January 27, 2009 

EA-08-272 

Mr. Michael D. Wadley 

Site Vice President 

Prairie Island Nuclear Generating Plant 

Northern States Power Company-Minnesota 

1717 Wakonade Drive East 

Welch, MN 55089 

SUBJECT: FINAL SIGNIFICANCE DETERMINATION FOR A WHITE FINDING AND 

NOTICE OF VIOLATION; NRC INSPECTION REPORT NO. 05000282/2008008; 

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 1 

Dear Mr. Wadley: 

The purpose of this letter is to provide you the final results of our significance determination of 

the preliminary White finding identified in the subject inspection report. The inspection finding 

was assessed using the Significance Determination Process and was preliminarily 

characterized as White, a finding with low to moderate increased importance to safety that may 

require additional U.S. Nuclear Regulatory Commission (NRC) inspections. This White finding 

is associated with your staff’s failure to adequately control the position of a normally open valve 

used to isolate the 11 turbine-driven auxiliary feedwater pump’s (TDAFWP) discharge pressure 

switch. The valve was left closed, causing the 11 TDAFWP to fail to operate as required 

subsequent to a Unit 1 reactor trip which occurred on July 31, 2008. The pump was rendered 

inoperable for a time period that significantly exceeded the 72 hour time limit allowed by the 

Technical Specifications. 

In a letter dated December 5, 2008, your staff provided information stating your staff’s position 

on this issue. Your staff acknowledged the violation, described the issue, the root cause, the 

corrective actions taken, and your assessment of the risk significance. Your staff performed a 

human reliability analysis for operator recovery of 11 TDAFWP discharge pressure trip remotely 

from control room and locally after the control room is abandoned. The analysis included 

detailed modeling and assessment of risk contribution from a postulated fire and concluded that 

the issue was of very low risk significance. 

After considering the information developed during the inspection and the additional information 

you provided in your letter dated December 5, 2008, the NRC has concluded that the inspection 

finding is appropriately characterized as White, a finding with low to moderate increased 

importance to safety that may require additional NRC inspections. Enclosure 1 to the letter 

provides a detailed description of the NRC final risk significance determination with the issue. 

You have 30 calendar days from the date of this letter to appeal the staff’s determination of 

significance for the identified White finding. Such appeals will be considered to have merit only 

if they meet the criteria given in the NRC Inspection Manual Chapter 0609, Attachment 2. 
M. Wadley -2- 

The NRC has also determined that the Unit 1 TDAFWP inoperability is a violation of Technical 

Specification 3.7.5, as cited in the enclosed Notice of Violation (Notice). The circumstances 

surrounding the violation are described in detail in the subject inspection report. 

In accordance with the NRC Enforcement Policy, the Notice is considered escalated 

enforcement action because it is associated with a White finding. 

The NRC has concluded that the information regarding the reason for the violation, the 

corrective actions taken, and the date when full compliance was achieved is already 

adequately addressed on the docket in the subject inspection report and your letter dated 

December 5, 2008. Therefore, you are not required to respond to this letter unless the 

description therein does not accurately reflect your corrective actions or your position. 

Because plant performance for this issue has been determined to be in the regulatory response 

band, we will use the NRC Action Matrix to determine the most appropriate NRC response for 

this event. We will notify you, by separate correspondence, of that determination. 

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its 

enclosures, and your response, if you choose to provide one, will be made available electronically 

for public inspection in the NRC Public Document Room or from the NRC’s document system 

(ADAMS), accessible from the NRC Web site at http://www.nrc.gov/readingrm/adams.html. To 

the extent possible, your response should not include any personal privacy, proprietary, or 

safeguards information so that it can be made available to the public without redaction. 

Sincerely, 

/RA/

James L. Caldwell 

Regional Administrator 

Docket No. 50-282 

License No. DPR-42 

Enclosures: 

1. Final Significance Determination 

2. Notice of Violation 

cc w/encl: D. Koehl, Chief Nuclear Officer 

 Regulatory Affairs Manager 

 P. Glass, Assistant General Counsel 

 Nuclear Asset Manager 

 J. Stine, State Liaison Officer, Minnesota Department of Health 

 Tribal Council, Prairie Island Indian Community 

 Administrator, Goodhue County Courthouse 

 Commissioner, Minnesota Department of Commerce 

 Manager, Environmental Protection Division 

 Office of the Attorney General of Minnesota 

 Emergency Preparedness Coordinator, Dakota 

 County Law Enforcement Center
M. Wadley -2- 

The NRC has also determined that the Unit 1 TDAFWP inoperability is a violation of Technical 

Specification 3.7.5, as cited in the enclosed Notice of Violation (Notice). The circumstances surrounding 

the violation are described in detail in the subject inspection report. In accordance with the NRC 

Enforcement Policy, the Notice is considered escalated enforcement action because it is associated with 

a White finding. 

The NRC has concluded that the information regarding the reason for the violation, the corrective actions 

taken, and the date when full compliance was achieved is already adequately addressed on the docket in 

the subject inspection report and your letter dated December 5, 2008. Therefore, you are not required to 

respond to this letter unless the description therein does not accurately reflect your corrective actions or 

your position. 

Because plant performance for this issue has been determined to be in the regulatory response band, we 

will use the NRC Action Matrix to determine the most appropriate NRC response for this event. We will 

notify you, by separate correspondence, of that determination. 

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its enclosures, 

and your response, if you choose to provide one, will be made available electronically for public 

inspection in the NRC Public Document Room or from the NRC’s document system (ADAMS), accessible 

from the NRC Web site at http://www.nrc.gov/readingrm/adams.html. To the extent possible, your 

response should not include any personal privacy, proprietary, or safeguards information so that it can be 

made available to the public without redaction. 

Sincerely, 

/RA/

James L. Caldwell 

Regional Administrator 

Docket No. 50-282 

License No. DPR-42 

Enclosures: 1. Final Significance Determination 

 2. Notice of Violation 

cc w/encl: D. Koehl, Chief Nuclear Officer 

 Regulatory Affairs Manager 

 P. Glass, Assistant General Counsel 

 Nuclear Asset Manager 

 J. Stine, State Liaison Officer, Minnesota Department of Health 

 Tribal Council, Prairie Island Indian Community 

 Administrator, Goodhue County Courthouse 

 Commissioner, Minnesota Department of Commerce 

 Manager, Environmental Protection Division 

 Office of the Attorney General of Minnesota 

 Emergency Preparedness Coordinator, Dakota 

 County Law Enforcement Center 

DISTRIBUTION: 

See next page 

DOCUMENT NAME: G:\EICS\ENFORCEMENT\Enforcement Cases 2008\EA-08-272 Prairie Island Mispositioned Valve\EA-08-272 

Prairie Island Draft final action WHITE NOV.doc 

; Publicly Available □Non-Publicly Available □Sensitive ; Non-Sensitive 

OFFICE RIII RIII RIII RIII D: OE D: NRR RIII RIII 

NAME Gryglak Lougheed Lerch for 

Giessner 

Pederson Hilton for 

Carpenter1

Cunningham2 O’Brien Caldwell 

DATE 01/22/09 01/22/09 01/22/09 01/23/09 01/21/09 01/21/09 01/23/09 01/26/09 

OFFICIAL RECORD COPY

 

1 OE concurrence received via e-mail from G. Bowman on January 21, 2009.

2 NRR concurrence received via e-mail from G. Bowman on January 21, 2009. 
Letter to Michael D. Wadley from James L. Caldwell dated January 27, 2009 

SUBJECT: FINAL SIGNIFICANCE DETERMINATION FOR A WHITE FINDING AND NOTICE OF 

VIOLATION; NRC INSPECTION REPORT NO. 05000282/2008008; PRAIRIE ISLAND 

NUCLEAR GENERATING PLANT, UNIT 1 

DISTRIBUTION: 

ADAMS (PARS) 

RidsSecyMailCenter Resource 

OCA 

Bill Borchardt, EDO 

Bruce Mallett, DEDR 

Cynthia Carpenter, OE 

Nick Hilton, OE 

Gregory Bowman, OE 

James Caldwell, RIII 

Mark Satorius, RIII 

Catherine Marco, OGC 

Marvin Itzkowitz, OGC 

Eric Leeds, NRR 

Bruce Boger, NRR 

Daniel Holody, RI 

Carolyn Evans, RII 

Kenneth OBrien, RIII 

William Jones, RIV 

MaryAnn Ashley, NRR 

Karla Stoedter, RIII 

Paul Zurawski, RIII 

Eliot Brenner, OPA 

Hubert Bell, OIG 

Guy Caputo, OI 

Mona Williams, OCFO 

John Giessner, RIII 

Scott Thomas, RIII 

Laura Kozak, RIII 

Diana Betancourt, RIII 

Viktoria Mitlyng, OPA RIII 

Prema Chandrathil, OPA RIII 

Allan Barker, RIII 

Paul Pelke, RIII 

Patricia Lougheed, RIII 

Magdalena Gryglak, RIII 

RidsNrrDirsIrib 

OEMAIL Resource 

OEWEB Resource 
Enclosure 1 

FINAL SIGNIFICANCE DETERMINATION 

In NRC Inspection Report No. 05000282/2008008; 05000306/2008008, an apparent violation 

of Technical Specification (TS) 3.7.5 was identified associated with the inoperability of the 

11 turbine-driven auxiliary feedwater pump (TDAFWP) for approximately 138 days, a time 

period which significantly exceeded the 72 hour time limit allowed by the TS. Based upon 

the NRC’s consideration of information provided by the licensee in a letter dated 

December 5, 2008, the NRC has determined that the preliminary finding is appropriately 

characterized as White, a finding with low to moderate increased importance to safety that 

may require additional NRC inspections. 

Apparent Violation: (AV) 05000282/2008001-01 

Final Significance: White 

The NRC reviewed the information provided in the letter dated December 5, 2008, and 

concluded that it was generally acceptable for use in the final significance determination with 

several exceptions as detailed below. 

With respect to the analysis of control room fires that could result in control room abandonment, 

the NRC disagreed with the results of the licensee’s evaluation of the time available for fire 

suppression activities before intolerable environmental conditions would develop. Specifically, 

the NRC found that the licensee’s estimate relied on the assumption that the control room 

ventilation system would continue to operate during a fire. The NRC’s review of the control 

room ventilation system operation and fire response procedures indicated that the system may 

isolate during a fire or that operators may secure the system as directed by procedures. 

Additionally, the licensee did not consider the potential for smoke to obscure the operators’ 

vision during a control room fire. As a result, the NRC concluded that the time available for fire 

suppression could be shorter than 25 minutes and used a best estimate of 15 minutes in the 

final Significance Determination Process (SDP) evaluation. The NRC also disagreed with the 

licensee’s consideration of both “prompt suppression” of a fire by the control room operators 

and suppression by the fire brigade. The guidance of NUREG/CR-6850 indicates that “prompt 

suppression” should only be considered for hot work fire scenarios where a fire watch is 

present.

Regarding the analysis of main control board fires that affect redundant trains of equipment and 

require control room abandonment, the NRC found that the licensee did not consider a fire 

affecting the Unit 2 main control board. The NRC determined that Procedure F5, Appendix B, 

“Control Room Evacuation (Fire),” would require control room abandonment for both units if 

either main control board was significantly affected by a fire. As a result, the NRC determined 

that the fire frequency for this scenario should have been multiplied by two to reflect a fire in 

either unit’s main control board. 

The relay room fire analysis assumed that the Unit 2 motor driven auxiliary feedwater (AFW) 

pump could be cross-tied to provide for decay heat removal. The NRC determined that the 

licensee’s control room evacuation procedure did not specify the use of the cross-tie and that 
2 Enclosure 1 

other operating procedures would have to be modified to use the cross-tie. Additionally, the 

licensee’s operations training program specifies the use of Procedure F5 for control room 

abandonment situations rather than emergency or other operating procedures. The NRC 

concluded that the successful use of the AFW cross-tie was unlikely and should not be credited 

in the final significance determination. 

Consistent with the NRC’s preliminary SDP evaluation, the licensee’s analysis considered the 

possibility of recovering the 11 TDAFWP. The NRC agreed that the estimate of the time 

available to recover the pump was reasonable. However, the NRC found the timeline for the 

operator actions for recovery in control room abandonment scenarios to be overly optimistic. As 

an example, the licensee did not consider the time impact of required actions, such as 

announcements and notifications to personnel, on the control room abandonment which would 

cause delays in arriving at the Hot Shutdown Panel. Also, the timeline was largely based on 

existing estimates of individual tasks, rather than a walk-through demonstration of the current 

procedure. The NRC concluded that individual task time estimates may not adequately capture 

the overall timeline of the coordinated crew response required in a control room abandonment 

fire scenario. Because of concerns with the timing analysis, the NRC determined that it was not 

appropriate to consider that the operator had “extra” time available for recovery. In the final 

significance determination, the NRC used a modified version of the licensee’s human error 

probability (HEP) by using the estimated HEP without recovery. 

The NRC developed several other concerns with the risk analysis but did not consider the 

quantitative impacts on the risk estimate due to the complexity involved and the low likelihood 

that rigorous evaluation would cause the risk of the finding to be greater than low to moderate 

safety significance. The NRC noted that the licensee’s evaluation credited the automatic fire 

suppression system in the relay room fire analysis without evaluating whether the system would 

actuate for those specific scenarios. In three scenarios, the time to target damage was 

estimated at 6 minutes or less. The assumption that the system would automatically actuate in 

these scenarios may not be appropriate given the short time to target damage. 

The NRC also noted that the licensee did not consider any dependency between the failure of 

the automatic suppression system and the failure of manual fire suppression which could be 

particularly important in the short time to damage fire scenarios. Lastly, the horizontal flame 

spread rate used in the analysis to determine the times to target damage was not adequately 

justified. 

In summary, the NRC considered the licensee’s information in the final significance 

determination with the exceptions noted above, where modified inputs were used in the 

quantitative analysis. The NRC analysis using the licensee’s information, with the modifications 

described above, resulted in a change in core damage frequency of approximately 2E-6/yr. The 

dominant core damage sequence was a control room fire which results in abandonment of the 

control room, followed by the failure of the 11 TDAFWP, and a failure of the operator to recover 

the pump. The dominant sequence was consistent with both the NRC’s preliminary significance 

determination and with the licensee’s risk evaluation. 
Enclosure 2 

NOTICE OF VIOLATION 

Northern States Power Company - Minnesota Docket No. 50-282 

Prairie Island Nuclear Generating Plant, Unit 1 License No. DPR-42 

EA-08-272 

During an NRC inspection conducted from August 4 through October 6, 2008, a violation of 

NRC requirements was identified. In accordance with the NRC Enforcement Policy, the 

violation is listed below: 

Technical Specification 3.7.5 requires, in part, that two auxiliary feedwater trains be 

operable during plant operation in Modes 1, 2, and 3. 

Technical Specification 3.7.5.B requires, in part, that if one auxiliary feedwater train is 

inoperable in Modes 1, 2, and 3, the affected train shall be restored to operable status 

within 72 hours or the plant placed in Mode 3 within 6 hours and Mode 4 within 12 hours. 

Contrary to the above, from March 15, 2008 to July 31, 2008, the 11 turbine-driven 

auxiliary feedwater pump was inoperable for a period of greater than 72 hours and the 

licensee did not restore the pump to operable status or place the plant into Mode 3 or 

Mode 4 within the required time periods. Specifically, the pump was inoperable for 

approximately 138 days due to the discharge low pressure switch being isolated and no 

actions were taken to restore the pump to operable status or to place the plant in Mode 3 

or 4. 

This violation is associated with a White Significance Determination Process finding. 

The NRC has concluded that information regarding the reason for the violation, the corrective 

actions taken and planned to correct the violation and prevent recurrence, and the date when 

full compliance was achieved, is already adequately addressed on the docket in Inspection 

Report No. 05000282/2008008, and your letter dated December 5, 2008. However, you are 

required to submit a written statement or explanation pursuant to 10 CFR 2.201 if the 

description therein does not accurately reflect your corrective actions or your position. 

In that case, or if you choose to respond, clearly mark your response as a "Reply to a 

Notice of Violation," EA-08-272, and send it to the U.S. Nuclear Regulatory Commission, 

ATTN: Document Control Desk, Washington, DC 20555-0001 with a copy to the Regional 

Administrator, Region III, and a copy to the NRC Resident Inspector at the Prairie Island 

Nuclear Generating Plant, within 30 days of the date of the letter transmitting this Notice of 

Violation (Notice). 

If you contest this enforcement action, you should also provide a copy of your response, with 

the basis for your denial, to the Director, Office of Enforcement, United States Nuclear 

Regulatory Commission, Washington, DC 20555-0001. 
Enclosure 2 

Notice of Violation -2- 

If you choose to respond, your response will be made available electronically for public 

inspection in the NRC Public Document Room or from the NRC=s document system (ADAMS), 

accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html. Therefore, to 

the extent possible, the response should not include any personal privacy, proprietary, or 

safeguards information so that it can be made available to the public without redaction. 

In accordance with 10 CFR 19.11, you may be required to post this Notice within two working 

days. 

Dated this 27th day of January 2009