ML20101A281
| ML20101A281 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/13/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20101A279 | List: |
| References | |
| NUDOCS 9204210221 | |
| Download: ML20101A281 (3) | |
Text
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NUCLE AR REGULATORY COMMISSION 5
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULAll0N RELATED TO AMENDMENT NO. 95 10 FAClllTY OPERATING L! CENSE NO. NPF-29 ENTERGY OPERATIONS. INC.. EllL GRAND GULF NUCLEAR STATION. UNIT 1 DOCKET NO. E0-416 1.0 INTRODVCTION By letter dated May 4, 1990, Entergy Operations, Inc., the licensee for Grand Gulf Nuclear Station, Unit 1, proposed to amend Technical Specification (TS)
Table 3/4.3.2-2 to clarify the location of the area temperature at.d delta temperature isolation actuation instrumentation for the Reactor Water Cleanup (RWCU) system.
In particular, the TS is being revised t' indicate the location of the temperature isolation instrumentation from "RWCU Valve Nest Room" to "RWCU Hx Valve Nest Area" in Table 3.3.2.2 Sections 4.C.3 and 4.D.3.
In a letter dated January 16, 1990, the licensee committed to the above change in response to a Quality Deficiency Report (QDR) 239-89 d.'ted July 18, 1s89, which identified discrepancies between the pipe break assumptions and the actual plant instrumentation used to detect and isolate RWCU pipe breaks.
In particular, the QDR identified that (1) the RWCU line break analysis relied on an isolation function time consistent with temperature instrument design (isolation time 60 seconds) for breaks detectable only by the flov:
instrumentation (isolation time 100 seconds) in those portions of the RWCU piping containing cold water (i.e., less than 120'F), and that (2) the RWCU Valve Nest Room did not contain area temperature and area delta temperature as listed in Table 3.3.2-2.
In its submittal, the licensee has provided tb results of a new break analysis for those portions of the RWCU system which are dependent on the delta flow instrumentation to justify the change.
2.0 _ EVALUATION The licensee indicated that TS requiremer,ts for the RWCU isolation instrumentation described in TS Table 3.3.2-2 Section 4 addresses leak detection instrumentation serving both " hot" process and " cold" process piping and components.
The requirements or, the RWCU " hot" process piping and components are both delth flow instrumentation and temperature (equipment area and equipment area delta) instrumentation.
The requirement on the RWCU " cold" 9204210221 920413 PDR ADOCK 05000416 P
2 (i.e., less than 120'F) process piping and component
" delta flow instrumentation, only.
The high area temperature an n gh area delta temperature isolation instrumentation for these areas are generally not effective for detection of leaks and were deleted from the TS in 1984 as part of TS Amendment No. 13 to prevent spuriou: operations.
The licensee has inditated that in response to the QDR, the pipe break design analyses for those postulated ' cold" RWCU break locations which are dependent on only the delta flow instrumentation for detection and automatic isolation were revised for isolation function time from 60 seconds consistent with temperature instrumentation to 100 seconds, consistent with delta flow instrumentation.
The larger time delay associated with delta flow trip logic was not accounted for in the existing analysis. The new line break analysis was performed for the following areas:
a.
RWCU pipe chase inside the containment b.
RK U Valve Nest Ruom c.
RWCU Holding Dump Room d.
RWCU filter /demineralizer rooms A and B, The licensee stated that from the results of the new RWCU line break analysis for the identified areas, the new isolation function time based on only the delta flow trip was determined to be acceptable since the higher resulting blowdown parameters are still well within existing design limits.
This is based on more accurate assessment of the increased blowdown parameters affecting systems, structures, t.nd components needed to m'itigate the postulated RWCU line breaks and perform the required safe shutdown functions.
This assessment included the dependent consequences such as room pressurization transients, environmental qualification profiles, etc. for not only the RWCU areas immediately affected but also for the adjoining areas up to and-including the containment structure.
The impact of flooding was found to be negligible.
The= offsite doses were also found to be much less than those already evaluated for the main steam line break outside containment event, _ The reactor vessel water level response to the postulated RWCU piping failures ~ was evaluated as a mild event in comparison to the more limiting pipe breaks.
The licensee indicated that the new RWCU line break analysis does not affect any of the associated TS instrument operability requirements or setpoint values nor are any new TS requirements being imposed for the delta flow or
" hot-pipe" temperature instruments.
The evaluation has shown that the line
-break detection and isolation functions for piping failures in the *RWCU Valve Nest Room" which contain only cold piping are adequately performed by the delta flow instrumentation and are consistent with other " cold" RWCU process component areas.
Therefore, additional TS requirements for temperature anonitoring the "RWCU Valve Nest Rooin" are not required. The temperature elements'specified in the TS as being in the "RWCU Valve Nest Room" are actually ;nstalled in the "RWCU Hx Room Valve Nest Area".
This discrepancy does not affect the analysis performed for the "RWCU Hx Room" and that the
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temperature setpoints listed in 15 are appropriate for the as-built i
configuration.
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The staff has reviewed the licensee submittal as discussed above and finds the proposed 15 change acceptable since reliance on the high delta flow i
instrumentation for detecting and isolating RWCU piping failures in the " cold" RWCU equipment rooms is su) ported by new analysis and meet all design functions. The proposed clange does not affect plant tafety as the r,ew parabeter values remain enveloped by the existing design.
7 Based on the abou evaluation, the staff concludes that the licensee proposed change to 15 Table 3.3.2-2 Sections 4.C.3 and 4.D,3 to revise the location of the RWCll aren temperattire and delta temperature isolation instrumentation from "RWCU Valve Nest Room" to RWCU Hx Valve Nest Area" and the isolation function L
tima bued nn the dalta flow instrumentation for isolation are acceptable.
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!n accordance with the Commission's regulations, the Mississippi State L
uffielal was notified of the proposed issuance of the amendment.
The State official had no romment.
4,0 [MJ@![iUllAllQMJDERAT10N The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC-staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent that may be released offsite, and that there is no signt 'icant increase in individual or cumulative occupational radiation exposure, i rca commission has previously issued a proposed finding that the amendment involves ns significant hazards consideration, and there has been nc a blic co:oment on such finding (56 FR 47236). Accordingly, the amendment mnts the eligibility criteria for categorical exclusion set forth in 10 CFR 51,22(c)(9),
pursuant to 10 CfR Sl.22(b) no environmental impact _ statement or environmental assessment need be prepared in connection with the issuance of the amend nent.
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The Commisalon has concluded, based on the considerations discussed above, that:
(1 there is reasonable assurance that the health and safety of the publicwil)lnotbeendangeredbyoperationintheproposedmanner,(2)such o
l utiviths will be conducted in compliance with the Commission's regulations, ud (3F the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
R. Goel Date: April 13, 1992 m
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