frequency) DHR suction valves in the RCS hot leg allowing early detection of inboard isolation valve leakage.

The estimated benefit for this basic event is LMBCWRT1 4.12E-02 1.043 CWR Train 1 unavailable due to maintenance below the cost of a hardware modification.

No SAMA candidate considered.

SAMA candidate AC/DC-14 evaluates EDG0012F 3.47E-02 1.036 EDG 1-2 fails to run adding a gas turbine generator as an additional source of on-site power.

This is a PRA model flag. It is not a FCIRCTMP 3.OOE-02 1.031 Circ water temperature not acceptable candidate for a SAMA.

No SAMA candidate considered.

The estimated benefit for this basic event is FW01 1BT 3.04E-02 1.031 AW ICS1 1B fails to reseat after steam below the cost of a hardware modification.

No SAMA candidate considered.

SAMA candidate CB-21 evaluates placing pressure measurements between the two LMVF01 1R 3.01 E-02 1.03 Internal rupture of DH 11 (annual frequency) DHR suction valves in the RCS hot leg allowing early detection of inboard isolation valve leakage.

L-12-244 Page 25 of 63 Table 5.c Basic Event LERF Importance (continued)

Event Name F-V RRW Description Disposition Numerous SAMA candidates that address LOOP were evaluated:

AC/DC-01, additional battery capacity AC/DC-14, install gas turbine generator ELOOPRT 2.93E-02 1.03 LOOP given reactor trip AC/DC-25, provide dedicated DC system to TDAFW pumps AC/DC-26, provide alternator/generator driven by TDAFW pumps AC/DC-27, increase SBO fuel oil tanks size RRW of 1.03 is estimated to have a cost of approximately $10,000. This value is assumed to be the minimum cost of a procedure change.

L-12-244 Page 26 of 63 Question RAI 5.d ER Section E.5.3, E.5.4, and E.5.5 discuss significant contributors to core damage frequency (CDF) and large early release frequency (LERF). These sections and the associated tables show that there are a number of operator errors and non-recovery actions that occur in these listings, but report that no weaknesses in training or procedures were identified. Given: 1) the significant number of operator errors in these lists, 2) that human errors are among the most dominant failure modes presented in the importance Tables E.5-2 (i.e., the first 9 basic events listed by RRW are human error events) and E.5-3, and 3) that operator errors often have relatively high failure probabilities, provide the following:

i. Explain the process used to make the determination that there were no opportunities to improve procedures and training.

ii. Discuss whether any of the risk significant operator action failures could be addressed by a SAMA to automate the function (i.e., automating tripping of the RCPs after a loss of seal cooling -see RAI 7.a).

RESPONSE RAI 5.d

[The response to RAI 5.d.ii is edited as shown in the middle of the 1 st paragraph.

Also, Tables 5.d-1, 5.d-2 and 5.d-3 are replaced in their entirety.]

[NOTE:

• One sensitivity case no longer applies and has been deleted; see the revised response to RAI 6.i.ii]

5.d.ii In-addition to the new SAMAs addressed in RAI 7, two additional SAMA candidates were evaluated to address automating risk significant operation actions: SAMA candidate AC/DC-28R (automatically start and load the SBODG on Bus D2 upon loss of power to the bus), and SAMA candidate OT-08R (automatically start and load the SBODG on Bus D2 upon loss of power to the bus in combination with automatically starting the MDFP). Table 5.d-1 and Table 5.d-2, below, provide the internal event and total benefit results for SAMA candidates AC/DC-28R and OT-08R, respectively. Table 5.d-3, below, provides the final results for the-ten nine [*] sensitivity cases for SAMA candidateAC/DC-28R and OT-08R. The implementation cost for SAMA candidate AC/DC-28R was estimated as $1,600,000. Therefore, this SAMA candidate is not cost-beneficial at Davis-Besse. The implementation cost for SAMA candidate OT-08R was estimated as $4,400,000. Therefore, this SAMA candidate is not cost-beneficial at Davis-Besse.

L-12-244 Page 27 of 63 Table 5.d-1: Internal Events Benefit Results for SAMA Candidates AC/DC-28R and OT-08R AC/DC-28R OT-08R Case (Auto (Auto SBODG SBODG) & MDFP)

Off-site Annual Dose (rem) 2.03E+00 1.92E+00 Off-site Annual Property Loss ($) 3.45E+03 3.26E+03 Comparison CDF 1.0E-05 1.0E-05 Comparison Dose (rem) 2.12E+00 2.12E+00 Comparison Cost ($) 3.59E+03 3.59E+03 Enhanced CDF 8.3E-06 5.7E-06 Reduction in CDF 17.00% 43.00%

Reduction in Off-site Dose 4.25% 9.43%

Immediate Dose Savings (On-site) $138 $348 Long Term Dose Savings (On-site) $600 $1,518 Total Accident Related Occupational $738 $1,866 Exposure (AOE)

Cleanup/Decontamination Savings (On- $22,502 $56,916 site)

Replacement Power Savings (On-site) $22,766 $57,584 Averted Costs of On-site Property $45,267 $114,500 Damage (AOSC)

Total On-site Benefit $46,005 $116,366 Averted Public Exposure (APE) $2,209 $4,908 Averted Off-site Damage Savings (AOC) $1,718 $4,049 Total Off-site Benefit $3,926 $8,957 Total Benefit (On-site + Off-site) $49,932 $125,323 Table 5.d-2: Total Benefit Result for SAMA Candidates AC/DC-28R and OT-08R AC/DC-28R OT-08R (Auto_SBODG) (Auto_SBODG &

MDFP)

Internal Events $49,932 $125,323 Fires, Seismic, Other $229,685 $576,486 Total Benefit $279,617 $701,809

L-12-244 Page 28 of 63 Table 5.d-3: Final Results of the Sensitivity Cases for SAMA Candidates AC/DC-28R and OT-08R Repair Low High On-site On-site SAMA ID Re Discount Discount ose Clean-up Rate Case Rate Case Case AC/DC-28R $177,626 $422,629 $193,345 $283,796 $321,619 OT-08R $443,832 $1,060,578 $484,871 $712,381 $808,052 SAMA ID Replacement Multiplier Evacuation 95" CDF Power Case Case Speed Case AC/DC-28R $365,190 $399,452 $279,617 $405,444 OT-08R $918,258 $1,002,584 $701,809 $1,017,623 Question RAI 5.g Several SAMA candidates identified in Table E.6-1 are subsumed in another SAMA candidate (e.g., AC/DC-06, AC/DC-09, AC/DC-20). For each subsumed SAMA candidate, provide an assessment of its implementation cost relative to that of the SAMA into which it was subsumed. Ifthe implementation cost of the subsumed SAMA is less, provide a revised basis for the Phase I screening and Phase IIcost-benefit evaluation if it meets Criterion F.

RESPONSE RAI 5.g

[The response to RAI 5.g is edited as shown in Table 5.g-1 .]

SAMA candidate CB-08 was subsumed in SAMA candidate CB-07 in Table E.6-1.

SAMA candidate CB-07 was screened as 'already implemented' at Davis-Besse. The nature of the operation action/training is similar in both SAMA candidates. Therefore, SAMA candidate CB-08 was re-screened as Criterion B (Already Implemented).

Accordingly, there was no need to determine the cost of implementation and assess the cost-benefit of SAMA candidate CB-08. ER Table E.6-1 is revised to identify the re-screening of SAMA candidate CB-08.

L-12-244 Page 29 of 63 The SAMA candidates subsumed in Phase I (AC/DC-06, AC/DC-09, AC/DC-20, and CC-08) have an equivalent or higher cost of implementation than the SAMA candidates evaluated in Phase I1. Nonetheless, an analysis was performed to assess the cost-benefit of the subsumed SAMA candidates. The total benefit was derived from the SAMA candidates into which they were subsumed and compared to the cost of implementation. Table 5.g-1 provides the results of the cost-benefit evaluation. None of the subsumed SAMA candidates are cost-beneficial to implement at Davis-Besse.

See the Enclosure to this letter for the revision to the Davis-Besse LRA.

Table 5.g-1: Final Results of the Cost-Benefit Evaluation for Subsumed SAMA Candidates SAMA ID Modification Estimated Cost Estimate Conclusion Benefit Provide additional DC AC/DC-06 power to the 120/240V $100,547 $1,750,000 Not Cost Effective vital AC system.

AC/DC-09 Provide an additional $ $2,800,000 Not Cost Effective diesel generator, $237,436 Add a new backup source AC/DC-20 of diesel generator $39,242 $700,000 Not Cost Effective cooling.

Add the ability to CC-08 automatically align ECCS $15,155 $1,500,000 Not Cost Effective to recirculation mode upon BWST depletion.

L- 12-244 Page 30 of 63 Item 6 Provide the following with regard to the Phase II cost-benefit evaluations:

Question RAI 6.i ER Section E.8.6 discusses six sensitivity cases. Relative to these sensitivity cases, provide the following:

ii. The description of the sixth sensitivity case states that off-site economic cost was increased by 25 percent. Table E.8-1 indicates that the total benefit for each of the SAMA candidates was increased by the same amount of $19,632, the offsite economic cost (AOC) value. Clarify how the increase of 25 percent in off-site economic cost correlates to the increase in total benefits of $19,632 for each SAMA.

RESPONSE RAI 6.i

[The response to RAI 6.i.ii is replaced in its entirety.]

6.i.ii The sensitivity case for which the off-site economic cost was increased by 25 percent has been removed as a sensitivity case as it is no longer germane, since the MACCS2 economic input values that formed the basis for the sensitivity case were increased to reflect 2009 dollars, the reference economic year for the SAMA analysis.

Question RAI 6.j ER Section 8.3 discusses a sensitivity case using a higher evacuation speed.

Provide the evacuation speed used for this analysis. Also, Table E.3-31 shows that the population dose decreased compared to the base case yet Table E.8-1 shows the total net benefit increased by $1,963 for each SAMA. Explain this anomalous result and describe the methodology for developing the $1,963 used for each SAMA.

L-12-244 Page 31 of 63 RESPONSE RAI 6.j

[The response to RAI 6.j is edited as shown.]

The evacuation speed used in the sensitivity case discussed in ER Section E.8.3 was 1.0 meter/second. The population dose risk used in the Section E.8.3 sensitivity case was the result of the Level 3 PRA sensitivity case El.

As noted in the RAI, with a decrease in population dose risk the net benefit for each SAMA candidate would be expected to decrease. The anomalous result (e.g., a net benefit increase) was due to the number of significant figures used in the Level 3 PRA and the cost-benefit evaluation. The population dose risk values differed in the third significant digit, which when rounded caused the unexpected results. As a result of the response to RAI 4.b, above, the population dose risk values have been revised for the Level 3 PRA sensitivity case El. The ER revisions due to population dose risk were identified in the response to RAI 4.b.

With the revised results from RAI 4.b and consistent use of significant figures between the Level 3 PRA and cost-benefit analysis, the value $1,963 is no longer germane to the sensitivity case in Section E.8.3.

As noted in the staff's RAI, a decrease in population dose risk was the result of sensitivity case El (where the evacuation speed was increased). Since NEI 05-01 suggested an evacuation speed sensitivity case to assess the impact on the results due to the uncertainty in the evacuation speed, it is logical to test (via a sensitivity case) the impact of a lower evacuation speed (which may cause a previously screened SAMA candidate to become cost-beneficial). Accordingly, the cost-benefit sensitivity case (Evacuation Speed from Table E.8-1) has been revised to use the results from Level 3 PRA sensitivity case E3 (see response to RAI 4.d) in which the evacuation speed is decreased by 9.6 percent, which caus-e a*sf,,light; results in no increasein population dose risk. ER Section E. 3.5.2.41,is .ri a,,nd n Fw Tab/c E. 3 33/i addod to ER i.ncorperatosens&t4vty Gasc E=3.

The total benefit for each SAMA candidate has been in.reased by $1374- did not increase, which is consistent with-the no increase in population dose risk. For the sensitivity case in Section E.8.3, the population doses risk values are taken from the Level 3 PRA sensitivity case E3 and replace the base case values in the determination of the averted public exposure (APE). SiRe* there is a difference in the

,onstant population dese values, for-tho Soction E.8.3 sensitivity ase, the total bhenefit for each SA MA is changed by the samoe dollar amoeunt. (See Table E.8 I for-Feslts of evacuation speed sensitivity cas in repose to RAI 4-.b-)

Sece the EnciGSUre to tnis letter for the rovision to thc uavs Mossc t'e

L-12-244 Page 32 of 63 Question RAI 6.k The ER provides no assessment of the uncertainty distribution for CDF. Relative to the uncertainty distribution, address the following:

" Provide the uncertainty distribution (5 th, mean, and 9 5 th percentiles) for the Davis-Besse PRA model CDF and describe how the distribution was developed.

• Provide an assessment of whether an uncertainty analysis using the 95th percentile CDF and the external events multiplier of 3.6 developed in RAI 3.c is bounded by the Multiplier Case sensitivity analysis. If not bounded, provide an uncertainty analysis using the 95th percentile CDF. In this analysis, provide an assessment of each Phase 1 SAMA eliminated using Screening Criterion D and E to determine whether any Phase 1 SAMAs originally screened should have a Phase 2 cost-benefit evaluation performed. Provide a Phase 2 cost-benefit evaluation for any SAMA not screened.

• If the Multiplier Case is bounding, provide an assessment of each Phase 1 SAMA eliminated using Screening Criteria D and E to determine whether any Phase 1 SAMAs originally screened should have a Phase 2 cost-benefit evaluation performed. Provide a Phase 2 cost-benefit evaluation for any SAMA not screened.

RESPONSE RAI 6.k

[The response to RAI 6.k is edited as shown in Tables 6.k-1 and 6.k-2. Table 6.k-3 is also revised (page 39 of 63) to change the steam generator replacement schedule from 2013 to 2014 to align with current FENOC plans and with the discussions in the ER.]

The following table provides the uncertainty distribution for the Davis-Besse SAMA PRA model CDF. The 5tV, mean, and 9 5 th percentile values are in bold font:

5% Mean 95%

Conf. ICo nf.1 Point Estimate 9.70E-06 Mean 1.06E-05 1.07E-05 1.09E-05 5 th percentile 7.18E-06 7.20E-06 7.22E-06 Median 9.51E-06 9.53E-06 9.55E-06 9 5 th percentile 1.53E-05 1.55E-05 1.56E-05 StdDev I 1.48E-05

L-12-244 Page 33 of 63 Skewness 5.75E+01 Kurtosis 4.55E+03 The SAMA analysis model database was modified to support performance of an uncertainty analysis using the UNCERT software package. Failure rate distributions were entered into the database and modifications were made to make the database compatible with the UNCERT software. The SAMA analysis level 1 model was re-quantified to provide a cutset file compatible with the UNCERT software, and the uncertainty analysis was performed using the revised cutset file and database.

An assessment of the impact of the 9 5 th percentile CDF uncertainty for internal events was performed for Davis-Besse. The uncertainty factor was derived from a ratio of the 9 5 th percentile CDF uncertainty (1.55E-05/yr) to the point estimate CDF (1.07E-05/yr) for internal events. The uncertainty factor used in this analysis was 1.45. The analysis also used an external events multiplier of 4.6 (see the response to RAI 3.c for additional information on the development of the external events multiplier). Table 6.k-1, below, provides the cost-benefit results for the 9 5 th percentile CDF uncertainty factor case. Also, the Multiplier Case was updated using an external events multiplier of seven (7). Table 6.k-2, below, provides the Multiplier Case cost-benefit results. The results of the 9 5 th percentile CDF uncertainty and Multiplier Case sensitivity analyses identified one SAMA candidate (AC/DC-03) to be cost effective.

Since the external event multiplier used in the base case and the sensitivity case have changed, the issue of bounding is no longer relevant. Nonetheless, the SAMA candidates designated as Criterion D (Very Low Benefit) were re-evaluated (see Table 6.k-3, below) based on the results of the 9 5 th percentile CDF uncertainty. For SAMA candidates where the 9 5 th percentile CDF uncertainty basic event data were available, these basic events' RRW data were used as a basis for the final determination. For some SAMA candidates, either basic event data were not available, or basic event data were not applicable to the determination; for those cases, the determination basis is also provided.

SAMA candidate FL-01 (improve inspection of rubber expansion joints on main condenser) was initially identified for cost-benefit analysis based on the 9 5 th percentile CDF uncertainty results. However, upon further investigation, the disposition of SAMA candidate FL-01 is changed to Criterion B (Already Implemented). The basis for the revised disposition is that the circulating water joints are currently inspected during outages and periodically replaced. ER Table E.6-1 is revised to include this change.

Further, based on additional information, SAMA candidate OT-05 (increase training and operating experience feedback to improve operator response) is changed from Criterion D (Very Low Benefit) to Criterion B (Already Implemented). The basis for the revised disposition is that Davis-Besse provides PRA information, such as risk

L-12-244 Page 34 of 63 significant initiating events, high worth operator actions and high worth equipment, to operators and other departments. Attachment 2 of FENOC procedure NOPM-CC-6000, "Probabilistic Risk Assessment Program," identifies items supported by the PRA Program; one item is PRA training support in areas such as new licensed operator training and operator re-qualification training cycles. ER Table E.6-1 is revised to include this change.

SAMA candidates screened with Criterion E (Subsumed) were addressed in the response to RAI 5.g, above.

See the Enclosure to this letter for the revision to the Davis-Besse LRA.

Table 6.k-1: 9 5 th Percentile Uncertainty Factor Cost-Benefit Results 9 5 th Percentile SAMA ID Uncertainty Factor Estimated Cost Conclusion Estimated Benefit AC/DC-01 $145,794 $1,750,000 Not Cost Effective AC/DC-03 $575,095 $330,000 Cost Effective AC/DC-14 $344,283 $2,000,000 Not Cost Effective AC/DC-19 $56,901 $700,000 Not Cost Effective AC/DC-21 $68912 $100,000 Not Cost Effective AC/DC-25 $354,521 $2,000,000 Not Cost Effective AC/DC-26 $354,521 $2,000,000 Not Cost Effective AC/DC-27 $0 $550,000 Not Cost Effective CB-21 $42,842 $550,000 Not Cost Effective CC-01 $4,982 $6,500,000 Not Cost Effective CC-04 $0 $5,500,000 Not Cost Effective CC-05 $0 $6,500,000 Not Cost Effective CC-19 $21,974 $1,500,000 Not Cost Effective HV-01 $1/993 $50,000 Not Cost Effective HV-03 $1/993 $400,000 Not Cost Effective AC/DC-28R $405,444 $1,600,000 Not Cost Effective CB-22R $162,566 $4,600,000 Not Cost Effective CC-22R $0 $2,200,000 Not Cost Effective CW-26R $529,319 $1,500,000 Not Cost Effective FW-17R $592,197 $2,800,000 Not Cost Effective OT-08R $1,017,623 $4,400,000 Not Cost Effective

L- 12-244 Page 35 of 63 Table 6.k-2: Multiplier Case Cost-Benefit Results SAMA ID Multiplier Case Estimated Cost Conclusion AC/DC-01 $143-639 $1,750,000 Not Cost Effective AC/DC-03 $566,596 $330,000 Cost Effective AC/DC-14 $339, 195 $2,000,000 Not Cost Effective AC/DC-19 $56,060 $700,000 Not Cost Effective AC/DC-21 $67,893 $100,000 Not Cost Effective AC/DC-25 $349,282 $2,000,000 Not Cost Effective AC/DC-26 $349,282 $2,000,000 Not Cost Effective AC/DC-27 $0 $550,000 Not Cost Effective CB-21 $42,209 $550,000 Not Cost Effective CC-01 $4,908 $6,500,000 Not Cost Effective CC-04 $0 $5,500,000 Not Cost Effective CC-05 $0 $6,500,000 Not Cost Effective CC-19 $21,649 $1,500,000 Not Cost Effective HV-01 11963 $50,000 Not Cost Effective HV-03 $1963 $400,000 Not Cost Effective AC/DC-28R $399,452 $1,600,000 Not Cost Effective CB-22R $160,164 $4,600,000 Not Cost Effective CC-22R $0 $2,200,000 Not Cost Effective CW-26R $521,496 $1,500,000 Not Cost Effective FW-17R $583,446 $2,800,000 Not Cost Effective OT-08R $1,002,584 $4,400,000 Not Cost Effective

L-12-244 Page 36 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" SAMA ID I ModificationII M Screening Criteria Basis for Screening/Modification Enhancements (Potential Enhancement) II Enhancements Related to AC and DC Power Abnormal Procedure DB-OP-2532 addresses the loss of both AC and DC power to both the Non-Nuclear Instrumentation Increase training on response (NNI) and the ICS that are powered from uninterruptible AC AC/DC- to loss of 120V AC buses that Criterion D instrumentation distribution panels YAU and YBU. It is 08 cause inadvertent actuation Very Low Benefit judged that operator awareness to the required actions is well signals. established.

This SAMA should remain CriterionD.

Based on the basic event RRW results from the 95% CDF uncertainty case, no basic event related to uninterruptible AC/DC- Improve uninterruptible power Criterion D power supplies has an RRW value above the minimum cost 16 supplies. Very Low Benefit of a hardware modification.

This SAMA should remain CriterionD.

Enhancements Related to ATWS Events Based on the basic event RRW results from the 95% CDF uncertainty case, no basic event related to emergency Add an independent boron AT-Olhardware Criterion D boration has an RRW value above the minimum cost of a modification.

injection system. Very Low Benefit This SAMA should remain CriterionD.

L-12-244 Page 37 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID otenian

((Potential cn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Based on the basic event RRW results from the 95% CDF Add a system of relief valves to uncertainty case, no basic event related to ATWS pressure 2prevent equipment damage Criterion D relief has an RRW value above the minimum cost of a AT-02 from pressure spikesprevnt during an equipmntedamagefriterion.

Very Low Benefit hardware modification.

ATWS.

This SAMA should remain CriterionD.

Based on the basic event RRW results from the 95% CDF uncertainty case, no basic event related to reactor trip has an RRW value above the minimum cost of a hardware modification AT-07 Install motor generator set trip Criterion D Also, if the reactor power is not decreasing, procedures breakers in control room. Very Low Benefit instruct the operators to first de-energize substations E2 and F2, and, if necessary, locally open reactor trip breakers in the Low Voltage Switchgear room.

This SAMA should remain Criterion D.

Enhancements Related to Containment Bypass Failure of containment isolation typically leads to a LERF if core damage has occurred. LERF results are dominated by containment bypass events such as SGTR and ISLOCA CB-02 Add redundant and diverse Criterion D events. Containment isolation is not shown to be a significant limit switches to each CIV. Very Low Benefit contributor to LERF in the 95% CDF uncertainty case.

This SAMA should remain Criterion D.

L-12-244 Page 38 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID Enhancmn (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements HPI and LPI injection check valves are leak tested per Appendix J. DHR suction lines are not tested, but rather than a leakage test, it is judged that continuously monitoring these valves at power would be preferable to leakage test. A SAMA CB-03 Increase leak testing of valves Criterion D candidate to continuously monitor the DHR suction valves is in ISLOCA paths. Very Low Benefit provided in SAMA candidate CB-21. This conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

Important CIVs receive a close signal from the safety actuation system. Many are air-operated and fail in the closed position. It is judged that self-actuating valves would not provide any significant increase in the reliability of Criterion D isolation.

CB-04 Install self-actuating CiVs.

Very Low Benefit Containment isolation is not shown to be a significant contributor to CDF or LERF in the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

L-12-244 Page 39 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements This SAMA candidate would have very little benefit. It is likely that the break would be well above floor drain level.

Ensure ISLOCA releases are Therefore, a significant height of water would be required scrubbed. One method is to Criterion D any scrubbing beforewould level likely havetook place. Ateffects, undesirable these levels, such asthe water CB-06 plug drains in potential break areas so that break point will Very Low Benefit threatening mitigating equipment due to flooding. This be covered with water. conclusion remains valid for the 95% CDF uncertainty results.

This SAMA should remain Criterion D.

Davis-Besse is scheduled to replace the steam generatorsin Institute a maintenance .2al 2014, which would result in inspecting new steam practice to perform a 100% generatortubes. Therefore, this SAMA candidate is CB-09 inspection of steam generator Criterion D considered very low benefit for Davis-Besse. This conclusion tubes during each refueling Very Low Benefit remains valid for the 95% CDF uncertainty case.

outage.

This SAMA should remain Criterion D.

Flooding the SG prior to core damage could impact efforts to mitigate the SGTR. For example, flooding may present a risk Direct steam generator Criterion D to the operation of the TDAFW pumps by risking steam CB-1 8 flooding after a SGTR, prior to Very Low Benefit generator overfill.

core damage.

Dispositionof this SAMA candidate is addressed in the response to RAI 5.i.

L-12-244 Page 40 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA I (D Modifia (Potential ancmn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements This SAMA candidate would result in plant decay heat being deposited into primary containment, resulting in a harsh environment. The possible advantages for SGTR will be offset by the negative impacts for other events where CB-19 Vent MSSVs in containment. Criterion D secondary steam is deposited into containment with intact Very Low Benefit steam generators. This conclusion remains valid for the 95%

CDF uncertainty case.

This SAMA should remain CriterionD.

Based on the top 100 cutsets and component basic event importance, ISLOCA in the CCW is not significant risk contributor at Davis-Besse. An ISLOCA occurring in the CB-20 Install relief valves in the CCW Criterion D CCW system is not a risk contributor in the 95% CDF system. Very Low Benefit uncertainty case.

This SAMA should remain CriterionD.

Enhancements Related to Core Cooling Systems Davis-Besse operators are prohibited from throttling LPI pumps earlier in medium or large break LOCAs to maintain BWST inventory. If BWST flow was throttled down to reduce Modify procedures to throttle flowrate, the additional time gained is approximately 20 CC-11 LPI pumps earlier in medium or Criterion D minutes, which, from a PRA perspective, is of low benefit for large break LOCAs to maintain Very Low Benefit a LOCA condition. This conclusion remains valid for the 95%

BWST inventory. CDF uncertainty case.

This SAMA should remain CriterionD.

L-12-244 Page 41 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA (Potential Enhancement) Screening Criteria Basis for ScreeninglModification Enhancements The make-up system can be used to provide make-up to the RCS in the event of a small LOCA. Because of the separate HPI and make-up systems, the plant has essentially four Upgrade the chemical and separate systems capable of injecting from the BWST into the CC-1 3 volume control system to Criterion D RCS at high pressure. This was identified as a unique safety mitigate small break LOCAs. Very Low Benefit feature in the IPE. This conclusion remains valid for the 95%

CDF uncertainty case.

This SAMA should remain CriterionD.

Reducing the level at which switchover occurs (nine feet) would not significantly extend the time to switchover, and would increase the probability of pump failure due to loss of Reduce the BWST level at suction head. Davis-Besse has installed more accurate CC-21 which switchover to Criterion D BWST level instrumentation that allows reaching a lower level containment recirculation is Very Low Benefit prior to switchover to recirculation. This conclusion remains initiated. valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

Enhancements Related to Containment Phenomena Davis-Besse has a very large dry containment. Containment Use the fire water system as a over-pressurization is not a significant risk contributor. This CP-03 Criterion D conclusion remains valid for the 95% LERF uncertainty case.

backup source for the V r o e ei containment spray system. Very Low Benefit This SAMA should remain CriterionD.

L-12-244 Page 42 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID (Potential Enhancmn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements This SAMA candidate addresses the scrubbing of radioactive releases into certain areas by actuating the fire protection system. Although some scrubbing benefits might be realized, this SAMA candidate presents the risk of impacting required equipment by spray or flooding. This could only be performed Enhance fire protection system Criterion D with fire protection systems that could be remotely actuated.

CP-06 hardware and procedures. Very Low Benefit If the temperature in certain areas became high enough, some existing fire protection systems may automatically actuate. This conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

The delay time that could be realized if containment spray was delayed would be less than 10 minutes. This SAMA Delay containment spray Criterion D candidate is considered to be of very low benefit. This CP-16 actuation LOCA. after a large break Vr o eei conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

The capability already exists at Davis-Besse to throttle containment spray after the switchover to the sump. The delay time that could be realized if containment spray was Install automatic containment Criterion D throttled would be less than. 10 minutes. This SAMA CP-17 spray pump header throttleBenefit candidate is considered to be of very low benefit. This conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

L-12-244 Page 43 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA I (D Modifia (Potential ancmn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Based on component basic event importance, containment fan coolers are not significant risk contributors at Davis-Besse. This SAMA candidate is considered to be very Install a redundant Criterion D low benefit. This conclusion remains valid for the 95% CDF containment fan system. Very Low Benefit uncertainty case.

This SAMA should remain CriterionD.

Install or use an independent Davis-Besse has a very large dry containment. Hydrogen power supply to the hydrogen burn does not present a significant risk in terms of LERF.

control system using either This SAMA candidate is considered to be very low benefit.

new batteries, a non-safety This conclusion remains valid for the 95% CDF uncertainty CP-20 grade portable generator, Criterion D case.

existing station batteries, or Very Low Benefit existing AC/DC independent power supplies, such as the This SAMA should remain CriterionD.

security system diesel generator.

This SAMA would mitigate large early releases resulting from a hydrogen burn. LERF is dominated by containment bypass events such as SGTR and ISLOCA. Failure of containment is Install a passive hydrogen Criterion D not a significant contributor to LERF. This SAMA candidate is CP-21 cconsidered to be very low benefit. This conclusion remains 1control system. Very Low Benefit valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

L-12-244 Page 44 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

SAMA ID T ModificationI

[II Screening Criteria Basis for Screening/Modification Enhancements (Potential Enhancement)

Enhancements Related to Cooling Water Failure of DC power would impact much more than service water and improving the reliability of DC power to only service water would have very limited value. Based on the basic event RRW results from the 95% CDF uncertainty case, no Add redundant DC control Criterion D basic event related to service water performance has an power for service water pumps. Very Low Benefit RRW value above the minimum cost of a hardware modification.

This SAMA should remain CriterionD.

Davis-Besse has three service water pumps. In addition, the normally running cooling tower makeup pump is the preferred supply of service water following loss of service water. Based on the basic event RRW results from the 95% CDF CW-04 Add a redundant service water Criterion D uncertainty case, no basic event related to service water pump. Very Low Benefit performance has an RRW value above the minimum cost of a hardware modification.

This SAMA should remain CriterionD.

L-12-244 Page 45 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID (Potential Enhancmn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements The Davis-Besse water supply from Lake Erie travels through a long canal before reaching the intake structure. There is a screen at the intake from Lake Erie. The long distance traveled through the canal results in a significant fraction of material passing through the initial screen settling out prior to CW-05 Enhance the screen wash Criterion D reaching the intake structure. Based on the basic event RRW system. Very Low Benefit results from the 95% CDF uncertainty case, no basic event related to service water performance has an RRW value above the minimum cost of a hardware modification.

This SAMA should remain CriterionD.

Loss of CCW through drain and vent lines is not considered to be a significant contributor to loss of CCW. These lines are Cap downstream piping of Criterion D small, and any leakage would likely be low. This conclusion CW-06 normally closed CCW drain remains valid for the 95% CDF uncertainty case.

and vent valves. Very Low Benefit This SAMA should remain CriterionD.

Seal LOCA is not a concern at Davis-Besse if the RCPs are tripped. On loss of CCW, the makeup pumps can continue Enhance loss of CCW operation for at least one hour. Therefore, if operators trip the CW-08 procedure to underscore the Criterion D RCPs within one hour of loss of CCW, an RCP seal LOCA is desirability of cooling down the not a risk concern. This conclusion remains valid for the 95%

Very Low BenefitCFunetiyca.

RCS prior to seal LOCA. CDF uncertainty case.

This SAMA should remain Criterion D.

L-12-244 Page 46 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Seal LOCA is not a concern at Davis-Besse if the RCPs are tripped. On loss of CCW, the makeup pumps can continue operation for at least one hour. Therefore, if operators trip the Additional training on loss of Criterion D RCPs within one hour of loss of CCW, an RCP seal LOCA is CW-09 Vnot CDFa uncertainty risk concern. This conclusion remains valid for the 95%

case.

This SAMA should remain CriterionD.

Davis-Besse makeup pumps can operate for at least one hour on loss of CCW. Based on the basic event RRW results from the 95% CDF uncertainty case, no basic event related to CW-12 Increase charging pump lube Criterion D charging (make-up) pump performance has an RRW value oil capacity. Very Low Benefit above the minimum cost of a hardware modification.

This SAMA should remain CriterionD.

Seal LOCA is not a concern at Davis-Besse if the RCPs are tripped. On loss of CCW, the makeup pumps can continue operation for at least one hour. Therefore, if operators trip the CW-1 5 Use existing hydro test pump Criterion D RCPs within one hour of loss of CCW, an RCP seal LOCA is for RCP seal injection. Very Low Benefit not a risk concern.

This SAMA should remain Criterion D.

L-12-244 Page 47 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMAID (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements The make-up system is continuously operating. Malfunctions of relief valves would be immediately detected during operation and corrected. Based on the basic event RRW Prevent make-up pump flow Criterion D results from the 95% CDF uncertainty case, no basic event CW-18 diversion through the relief related make-up flow diversion has an RRW value above the valves. Very Low Benefit minimum cost of a hardware modification.

This SAMA should remain CriterionD.

Enhancements Related to Internal Flooding Revised to read: A large circulating water flood in the turbine building has Improve inspection of rubber Criterion F associated basic event FL7 that is above the minimum cost of FL-01 expansion joints on main a procedure change (although less that a hardware condenser. Considered for Further modification). This SAMA candidate will be considered for Evaluation further evaluation.

Enhancements Related to Fire Risk Inadvertent actuation of fire protection water is not considered risk significant and currently not modeled in the PRA. Any fire protection system water should be handled by existing drains FR-01 Replace mercury switches in Criterion D and is not considered a significant flooding threat. This fire protection system. Very Low Benefit conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

L-12-244 Page 48 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID (Potential Enhancmn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements The Davis-Besse IPEEE did not identify any weakness in the fire barrier performance. This conclusion remains valid for FR-02 Upgrade fire compartment Criterion D the 95% CDF uncertainty case.

barriers. Very Low Benefit This SAMA should remain CriterionD.

Currently, isolation switches exist for a control evacuation.

Some manual actions beyond operation of isolation switches are required (e.g., plugging connectors, removing/inserting Install additional transfer and Criterion D fuse blocks). Adding additional transfer/isolation switches is FR-03 isolation switches. Very Low Benefit not considered to be of significant benefit. This conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain CriterionD.

The Davis-Besse IPEEE did not identify any weakness in fire brigade performance. This conclusion remains valid for the FR-04 Enhance fire brigade Criterion D 95% CDF uncertainty case.

awareness. Very Low Benefit This SAMA should remain CriterionD.

The Davis-Besse IPEEE did not identify any weakness in the Enhance control of Criterion D combustible control program. This conclusion remains valid FR-05 combustibles and ignition for the 95% CDF uncertainty case.

sources. Very Low Benefit This SAMA should remain CriterionD.

L-12-244 Page 49 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

ModificationII SAMA ID ((Potential otenia Enhancement)II ancmn Screening Criteria Basis for Screening/Modification Enhancements Enhancements Related to Feedwater and Condensate Davis-Besse has the capability of replenishing the CST using fire protection water. This can be done even on loss of AC power. Adding diesel for condensate makeup pumps would FW-03 Install an independent diesel Criterion D add little benefit. This conclusion remains valid for the 95%

for the CST make-up pumps. Very Low Benefit CDF uncertainty case.

This SAMA should remain CriterionD.

The purpose of the SAMA candidate was to reduce dual turbine-driven pump maintenance unavailability. Although manual isolation valves do not exist, Davis-Besse has valves Install manual isolation valves Criterion D within the steam lines that allow isolation of one TDAFW FW-05 around the TDAFW pump Very Low Benefit pump for maintenance while leaving the second TDAFW steam admission valves, pump available. This conclusion remains valid for the 95%

CDF uncertainty case.

This SAMA should remain CriterionD.

Based on the basic event RRW results from the 95% CDF uncertainty case, no basic event related to CST performance Install a new condensate Criterion D has an RRW value above the minimum cost of a hardware FW-07 storage tank (AFW storage Very Low Benefit modification.

tank).

This SAMA should remain Criterion D.

L-12-244 Page 50 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements On loss of air or electric power, several components required Change failure position of for secondary heat removal would be lost; therefore the state condenser make-up valve ifthe Criterion D of the condenser make-up valve is not relevant. This FW-12 condenser make-up valve fails Very Low Benefit conclusion remains valid for the 95% CDF uncertainty case.

open on loss of air or power.

This SAMA should remain CriterionD.

Failure of the PORV to open only shows up in the Level 1 PRA importance measures with a RRW of 1.006 (cutoff 1.005). Itdoes not show up in the top cutsets or the LERF Replace existing pilot-operated importance list. Therefore, it is judged to be very low benefit.

relief valves with larger ones, Criterion D Based on the basic event RRW results from the 95% CDF FW-15 such that only one is required Very Low Benefit uncertainty case, no basic event related to PORV opening or for successful feed and bleed. capacity has an RRW value above the minimum cost of a hardware modification This SAMA should remain Criterion D.

Enhancements Related to Heating, Ventilation and Air Conditioning (HVAC)

The high voltage switchgear rooms do not require forced ventilation. Low voltage switchgear rooms require forced ventilation. Operators monitor the temperature of the low voltage switchgear rooms during their plant tours. Based on Add a switchgear room high Criterion D the basic event RRW results from the 95% CDF uncertainty HV-04 temperature alarm. Very Low Benefit case, no basic event related to switchgear ventilation has an RRW value above the minimum cost of a hardware modification.

This SAMA should remain CriterionD.

L-12-244 Page 51 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID otenian

((Potential cn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Loss of ventilation to AFW is not a risk significant contributor Create ability to switch at Davis-Besse. This conclusion remains valid for the 95%

HV-05 emergency feedwater room fan Criterion D CDF uncertainty case.

power supply to station Very Low Benefit batteries in an SBO.

This SAMA should remain CriterionD.

Service water ventilation includes four 50% fans. Loss of service water ventilation is not a significant risk contributor at Provide procedural guidance Davis-Besse. Based on the basic event RRW results from HV-06 for establishing an alternate Criterion D the 95% CDF uncertainty case, no basic event related to means of room ventilation to Very Low Benefit mnmmcs fahrwr service water room oiiain ventilation has an RRW value above the the service water pump room. minimum cost of a hardware modification.

This SAMA should remain Criterion D.

Enhancements Related to Instrument Air and Nitrogen Supply Service Air and Instrument Air are not significant risk contributors based on top cutsets and risk importance measures. Based on the basic event RRW results from the Modify procedure to provide Criterion D 95% CDF uncertainty case, no basic event related to air IA-02 ability to align diesel power to compressors has an RRW value above the minimum cost of a more air compressors. Very Low Benefit hardware modification.

This SAMA should remain Criterion D.

L-12-244 Page 52 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA ID ( otenian (Potential cn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Service Air and Instrument Air are not significant risk contributors based on top cutsets and risk importance Replace service and measures. Based on the basic event RRW results from the instrument air compressors Criterion D 95% CDF uncertainty case, no basic event related to service IA-03 with more reliable compressors Very Low Benefit or instrument air compressors has an RRW value above the that have self-contained air minimum cost of a hardware modification cooling by shaft-driven fans.

This SAMA should remain Criterion D.

Enhancements Related to Seismic Risk The Seismic Qualifications Utility Group (SQUG) previously identified the need for additional seismic restraints in the Increase seismic ruggedness Criterion D plant. These restraints have already been added. This SR-01 of plant components. Very Low Benefit conclusion remains valid for the 95% CDF uncertainty case.

This SAMA should remain Criterion D.

The C02 tanks are located outdoors. These tanks supply only the turbine generator. No other components are protected with C02. A seismic failure of the C02 tanks has Provide additional restraints for Criterion D minimal risk. This conclusion remains valid for the 95% CDF C02 tanks. Very Low Benefit uncertainty case.

This SAMA should remain Criterion D.

L-12-244 Page 53 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

SAMA ID M Screening Criteria Basis for Screening/Modification Enhancements (Potential Enhancement) I I Other Enhancements Large break LOCA is not a significant risk contributor (0.2%

CDF). Davis-Besse has a Containment Leakage Detection System (FLUS) to identify leaks from vessel penetrations and OT01 Install digital large break LOCA Criterion D nozzles. This conclusion remains valid for the 95% CDF protection system. Very Low Benefit uncertainty case.

This SAMA should remain CriterionD.

Davis-Besse has a qualified Maintenance Rule program in place. No deficiencies in maintenance practices have been Improve maintenance Criterion D identified. This conclusion remains valid for the 95% CDF OT-04 procedures. Very Low Benefit uncertainty case.

This SAMA should remain Criterion D.

FENOC provides PRA information, such as risk-significant Increase training and operating Revised to read: initiating events, high worth operator actions and high worth OT-05 experience feedback to Criterion B equipment, to various departments, including Operations improve operator response. Already Implemented Training, and presents this information on posters throughout the plant.

L-12-244 Page 54 of 63 Table 6.k-3: Re-evaluation of SAMA Candidates Screened as "Very Low Benefit" (continued)

Modification SAMA I (D Modifia (Potential ancmn Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Steam line breaks are not a significant contributor to CDF or LERF based on top cutsets or basic event importance. The derived benefit would not justify the implementation cost required. Based on the basic event RRW results from the OT-07 Install secondary side guard Criterion D 95% CDF uncertainty case, no basic event related to main pipes up to the MSIVs. Very Low Benefit steam breaks has an RRW value above the minimum cost of a hardware modification.

This SAMA should remain Criterion D.

L-12-244 Page 55 of 63 Item 7 For certain SAMAs considered in the ER, there may be lower-cost alternatives that could achieve much of the risk reduction at a lower cost. In this regard, discuss whether any lower-cost alternatives to those Phase II SAMAs considered in the ER would be viable and potentially cost-beneficial. Evaluate the following SAMAs (previously found to be potentially cost-beneficial at other Babcock and Wilcox plants), or indicate if the particular SAMA has already been considered. If the latter, indicate whether the SAMA has been implemented or has been determined to not be cost-beneficial at Davis-Besse Nuclear Power Station.

Question RAI 7.a Automate reactor coolant pump trip on high motor bearing cooling temperature.

RESPONSE RAI 7.a

[The response to RAI 7.a is edited as shown in the text and Tables 7.a-1, 7.a-2 and 7.a-3.]

[NOTE:

• One sensitivity case no longer applies and has been deleted; see the revised response to RAI 6.i.ii]

A SAMA candidate (CW-26R) to provide an automatic reactor coolant pump trip on loss of cooling to the RCP seal thermal barrier cooler and loss of seal injection flow was evaluated for Davis-Besse. Table 7.a-1 and Table 7.a-2, below, provide the internal event and total benefit results for SAMA candidate CW-26R, respectively. Table 7.a-3, below, provides the final results for the-ten nine [*] sensitivity cases for SAMA candidate CW-26R. The implementation cost for this SAMA candidate was estimated as

$1,500,000. Therefore, this SAMA candidate is not cost-beneficial at Davis-Besse.

L-12-244 Page 56 of 63 Table 7.a-1: Internal Events Benefit Results for SAMA Candidate CW-26R Case CW-26R Case _ _ (AutoRCP)

Off-site Annual Dose (rem) 2.05E+00 Off-site Annual Property Loss ($) 3.49E+03 Comparison CDF 1.OE-05 Comparison Dose (rem) 2.12E+00 Comparison Cost ($) 3.59E+03 Enhanced CDF 7.7E-06 Reduction in CDF 23.00%

Reduction in Off-site Dose 3.30%

Immediate Dose Savings (On-site) $186 Long Term Dose Savings (On-site) $812 Total Accident Related Occupational $998 Exposure (AOE)

Cleanup/Decontamination Savings (On- $30,443 site)

Replacement Power Savings (On-site) $30,801 Averted Costs of On-site Property $61,244 Damage (AOSC)

Total On-site Benefit $62,242 Averted Public Exposure (APE) $1,718 Averted Off-site Damage Savings (AOC) $1227 Total Off-site Benefit $2.945 Total Benefit (On-site + Off-site) $65,187 Table 7.a-2: Total Benefit Result for SAMA Candidate CW-26R CW-26R (AutoRCP)

Internal Events $65 187 Fires, Seismic, Other $299,860 Total Benefit 2$365,047

L-12-244 Page 57 of 63 Table 7.a-3: Final Results of the Sensitivity Cases for SAMA Candidate CW-26R Question RAI 7.d Automate refill of the borated water storage tank (BWST).

RESPONSE RAI 7.d

[The response to RAI 7.d is edited as shown in the text and Tables 7.d-1 and 7.d-3.]

[NOTE:

• One sensitivity case no longer applies and has been deleted; see the revised response to RAI 6.i.ii]

A SAMA candidate (CC-22R) to provide an automatic refill of the borated water storage tank was evaluated for Davis-Besse. Table 7.d-1 and Table 7.d-2, below, provide the internal event and total benefit results for SAMA candidate CC-22R, respectively. Table 7.d-3, below, provides the final results for the-ten nine [*] sensitivity cases for SAMA candidate CC-22R. The implementation cost for this SAMA candidate was estimated as

$2,200,000. Therefore, this SAMA candidate is not cost-beneficial at Davis-Besse.

L-12-244 Page 58 of 63 Table 7.d-1: Internal Events Benefit Results for SAMA Candidate CC-22R Case CC-22R Case_ (Auto_BWST)

Off-site Annual Dose (rem) 2.12E+00 Off-site Annual Property Loss ($) 3.59E+03 Comparison CDF 1.OE-05 Comparison Dose (rem) 2. 12E+00 Comparison Cost ($) 3.59E+03 Enhanced CDF 1.OE-05 Reduction in CDF 0.00%

Reduction in Off-site Dose 0.00%

Immediate Dose Savings (On-site) $0 Long Term Dose Savings (On-site) $0 Total Accident Related Occupational $0 Exposure (AOE)

Cleanup/Decontamination Savings (On- $0 site)

Replacement Power Savings (On-site) $0 Averted Costs of On-site Property $0 Damage (AOSC)

Total On-site Benefit $0 Averted Public Exposure (APE) $0 Averted Off-site Damage Savings (AOC) $0 Total Off-site Benefit $0 Total Benefit (On-site + Off-site) $0 Table 7.d-2: Total Benefit Result for SAMA Candidate CC-22R CC-22R (Auto_BWST)

Internal Events $0 Fires, Seismic, Other $0 Total Benefit $0

L-12-244 Page 59 of 63 Table 7.d-3: Final Results of the Sensitivity Cases for SAMA Candidate CC-22R LowHighOn-site SAMA Repair Low High On-site Clean-up ID Case Discount Discount Dose Case Cenu Rate Case Rate Case Case CC-22R $0 $0 $0 $0 $0 SAMA Replacement Multiplier Evacuation 9 5 th CDF ID Power Case Case Speed Case CC-22R $0 $0 $0 $0 Question RAI 7.e Automate start of auxiliary feedwater (AFW) pump in the event the automated emergency feedwater (EFW) system is unavailable.

RESPONSE RAI 7.e

[The response to RAI 7.e is edited as shown in the text and Tables 7.e-1, 7.e-2 and 7.e-3. ]

[NOTE:

• One sensitivity case no longer applies and has been deleted; see the revised response to RAI 6.i.ii]

A SAMA candidate (FW-17R) to automatically start the auxiliary feedwater pump when the emergency feedwater system is unavailable was evaluated for Davis-Besse. Based on the Davis-Besse design, this SAMA was interpreted as automatically starting the motor driven feedwater pump in the event both turbine-driven auxiliary feedwater pumps were not available. Table 7.e-1 and Table 7.e-2, below, provide the internal event and total benefit results for SAMA candidate FW-17R, respectively. Table 7.e-3, below, provides the final results for the-ten nine [*] sensitivity cases for SAMA candidate FW-17R. The implementation cost for this SAMA candidate was estimated as

$2,800,000. Therefore, this SAMA candidate is not cost-beneficial at Davis-Besse.

L-12-244 Page 60 of 63 Table 7.e-1: Internal Events Benefit Results for SAMA Candidate FW-17R Case FW-17R (AutoMDFP)

Off-site Annual Dose (rem) 2.OOE+00 Off-site Annual Property Loss ($) 3.40E+03 Comparison CDF 1.0E-05 Comparison Dose (rem) 2.12E+00 Comparison Cost ($) 3.59E+03 Enhanced CDF 7.5E-06 Reduction in CDF 25.00%

Reduction in Off-site Dose 5.66%

Immediate Dose Savings (On-site) $202 Long Term Dose Savings (On-site) $882 Total Accident Related Occupational $1,085 Exposure (AOE)

Cleanup/Decontamination Savings (On- $33,091 site)

Replacement Power Savings (On-site) $33,479 Averted Costs of On-site Property $66,570 Damage (AOSC)

Total On-site Benefit $67,655 Averted Public Exposure (APE) $2,945 Averted Off-site Damage Savings (AOC) $2,331 Total Off-site Benefit $5,276 Total Benefit (On-site + Off-site) $72,931 Table 7.e-2: Total Benefit Result for SAMA Candidate FW-17R FW-17R (Auto_MDFP)

Internal Events $72,931 Fires, Seismic, Other $335,481 Total Benefit $408.4_12

L-12-244 Page 61 of 63 Table 7.e-3: Final Results of the Sensitivity Cases for SAMA Candidate FW-17R Question RAI 7.f Purchase or manufacture of a "gagging device" that could be used to close a stuck-open steam generator safety valve for a SGTR event prior to core damage.

RESPONSE RAI 7.f

[The response to RAI 7.f is edited as shown in the text and Tables 7.f-1, 7.f-2 and 7.f-3.]

[NOTE:

• One sensitivity case no longer applies and has been deleted; see the revised response to RAI 6.i.ii]

A SAMA candidate (CB-22R) to use a "gagging" device that could be used to close a stuck-open steam generator safety valve for a SGTR was evaluated for Davis-Besse.

Table 7.f-1 and Table 7.f-2, below, provide the internal event and total benefit results for SAMA candidate CB-22R, respectively. Table 7.f-3, below, provides the final results for the-ten nine [*] sensitivity cases for SAMA candidate CB-22R. The implementation cost for this SAMA candidate was estimated as $4,600,000. The high implementation cost of this SAMA candidate is based on replacement of the safety valves with a new design that includes a gagging feature. Therefore, this SAMA candidate is not cost-beneficial at Davis-Besse.

L-12-244 Page 62 of 63 Table 7.f-1: Internal Events Benefit Results for SAMA Candidate CB-22R CB-22R Case (GaggingDevice)

Off-site Annual Dose (rem) 1.86E+00 Off-site Annual Property Loss ($) 3.14E+03 Comparison CDF 1.OE-05 Comparison Dose (rem) 2.12E+00 Comparison Cost ($) 3.59E+03 Enhanced CDF 9.7E-06 Reduction in CDF 3.00%

Reduction in Off-site Dose 12.26%

Immediate Dose Savings (On-site) $24 Long Term Dose Savings (On-site) $106 Total Accident Related Occupational $130 Exposure (AOE)

Cleanup/Decontamination Savings (On- $3,971 site)

Replacement Power Savings (On-site) $4,018 Averted Costs of On-site Property $7,988 Damage (AOSC)

Total On-site Benefit $8,119 Averted Public Exposure (APE) $6,380 Averted Off-site Damage Savings (AOC) $5,522 Total Off-site Benefit 11$902 Total Benefit (On-site + Off-site) $20,020 Table 7.f-2: Total Benefit Result for SAMA Candidate CB-22R CB-22R (GaggingDevice)

Internal Events $20,020 Fires, Seismic, Other $92,094 Total Benefit $112,115

L-12-244 Page 63 of 63 Table 7.f-3: Final Results of the Sensitivity Cases for SAMA Candidate CB-22R

Attachment 3 L-1 2-244 Review for Impacts to Responses to Requests for Additional Information for the Review of the Davis Besse Nuclear Power Station, Unit No. 1 (Davis-Besse),

License Renewal Application, Environmental Report, Attachment E, Severe Accident Mitigation Alternatives Analysis Submitted by FENOC Letter Dated September 1, 2011 (ML11250A068)

Page 1 of 1 FirstEnergy Nuclear Operating Company (FENOC) performed a review, based on the revised SAMA Analysis, for impacts to the supplemental responses to Nuclear Regulatory Commission (NRC) supplemental requests for additional information (RAIs) for the Severe Accident Mitigation Alternatives (SAMA) Analysis submitted by FENOC letter dated September 1, 2011 (ML11250A068). Based on the changes to the SAMA Analysis, no revision to the FENOC supplemental responses provided in the September 1, 2011, letter is necessary. The list of supplemental RAI s contained in the letter is as follows:

SAMA RAI Supplemental Responses - No Revision 1.d 7.b 4.b 7.c 5.b 7.d 5.d 7.e 6.j 7.f 7.a

Enclosure Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse)

Letter L-12-244 Amendment No. 29 to the Davis-Besse License Renewal Application Page 1 of 49 License Renewal Application Environmental Report (ER) Sections Affected Environmental Report Section E.8.6 Table E.3-27 Section 4.20 Section E.9 Table E.3-28 Table E.3-29 ER Attachment E Section E.10 Table E.3-30 Executive Summary Table E.3-6 Table E.3-31 Section E.3.1.2.4 Table E.3-11 Table E.3-32 Section E.3.4.1 Table E.3-13 Table E.3-33 Section E.3.4.8 Table E.3-18 Table E.4-1 Section E.3.5.2.2 Table E.3-19 Table E.5-4 Section E.3.5.2.3 Table E.3-20 Table E.6-1 Section E.3.5.2.4 Table E.3-21 Table E.7-2 Section E.4.1 Table E.3-22 Table E.7-3 Section E.4.2 Table E.3-23 Table E.7-5 Section E.4.5 Table E.3-24 Table E.8-1 Section E.5.6 Table E.3-25 Section E.7.1.2 Table E.3-26 Section E. 11 The amendment to the License Renewal Application (LRA) ER Sections and Tables included in this Enclosure are a result of the revision to the Severe Accident Mitigation Alternatives (SAMA) Analysis based on correction of the five SAMA Analysis errors, unless otherwise indicated. The Enclosure identifies the change to the LRA by Affected LRA Section, LRA Page No., and Affected Paragraph and Sentence. The count for the affected paragraph, sentence, bullet, etc., starts at the beginning of the affected Section or at the top of the affected page, as appropriate. The sentence affected is printed in italics with deleted text hied-e and added text underlined.

Enclosure L-1 2-244 Page 2 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section 4.20 4.20-3 & 4.20-4 Final paragraph Based on the responses to RAIs 4.b (see FENOC Letter dated June 24, 2011 (ML11180A233) and 5.c, and the revised SAMA Analysis, Environmental Report (ER) Section 4.20, "Severe Accident Mitigation Alternatives," the last bulleted item and final paragraph, are replaced in their entirety to read as follows:

Sensitivity Analysis - Sensitivity cases were performed to investigate the sensitivity of the results to certain modeling assumptions in the Davis Besse SAMA analysis. Nine sensitivity cases were investigated. These cases examined the impacts of assuming damaged plant equipment is repaired and refurbished following an accident, a lower discount rate, a higher discount rate, higher on-site dose estimates, higher total on-site cleanup costs, higher costs for replacement power, a higher external event hazard groups' multiplier, a reduced evacuation speed, and use of a 95th percentile core damage frequency uncertainty factor for internal events. Details on the sensitivity cases are discussed in Attachment E, Section E.8.

The results of the evaluation of 168 SAMA candidates identified one cost-beneficial enhancement at Davis Besse. Assuming a lower discount rate, higher dose rates, higher onsite clean-up costs, increased replacement power costs, increased external event multiplier, reduced evacuation speed, and use of a 9 5 th percentile core damage frequency uncertainty factor for internal events identified the same SAMA candidate to be cost-beneficial. The SAMA candidate identified in the base case and sensitivity cases is not related to plant aging.

Therefore, the identified cost-beneficial SAMA candidate is not a required modification for the license renewal period. Nevertheless, this SAMA candidate will be considered through the normal FENOC processes for evaluating possible modifications to the plant.

Enclosure L-1 2-244 Page 3 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Attachment E - E-9 4 th and 5 th paragraphs Executive Summary Based on the responses to RAIs 4.b (see FENOC Letter dated June 24, 2011 (MLl 1180A233) and 5.c, and the revised SAMA Analysis, the Executive Summary of ER Attachment E, "Severe Accident Mitigation Alternatives Analysis," paragraphs four and five, are revised to read as follows:

The cost-benefit evaluation of SAMA candidates performed for Davis-Besse provides significant insight into the continued operation of Davis-Besse. The results of the evaluation of 4-67 168 SAMA candidatesindicate no enhancements one enhancement to be cost-beneficial for implementation at Davis-Besse. The cost-beneficial SAMA candidate is AC/DC-03, which adds a portable diesel-driven battery chargerto the DC system.

Heweve--the The sensitivity cases performed for this analysis found eqe the same SAMA candidate (AC/DC-03) to be cost-beneficial for implementation at Davis-Besse under the assumptions of three Of the SenSiti.ty "aSeS OGwe..

diScOUnt rate, replacement power-, and multiplier,. SAMA candidate AG4[DC 03 conSidered tho addition of a portable dieRei driven battery charger for thoeD

&ystem. a lower discount rate, higher dose rates, higher onsite clean-up costs, increased replacementpower costs, increasedexternal event multiplier, reduced evacuation speed, and use of a 95th percentile core damage frequency uncertainty factor for internal events. While the identified SAMA candidate is not related to plant aging and therefore not required to be resolved as part of the relicensing effort, FENOC will, nonetheless, consider implementation of this candidate through normal processes for evaluating possible changes to the plant.

Enclosure L-1 2-244 Page 4 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.3.1.2.4 E-28 Entire Section In response to RAI 3.c, ER Section E.3.1.2.4, "External Event Severe Accident Risk," is deleted in its entirety, as follows:

E.3. 1.2. 4 Externl Event Se,-ere Accident Risk*

This Section deScribes the m~ethOd USed tO addr-ess external events Fisk.

As diSc' '8-ed i Section E=.3.41.2.2, Davis Besse used the SMA to evaluate the risk from se*VV i e 4. Wh#le this me19thodloigy doges Pot provide a quantitative result, the r.esolution of outlers en.s.ures that the seismic risk is, low an.d fut',-

sesmi imroemets are not expec~ted. Also, as dcsedin cos beefiia Section E=.3.41.2.3, no othe-r externqal events were found to exceed the scr eeningj ctoa.Therefo9re, theq FIVEnreults were us~ed a&a measuf re of total extera A& discussedf in Section usinjg the EýR!FIVEmtoooy DaviS 4....,

Bes98se con -serpativelyestimated the Fire CDF to be 2.5E= 05r Since the F!V methodology, contains numer-ous conser-vatiisms, a moe r-ealistic assesmn could,%resut in a substantially lower-fire CDF-. AS no-ted- in NE! 05 01 (Reeec, 2-, the NRC staff has accepted that a mere realistic fire CDF= May be aator of estan the screening value obtained from a FIVE= analysis thre Based on the- Davis8 Besse F4VE CDF= of 2.5E= 051yr-, a factor of three reductio would result in a fire CDF= of approxim4ately 9. 3E= 06/yr-. This value is the same9 or-der of magnitude as the internal events CDF= of 9.2E5 06/yr. Th4er-efor-e, this justifies us-e of an ox*ternal. events multiplier- of three to the avedted cost estimae (for internal events) to r-epresent the additional SAMA benefits in external evens

Enclosure L-1 2-244 Page 5 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.3.4.1 E-33 & E-34 Last paragraph and bulleted list ER Section E.3.4.1, "Introduction," last paragraph and bulleted list, are revised to read as follows:

The Level 3 PRA analysis considered a base case and-ewene* ten sensitivity cases to account for variation in data and assumptions. The following list describes the sensitivity cases, which are discussed in Section-E--8 E.3.5.2:

• Case S1 - Use estimated 2060 site population data (with an escalation rate of 4.7%/decade); the same escalation rate for the base case population to 2040

• Case S2 - Use a less conservative escalation rate of 1.5% to estimate the 50-mile population around Davis Besse in 2040

• Case S3 - Set all watershed indices to "1"

• Case M1 - Use 2007 meteorological data

" Cas-e*2 -I meteGr'*!*gica! data fro3r, iF-a late 4990-

• Case Al - Use an alternative method to estimate PLHEAT

• Case A2 - Use more extreme meteorological boundary conditions

• Case A3 - Use a longer OALARM value to better reflect operator's ability to react

" Case El - Use a more realistic(ih~ler-faster) evacuation speed A-4-v4 ua11on (ESPEED)

" Case E2 - Set sheltering shielding factors based on brick house (versus wood housing used in the base case)

" Case E3 - Use a slower evacuation speed (ESPEED)

Enclosure L-1 2-244 Page 6 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.3.4.8 E-41 RELCST (Relocation Cost),

2 nd and 4' paragraphs ER Section E.3.4.8, "Economic Data," "RELCST" subsection, 2 nd and 4 th paragraphs, are revised to read as follows:

RELCST was estimated using the evacuation costs plus the average property cost per person. The average property cost per person was calculated from the total property value in the state, which can be found' on the individual state's Department of Revenue websites:

$256,088,369,000 for Ohio (Reference 25, Table PD-30);

Ohio property values obtained were 'tax assessment' values, which are 35% of total property value, so the Ohio property value needs to be correctedby dividing by 0.35 to obtain total property value

" $340,545,761,049 for Michigan (Reference 26, Exhibit 22)

The total property cost was divided by the total population (11,353,140 for Ohio and 9,938,444 for Michigan) (Reference 27).

For Ohio State, RELCST is $266.34*/eprson day $381.1 1/person-day: for Michigan State, RELCST is $310.61/person-day. The average of the Ohio and Michigan RELCST values was used as input in the CHRONC file.

Enclosure L-1 2-244 Page 7 of 49 Affected LRA Section LRA Page No. Affected Paraqraph and Sentence ER Section E.3.5.2.2 E-43 & E-44 Case M2 subsection - entire subsection ER Section E.3.5.2.2, "Meteorological," "Case M2" subsection, is deleted in its entirety, as follows:

Case M2 An additional Sensitivity caSe was pe~rfmoed to fugher-demonstrate the typica naturo of any pa.gcula~r yoar' worth of met-e-orOIgica! data. These data pro circa late '990 btn.p

,, I,;AifG c year could be ide;tfiod, and thr, foe*-

are on.y to be used as a Secondniti cSnoify .ase.

Tho resulta in Table E=.3 27 are sLim~ar to senSitivity Gase A41, Kith Foem~e variabilty in the consequ~ence, demonstrating the rOPro septativenoss of any year's&wodh of meteoroloegical data.

Enclosure L-1 2-244 Page 8 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.3.5.2.3 E-44 Case A2 subsection, 3 rd and 4 th sentences ER Section E.3.5.2.3, "ATMOS," "Case A2" subsection, 3 rd and 4 th sentences, are revised to read as follows:

Case M2 - A sensitivity case was run with more extreme values of the meteorological boundary parameters, i.e., mixing height (BNDMXH), stability class (IBDSTB), rain rate (BNDRAN), wind speed (BNDWND). In general, the sensitivity case considered all of these boundary parameters collectively (i.e., all considered in one case). The rain rate boundary condition was set at-"7 mR4,ho.r. fo, the baS, cGaS, there i9 no valule m",or-e .onsRQ..'ative than that 30.73 mm/hour (the maximum rainfallin any hour) as a sensitivity case againstthe base case value of 0.0 mm/hr. The-ceGnseiwaUA more extreme boundary parametershad no impact on the results as shown in Table E.3-29.

Enclosure L-1 2-244 Page 9 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.3.5.2.4 E-45 New subsection Based on the response to RAI 4.d, and the revised SAMA Analysis, ER Section E.3.5.2.4, "Early," previously revised by FENOC letter dated June 24, 2011 (MLI 1180A233), to include a new paragraph for sensitivity case E3 at the end of the section, is revised to read as follows:

Case E3 - The base case was performed with an evacuation speed of 0.58 meters/second, based on Davis-Besse-specific evaluation information, without any correction factor to account for the escalated population. In response to an NRC request for additional information, this sensitivity case was performed to gauge the sensitivity of reducing the evacuation speed. As the population was increased 4.7 percent per decade for the 20 years of license renewal (total increase of 9.6 percent), it was assumed for this sensitivity case that the increase in population was directly proportional to the decrease in evacuation speed. The evacuation speed for this sensitivity is a 9.6 percent decrease from the base case, i.e., 0.52 meters/second. This change resulted in a niono increase in the.co...q..nc, v.l.es population dose risk, as shown in Table E.3-33 and only a minor increase in the other consequence values. This These results are expected as slower evacuation should remove the population from the radiologicaldamage less quickly.

Enclosure L-1 2-244 Page 10 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.4.1 E-47 Ist paragraph on page ER Section E.4.1, "Off-site Exposure Cost," the first paragraph on page E-47, previously revised by FENOC Letter dated June 24, 2011 (ML11180A233), is revised to read as follows:

Table E.3-21 provides the off-site dose for each release category obtained for the base case of the Davis Besse Level 3 PRA weighted by the release category frequency. The total off-site dose for internalevents (Dr) was estimated to be 2,30 2.12 person-rem/year. The APE cost was determined using Equation E.4-2 (Reference 1, Section 5.7.1).

Enclosure L-1 2-244 Page 11 of 49 Affected LRA Section LRA Page No. Affected Paraqraph and Sentence ER Section E.4.1 E-48 Equations E.4-6 and E.4-7 ER Section E.4.1, "Off-site Exposure Cost," equations E.4-6 and E.4-7,'

previously revised by FENOC Letter dated June 24, 2011 (ML11180A233), are replaced in their entirety to read as follows:

$ yerson-rem Z pha 2,0 person - rem)( 2.12 perso-r = $4240/yr (E.4-6) where, R = $2,000/person-rem Dt= 2.12 person-rem/year The values for the best estimate case are:

C = 12.27 yr Zpha = $4,240/yr APE = (12.27yr)$424 = $52,025 (E.4-7)

Enclosure L-12-244 Page 12 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.4.2 E-49 1st paragraph, 4th sentence, and equations E.4-8 and E.4-9 ER Section E.4.2, "Off-site Economic Cost," the first paragraph, fourth sentence and equations E.4-8 and E.4-9, previously revised by FENOC Letter dated June 24, 2011 (ML11180A233), are revised to read as follows:

The term used for off-site economic cost is designated as averted off-site property damage costs (AOCs). The off-site economic loss for a 50-mile radius of the site was determined using the MACCS2 model developed for the Davis Besse Level 3 PRA in Section E.3.4. Table E.3-21 provides the economic loss for each release category obtained for the base case of the Level 3 PRA weighted by the release category frequency. The total economic loss from internalevents (It) was estimated to be $4,B00$3,590 ($3.59E+03)per year.

The averted cost was determined using Equation E.4-8 from Reference (1),

Section 5.7.5.

AOC = (C)(It) (E.4-8) where, AOC = off-site economic costs associated with a severe accident ($)

C = present value factor (yr)

It = monetary value of economic loss per year from internal events before discounting ($/yr)

The values for the base case are:

C = 12.27 yr It=$4,91 $3,590/yr AOC = (12.27yr) 3,5901) = $44,049 (E.4-9)

Enclosure L-1 2-244 Page 13 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.4.5 E-55 Entire section, including equations Based on the responses to RAIs 3.c and 4.b (see FENOC letter dated June 24, 2011 (ML11180A233), and the revised SAMA Analysis, ER Section E.4.5, "Total Cost of Severe Accident Risk," is revised to read:

The total cost of severe accident impact for internal events was calculated by summing the public exposure cost, off-site property damage cost, occupational exposure cost, and on-site economic cost. The cost of the impact of a severe accident for internal events was $339,33! $366,693 as shown in Table E.4-1.

Davis Besse does not have external events (i.e., fire, seismic and other external events) PRA from which risk contributorscould be combined with the internal events risk. This anal..i4s assumed that the benefit from each hazard gr-OUP's OLe., fire, seismic-, and GotherF external events) contribution is equivalent to that of internal events. This approeach is conservative, based on the discusoni Section E.3 1.2. Therefor-e, the .ost of &,44A andidate implementation was compared wi4th a benefit value of four times (i.e., 4lx for internal events plus 3x*for ex*ternal events) that calculated 9fointernal events to includo the cOntribution fronm internal events, fire, seismic, and othe,r hazard groups. Based on the NRC staff's best estimate, the fire CDF for Davis-Besse is 2.9x10-5/yr [391. To account for the risk contribution from the fire hazard, a ratio between the fire CDF and internal events CDF was used to determine a fire multiplier of 2.90 (see equation E.4-24).

Fire CDF - 2.9x10- 5 /yr =2.90 (E.4-24)

Internal Events CDF 1.0x10-5/yr Based on updated probabilisticseismic hazard estimates due to Generic Issue 199, the NRC staff estimated a "weakestlink model" seismic CDF for Davis-Besse of 6.7x1O-6/yr [401. To account for the risk contribution from the seismic hazard, a ratio between the seismic CDF and internal events CDF was used to determine a seismic multiplier of 0. 67 (see equation E.4-25).

Seismic CDF 6.7x10-6/yr Internal Events ODE - 1.0x10- 5 /yr = 0.67 (E.4-2 5)

Enclosure L-1 2-244 Page 14 of 49 This analysis conservatively assumed that the benefit from other hazard groups contribution is equivalent to that of internalevents. Therefore, the other hazard groups multiplier is 1.0.

To determine the multiplier to account for fire, seismic, and other hazard groups, the individual multipliers are summed; the resulting multiplier is 4.6.

This approach provided a comparison of the cost to the risk reduction estimated for internal and external events for each SAMA candidate. The maximum benefit for Davis Besse was $1,357-,32 $2,053.481 as shown in Table E.4-1.

Enclosure L-1 2-244 Page 15 of 49 Affected LRA Section LRA Page No. Affected Paragraoh and Sentence ER Section E.5.6 E-63 1 st sentence In response to RAIs 4.b (see FENOC letter dated June 24, 2011 (MLI 11180A233) and 5.c, ER Section E.5.6, "Initial SAMA Candidate List," the first sentence in the section is 2 nd revised to read:

Based on the review of the aforementioned sources, an initiallist of 6-7 168 SAMA candidates was assembled.

Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.7.1.2 2 nd paragraph, 6 th & 7 th sentence E-68 ER Section E.7.1.2, "Best-Estimate Benefit Calculation," 2 nd paragraph, 6 th and 7 th sentences are revised to read:

For each case, the benefit from internalevents and external events (fire, seismic, and other hazard groups) were summed in a worksheet to-*rdete#Fne estimate the total benefit of implementing the SAMA candidate. As discussed in Section E.4.5, the fire, seismic, and other hazard group risk contribution was conservatively estimated to be equivalent to-three 4.6 times the internal events risk contribution.

Enclosure L-12-244 Page 16 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.8.6 E-73 Last two bullets and last paragraph ER Section E.8.6, "Other Sensitivity Cases," the last two bullets and last paragraph, are revised to read as follows:

" The fifth sensitivity case investigated the sensitivity of each analysis to the Pfon~RntemaJ external events hazard groups' multiplier by assuming a multiplier of-five seven.

" Tho sixth sensitivity case investigated tho sensitivity of each analysis to the Off-Site ecoPnomic cost. Thig SenSitiviy caso assumed the off site9

.c.mo.ic coSt was G...a.s.d by twenty five percent. The sixth sensitivity case assessed the impact of using an uncertainty factor for internal events based on the 9 5 th percentile CDF for internal events. The uncertainty factor used in this sensitivity case was 1.45.

The results of the sensitivity cases (Repair, On-site Dose, On-site Cleanup, Replacement Power, Multiplier, and Off*ite Economic Cost 9 5 th percentile CDF) are summarized in Table E. 8 1.

Enclosure L-1 2-244 Page 17 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.9 E-74 Ist and 2nd paragraphs Based on the responses to RAIs 4.b (see FENOC letter dated June 24, 2011 (ML11180A233) and 5.c, and the revised SAMA Analysis, the first and second paragraphs of ER Section E.9, "Conclusions," are revised to read:

The cost-benefit evaluation of SAMA candidates performed for the Davis-Besse license renewal process provided significant insight into the continued operation of Davis-Besse. The results of the evaluation of 4-67 168 SAMA candidates indicatedno. enhacR. en.t" to be potentially one enhancement to be cost-beneficial for implementation at Davis-Besse. The cost-beneficial SAMA candidateis AC/DC-03, which adds a portable diesel-driven battery chargerto the DC system.

Hoewever-, The sensitivity cases performed for this analysis also found one the same SAMA candidate(AC/DC-03) to be peteng#y cost-beneficialfor implementation at Davis-Besse under the assumptions of the lower discount rate, higher dose rates, higher on-site clean-up costs, increasedreplacementpower costs, increased external event multiplier,reduced evacuation speed, and 9 5 th sensitivity percentile CDF sensitivity cases. thre o.f the.ases. (o.i c...t raOte r-eplacement power-, and multiplier,. &4MA candidate AC/DC 03 consideredth addition of a porable diesel driven battery har.ger. for-the DC s*st. While the identified SAMA candidate is not related to plant aging and therefore not a required modification for the license renewal period, FENOC will, nonetheless, consider implementation of this candidate through the normal processes for evaluating possible plant modifications.

Enclosure L-1 2-244 Page 18 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.3-6 E-83 Entire Table ER Table E.3-6, "Release Severity Source Term Release Fraction," is replaced in its entirety, and reads as follows:

Table E.3-1: Release Severity Source Term Release Fraction Release Category Cesium Iodine % Release 2.1 34.40%

3.4 31.10%

3.2 30.30%

2.2 28.90%

5.2 11.60%

5.4 11.10%

7.2 9.93%

6.2 7.16%

1.2 7.05%

1.4 5.95%

8.2 4.84%

1.3 4.42%

1.1 4.04%

6.1 3.12%

7.1 2.34%

7.6 2.16%

4.2 1.96%

6.4 1.91%

7.8 1.76%

5.1 0.83%

5.3 0.73%

3.1 0.63%

4.4 0.62%

3.3 0.46%

7.5 0.21%

6.3 0.20%

7.4 0.03%

7.3 0.02%

4.1 0.01%

4.3 0.01%

9.2 0.00%

7.7 0.00%

8.1 0.00%

9.1 0.00%

Enclosure L-12-244 Page 19 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.3-11 E-86 New row ER Table E.3-1 1, "Total (Permanent and Transient) Escalated Population (50-Mile Radius - Davis Besse) for the Year 2040," previously revised by FENOC letter dated June 24, 2011 (ML11180A233), is revised to add a 'Total Population' row at the bottom of the table, and now reads:

Table E.3-11: Total (Permanent and Transient) Escalated Population (50-Mile Radius - Davis-Besse) for the Year 2040 1 2 3 4 5 10 20 30 40 50 mile miles miles miles miles miles miles miles miles miles N 0 0 0 0 0 0 0 0 151518 448232 NNE 6 0 0 0 0 0 0 0 154651 193313 NE 0 0 0 0 0 0 0 0 38663 96657 ENE 0 0 0 0 0 0 828 0 0 0 E 0 0 0 0 0 0 2229 219 0 13561 ESE 0 0 320 0 0 0 11198 50152 20763 104445 SE 662 661 0 0 6786 27558 7443 9301 35612 11828 SSE 661 729 60 71 109 1593 2075 23880 6229 20419 S 4 12 55 328 651 1680 34083 7301 34694 7138 SSW 17 5 82 79 482 5743 4141 6025 26881 12565 SW 37 20 20 469 197 1728 9970 9130 7669 64607 WSW 0 50 0 35 84 1050 8246 12404 47735 14163 W 0 53 72 66 87 847 19318 259606 102087 25871 WNW 683 723 156 0 7274 4821 7009 207932 58896 13460 NW 0 165 595 0 0 1763 0 53092 20356 25771 NNW 20 138 0 0 0 0 0 20080 77289 233548 Total Population 2.909.792

Enclosure L-12-244 Page 20 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.3-13 E-87 thru E-93 Entire Table ER Table E.3-13, "MAAP Output for MACCS2," is replaced in its entirety, to read as follows:

Table E.3-13: MAAP Output for MACCS2 Davis-Besse STIIRIYVXIN ST12_RIYVXINN ST13_RIYVXINN ST14_RIYVXINN ST21-ISLOCA MAAP Case ID N 52Y-0021a 52Y-0021a 52Y-0021a 52Y-0021a C Release Category 1.1 1.2 1.3 1.4 2.1 QALARM (uncovery) (hrs Core Uncovery 1.67 1.67 1.67 1.67 8.35E-02 (IEVNT(49))

QALARM (uncovery) (s) Core Uncovery 6012 6012 6012 6012 301 (IEVNT(49))

PLHEAT (watts) 3.87E+07 1.45E+07 3.87E+07 1.45E+07 8.91 E+06 PLHITE (meters) TDPLHITE 18.44 18.44 18.44 18.44 2.13 RELFRC FREL(1) 1.OOE+00 3.70E-01 1.OOE+00 3.70E-01 1.OOE+00 FREL(2) 4.04E-02 7.05E-02 4.42E-02 5.95E-02 3.44E-01 FREL(3) 1.06E-02 3.05E-02 1.52E-02 2.88E-02 3.18E-01 FREL(4) 2.16E-04 3.93E-05 2.46E-04 8.30E-05 2.64E-02 FREL(5) 3.94E-03 3.36E-03 3.94E-03 3.41 E-03 1.03E-02 FREL(6) 1.51 E-02 2.90E-02 2.39E-02 2.40E-02 3.20E-01 FREL(7) 1.11E-03 4.81E-04 1.12E-03 5.14E-04 2.27E-02 FREL(8) 6.05E-06 2.43E-06 1.17E-05 1.40E-05 3.53E-03 FREL(9) 4.11 E-05 1.10E-05 1.40E-04 1.65E-04 3.85E-02 FREL(10 3.58E-01 1.16E-02 4.19E-01 8.85E-03 2.56E-01 FREL( 11) 7.85E-11 4.97E-06 1.92E-06 2.26E-05 2.96E-03 FREL(12 3.60E-15 1.14E-08 1.35E-06 1.50E-06 3.25E-04 PDELAY (hrs) 73.80 2.25 73.80 2.25 0.5 PDELAY(s) 265680 8100 265680 8100 1800 PLUDUR (hrs) 74.18 51.39 74.17 29.95 36.07 PLUDUR (s) 267048 185004 267012 107820 129852 End of Release (hrs) 147.98 53.64 147.97 32.20 36.57

Enclosure L-1 2-244 Page 21 of 49 Table E.3-13: MAAP Output for MACCS2 (continued)

Davis-Besse ST22_ISLOCA ST31_AXIIA_4 ST32_AXlIA_4 ST33_AXIIA_4 ST34_AXIIA_4 MAAP Case ID_

Release Category 2.2 3.1 3.2 3.3 3.4 QALARM (uncovery) (hrs Core Uncovery 8.37E-02 8.34E-02 8.39E-02 8.34E-02 8.39E-02 (IEVNT(49))

QALARM (uncovery) (s Core Uncovery 301 300 302 300 302 OALARM__(uncovey)_(s) (IEVNT(49))

PLHEAT (watts) 6.68E+06 2.22E+06 2.61 E+06 2.22E+06 2.61 E+06 PLHITE (meters) TDPLHITE 2.13 45.42 45.42 45.42 45.42 RELFRC FREL(1) 9.40E-01 1.OOE+00 9.66E-01 9.90E-01 9.92E-01 FREL(2) 2.89E-01 6.34E-03 3.03E-01 4.55E-03 3.11 E-01 FREL(3) 2.65E-01 3.61 E-03 2.52E-01 3.42E-03 2.73E-01 FREL(4) 4.51 E-03 1.17E-04 3.58E-03 1.17E-04 1.56E-02 FREL(5) 1.25E-02 2.10E-04 1.23E-02 2.09E-04 1.31 E-02 FREL(6 2.75E-01 5.94E-03 2.56E-01 4.36E-03 2.81 E-01 FREL(7) 1.01 E-02 2.40E-04 9.08E-03 2.39E-04 1.48E-02 FREL(8) 1.64E-04 2.55E-06 1.36E-04 2.70E-06 2.82E-03 FREL(9) 6.61 E-04 1.20E-05 6.05E-04 1.35E-05 3.24E-02 FREL(10) 1.55E-01 8.62E-03 2.02E-01 4.85E-03 2.62E-01 FREL(11) 2.12E-05 1.99E-07 0.OOE+00 1.97E-07 2.28E-03 FREL( 12) 1.48E-07 3.34E-10 7.26E-08 1.76E-08 2.80E-04 PDELAY (hrs) 0.58 0.42 0.42 0.42 0.42 PDELAY(s) 2088 1512 1512 1512 1512 PLUDUR (hrs) 14.62 49.52 29.58 9.08 43.38 PLUDUR (s) 52632 178272 106488 32688 156168 End of Release (hrs) 15.20 49.94 30 9.5 43.8

Enclosure L-1 2-244 Page 22 of 49 Table E.3-13: MAAP Output for MACCS2 (continued)

Davis-Besse ST41AXIIA_4 ST42_AXIIA_4 ST43_AXlIA_4 ST44_AXlIA_4 ST51_SIYYFYYN MAAP Case ID . .. .. ...

__36Y-002 Release Category 4.1 4.2 4.3 4.4 5.1 QALARM (uncovery) (hrs) Core Uncovery 8.38E-02 8.38E-02 8.38E-02 8.38E-02 6.68E-01 OALARM___(uncover__) (r)(IEVNT(49))

(uncovery) (S) CALARM ore Uncovery 302 302 302 302 2405 (IEVNT(49))

PLHEAT (watts) 9.17E+05 2.24E+05 6.77E+05 2.1OE+05 3.17E+06 PLHITE (meters) TDPLHITE 2.13 2.13 2.13 2.13 45.42 RELFRC FREL(1) 5.31 E-01 5.60E-01 4.69E-01 5.49E-01 9.99E-01 FREL(2) 9.90E-05 1.96E-02 7.73E-05 6.16E-03 8.28E-03 FREL(3 2.94E-06 1.08E-02 2.64E-06 3.35E-03 1.26E-03 FREL(4) 2.95E-14 7.14E-05 4.92E-09 2.08E-03 3.27E-07 FREL(5) 2.89E-13 1.98E-04 7.90E-09 1.02E-04 7.66E-07 FREL(6) 6.33E-05 1.30E-02 7.46E-05 4.06E-03 1.50E-03 FREL(7) 7.53E-14 1.81 E-04 3.43E-08 9.72E-04 1.03E-06 FREL(8) 3.75E-16 2.71 E-06 6.18E-10 3.69E-04 1.03E-08 FREL(9) 9.19E-16 1.05E-05 7.73E-09 4.38E-03 2.25E-08 FREL(10 7.54E-04 7.62E-03 6.81 E-04 1.44E-02 8.29E-04 FREL(11j) 0.OOE+00 0.OOE+00 1.40E-04 7.60E-04 5.33E-08 FREL(12) 0.OOE+00 0.OOE+00 6.44E-09 3.25E-05 1.57E-11 PDELAY (hrs) 12.5 0.58 14 0.58 4.1 PDELAY(s) 45000 2088 50400 2088 14760 PLUDUR (hrs) 37.21 49.14 35.71 49.16 22.50 PLUDUR (s) 133956 176904 128556 176976 81000 End of Release (hrs) 49.71 49.72 49.71 49.74 26.6

Enclosure L-1 2-244 Page 23 of 49 Table E.3-13: MAAP Output for MACCS2 (continued)

Davis-Besse ST52_TINYNI ST53_SIYYFYYN ST54_TINYNINN ST61_TINYNINN ST62_TINYNINN MAAP Case ID NN 53Y 36Y-002 53Y 53Y 53Y Release Category 5.2 5.3 5.4 6.1 6.2 OALARM (uncovery) (hrs) Core Uncovery 9.17E-01 6.68E-01 9.17E-01 9.17E-01 9.17E-01 (IEVNT(49))

ALARM (uncovery) (S) Core Uncovery 3301 2405 3301 3301 3301 (IEVNT(49))

PLHEAT (watts) 1.09E+07 2.83E+06 9.59E+06 7.35E+07 1.14E+08 PLHITE (meters) TDPLHITE 45.42 45.42 45.42 2.13 2.13 RELFRC FREL(1 9.65E-01 9.85E-01 9.95E-01 9.93E-01 9.91 E-01 FREL(2) 1.16E-01 7.31 E-03 1. 11 E-01I 3.12E-02 7.16E-02 FREL(3) 1.72E-01 1.03E-03 1.71 E-01 1.55E-02 3.15E-02 FREL(4) 1.71 E-04 1.02E-06 2.50E-02 3.09E-05 3.22E-05 FREL(5) 1.09E-03 7.15E-07 9.33E-04 1.88E-04 1.13E-04 FREL(6) 9.05E-02 1.33E-03 9.12E-02 1.62E-02 2.50E-02 FREL(7) 1.19E-03 1.24E-06 1.21 E-02 1.58E-04 2.55E-04 FREL(8) 1.71 E-05 2.26E-07 4.10E-03 1.84E-06 3.14E-06 FREL(9) 9.08E-05 2.79E-06 6.37E-02 1.50E-05 1.53E-05 FREL( 10) 2.48E-02 7.82E-04 1.91 E-01 5.90E-03 1.48E-02 FREL( 11 )0.00E+00 1.97E-07 6.29E-03 1.92E-08 4.41 E-07 FREL( 12) 0.00E+00 2.68E-08 3.68E-04 0.OOE+00 0.OOE+00 PDELAY (hrs) -2.08 4.1 2.08 2.34 2.42 PDELAY(s) 7488 14760 7488 8424 8712 PLUDUR (hrs) 12.92 5.90 48.02 1.46 37.58 PLUDUR (s) 46512 21240 172872 5256 135288 End of Release (hrs) 15 10 50.1 3.8 40

Enclosure L-1 2-244 Page 24 of 49 Table E.3-13: MAAP Output for MACCS2 (continued)

Davis-Besse ST63_TINYNIN ST64_TINYNINN ST71 AXlIA 4 ST72-AXIIA-4 ST73_TINYNINN MAAP Case ID N 53Y 53Y . .. A 53Y Release Category 6.3 6.4 7.1 7.2 7.3 QALARM (uncovery) (hrs) Core Uncovery 9.17E-01 9.17E-01 8.35E-02 8.35E-02 3.51 (IEVNT(49))

QALARM (uncovery) (s) Core Uncovery 3301 3301 301 301 12636 (IEVNT(49))

PLHEAT (watts) 6.10E+07 1.16E+08 3.02E+07 2.79E+07 2.82E+07 PLHITE (meters) TDPLHITE 2.13 2.13 45.42 45.42 45.42 RELFRC FREL(1) 9.99E-01 9.95E-01 1.OOE+00 1.00E+00 9.99E-01 FREL(2 2.03E-03 1.81 E-02 2.34E-02 9.93E-02 2.35E-04 FREL(3) 1.82E-04 1.93E-03 3.96E-03 9.82E-03 1.55E-05 FREL(4) 1.12E-09 2.30E-04 1.14E-08 1.80E-08 4.68E-10 FREL(5) 2.72E-09 1.73E-06 1.98E-08 6.96E-08 6.48E-10 FREL(6) 9.44E-04 2.82E-03 2.31 E-02 4.08E-02 4.91 E-05 FREL(7) 8.60E-09 1.07E-04 2.90E-08 5.37E-08 2.23E-09 FREL(8) 2.99E-1 0 4.29E-05 3.40E-1 0 4.35E-1 0 2.34E-1 1 FREL(9) 8.30E-10 8.20E-04 1.29E-09 1.59E-09 2.07E-10 FREL( 0) 3.91 E-04 2.92E-02 1.50E-02 1.55E-02 1.07E-05 FREL( 1)) 2.36E-07 1.57E-04 0.OOE+00 0.OOE+00 0.OOE+00

________FREL(1_2) 8.30E-11 6.50E-06 0.00E+00 0.00E+00 0.OOE+00 PDELAY (hrs) 11.9 11 29.0 33.3 35.6 PDELAY(s) 42840 39600 104400 119880 128160 PLUDUR (hrs) 48.07 48.04 47.95 47.98 48.00 PLUDUR (s) 173052 172944 172620 172728 172800 End of Release (hrs) 59.97 59.04 76.95 81.28 83.6

Enclosure L-1 2-244 Page 25 of 49 Table E.3-13: MAAP Output for MACCS2 (continued)

Davis-Besse MAAP Case ST74_TINYNIN ST77_TINYNINN ST78_TINYNINN ID N 53Y ST75_AXlIA_4 ST76_AXlIA_4 53Y 53Y Release Category 7.4 7.5 7.6 7.7 7.8 QALARM (uncovery) (hrs) Core Uncovery 3.51 8.35E-02 8.36E-02 3.51 3.51 (IEVNT(49))

QALARM (uncovery) (S) Core Uncovery 12636 301 301 12636 12636 OALARM___(uncovery)__( (IEVNT(49))

PLHEAT (watts) 2.80E+07 2.01 E+07 2.36E+07 1.93E+07 2.45E+07 PLHITE (meters) TDPLHITE 45.42 45.42 45.42 45.42 45.42 RELFRC FREL(1) 1.00E+00 9.97E-01 9.93E-01 9.99E-01 9.89E-01 FREL(2 3.36E-04 2.06E-03 2.16E-02 1.07E-05 1.76E-02 FREL(3) 3.72E-05 1.80E-05 3.78E-03 5.97E-07 1.69E-03 FREL(4 4.69E-10 1.16E-08 6.37E-06 5.66E-10 1.10E-05 FREL(5) 6.48E-10 2.07E-08 1.05E-06 6.96E-10 2.95E-07 FREL(6 2.01 E-05 8.58E-04 7.49E-03 1.41 E-06 1.37E-03 FREL(7) 2.23E-09 2.95E-08 4.95E-06 2.35E-09 5.78E-06 FREL 8 2.34E-1 1 3.44E-10 8.77E-07 4.32E-1 1 1.86E-06 FREL 9 2.07E-10 1.33E-09 1.15E-05 4.86E-10 3.64E-05 FREL( 10) 1.24E-06 5.66E-03 2.08E-02 2.05E-06 1.90E-02 FREL(11 ) 0.OOE+00 8.59E-08 1.96E-03 2.74E-08 1.03E-03 FREL(12) 0.OOE+00 7.84E-12 2.22E-07 7.57E-12 2.96E-07 PDELAY (hrs) 40.8 42 37.2 50.9 42.5 PDELAY(s) 146880 151200 133920 183240 153000 PLUDUR (hrs) 11.90 48.01 48.08 48.01 48.04 PLUDUR (s) 42840 172836 173088 172836 172944 End of Release (hrs) 52.7 90.01 85.28 98.91 90.54

Enclosure L-12-244 Page 26 of 49 Table E.3-13: MAAP Output for MACCS2 (continued)

Davis-Besse ST81_AXI~a_4 ST82_AXiIa 4 ST91_AXlIA_4 ST92_AXIIA_4 MAAP Case ID __ _ __ _ _ __ _ _ _ _ _ __ _ _ _ _ _ __ __ _ __

Release Category 8.1 8.2 9.1 9.2 QALARM (uncovery) (hrs) Core Uncovery 8.36E-02 8.36E-02 8.36E-02 8.34E-02

_ALARM_(uncovery) (hrs) (IEVNT(49))

QALARM (uncovery) (s) Core Uncovery 301 301 301 300 (IEVNT(49))

PLHEAT (watts) 8.71 E+06 9.78E+07 2.63E+02 3.30E+02 PLHITE (meters) TDPLHITE 0.00 0.00 45.42 45.42 RELFRC FREL(1) 9.32E-01 9.93E-01 1.47E-03 1.51 E-03 FREL(2) 5.57E-06 4.84E-02 5.66E-07 4.51 E-05 FREL(3) 5.03E-07 9.35E-03 4.64E-07 3.38E-05

_FREL4) 2.14E-08 7.64E-05 2.09E-08 6.01 E-07 FREL(5) 1.85E-07 7.72E-06 2.OOE-07 1.78E-06 FREL(6) 3.17E-06 2.85E-02 5.26E-07 3.49E-05 FREL(7) 5.58E-08 4.63E-05 5.74E-08 1.36E-06 FREL(8) 5.32E-10 1.14E-05 5.11 E-10 1.99E-08 FREL 9 1.60E-09 1.53E-04 1.60E-09 9.08E-08 FREL 10 2.50E-05 1.92E-02 5.22E-07 3.09E-05 FREL 11 9.20E-09 1.86E-03 0.OOE+00 3.29E-09 FREL 12 3.OOE-12 2.22E-06 0.OOE+00 8.69E-12 PDELAY (hrs) 33.2 15.4 0.33 0.5 PDELAY(s) 119520 55440 1188 1800 PLUDUR (hrs) 47.90 47.95 15.27 49.42 PLUDUR (s) 172440 172620 54972 177912 End of Release (hrs) 81.1 63.35 15.6 49.92

Enclosure L-12-244 Page 27 of 49 Affected LRA Section LRA Page No. Affected ParaqraDh and Sentence ER Table E.3-18 E-96 Farm & Nonfarm (last 2) columns ER Table E.3-18, "Economic Data," the 'Farmland Property Value for the Region' and 'Nonfarm Property Value for the Region' columns, are replaced in their entirety, to read as follows:

Table E.3-18: Economic Data Fraction of Fraction of Total Annual Farmland Nonfarm Region Name, Land Devoted Farm Sales Farm Sales Property Property Value State to Farming in Resulting for the Value for the for the Region Region from Dairy in Region Region Region ($/hectare) ($/hectare) ($/person)

Crawford, OH 0.854 0.044 1301 7,907 34,979 Erie, OH 0.522 0.025 1186 9,869 82,281 Fulton, OH 0.709 0.086 1802 8,859 59,090 Hancock, OH 0.729 0.032 1007 8,033 56,893 Huron, OH 0.697 0.055 1507 8,540 42,523 Lorain, OH 0.395 0.106 2612 11,120 71,245 Lucas, OH 0.289 0.000 1881 10,751 68,848 Ottawa, OH 0.706 0.019 990 7,144 117,709 Sandusky, OH 0.694 0.024 1081 7,630 54,067 Seneca, OH 0.764 0.021 985 7,719 37,526 Wood, OH 0.698 0.044 1125 8,300 70,940 Lenawee, MI 0.727 0.244 1142 7,902 23,140 Monroe, MI 0.591 0.011 1547 9,454 34,958 Wayne, MI 0.045 0.000 4074 19,128 28,338

Enclosure L-1 2-244 Page 28 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.3-19 E-96 Entire table ER Table E.3-19, "MACCS2 Economic Parameters Used in CHRONC," is replaced in its entirety, to read as follows:

Table E.3-19: MACCS2 Economic Parameters Used in CHRONC Variable Value Description (in Davis-Besse model)

DPRATE Property depreciation rate (/year) 0.20 DSRATE Investment rate of return (/year) 0.12 POPCST Population relocation cost ($/person) $9,750/person Cost of farm decontamination for various levels of $1,096.90/hectare, decontamination ($/hectare) $2,437.50/hectare Cost of non-farm decontamination per person for various $5,850/person, levels of decontamination ($/person) $15,600/person DLBCST Average cost of decontamination labor ($/person-year) $68,250/person-year Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.3-20 E-97 Release Category rows 2.1 and 2.2 ER Table E.3-20, "Frequency Vector," 'Release Category rows 2.1 and 2.2,

'Frequency (/year)' column data are reversed, and the rows are revised to read as follows:

Release Category Frequency (/year) Percent 2.1 54E-O 6.OE-09 0.06%

2.2 6OE=-9 5.4E-08 0.53%

Enclosure L-1 2-244 Page 29 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.3-21 E-98 Entire table ER Table E.3-21, "Base Case Results for Internal Events at 50 Miles," previously revised by FENOC letter dated June 24, 2011 (ML11180A233), is replaced in its entirety, and now reads:

Table E.3-21: Base Case Results for Internal Events at 50 Miles Release Whole Body Dose Economic Impact Category (50, rem)/yr (50, $)/yr 1.1 4.29E-02 5.70E+01 1.2 2.41 E-02 5.15E+01 1.3 1.28E+00 2.23E+03 1.4 2.12E-03 4.20E+00 2.1 4.89E-02 6.78E+01 2.2 3.05E-01 5.1OE+02 3.1 2.43E-03 1.44E+00 3.2 1.52E-04 2.62E-01 3.3 1.90E-05 9.05E-03 3.4 1.27E-02 1.84E+01 4.1 2.47E-05 5.25E-03 4.2 4.69E-02 5.92E+01 4.3 3.03E-07 6.OOE-05 4.4 1.05E-02 1.54E+01 5.1 9.69E-03 4.26E+00 5.2 1.15E-02 2.46E+01 5.3 7.67E-04 3.78E-01 5.4 6.51 E-03 7.70E+00 6.1 5.68E-04 8.62E-01 6.2 5.68E-05 1.13E-01 6.3 9.45E-04 3.09E-01 6.4 2.44E-02 1.36E+01 7.1 2.17E-05 4.55E-02 7.2 1.05E-03 2.65E+00 7.3 3.83E-08 5.32E-06 7.4 2.24E-05 3.98E-03 7.5 5.72E-06 2.05E-03 7.6 2.11E-02 1.55E+01 7.7 4.25E-08 8.86E-07 7.8 3.68E-02 1.60E+01 8.1 1.32E-04 2.33E-03

Enclosure L-12-244 Page 30 of 49 Release Whole Body Dose Economic Impact Category (50, rem)/yr (50, $)/yr 8.2 2.08E-01 4.88E+02 9.1 1.92E-03 2.03E-06 9.2 1.75E-02 2.25E+00 Total 2.12E+00 3.59E+03

Enclosure L-12-244 Page 31 of 49 Affected LRA Section LRA Page No. Affected Paraaraph and Sentence ER Table E.3-22 E-99 Entire table ER Table E.3-22, "Base Case Consequence Input to SAMA Analysis," previously revised by FENOC letter dated June 24, 2011 (ML11180A233), is replaced in its entirety, and now reads:

Table E.3-22: Base Case Consequence Input to SAMA Analysis Release Whole Body Dose Economic Impact Category (50, rem) (50, $)

1.1 1.95E+06 2.59E+09 1.2 1.85E+06 3.96E+09 1.3 2.17E+06 3.78E+09 1.4 1.77E+06 3.50E+09 2.1 8.15E+06 1.13E+10 2.2 5.64E+06 9.45E+09 3.1 9.73E+05 5.77E+08 3.2 5.44E+06 9.36E+09 3.3 7.58E+05 3.62E+08 3.4 7.48E+06 1.08E+10 4.1 2.47E+04 5.25E+06 4.2 1.38E+06 1.74E+09 4.3 2.75E+04 5.45E+06 4.4 1.36E+06 2.OOE+09 5.1 3.34E+05 1.47E+08 5.2 3.02E+06 6.47E+09 5.3 2.74E+05 1.35E+08 5.4 7.31 E+06 8.65E+09 6.1 1.29E+06 1.96E+09 6.2 1.72E+06 3.41 E+09 6.3 2.1OE+05 6.87E+07 6.4 7.86E+05, 4.39E+08 7.1 1.55E+06 3.25E+09 7.2 1.85E+06 4.65E+09 7.3 1.74E+04 2.42E+06 7.4 9.32E+03 1.66E+06 7.5 2.12E+05 7.60E+07 7.6 1.11E+06 8.17E+08 7.7 1.18E+03 2.46E+04 7.8 3.76E+05 1.63E+08 8.1 2.10E+03 3.70E+04

Enclosure L-1 2-244 Page 32 of 49 Release Whole Body Dose Economic Impact Category (50, rem) (50, $)

8.2 1.60E+06 3.75E+09 9.1 2.53E+02 2.67E-01 9.2 1.25E+04 1.61 E+06 Total 6.07E+07 9.34E+10

Enclosure L-1 2-244 Page 33 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Tables E.3-23 E-100 & E-101 Entire Tables (10 tables) through E.3-32 ER Tables E.3-23 through E.3-32, "Comparison of Base Case and Case [XX],"

previously revised by FENOC letter dated June 24, 2011 (MLI 11180A233), are replaced in their entirety, with the exception of Table E.3-27, "Comparison of Base Case and Case M2," which is no longer used and is deleted, and the tables read as follows:

Table E.3-23: Comparison of Base Case and Case S1 Internal Events Base S1  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.32E+00 9.4%

Economic Impact (50) ($/yr) 3.59E+03 3.92E+03 9.2%

Table E.3-24: Comparison of Base Case and Case S2 Internal Events Base S2  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 1.88E+00 -11.3%

Economic Impact (50) ($/yr) 3.59E+03 3.20E+03 -10.9%

Table E.3-25: Comparison of Base Case and Case S3 Internal Events Base S3  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.18E+00 2.8%

Economic Impact (50) ($/yr) 3.59E+03 3.59E+03 0.0%

Table E.3-26: Comparison of Base Case and Case M1 Internal Events Base MI  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.11E+00 -0.5%

Economic Impact (50) ($/yr) I 3.59E+03 3.63E+03 1 1.1%

Enclosure L-1 2-244 Page 34 of 49 Table E.3-27: Cr,,na,-,".... S,,, p .....ad ,as, 4A,

/Tabl'e E3-27is not used,andis deleted.

Table E.3-28: Comparison of Base Case and Case Al Internal Events Base Al  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.05E+00 -3.3%

Economic Impact (50) ($/yr) 3.59E+03 3.40E+03 -5.3%

Table E.3-29: Comparison of Base Case and Case A2 Internal Events Base A2  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.12E+00 0.0%

Economic Impact (50) ($/yr) 3.59E+03 3.59E+03 0.0%

Table E.3-30: Comparison of Base Case and Case A3 Internal Events Base A3  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.12E+00 0.0%

Economic Impact (50) ($/yr) 3.59E+03 3.59E+03 0.0%

Table E.3-31: Comparison of Base Case and Case El Internal Events Base El  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.11E+00 -0.5%

Economic Impact (50) ($/yr) 3.59E+03 3.59E+03 0.0%

Table E.3-32: Comparison of Base Case and Case E2 Internal Events Base I E2 I% diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 1.62E+00 -23.6%

Economic Impact (50) ($/yr) 3.59E+03 2.16E+03 -39.8%

Enclosure L-1 2-244 Page 35 of 49 Affected LRA Section LRA Page No. Affected Paralraph and Sentence ER Table E,3-33 E-101 Entire table Based on the revised response to RAI 4.d, ER Table E.3-33, "Comparison of Base Case and Case E3," previously added in response to RAI 6.j (see revised response to RAI 6.j in this letter) by FENOC letter dated June 24, 2011 (ML11180A233), reads as follows:

Table E.3-33: Comparison of Base Case and Case E3 Internal Events Base S1  % diff.

Whole Body Dose (50) (person-rem/yr) 2.12E+00 2.12E+00 0.0%

Economic Impact (50) ($/yr) 3.59E+03 3.59E+03 0.0%

Enclosure L-1 2-244 Page 36 of 49 Affected LRA Section LRA Page No. Affected Paraaraph and Sentence ER Table E.4-1 E-101 Entire table Based on the responses to RAIs 3.c and 4.b (see FENOC letter dated June 24, 2011 (ML11180A233), and the revised SAMA Analysis, ER Table E.4-1, "Total Cost of Severe Accident Impact," is revised to read as follows:

Table E.4-1: Total Cost of Severe Accident Impact APE $52,025 AOC $44,049 AOE $4,340 AOSC $266,279 Severe Accident Impact $366693 (Internal Events)

Fire, Seismic, Other $1,686,788 Maximum Benefit

$2,053,481 (Internal Events, Fire, Seismic, Other)

Enclosure L-12-244 Page 37 of 49 Affected LRA Section LRA Page No. Affected Paraqraph and Sentence ER Table E.5-4 E-144 thru 154 6 rows revised; 1 new row In response to RAIs 5.c and 5.f (see FENOC letter dated June 24, 2011 (ML11180A233), ER Table E.5-4, "List of Initial SAMA Candidates," is revised as follows:

Table E.5-4: List of Initial SAMA Candidates SAMA Candidate SAMA Candidate Description Derived Benefit Source Identifier This SAMA candidate would provide [2, Table 14]

Install pressure measurements indication of failure of inboard isolation [Table E. 5-2i CB-21 between the two DHR suction valves vle loigtm oiiit te lne CS ot eg.

inromthe valves allowing time to initiate in the line from the RCS hot leg. mitigating actions to prevent ISLOCA.

This SAMA candidate will increase the [Table E.5-1l Provide automatic switchover of HPI reliability of switchover of suction from CC-19 and LPI suction from the BWST to the BWST to the containment sump by containment sump for LOCAs. providing both manual and automatic switchover.

This SAMA candidate would increase Davis-Besse containment heat removal ability, containment Install a redundant containment fan SAMA candidate CP-19 was added cooling design CP-19 syas a variation to CP-18 to provide a system. redundantcontainment cooling function, in the form of containment fan coolers.

Replace the standby CCW pump This SAMA candidate would improve [Table E.5-1 Repac tith e sta pump diversefCCW reliability by reducing the [Table E.5-21 CW-24 with a pump diverse from the other lklho faCFo l he C two CW pmps.likelihood two CCW pumps. pms of a CCF of all three CCW _____

pumps.

Provide the ability to cool make-up This SAMA candidate would allow [Table E.5-1l CW-25 pumps using fire water in the event continued injection of RCP seal water in [Table E.5-21 of loss of CCW. the event of loss of CCW.

Perform surveillances on manual This SAMA candidate would improve R,- Table

.4, FW16 Palversor usurvebancepon pumaa the success probability for providing an [Table E.5-1l valves used for backup AFW pump alternate water supply to the AFW [Table E.5-21 suctionpumps.

PRA results show that operatoractions Table E. 5-2 Provide operator training with are significantcontributors to overall OT-09R PRA-identified high risk important plant risk. By highlighting those human actions to be emphasized in operatoractions shown to have the training. highest risk importance, the reliabilityof those actions will be improved.

Enclosure L-12-244 Page 38 of 49 Affected LRA Section LRA Page No. Affected Paraqraph and Sentence ER Table E.6-1 E-155 thru 180 8 rows revised, and 1 new row In response to RAIs 5.c, 5.g, 5.h, 6.b (for RAls 5.h and 6.b, see FENOC letter dated June 24, 2011 (MLI 1180A233), and 6.k, and to align with current FENOC plans and with the discussions in the ER regarding the steam generator replacement schedule, Table E.6-1, "Qualitative Screening of SAMA Candidates," is revised as follows:

Table E.6-1: Qualitative Screening of SAMA Candidates 5AMA IDModification SAMA ID (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements This SA44A WON' d 'PodifOR tho 'risRko f 'SLOW A events by'ipovn tholiklihodof timo'y idontifiaation ;;nd di gnoEis of 1,31=CA ovonts and thoroby incroas t 1. oh iklhood o~f 6s!10cossful.' mitigating B-aImprove operator training on .. tions.

. This . SAMA be subsu. d in G9 07.

CB-08 Imrove coperator traininn BDavis-Besse has several proceduresin place to address small and interfacing system LOCAs. Operatorsreceive training on LOCAs, Already Implemented and there are a number of indicationsto support the likelihood and timely identificationand diagnosisof ISLOCA events (including tank level indications, lifting relief valves, and running sump pumps).

Institute a maintenance practice to Davis-Besse is scheduled to replace the steam generators in-204-3 CB-09 perform a 100% inspection of Criterion D 2014, which would result in inspecting new steam generatortubes.

steam generator tubes during Very Low Benefit Therefore, this SAMA candidate is considered very low benefit for each refueling outage. Davis-Besse.

CB-10 Replace steam generators with a Criterion B Davis-Besse is scheduled to replace the steam generatorsin-204-3 new design. 2014. Therefore, the intent of the SAMA candidate has already Already Implemented been implemented at Davis-Besse.

Enclosure L-12-244 Page 39 of 49 Table E.6-1: Qualitative Screening of SAMA Candidates (continued)

SAMA IDModification SAMA ID (Potential Enhancement) Screening Criteria Basis for Screening/Modification Enhancements Davis-Besse currently has the ability to initiate automatic switchover Add the ability to automatically Criterion E from the BWST to the containment sump on low BWST level, but CC-08 align ECCS to recirculation mode this feature has been deactivated. The cost ;4oeuld by minor to upon BWST depletion. Subsumed :oacti.'to this fatu're. This SAMA candidate will be subsumed in SAMA candidate CC-19.

Provide automatic switchover of Davis-Besse currently has the ability to initiate automatic switchover HPI and LPI suction from the Criterion F from the BWST to the containment sump on low BWST level, but BWST9toi t prnthis feature has been deactivated. The cost ,o-4,-ld by mineo to CBWST to containment sump for Considered for Further Evaluation rqact."ivot thiS foea4ur. Therefore, this SAMA candidate is LOCAs. considered for further evaluation.

Ra-sod on tho top 400 cutsots and componont basic oveni impo.ae, ... i.culating watier broaks aro not a significantrsk Improve inspection of rubber Le w The circulating water joints are currently inspected durnin outages, FL-01 expansion joints on main condenser. Criterion B and include both interiorand exterior inspections. Exterior Already Implemented inspections of the visible portion of the expansion ioint are performed during Engineering system walkdowns and Operatortours.

Additionally, the expansion joints are periodicallyreplaced.

oiior~n-D No dofticincios in operator-training or: foodback aro idontiid.

Increase training and operating Low FENOCprovides PRA information, such as risk-siqnificantinitiating OT-05 experience feedback to improve events, high worth operatoractions and high worth equipment, to operator response. CriterionB various departments, including Operations Training, and presents Already Implemented this information on posters throughoutthe plant.

OT-07 Install secondary side guard pipes Criterion D Steam line breaks are not a significant contributorto CDFor LERF.

The derived benefit would not justify the implementation cost up to the MSIVs. Very Low Benefit required.

Provide operatortraining with Davis-Besse provides PRA information such as risk significant OT-09R PRA-identified high risk important CriterionB initiating events, high worth operatoractions and high worth human actions to be emphasized Already Implemented equipment. This information is provided to various departmentsand in training, is presented on posters throuqhout the plant.

Enclosure L-12-244 Page 40 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Table E.7-2 E-183 - 185 Entire table ER Table E.7-3 E-186 Entire table ER Table E.7-5 E-188 Entire table ER Table E.8-1 E-189 - 190 Entire table Based on the responses to RAIs 3.c and 4.b (see FENOC letter dated June 24, 2011 (ML11180A233), and the revised SAMA Analysis, ER Tables E.7-2, E.7-3, E.7-5 and E.8-1 are replaced in their entirety, to read as shown on the following pages:

Enclosure L-12-244 Page 41 of 49 Table E.7-2: Internal Events Benefit Results for Analysis Case Case Maximum Benefit AC/DC-01 AC/DC-03 AC/DC-14 (DCBattery) (Battery Charger) (GasTurbineGen)

Off-site Annual Dose (rem) 2.12E+00 2.08E+00 1.87E+00 1.78E+00 Off-site Annual Property Loss ($) 3.59E+03 3.53E+03 3.17E+03 3.02E+03 Comparison CDF ---- 1.OE-05 1.0E-05 1.OE-05 Comparison Dose (rem) --- 2.12E+00 2.12E+00 2.12E+00 Comparison Cost ($) ---- 3.59E+03 3.59E+03 3.59E+03 Enhanced CDF --- 9.4E-06 7.8E-06 9.0E-06 Reduction in CDF -- 6.00% 22.00% 10.00%

Reduction in Off-site Dose -- 1.89% 11.79% 16.04%

Immediate Dose Savings (On-site) $810 $49 $178 $81 Long Term Dose Savings (On-site) $3,530 $212 $777 $353 Total Accident Related Occupational $4,340 $260 $955 $434 Exposure (AOE)

Cleanup/Decontamination Savings (On-site) $132,362 $7,942 $29,120 $13,236 Replacement Power Savings (On-site) $133,917 $8,035 $29,462 $13,392 Averted Costs of On-site Property Damage $266,279 $15,977 $58,581 $26,628 (AOSC)

Total On-site Benefit $270,619 $16,237 $59,536 $27,062 Averted Public Exposure (APE) $52,025 $982 $6,135 $8,344 Averted Off-site Damage Savings (AOC) $44,049 $736 $5,153 $6,994 Total Off-site Benefit $96,074 $1,718 $11,288 $15,338 Total Benefit (On-site + Off-site) $366,693 $17,955 $70,824 $42,399

Enclosure L-1 2-244 Page 42 of 49 Table E.7-2: Internal Events Benefit Results for Analysis Case (continued)

Case AC/DC-19 AC/DC-21 ACIDC-25 AC/DC-26 (FireWaterBackup) (RepairBreakers) (DedDCPower) (Generator TDAFW)

Off-site Annual Dose (rem) 2.08E+00 2.11 E+00 2.05E+00 2.05E+00 Off-site Annual Property Loss ($) 3.54E+03 3.58E+03 3.48E+03 3.48E+03 Comparison CDF 1.0E-05 1.OE-05 1.OE-05 1.OE-05 Comparison Dose (rem) 2.12E+00 2.12E+00 2.12E+00 2.12E+00 Comparison Cost ($) 3.59E+03 3.59E+03 3.59E+03 3.59E+03 Enhanced CDF 9.8E-06 9.7E-06 8.5E-06 8.5E-06 Reduction in CDF 2.00% 3.00% 15.00% 15.00%

Reduction in Off-site Dose 1.89% 0.47% 3.30% 3.30%

Immediate Dose Savings (On-site) $16 $24 $121 $121 Long Term Dose Savings (On-site) $71 $106 $529 $529 Total Accident Related Occupational Exposure $87 $130 $651 $651 (AOE)

Cleanup/Decontamination Savings (On-site) $2,647 $3,971 $19,854 $19,854 Replacement Power Savings (On-site) $2,678 $4,018 $20,088 $20,088 Averted Costs of On-site Property Damage $5,326 $7,988 $39,942 $39,942 (AOSC)

Total On-site Benefit $5,412 $8,119 $40,593 $40,593 Averted Public Exposure (APE) $982 $245 $1,718 $1,718 Averted Off-site Damage Savings (AOC) $614 $123 $1,350 $1,350 Total Off-site Benefit $1,595 $368 $3,068 $3,068 Total Benefit (On-site + Off-site) $7,007 $8,487 $43,660 $43,660

Enclosure L-12-244 Page 43 of 49 Table E.7-2: Internal Events Benefit Results for Analysis Case (continued)

Case ACIDC-27 CB-21 CC-01 CC-04 (SBO_DieselTank) (DHR-valves) (HPISystem) (LPIpump)

Off-site Annual Dose (rem) 2.12E+00 2.OOE+00 2.10E+00 2.12E+00 Off-site Annual Property Loss ($) 3.59E+03 3.40E+03 3.58E+03 3.59E+03 Comparison CDF 1.OE-05 1.0E-05 1.OE-05 1.OE-05 Comparison Dose (rem) 2.12E+00 2.12E+00 2.12E+00 2.12E+00 Comparison Cost ($) 3.59E+03 3.59E+03 3.59E4:03 3.59E+03 Enhanced CDF 1.OE-05 1.0E-05 1.0E-05 1.OE-05 Reduction in CDF 0.00% 0.00% 0.00% 0.00%

Reduction in Off-site Dose 0.00% 5.66% 0.94% 0.00%

Immediate Dose Savings (On-site) $0 $0 $0 $0 Long Term Dose Savings (On-site) $0 $0 $0 $0 Total Accident Related Occupational $0 $0 $0 $0 Exposure (AOE)

Cleanup/Decontamination Savings (On-site) $0 $0 $0 $0 Replacement Power Savings (On-site) $0 $0 $0 $0 Averted Costs of On-site Property Damage $0 $0 $0 $0 (AOSC)

Total On-site Benefit $0 $0 $0 $0 Averted Public Exposure (APE) $0 $2,945 $491 $0 Averted Off-site Damage Savings (AOC) $0 $2,331 $123 $0 Total Off-site Benefit $0 $5,276 $614 $0 Total Benefit (On-site + Off-site) $0 $5,276 $614 $0

Enclosure L-12-244 Page 44 of 49 Table E.7-2: Internal Events Benefit Results for Analysis Case (continued)

Case CC-05 CC-19 HV-01 HV-03 (LPIDieselpump) (BWSTto Sump) (Redundant HVAC) (Backup fans)

Off-site Annual Dose (rem) 2.12E+00 2.12E+00 2.11E+00 2.11 E+00 Off-site Annual Property Loss ($) 3.59E+03 3.59E+03 3.59E+03 3.59E+03 Comparison CDF 1.OE-05 1.0E-05 1.0E-05 1.OE-05 Comparison Dose (rem) 2.12E+00 2.12E+00 2.12E+00 2.12E+00 Comparison Cost ($) 3.59E+03 3.59E+03 3.59E+03 3.59E+03 Enhanced CDF 1.OE-05 9.9E-06 1.OE-05 1.OE-05 Reduction in CDF 0.00% 1.00% 0.00% 0.00%

Reduction in Off-site Dose 0.00% 0.00% 0.47% 0.47%

Immediate Dose Savings (On-site) $0 $8 $0 $0 Long Term Dose Savings (On-site) $0 $35 $0 $0 Total Accident Related Occupational $0 $43 $0 $0 Exposure (AOE)

Cleanup/Decontamination Savings (On-site) $0 $1,324 $0 $0 Replacement Power Savings (On-site) $0 $1,339 $0 $0 Averted Costs of On-site Property Damage $0 $2,663 $0 $0 (AOSC)

Total On-site Benefit $0 $2,706 $0 $0 Averted Public Exposure (APE) $0 $0 $245 $245 Averted Off-site Damage Savings (AOC) $0 $0 $0 $0 Total Off-site Benefit $0 $0 $245 $245 Total Benefit (On-site + Off-site) $0 $2,706 $245 $245

Enclosure L-1 2-244 Page 45 of 49 Table E.7-3: Total Benefit Results for Analysis Case Maximum Benefit AC/DC-01 AC/DC-03 AC/DC-14 AC/DC-19 ACIDC-21 (DCBattery) (Battery Charger) (GasTurbineGen) (FireWaterBackup) (RepairBreakers)

Internal Events $366,693 $17,955 $70,824 $42,399 $7,007 $8,487 Fires, Seismic, Other $1,686,788 $82,593 $325,792 $195,037 $32,234 $39,039 Total Benefit $2,053,481 $100,547 $396,617 $237,436 $39,242 $47,525 AC/DC-25 AC/DC-26 ACIDC-27 CB-21 CC-01 (DedDCPower) (Generator TDAFW) (SBO DieselTank) (DHR valves) (HPISystem)

Internal Events $43,660 $43,660 $0 $5,276 $614 Fires, Seismic, Other $200,837 $200,837 $0 $24,270 $2,822 Total Benefit $244,497 $244,497 $0 $29,546 $3,436 CC-04 CC-05 CC-19 HV-01 HV-03 (LPIpump) (LPlDieselpump) (BWST to Sump) (Redundant HVAC) (Backup fans)

Internal Events $0 $0 $2,706 $245 $245 Fires, Seismic, Other $0 $0 $12,448 $1,129 $1,129 Total Benefit $0 $0 $15,155 $1,374 $1,374

Enclosure L-1 2-244 Page 46 of 49 Table E.7-5: Final Results of Cost Benefit Evaluation SAMA 2009 Candidate Modification Estimated Estimate Conclusion ID Benefit Cost AC/DC-01 Provide additional DC battery $100,547 $1,750,000 Not Cost Effective capacity.

Add a portable, diesel-driven AC/DC-03 battery charger to existing DC $396,617 $330,000 Cost Effective system.

AC/DC-14 Install a gas turbine generator. $237,436 $2,000,000 Not Cost Effective AC/DC-19 Use fire water system as a backup source for diesel cooling. $39,242 $700,000 Not Cost Effective AC/DC-21 Develop procedures to repair or $47,525 $100,000 Not Cost Effective replace failed 4kV breakers.

Provide a dedicated DC power system (battery/battery charger)

AC/DC-25 for the TDAFW control valve and $244,497 $2,000,000 Not Cost Effective NNI-X for steam generator level indication.

Provide an alternator/generator AC/DC-26 that would be driven by each $244,497 $2,000,000 Not Cost Effective TDAFW pump.

AC/DC-27 Increase the size of the SBO fuel $0 $550,000 Not Cost Effective oil tank.

Install pressure measurements CB-21 between the two DHR suction valves in the line from the RCS $29,546 $550,000 Not Cost Effective hot leg.

CC-01 Install an independent active or $3,436 $6,500,000 Not Cost Effective passive HPI system.

CC-04 Add a diverse LPI system. $0 $5,500,000 Not Cost Effective Provide capability for alternate CC-OS LPI via diesel-driven fire pump. $0 $6,500,000 Not Cost Effective Provide automatic switchover of HPI and LPI suction from the CC-i9~ BWST to containment sump for $15,155 $1,500,000 Not Cost Effective LOCAs.

HV-01 Provide a redundant train or $i,374 $50,000 Not Cost Effective means of ventilation.

HV-03 Stage backup fans in switchgear $1,374 $400,000 Not Cost Effective rooms.

Enclosure L-1 2-244 Page 47 of 49 Table E.8-1: Final Results of the Sensitivity Cases SAMA Repair Low High On-site On-site 2009 Candidate Case Discount Discount Dose Cleanup Estimated Conclusion ID Rate Case Rate Case Case Case Cost AC/DC-01 $64,551 $152,033 .$69,662 $102,023 $115,372 $1,750,000 Not Cost Effective AC/DC-03 $264,628 $600,596 $276,817 $402,026 $450,974 $330,000 Cost Effective AC/DC-14 $177,442 $361,238 $169,575 $239,895 $262,144 $2,000,000 Not Cost Effective AC/DC-19 $27,243 $59,518 $27,604 $39,734 $44,183 $700,000 Not Cost Effective AC/DC-21 $29,527 $71,774 $32,727 $48,263 $54,938 $100,000 Not Cost Effective AC/DC-25 $154,505 $369,476 $168,897 $248,186 $281,559 $2,000,000 Not Cost Effective AC/DC-26 $154,505 $369,476 $168,897 $248,186 $281,559 $2,000,000 Not Cost Effective AC/DC-27 $0 $0 $0 $0 $0 $550,000 Not Cost Effective CB-21 $29,546 $45,615 $22,616 $29,546 $29,546 $550,000 Not Cost Effective CC-01 $3,436 $5,304 $2,630 $3,436 $3,436 $6,500,000 Not Cost Effective CC-04 $0 $0 $0 $0 $0 $5,500,000 Not Cost Effective CC-05 $0 $0 $0 $0 $0 $6,500,000 Not Cost Effective CC-19 $9,155 $22,864 $10,383 $15,401 $17,625 $1,500,000 Not Cost Effective HV-01 $1,374 $2,122 $1,052 $1,374 $1,374 $50,000 Not Cost Effective HV-03 $1,374 $2,122 $1,052 $1,374 $1,374 $400,000 Not Cost Effective

Enclosure L-12-244 Page 48 of 49 Table E.8-1: Final Results of the Sensitivity Cases (continued)

SAMA Replacement Multiplier Evacuation 9 5 th Percentile 2009 Candidate Power Case Case Speed CDF Estimated Conclusion ID Cost AC/DC-01 $130,750 $143,639 $100,547 $145,794 $1,750,000 Not Cost Effective AC/DC-03 $507,358 $566,596 $396,617 $575,095 $330,000 Cost Effective AC/DC-14 $287,773 $339,195 $237,436 $344,283 $2,000,000 Not Cost Effective AC/DC-1 9 $49,309 $56,060 $39,242 $56,901 $700,000 Not Cost Effective AC/DC-21 $62,626 $67,893 $47,525 $68,912 $100,000 Not Cost Effective AC/DC-25 $320,003 $349,282 $244,497 $354,521 $2,000,000 Not Cost Effective AC/DC-26 $320,003 $349,282 $244,497 $354,521 $2,000,000 Not Cost Effective AC/DC-27 $0 $0 $0 $0 $550,000 Not Cost Effective CB-21 $29,546 $42,209 $29,546 $42,842 $550,000 Not Cost Effective CC-01 $3,436 $4,908 $3,436 $4,982 $6,500,000 Not Cost Effective CC-04 $0 $0 $0 $0 $5,500,000 Not Cost Effective CC-05 $0 $0 $0 $0 $6,500,000 Not Cost Effective CC-19 $20,188 $21,649 $15,155 $21,974 $1,500,000 Not Cost Effective HV-01 $1,374 $1,963 $1,374 $1,993 $50,000 Not Cost Effective HV-03 $1,374 $1,963 $1,374 $1,993 $400,000 Not Cost Effective

Enclosure L-12-244 Page 49 of 49 Affected LRA Section LRA Page No. Affected Paragraph and Sentence ER Section E.11 E-194 New references In response to RAI 3.c, ER Section E.1 1, "References," is revised to include two new references cited in revised ER Section E.4.5, as follows:

39. Nuclear Requlatory Commission, "Requestsfor Additional Information for the Review of the Davis-Besse Nuclear Power Station, Unit 1, License Renewal Application,"Accession Number ML110910566, April 20, 2011.

40. Nuclear Regulatory Commission, Results of Safety/Risk Assessment of Generic Issue 199, "Implicationsof Updated ProbabilisticSeismic Hazard Estimates in Central and Eastern United States on Existing Plants,"

Accession Number ML100270582, September 7, 2010.