ML053480126
| ML053480126 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/05/2005 |
| From: | Lampert M Pilgrim Watch |
| To: | Diaz N NRC/Chairman |
| Shared Package | |
| ML060260038 | List: |
| References | |
| G20050841, LTR-05-0588 | |
| Download: ML053480126 (5) | |
Text
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.P EDO Principal Correspondence Control FROM:
DUE:
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EDO CONTROL: G20050841 DOC DT: 12/05/05 FINAL REPLY:
Mary Lampert Pilgrim Watch TO:
Chairman Diaz FOR SIGNATURE OF :
- GRN CRC NO: 05-0588 DESC:
ROUTING:
Single Loop Operation, Pilgrim NPS DATE: 12/09/05 Reyes Virgilio Kane Silber Dean Cyr/Burns Collins, RI ASSIGNED TO:
NRR CONTACT:
Dyer SPECIAL INSTRUCTIONS OR REMARKS:
For Appropriate Action.
Bei" Iour. sN - I E--ltbG: SECN-w
OFFICE OF THE SECRETARY CORRESPONDENCE CONTROL TICKET Date Printed: Dec 08, 2005 09.56 PAPER NUMBER:
ACTION OFFICE:
LTR-05-0588 EDO LOGGING DATE:
12/08/2005.
AUTHOR:
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SUBJECT:
ACTION:
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LETTER DATE:
ACKNOWLEDGED SPECIAL HANDLING:
Mary Lampert MA Nils Diaz Single loop operation, Pilgrim NPS Appropriate Chairman, Comrs, RF 12/05/2005 No NOTES:
FILE LOCATION:
ADAMS DATE DUE:
DATE SIGNED:
EDO -- G20050841
f F7E Nf WIcki olina - Sinale loon oneration. Pilarim NPS
-1 Page I I From:
To:
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"lampert" <lampert~adelphia.net>
"Nils Diaz" <vmb~nrc.gov>
Monday, December 05, 2005 12:16PM Single loop operation, Pilgrim NPS December 5, 2005 NRC Commission U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Chairman Diaz and Commissioners McGaffigan, Merrifield, Jaczko, Lyons:
RE: Single loop operation, Pilgrim NPS I understand that Pilgrim NPS may receive approval for single loop operations within the month. Further that Pilgrim being allowed to operate in single loop for an indefinite period is a bad idea.
I understand that In the last 20 years Pilgrim had to perform shutdowns 3 or 4 times to repair recirculation pumps.
Single loop, I understand, Is one recirculation pump out of service. Determining core flow while in single loop is somewhat of a best guess process, reverse flow detection equipment Is not installed. Shutting down to fix the equipment is the best, and safest course, and in the best interests of our community and the workers.
I understand that determining core flow is anything but science. For example, in 1988 at Hope Creek PSEG decided to give up on single loop operation and shut down if a recirculation pump failed.
BWRs have two recirculation pumps that force water flow through the reactor core. Since this water boils in the reactor core itself (unlike a PWR), there's a problem with providing equal flow through all fuel bundles. Without the recirculation pumps, the uhottestr fuel bundles would get the least cooling flow
I Ap9le loop operation I
cr Page 2 because the steam produced from boiling tends to slow down flow rates.
The two recirculation pumps essentially provide flow to half the reactor core. When one pump Is shut down, the running pump actually forces flow backwards through the recirculation pump flow equipment on the other side. [The flow through the core stays in the same direction, but the flow through the recirculation pump equipment reverses.] The equipment is calibrated to accurately measure flow rate, but only when water flows through the equipment In the forward direction. During single loop operation (SLO, or SLOW),
you try to subtract the reverse flow from the forward flow to figure out the total flow - a process resembling guessing since the reverse flow value comes from uncalibrated equipment.
The total flow value Is important from a safety perspective in that It is used to calculate margin to limits that protect against fuel damage. Safe reactor operation is a balancing act -- you strive to balance the heat producing from atoms splitting with the heat removed by the water. Obviously, having more precision than a guess is helpful when assuring that balance is maintained.
We do not want guess work. We do not want NRC to approve single loop operations at Pilgrim Nuclear Power Station. Additionally a matter of this seriousness to the safety of our community and workers should never proceed without a full local public hearing wherein the public has the opportunity to present our technical experts to make statements and question both the NRC and licensee.
Thanking you for your attention, I am sincerely, Mary Lampert Pilgrim Watch, Director/ Duxbury Nuclear Advisory Committee, Chair 148 Washington Street Duxbury, MA 02332 Tel 781-934-0389 Email Lampert~adelphia.net CC:
"William Raymondn <WJR@nrc.gov>
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