PWRRM January 2009

pwrrm@retaqs.com

6 participants
3 discussions

Re: [Pwrrm] Reactivity anomaly calculation
by paul_gurney＠fpl.com 22 Jan '09

22 Jan '09

Answers from Seabrook 1) Surry uses IFBA fuel. Core modeling is performed using the CASMO-4/SIMULATE-3 computer codes. In making comparisons between measured and predicted boron concentrations (corrected for B-10, power, xenon, rod position, and RCS temperature), we notice a tendency to for the core models to underpredict the measured critical boron between 2 and 4 GWD/MTU by 10-20 ppm (about 80-160 pcm) more than at other times in life (such as at BOC equilibrium xenon or between MOC and EOC). Have you observed this tendency at your plant? Core design is with ANC and we use IFBA. We always see measured boron above predicted for most of core life. Some attributed to B-10 depletion and some to modeling. 2) For the monthly reactivity anomaly calculation, is a B-10 corrected value used to meet Tech Spec requirements, or is the non-corrected value used? (Surry uses the non-corrected value) We correct for B-10 depletion in the monthly reactivity balance surveillance, shutdown margin curves and ECPs. 3) Does your anomaly procedure have a threshold (such as +/-500 pcm) at which the anomaly would be documented in the corrective action system? No threshold. Although if we saw something out of the ordinary we would propbably address it in CAPS. Paul Gurney 603-773-7776

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PWRRM Request for B-10 Information(in preparation for INPO)
by Charlene.N.Chotalal＠dom.com 22 Jan '09

22 Jan '09

Greetings, INPO will be coming to Surry Power Station in a week and I would like to ask two questions to the group. In your response, you do not need to reply to everyone. I will be gathering the information and putting it into one excel file. If you would like a copy, please let me know. 1) This question has been asked already, but we did not get many responses. Core modeling is performed using the CASMO-4/SIMULATE-3 computer codes. Our most recent Reactivity Anomaly calculation(the comparison between measured and predicted boron concentrations) gave us an uncorrected value of about 750pcm. This is quite close to our tech spec limit of 1000pcm. If we corrected for B-10, the anomaly value would be closer to 300pcm. Currently we use the uncorrected value in our comparison to the predicted model. What is your typical maximum offset between your measured and predicted Reactivity Anomaly? Is this with or without B-10 depletion? Do you use your B-10 depletion value for the tech spec surveillance? 2) This question is regarding Estimated critical conditions/position. What is the pcm delta typically observed at your plant between the predicted critical conditions and the actual conditions? If a delta is observed, does the predicted critical calculation account for B-10 depletion? At what point (i.e. >100 pcm delta) would Operations or Reactor Engineering write a condition report? Charlene Chotalal Lead Reactor Engineer Surry Power Station Work: (757)-365-2819 Did you know..... the East Japan Railway Company (JR-East), as part of research aimed at developing more environmentally friendly train stations, is testing an experimental system that produces electricity as people pass through ticket gates. CONFIDENTIALITY NOTICE: This electronic message contains information which may be legally confidential and/or privileged and does not in any case represent a firm ENERGY COMMODITY bid or offer relating thereto which binds the sender without an additional express written confirmation to that effect. The information is intended solely for the individual or entity named above and access by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution, or use of the contents of this information is prohibited and may be unlawful. If you have received this electronic transmission in error, please reply immediately to the sender that you have received the message in error, and delete it. Thank you.

3 2

Reactivity anomaly calculation
by Adina.K.Lafrance＠dom.com 22 Jan '09

22 Jan '09

1) Surry uses IFBA fuel. Core modeling is performed using the CASMO-4/SIMULATE-3 computer codes. In making comparisons between measured and predicted boron concentrations (corrected for B-10, power, xenon, rod position, and RCS temperature), we notice a tendency to for the core models to underpredict the measured critical boron between 2 and 4 GWD/MTU by 10-20 ppm (about 80-160 pcm) more than at other times in life (such as at BOC equilibrium xenon or between MOC and EOC). Have you observed this tendency at your plant? 2) For the monthly reactivity anomaly calculation, is a B-10 corrected value used to meet Tech Spec requirements, or is the non-corrected value used? (Surry uses the non-corrected value) 3) Does your anomaly procedure have a threshold (such as +/-500 pcm) at which the anomaly would be documented in the corrective action system? Adina LaFrance It's a healthy thing now and then to hang a question mark on the things you have long taken for granted. -Betrand Russell Nuclear Analysis & Fuel Reactor Engineer Surry Power Station Email: Adina.K.LaFrance(a)Dom.com Phone: 757-365-2658 Pager #: 4290 CONFIDENTIALITY NOTICE: This electronic message contains information which may be legally confidential and/or privileged and does not in any case represent a firm ENERGY COMMODITY bid or offer relating thereto which binds the sender without an additional express written confirmation to that effect. The information is intended solely for the individual or entity named above and access by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution, or use of the contents of this information is prohibited and may be unlawful. If you have received this electronic transmission in error, please reply immediately to the sender that you have received the message in error, and delete it. Thank you.

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PWRRM January 2009