ML17059A499
| ML17059A499 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 10/26/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17059A498 | List: |
| References | |
| NUDOCS 9410310244 | |
| Download: ML17059A499 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SUPPLEMEN AL SAFETY ALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING 0
0 MANCE TO REGULA OR GUIDE 1.97 REVISIO 2
IAGARA MOHAWK POW CO ORATION NIN MILE POINT NUC EAR STATION UNIT NO.
DOCKE NO. 50-220 1.0 JIITRODUICTI I On March 17, 1993, the NRC staff issued its second Supplemental Safety Evaluation (SSE) regarding Niagara Hohawk Power Corporation's (the licensee's) conformance to Regulatory Guide (R.G.) 1.97, Revision 2, for Nine Mile Point Nuclear Station Unit No.
1 (NHP-1).
The staff accepted the licensee's deviations from the guidance in R.G. 1.97, Revision 2.
In a submittal dated August 23, 1994, the licensee documented an additional deviation from the guidance in R.G. l.'97, Revision 2, for instrumentation that monitors drywell water level.
2.0 UUUAIVATI I Drywell water level is not one of the variables that R.G. 1.97, Revision 2, recommends be monitored.
However, in the licensee's July 31, 1989, letter, the licensee declared it to be an Emergency Operating Procedure (EOP)
Key Parameter.
In the licensee's October 29, 1990, letter, the licensee committed to provide a dedicated strip chart recorder for monitoring drywell water level.
In the Technical Evaluation Report, attached to our November 14,
- 1991, SSE, we determined that the definition of EOP Key Parameters is inclusive of the definition R.G. 1.97, Revision 2, of Type A variables.
Therefore, we concluded that instrumentation to monitor EOP Key Parameters should meet, the R.G. 1.97, Revision 2, Category 1, criteria unless we accepted deviations from the Category 1 criteria for that particular instrumentation.,
Therefore, we considered drywell water level to be a Type A variable.
R.G. 1.97, Revision 2, recommends that Type A variables (which are defined as plant specific) have redundant, qualified channels of instrumentation with at least one channel recorded.
In the August 23, 1994, letter, the licensee reversed their earlier commitment and stated that a drywell water level recorder would not be installed.
ENCLOSURE 9410310244 941026 PDR ADQCK 05000220 P
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The basis for this decision is that the drywell flooding evolution is the only scenario where a drywell level recorder would provide useful information.
Entry into drywell flooding is directed by the EOPs if reactor pressure vessel (RPV) water level cannot be maintained above the top of active fuel or if conditions specified in the RPV flooding procedure cannot be obtained.
A drywell water level recorder would not be used during normal operation.
The definition of Type A variables in R.G. 1.97, Revision 2, states that a
Type A variable does not include those variables that are associated with contingency actions that may also be identified in written procedures.
The licensee stated in its July 31, 1989, letter that monitoring of drywell water level is only required when RPV water level cannot be determined.
Based on the information provided, operator actions based on drywell water level would be a contingency action and, therefore, does not meet the definition of a Type A variable.
Since drywell water level is not a R.G.
1.97, Revision 2, recommended
- variable, the drywell water level instrumentation does not need to meet the Category 1 criteria.
Therefore, a
drywell water level recorder is not needed.
- 3. 0 CONCLUSION Based on our review of the licensee's submittal, we conclude that the licensee has provided adequate justification for not providing a recorder for the instrumentation that monitors drywell water level.
Therefore, we find the above deviation from R.G. 1.97, Revision 2, acceptable.
Principal Contributor:
B. Marcus Dated:
October 26, 1994
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