Press Release-III-11-036, NRC Concludes Davis-Besse Nuclear Plant Safe to Restart and Issues Confirmatory Action Letter

Press Release-III-11-036: NRC Concludes Davis-Besse Nuclear Plant Safe to Restart and Issues Confirmatory Action Letter

ML16141B149
Person / Time
Site:	Davis Besse
Issue date:	12/02/2011
From:	Office of Public Affairs Region II
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Category:Press Release
References
Press Release-III-11-036
Download: ML16141B149 (1)

Text

NRC NEWS U.S. NUCLEAR REGULATORY COMMISSION Office of Public Affairs Region III 2443 Warrenville Road Lisle IL 60532 Site: www.nrc.gov Blog: http://public-blog.nrc-gateway.gov No. III-11-036 December, 2 2011

Contact:

Viktoria Mitlyng (630) 829-9662 E-Mail: OPA3.RegionIII@nrc.gov Prema Chandrathil (630) 829-9663 NRC CONCLUDES DAVIS-BESSE NUCLEAR PLANT SAFE TO RESTART AND ISSUES CONFIRMATORY ACTION LETTER The U.S. Nuclear Regulatory Commission has determined that the operators of the Davis-Besse nuclear power plant, FirstEnergy Nuclear Operating Corp. (FENOC) have provided reasonable assurance that the shield building is capable of performing its safety functions and that the utility can proceed with restarting the plant. The NRCs independent assessment evaluated a wide range of information such as technical details ranging from the size of the cracks, the utilitys sampling and testing of the concrete in the building to determine the extent of the cracks, and its structural analysis. The plant is located in Oak Harbor, Ohio about 40 miles southeast of Toledo.

The NRC will hold a public meeting in which FENOC will discuss their technical analysis and explain why the plant is safe to continue to operate with the cracks in the shield building. The meeting will take place in the near future with details to be issued once finalized.

However, the NRC has issued a Confirmatory Action Letter (CAL-attached) to the operator of the plant, FENOC. The CAL details and confirms FENOCs agreement to take certain actions to monitor and ensure the cracks in the shield building continue to not adversely impact safety going forward. The NRC will review and evaluate FENOCs actions in response to the CAL in order to make sure they are thorough and complete.

The FENOC commitments to the NRC include:

- Determine and provide the root cause of the cracks in the shield building, corrective actions, and develop a long-term monitoring program.

- Select multiple areas in the shield building that have no cracks but are adjacent to known cracks to determine whether the area of the cracks has spread.

- Perform additional analysis in known cracked areas to determine whether the width of the cracks has increased.

Even though the NRC has concluded the shield building can perform its safety functions, the NRC will continue to inspect whether the shield building in its current condition meets all design requirements in the plants license.

Failure to meet the commitments in the CAL may result in additional regulatory action if the utility does not provide reasonable assurance that the NRC can rely on the FENOC to meet the NRCs requirements and protect public health and safety.

On Oct. 10 the NRC was informed by FENOC that while conducting work to replace the Davis-Besse reactor vessel head its workers identified cracks in the shield building. The shield building is a 2.5 foot thick reinforced concrete building that surrounds a 1.5 inch thick steel containment vessel that encloses the reactor. The two buildings are separated by a 4.5 foot space.

The NRC will issue an inspection report documenting its review of this issue and the agencys conclusions 45 days after the inspection is complete.

News releases are available through a free listserv subscription or by clicking on the EMAIL UPDATES link on the NRC homepage (www.nrc.gov). E-mail notifications are sent to subscribers when news releases are posted to NRC's website.

UNITED STATES NUCLEAR REGULATORY COMMISSION REGION III 2443 WARRENVILLE ROAD, SUITE 210 LISLE, IL 60532-4352 December 2, 2011 CAL No. 3-11-001 Mr. Barry Allen Site Vice President FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State Route 2, Mail Stop A-DB-3080 Oak Harbor, OH 43449-9760

SUBJECT:

CONFIRMATORY ACTION LETTER - DAVIS-BESSE NUCLEAR POWER STATION

Dear Mr. Allen:

This letter confirms commitments by FirstEnergy Nuclear Operating Company (FENOC) regarding the identification of cracks in the reinforced concrete shield building at the Davis-Besse Nuclear Power Station. During the recent mid-cycle outage to replace the reactor vessel closure head, which began on October 1, 2011, FENOC discovered laminar cracking in the safety-related shield building of the containment system while performing hydrodemolition operations. Based on an evaluation of FENOCs extent of condition and technical analysis of the Davis-Besse shield building laminar cracking, the NRC staff concluded that FENOC provided reasonable assurance that the shield building is capable of performing its safety functions. In order to provide continued long-term confidence, FENOC has agreed in telephone conversations between you, Steven West, and Steven Reynolds, on November 21, 2011; a followup telephone conversation between you and Jamnes Cameron on November 22, 2011; in a FENOC commitment letter dated November 23, 2011 (ML11329A033); and a telephone conversation between you and Steven Reynolds on December 2, 2011, to the following actions (both completed and planned):

1. FENOC will provide the results of the root cause evaluation and corrective actions to the NRC, including any long-term monitoring requirements, by February 28, 2012.

2. FENOC will identify four shield building locations, which were core bored during this evaluation, for examination. These uncracked locations will be directly adjacent to locations that have been confirmed to be cracked. The four uncracked locations, as designated on FENOC drawing C-111A, are:

a. adjacent to a flute shoulder [S9-666.0-12];

b. in a flute area [F4-1-666.0-3];

c. adjacent to Main Steam Line penetration 39 [S7-652.0-6.5]; and

d. adjacent to Main Steam Line penetration 40 [S9-650.0-9].

B. Allen 3. FENOC will examine the four core bore locations from Commitment 2 above with a borescope to verify cracking has not migrated to these core bores located in solid (i.e., uncracked) concrete, within 90 days following plant restart (Mode 2) from the 2011 mid-cycle outage.

4. FENOC will examine the crack interface to identify any changes by performing a core bore in a known crack area within the Main Steam Line Room, within 90 days following plant restart (Mode 2) from the October 2011 mid-cycle outage.

5. FENOC will identify two additional shield building locations, which were core bored during this evaluation, for examination. These uncracked locations will be directly adjacent to locations that have been confirmed to be cracked. The two uncracked locations, as designated on FENOC drawing C-111A, are:

a. in a flute area [F5-777.0-4]; and

b. adjacent to a flute shoulder [S2-783.5-4.0].

6. FENOC will examine the four core bore locations from Commitment 2 along with the two core bore locations from Commitment 5 with a borescope to verify cracking has not migrated to these core bores located in solid (i.e., uncracked) concrete, during the seventeenth refueling outage currently scheduled to commence in 2012.

7. FENOC will examine the crack interface to identify any changes by examining either existing core bore locations with known cracks, or by performing a core bore in a similar area:

a. adjacent to a flute shoulder [S9-666.0-11];

b. near the top of the shield building [S9-785-22.5]; and

c. adjacent to Main Steam Line penetration [core bore from Commitment 4].

during the seventeenth refueling outage currently scheduled to commence in 2012.

Pursuant to Section 182 of the Atomic Energy Act, 42 U.S.C. 2232, you are required to:

1) Notify me immediately if your understanding differs from that set forth above;

2) Notify me if for any reason you cannot complete the actions and commitments within the specified schedule and advise me in writing of your modified schedule in advance of the change; and

3) Notify me in writing when you have completed the actions and commitments addressed in this Confirmatory Action Letter.

Issuance of this Confirmatory Action Letter does not preclude issuance of an Order formalizing the above commitments or requiring other actions on the part of FENOC, nor does it

NRC NEWS U.S. NUCLEAR REGULATORY COMMISSION Office of Public Affairs Region III 2443 Warrenville Road Lisle IL 60532 Site: www.nrc.gov Blog: http://public-blog.nrc-gateway.gov No. III-11-036 December, 2 2011

Contact:

Viktoria Mitlyng (630) 829-9662 E-Mail: OPA3.RegionIII@nrc.gov Prema Chandrathil (630) 829-9663 NRC CONCLUDES DAVIS-BESSE NUCLEAR PLANT SAFE TO RESTART AND ISSUES CONFIRMATORY ACTION LETTER The U.S. Nuclear Regulatory Commission has determined that the operators of the Davis-Besse nuclear power plant, FirstEnergy Nuclear Operating Corp. (FENOC) have provided reasonable assurance that the shield building is capable of performing its safety functions and that the utility can proceed with restarting the plant. The NRCs independent assessment evaluated a wide range of information such as technical details ranging from the size of the cracks, the utilitys sampling and testing of the concrete in the building to determine the extent of the cracks, and its structural analysis. The plant is located in Oak Harbor, Ohio about 40 miles southeast of Toledo.

The NRC will hold a public meeting in which FENOC will discuss their technical analysis and explain why the plant is safe to continue to operate with the cracks in the shield building. The meeting will take place in the near future with details to be issued once finalized.

However, the NRC has issued a Confirmatory Action Letter (CAL-attached) to the operator of the plant, FENOC. The CAL details and confirms FENOCs agreement to take certain actions to monitor and ensure the cracks in the shield building continue to not adversely impact safety going forward. The NRC will review and evaluate FENOCs actions in response to the CAL in order to make sure they are thorough and complete.

The FENOC commitments to the NRC include:

- Determine and provide the root cause of the cracks in the shield building, corrective actions, and develop a long-term monitoring program.

- Select multiple areas in the shield building that have no cracks but are adjacent to known cracks to determine whether the area of the cracks has spread.

- Perform additional analysis in known cracked areas to determine whether the width of the cracks has increased.

Even though the NRC has concluded the shield building can perform its safety functions, the NRC will continue to inspect whether the shield building in its current condition meets all design requirements in the plants license.

Failure to meet the commitments in the CAL may result in additional regulatory action if the utility does not provide reasonable assurance that the NRC can rely on the FENOC to meet the NRCs requirements and protect public health and safety.

On Oct. 10 the NRC was informed by FENOC that while conducting work to replace the Davis-Besse reactor vessel head its workers identified cracks in the shield building. The shield building is a 2.5 foot thick reinforced concrete building that surrounds a 1.5 inch thick steel containment vessel that encloses the reactor. The two buildings are separated by a 4.5 foot space.

The NRC will issue an inspection report documenting its review of this issue and the agencys conclusions 45 days after the inspection is complete.

News releases are available through a free listserv subscription or by clicking on the EMAIL UPDATES link on the NRC homepage (www.nrc.gov). E-mail notifications are sent to subscribers when news releases are posted to NRC's website.

UNITED STATES NUCLEAR REGULATORY COMMISSION REGION III 2443 WARRENVILLE ROAD, SUITE 210 LISLE, IL 60532-4352 December 2, 2011 CAL No. 3-11-001 Mr. Barry Allen Site Vice President FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State Route 2, Mail Stop A-DB-3080 Oak Harbor, OH 43449-9760

SUBJECT:

CONFIRMATORY ACTION LETTER - DAVIS-BESSE NUCLEAR POWER STATION

Dear Mr. Allen:

This letter confirms commitments by FirstEnergy Nuclear Operating Company (FENOC) regarding the identification of cracks in the reinforced concrete shield building at the Davis-Besse Nuclear Power Station. During the recent mid-cycle outage to replace the reactor vessel closure head, which began on October 1, 2011, FENOC discovered laminar cracking in the safety-related shield building of the containment system while performing hydrodemolition operations. Based on an evaluation of FENOCs extent of condition and technical analysis of the Davis-Besse shield building laminar cracking, the NRC staff concluded that FENOC provided reasonable assurance that the shield building is capable of performing its safety functions. In order to provide continued long-term confidence, FENOC has agreed in telephone conversations between you, Steven West, and Steven Reynolds, on November 21, 2011; a followup telephone conversation between you and Jamnes Cameron on November 22, 2011; in a FENOC commitment letter dated November 23, 2011 (ML11329A033); and a telephone conversation between you and Steven Reynolds on December 2, 2011, to the following actions (both completed and planned):

1. FENOC will provide the results of the root cause evaluation and corrective actions to the NRC, including any long-term monitoring requirements, by February 28, 2012.

2. FENOC will identify four shield building locations, which were core bored during this evaluation, for examination. These uncracked locations will be directly adjacent to locations that have been confirmed to be cracked. The four uncracked locations, as designated on FENOC drawing C-111A, are:

a. adjacent to a flute shoulder [S9-666.0-12];

b. in a flute area [F4-1-666.0-3];

c. adjacent to Main Steam Line penetration 39 [S7-652.0-6.5]; and

d. adjacent to Main Steam Line penetration 40 [S9-650.0-9].

B. Allen 3. FENOC will examine the four core bore locations from Commitment 2 above with a borescope to verify cracking has not migrated to these core bores located in solid (i.e., uncracked) concrete, within 90 days following plant restart (Mode 2) from the 2011 mid-cycle outage.

4. FENOC will examine the crack interface to identify any changes by performing a core bore in a known crack area within the Main Steam Line Room, within 90 days following plant restart (Mode 2) from the October 2011 mid-cycle outage.

5. FENOC will identify two additional shield building locations, which were core bored during this evaluation, for examination. These uncracked locations will be directly adjacent to locations that have been confirmed to be cracked. The two uncracked locations, as designated on FENOC drawing C-111A, are:

a. in a flute area [F5-777.0-4]; and

b. adjacent to a flute shoulder [S2-783.5-4.0].

6. FENOC will examine the four core bore locations from Commitment 2 along with the two core bore locations from Commitment 5 with a borescope to verify cracking has not migrated to these core bores located in solid (i.e., uncracked) concrete, during the seventeenth refueling outage currently scheduled to commence in 2012.

7. FENOC will examine the crack interface to identify any changes by examining either existing core bore locations with known cracks, or by performing a core bore in a similar area:

a. adjacent to a flute shoulder [S9-666.0-11];

b. near the top of the shield building [S9-785-22.5]; and

c. adjacent to Main Steam Line penetration [core bore from Commitment 4].

during the seventeenth refueling outage currently scheduled to commence in 2012.

Pursuant to Section 182 of the Atomic Energy Act, 42 U.S.C. 2232, you are required to:

1) Notify me immediately if your understanding differs from that set forth above;

2) Notify me if for any reason you cannot complete the actions and commitments within the specified schedule and advise me in writing of your modified schedule in advance of the change; and

3) Notify me in writing when you have completed the actions and commitments addressed in this Confirmatory Action Letter.

Issuance of this Confirmatory Action Letter does not preclude issuance of an Order formalizing the above commitments or requiring other actions on the part of FENOC, nor does it