PWRRM September 2009

pwrrm@retaqs.com

11 participants
4 discussions

Use of Spreadsheets for Surveillances
by Gore, Duane 03 May '10

03 May '10

We at STP use spreadsheets to perform surveillance calculations. The results are then independently verified by a second engineer using an independently generated spreadsheet. Neither spreadsheet has been formally verified per our station Software Quality Assurance procedure. In cases where the results are used without further verification, we do properly QA the spreadsheets (usually in the cases where other groups use the spreadsheets). Our QA department is of the opinion that at least one of these spreadsheets used for surveillances must by fully verified and documented per our station Software Quality Assurance procedure. It would help my case if I could cite other Rae's practices with regards to the use of spreadsheets. What is the practice at your plant? Thank you, Duane Gore Supervisor, Reactor Engineering STPNOC (361) 972-8909

8 8

Reactivity Management
by SCHAWE, BARTON P 16 Oct '09

16 Oct '09

>From INPO 06-006: Repetitive tasks controlled by procedures or work documents are distinctively marked to highlight those steps or sections that will impact reactivity. Can anyone provide an example of how they meet this characteristic of the INPO guideline? FCS generally has a "Precaution and Limitation" at the beginning of a procedure, or a "Caution" prior to a step that affects reactivity. But, this is not always consistent. Barton P. Schawe, P.E. Principal Reactor Engineer Omaha Public Power District Tel: 402-533-7211 email: bschawe(a)oppd.com<mailto:bschawe@oppd.com> This transmission contains information which may be confidential and which may also be privileged. It is intended for the named addressee only. Unless you are the named addressee, or authorized to receive it on behalf of the addressee, you may not copy or use it, or disclose it to anyone else. If you have received this transmission in error please contact the sender. Thank you for your cooperation. This e-mail contains Omaha Public Power District's confidential and proprietary information and is for use only by the intended recipient. Unless explicitly stated otherwise, this e-mail is not a contract offer, amendment, nor acceptance. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.

5 4

RCS time to boil
by ddgoff＠aep.com 08 Oct '09

08 Oct '09

I'd like to know how others are handling decay heat projections. Our Ops procedures here at Cook were recently changed to link containment closure time requirements to RCS time-to-boil projections. Our operators are asking for more realistic, less conservative (.i.e., longer) times. First, the source term. We are still using the old Branch Technical Position paper ASB 9-2 that was part of earlier NUREG-0800 revisions. The latest NUREG-0800 now references ANSI/ANS-5.1-2005 for calculating decay heat. We would start using that; however, we cannot find a defensible value for R ("atoms of U-239 produced per second per fission per second evaluated for the reactor composition at the time of shutdown; the value of R shall be supplied and justified by the user") for the heavy element contribution in section 4. The examples in the appendices use R=0.6. What are you using for decay heat calcs? Second, the sink term. We have no heat transfer modeling of our vessel and RCS. Rather, we make some very conservative assumptions about vessel internal volumes and then credit only the water volume within the vessel for cases when the cavity is not flooded. Now, we know that there is metal and air and concrete as well as natural circulation within the RCS that will act as the decay heat sink. We just can't model all that. How do you model the decay heat sink for time-to-boil calcs? Thanks. David Goff Reactor Engineer Donald C. Cook Nuclear Plant 269-465-5901 x1465 ---------------------------------------------------------------- This e-mail message and all attachments transmitted with it from the Nuclear Generation Group of American Electric Power are for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.

2 1

OE29438 Questions
by Charlene N Chotalal 28 Sep '09

28 Sep '09

Good Afternoon, Attached to this email is a document that contains a Surry OE that was generated by our Corporate personnel regarding source range detector response during Core Onload (Basically, the SRD indication for an elevated count rate would still occur but could be later than expected). If you have not yet read this, please take the time to do so. Once read, please answer the following questions to the best of your ability: Is your plant aware of this? If so, have you done anything to safeguard against a potential core misloading and/or a boron dilution event? At Surry Power Station, during cold shutdown a dilution is prevented by closing the demin water valve. Surry will also be taking a look at our historical source range detector response and come up with a lesser 1/M stop criteria during onload. We will also be providing training to Operations and Fuel Handling so that they are aware of this condition. If you require more information on this OE, please do not hesitate to contact me. __________________________________________________________ Charlene Chotalal Lead Reactor Engineer Surry Power Station Dominion Generation Work: (757)-365-2819 __________________________________________________________ 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.

2 2

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

PWRRM September 2009