ML20006E150
| ML20006E150 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 02/13/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20006E147 | List: |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9002220165 | |
| Download: ML20006E150 (2) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING DEVIATION FROM REGULATORY GUIDE 1.97 REQUIREMENT FOR A NARROW RANGE ORYWELL PRESSURE INSTRUMENT
_ GRAND GULF NUCLEAR STATION. UNIT 1 DOCKET NO. 50-416
1.0 INTRODUCTION
Regulatory Guide 1.97, Revision 2, " Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environ Conditions During and r
Following an Accident," (RG 1.07), describes instrumentation acceptable for monitoring plant variables and systems during and following an i
accident.
By letter dated Februar the licensee for Grand Gulf Nuclear Station, Unit 1, (GGNS-1) y 28,1985, submitted a report describing conformance t
of GGNS-1 to RG 1.97.
Deviations of GGNS-1 instruments from the guidelines of RG 1.97 were justified in position statements.
By letter dated January 12, 1987, the NRC staff concluded, based on its review of the licensee's report, that the licensee had either conforned to, or adequately Justified deviations from, the guidance of RG 1.97, except for the neutron flux instrument. An excore neutron flux monitor meeting the requirements of 7S 1.97 will be installed in the fourth refueling outage.
DuringaninspectionofRG1.97instrumentsatGGNS-1(InspectionReport No. 50-416/88-11, dated July 5,1988), the NRC staff found a deviation from a RG 1.97, Type D, variable guideline for monitoring the drywell pressure over the range of -5 psig to 3 psig.
The licensee had designated a wide range crywell pressure instrument (-10 to +40 psig) for this variable but had not justified its use in a position statement.
The purpose of the narrow range pressure instrument is to monitor the operation of the drywell purge and post-LOCA vacuum relief system.
During the inspection, the licensee stated that narrow range differential pressure instrumentation is installed to measure drywell-to-containment pressure difference over the range of +2 psid to -2 psid and that this instrument could be used for this RG 1.97, Type D, Category 2, variable in addition to the wide range instrument.
By letter dated July 22, 1988, the licensee provided a position statement to justify use of the pressure differential instrunent and the wide range pressure instrument to monitor this variable. Our evaluation is provided below.
2.0 EVALUATION For GGNS-1, the RG 1.97 narrow range drywell pressure instrument would be used to irdicate operation of the combustible gas control system (CGCS),
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including the drywell purge system and vacuum relief systems, following a 9002220165 900213 ADDCX0500g6 DR
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loss-of-coolant-accident (LOCA).
For the Mark III containment of GGNS-1, the drywell is located inside the primary containment.
Following a LOCA, vacuum relief breakers open if containnent pressure exceeds drywell pressure by more than I psi due to condensing steem in the drywell after the initial drywell pressure transient. This prevents overflow of the wier wall from the suppression pool to the drywell.
The drywell purge compressors operate to pressurize the drywell up to 1 psi above containment pressure to purge non-condensible gases, including hydrogen.
from the drywell through the vents and suppression pool to the containment. Hydrogen recombiners in containment control hydrogen concentration below the combustible limit of 4 volume percent.
A narrow range drywell pressure differential instrument is installed at GGNS-1 to neasure and provide indication of drywell-to-containment pressure over a range of +2 psid to -2 psid.
CGCS operation and valve opening pressures are based on set points to assure differential pressures within +1 psid to -1 psid.
Therefore, the existing narrow range instrumentation is sufficient to monitor CGCS operation following a LOCA.
3.0 CONCLUSION
The staff has reviewed the deviation of the GGNS-1 instruments designated to monitor the RG 1.97, Type D, Category 2, variable of drywell pressure.
The deviation is a containment-to-drywell differential pressure instrument range of +2 psid to -2 psid instead of the RG 1.97 drywell pressure range of -5 psig to 3 psig. The differential pressure instrument, in additon to the wide range pressure instrument, will be designated to monitor this variable. The staff concludes that the licensee has adequately justified this deviation.
The licensee has committed to revise the Updated Final Safety Analysis Report, Section 7.5, and Table 7.5.2, " Post Accident Monitoring Instrumentation," to reflect the use of this instrument for post-accident monitoring.
Principal Contributor:
L. Kintner Dated: February 13, 1990 1
Mr. W. T. Cottle System Energy Resources, Inc.
GrandGulfNuclearStation(GENS) i CC:
Mr. T. H. Cloninger Mr. C. R. Hutchinson Vice President, Nuclear Engineering GGNS General Manager
& Support System Energy Resources, Inc.
System Energy Resources, Inc.
P. O. Box 756 P. O. Box 31995 Port Gibson, Mississippi 39150 Jackson, Mississippi 39286 Robert B. McGehee, Esquire The Honorable William J. Guste, Jr.
Wise, Carter, Child, and Attorney General Caraway Department of Justice P. O. Box 651 State of Louisiana Jackson, Mississippi 39205 F. O. Box 94005 Nicholas S. Reynolds, Esquire Bishop, Cook, Purcell Alton B. Cobb, M.D.
and Reynolds State Health Officer i
la00 L Street, N.W. - 12th Floor State Board of Health Washington, D.C.
20005-3502 P. O. Box 1700 Jackson, Mississippi 39205 fir. Ralph T. Lally Manager of Quality Assurance Entergy Services, Inc.
Office of the Governor P. O. Box 31995 State of Mississippi Jackson, Mississippi 39286 Jackson, Mississippi 39201 Mr. Jack McMillan, Director President, Division of Solid Waste Management Claiborne County Board of Supervisors Mississippi Department of Natural Port Gibson, Mississippi 39150 Resources P. O. Box 10385 Jackson, Mississippi 39209 Regional Administrator, Region II U.S. Nuclear Regulatory Commission Mr. John G. Cesare 101 Marietta St., Suite 2900 Director, Nuclear Licensing Atlanta, Georgia 30323 System Energy Resources, Inc.
P. O. Box 469 Port Gibson, Mississippi 39150 Mike Moore, Attorney General Frank Spencer, Assist. Attorney General I
Mr. C. B. Hogg, Project Manager State of Mississippi i
Bechtel Pcwer Corporation Post Office Box 22947 P. O. Box 2166 Jackson, Mississippi 39225 Houston, Texas 77252-2166 Mr. H. O. Christensen Senior Resident Inspector U.S. Nuclear Regulatory Commission Route 2, Box 399 Port Gibson, Mississippi 39150 l
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