2CAN110501, Unit 2, NRC Bulletin 2003-01 - Additional Review
| ML053410404 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/29/2005 |
| From: | James D Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2CAN110501, BL-03-001, GL-04-002 | |
| Download: ML053410404 (2) | |
Text
hEntergy Entergy Operations, Inc.
1448 SR. 333 Russeliville, AR 72802 Tel 501858 5000
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'Qvertiber 29g, 2005 U.S. Nuclear Regulatory Commission Aftn: Document Control Desk.-
Washington, OC 20555-0001 SubjedCt:
I"NRC BuNletii 2003-01 AdditibRaIkeview Arkansas'Nuclear One - Unit 2 PDqpketNo. 5p-368 License.No PF-6 D1ear'Sir or Madam:
On September 30, 2005, the NRC held a public meeting with the Nuclear Energy Institute MCNEI) and industry regarding the pressurized water reactor4PWR) sump blockage generic safety issue (GSI-191). The purpose of the meeting was to review the results of chemical effects head loss tests conducted at the Argonne National Laboratory (ANL) as described in Information Notice (IN) 2005-26, Results of Chemical Effects Head Loss Tests in a Simulated PWR Sump Pool Environment. The ANL test results indicate that a simulated sump pool environment containing phosphate and dissolved calcium can rapidly produce a calcium phosphate precipitate that, if transported to a fiber bed covered sump screen, produces significant hIead lQs.
During the meeting 6n September 30,. 20Q5, NEI presented industry actions to be undertaken in response to IN 2005-26. Since Arkansas Nuclear One, Unit 2 (ANO-2) utilizes tri-sodium phosphate (TSP) as a sump pool pH buffering agent and calcium-silicate for insiulation, IN 2005-26,was entered into the corrective action program and evaluated for ANO-2 (CR-AN'-9-05-2307).
Entergy has reviewed the compensatory measures taken in response to NRC Bulletin (NRCB) 2003-01, 'Potential Impact of Debris Blockage on Emergency Sump Recirculation qt PWRs, in light of IN 2005-06 and concluded that no additional actions are warranted at this time: The compensatory measures taken in response to NRCB 2003-0 1 are for any situation creating sump screen blockage, regardless of the cause. Certain ANO-2 design features would mitigate possible effects of calcium-silicate/TSP on the sump. The sump is located outside the D-ring (the reinforced concrete cavity which surrounds one of the reactor coolant system (RCS) loops and includes the steam generator, pressurizer, reactor coolant pumps, and RCS piping); therefore, debris must be transported to the sump (60
2CAN1 10501 Page 2 through a torturous path. ANO-2 has very low transport velocities and contains a small amount of calcium-silicate (less than 1 % of the amount assumed in IN 2005-26).
As a part of the resolution of GSI-191 in response to generic letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at PWRs, Entergy is participating in industry testing in order to further characterize the chemical effects on sump screen head loss. As actions taken in response to GL 2004-02 are addressed, chemical effects on sump screen head loss will be resolved.
There are no new commitments contained in this submittal. Should you have any questions concerning this submittal, please contact Ms. Natalie Mosher at (479) 858-4635.
cc:
Dr. Bruce S. Mallett Regional Administrator.__
U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Drew Holland Mail Stop 0-7 D1 Washington, DC 20555-0001