View source for BSEP-97-0332, Satisfies Commitment Which Informed Util of Results of Efforts Being Taken to Improve Reliability of Chlorine Detection Sys Re Insp Repts 50-324/96-15 & 50-325/96-15

{{Adams
| number = ML20198E735
| issue date = 08/01/1997
| title = Satisfies Commitment Which Informed Util of Results of Efforts Being Taken to Improve Reliability of Chlorine Detection Sys Re Insp Repts 50-324/96-15 & 50-325/96-15
| author name = Hinnant C
| author affiliation = CAROLINA POWER &amp; LIGHT CO.
| addressee name = 
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000324, 05000325
| license number = 
| contact person = 
| document report number = 50-324-96-15, 50-325-96-15, BSEP-97-0332, BSEP-97-332, NUDOCS 9708080080
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE
| page count = 5
}}

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                      .CP&L Carolina Power & Light Company                                                C. S. Hinnant
                     . PO Box 10429                                                                   Vice President Southport. NC 2B4610429                                                       Brunswick Steam Electric Plant SERIAL: BSEP 97-0332 10 CFR 2.201 AUG 011997 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk -
Washington, D. C. 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS.1 AND 2 DOCKET NOS. 50-325 AND 50-324/ LICENSE NOS. DPR 71 AND DPR 62 NRC INSPECTION REPORT 50 325 & 50-324 I 96-15 SUPPLEMENTAL INFORMATION Gentlemen:
In a {{letter dated|date=February 14, 1997|text=letter dated February 14,1997}}, (Serial: BSEP 97-0070), Carolina Power & Light (CP&L)
Company committed to informing you and your staff of the results of the efforts being taken to improve the, reliability of the Chlorine Detection System at the Brunswick Steam Electric Plant (BSEP).' This letter serves to satisfy that commitment.
To support the objective to resolve the chlorine sensor reliability issues at the BSEP the actions as discussed below have been completed.-
The chlorine detection system test plan has been revised to incorporate a monthly calibration check. This monthly test is performed via Special Procedure OSP-97-006. The test has been successfully performed six times with only one sensor failing to meet                   /
acceptance criteria. This represents a significant improvement over the failure rate that existed prior to implementation of the recent sensor reliability improvements (i.e., with 47 of 48 individual sensors meeting response time test requirements).-                                    /)
A review of alternate Control Building Intake chlorine sensor locations was performed and          -
the sensors have been relocated to a less harsh environment while maintaining a                  ()     /
representative sample of the Control Room complex air supply at the new sensor locations.#g /
Engineering Service Request (ESR) 97-00147 was prepared which compared air flow readings and other factors which would affect sensor life. The ESR determined that a location just behind the air intake filter media was most beneficial. This was based on a
                                  - nearly 10 times reduction in air flow rates in this location as well as the filtered air flow benefit.
9708000000 970801                             *"
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a Document Control Desk BSEP 97-0332/Page 2 An independent laboratory analysis of chlorine sensor failure mode was performed. The CP&L Harris Energy and Environmental Center performed failure analysis on the sensors and determined that the most probable causes of failure are attributed to:
a)      the presence of coastal dirt deposits clogging the sensor membrane b)      tears in the sensor membrane c)      dilution and/or drying of the gel electrolyte d)      buildup of silver chloride deposits on the silver anode.
Each of these failure modes is being addressed under the current action plan. The combination of sensor relocation behind the air filters, lower air flow, and increased test frequency, all serve to improve sensor performance.
An evaluation to determine the benefit of increasing detector gain settings related to improving sensor response time was completei This analysa svas performed under ESR
'        97-00249. The conclusion reached in the analysis is that increased detector gains could be utilized to improve sensor performance without a significant increase in the probability for spurious alarms. Based on the current satisfactory sensor performance as evidenced during monthly testing, the option of increasing sensor gain settings will not be implemented unless deemed necessary based on future test results.
A study was performed to determine whether alternate chlorine detection systems could be installed to provide increased reliability. This study is documented in an engineering evaluation via ESR 97-00148. Gas monitoring systems supplied by 7 vendors were reviewed. None of the alternate systems were considered to have superior performance characteristics aa compared to the currently installed Rosemount Analytical Chlorine Detection system. Factors included in the study include seismic qualification, operational performance data from other nuclear utilities, and technological improvements over the existing installation.
To date, the completion of actions related to improving Chlorine Detection system performance have been successful. This is evident in the successful completion of 47 out of 48 sensor tests in a six month period. Additionally, the actions taken to improve performance address each of the failure modes attributed to degraded sensor performance. Based on the results of these actions, permanent improvements to the Chlorine Detection system reliability have been demonstrated. In addition, chlorine sensor performance trending will continue; additional corrective actions will be implemented as appropriate.
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Document Control Desk -
BSEP 97-0332/Page 3 Please refer any questions regarding this submittal to Mr. Keith Jury, Manager - Regulatory Affairs, at (910) 457-2783.
Sincerely, CB/-
C. S. Hinnant
>                                                              SFT/sft

==Enclosure:==

List of Regulatory Commitments 4

  .....p....
p Document Control Desk '
BSEP 97 0332/Page 4 -
pc (with' enclosures):
U. S. Nuclear Regulatory Commission, Region'll ATTN.: Mr. Luis A. Reyes, Regional Administrator--
Atlanta Federal Center
_61 Forsyth Street, SW, Suite 23T85 Atlanta, GA 30303
                                       .U. S. Nuclear Regulatory Commission ATTN::~ Mr. C. A. Patterson, NRC Senior Resident inspector 8470 River Road Southport, NC 28481 U. S. Nuclear Regulatory Commission ATTN : Mr. David C. Trimble, Jr. (Mail Stop OWFN 14H22) 11555 Rockville Pike-Rockville, MD 20852-2738 L
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ENCLOSURE                                              !!
i LIST OF REGULATORY COMMITMENTS The following table identifies those actions committed to by Carolina Power & Light Company in this document.; Any other actions discussed in the submittal repretent intended or planned '         ,
actions by Carolina Power & Light Company. They are described to the NRC for the NRC's             1 l             Information and are not regulatory commitments. Please notify the Manager-Regulatory Affairs at the Brunswick Nuclear Plant of any questions regarding this document or any asso;Jated -
regulatory commitments.
Commitment                                     Committed date or outage None i
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