ML18064A666
| ML18064A666 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/27/1995 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML18064A665 | List: |
| References | |
| NUDOCS 9504030002 | |
| Download: ML18064A666 (2) | |
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WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO MODIFICATION OF POST-ACCIDENT SAMPLING PROCEDURES CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255
1.0 INTRODUCTION
By letter dated February 2, 1995, Consumers Power Company (CPCo) submitted a request for modification of some of the procedures in its post-accident sampling system (PASS).
The modification consists of removing the requirements for measuring reactor coolant pH and monitoring hydrogen concentration in the containment atmosphere. Also, CPCo requested confirmation of its request, documented in a letter dated March 2, 1987, to withdraw its commitment to monitor oxygen concentration in the reactor coolant.
CPCo referenced the Combustion En~ineering Owners Group (CEOG)
Topical Report, CEN-415, Revision 1-A, "Modification of Post Accident Sampling System Requirements," as the basis for its request to remove the requirements discussed above.
The NRC approved the CEOG Topical Report for use in referencing in a Safety Evaluation Report issued on April 12, 1993.
2.0 EVALUATION 2.1 Measurement of Reactor Coolant pH CPCo plans to maintain the in-line pH monitoring system, but without the backup probes.
The analysis for reactor coolant pH could be performed, if desirable, using the in-line pH monitor, but if the in-line monitor were not available, no sump pH analyses would be performed.
This allows reactor coolant pH measurements, but without the possibility of always maintaining the pH monitoring capability. This change would not become effective until the existing method of sump pH control, manual sodium hydroxide injection, has been replaced by a passive trisodium phosphate addition system, which is currently scheduled for installation in the 1995 refueling outage.
In the staff's safety evaluation of the CEOG Topical Report, the NRC stated that monitoring of the sump pH by PASS can be deleted. High reliability for maintaining post-accident pH in the containment sump and lack of a specific requirement to measure its value, makes this monitoring redundant.
Removing the requirement for pH measurement by PASS, as proposed by CPCo, is therefore acceptable.
2.2
~easurement of Containment Hydrogen and Oxygen Concentrations CPCo requested deletion of the requirement for PASS to monitor hydrogen and oxygen concentrations in the containment atmosphere.
Hydrogen concentration is already measured using a safety-grade hydrogen monitor which is required by 9504030002 950317 PDR ADOCK 05000255 P
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Item 11.F.l of NUREG-0737, "Clarification of TMI Action Plan Requirements."
The PASS monitoring is redundant and therefore, not needed.
In addition, the PASS was newer required to have the capability for oxygen monitoring (Item II.B.3 of NIUJIREG-0737}.
Removal of both of these requirements was addressed in the CEOG To,pi cal Report and approved by the NRC.
The licensee request for deletion of hydrogen and oxygen monitoring in the containment atmosphere is, therefore, acceptable.
2.3 Oxygen Analysis of Reactor Coolant By letter dated March 2, 1987, CPCo withdrew its commitment to perform oxygen analyses on the post-accident primary coolant samples.
By letter dated February 2, 1995, CPCo requested confirmation by the staff that withdrawal of this commitment is acceptable.
CPCo's basis for withdrawin9 the original commitment was that the personnel operating the polarograph1c probe, used for oxygen meas1urement, would receive very high radiation doses.
NUREG-0737 recommends., but does not require, oxygen measurement in the reactor coolant.
Also, Regulatory Guide 1.97 stipulates that within the first 30 days after an accident, there is no need for oxygen analysis.
However, such analysis is recommended for the case where high concentration of chloride and low concentration of dissolved hydrogen make corrosion potentials high.
CPCo committed to determine the oxygen concentration of post-accident coolant samples when the measured chloride or hydrogen concentrations indicate a corrosion potential exists, and when the analysis is consistent with ALARA considerations.
The licensee's basis for withdrawal of its commitment to monitor oxygen concentration in the reactor coolant is, therefore, acceptable.
- 3. 0 CONCLUSIONS CPCo's request to modify its PASS procedures is acceptable because deletion of
- 1) the requirements for pH measurement of the reactor coolant, and 2) monitoring of hydrogen and oxygen concentrations in the containment atmosphere conform to the NRC approved modifications as described in the CEOG Topical Report, and 3) monitoring of oxy~en in the post-accident reactor samples was only recommended, but never required, by NUREG-0737.
Principal Contributor:
K. Parczewski Dated: March 27, 1995 2