ML19282A412
| ML19282A412 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 10/10/1978 |
| From: | Newberry S Office of Nuclear Reactor Regulation |
| To: | Daniels H Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 NUDOCS 7810180059 | |
| Download: ML19282A412 (5) | |
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OCT 101978 Docket Nos. '0-329 30 MD10RAN00M FOR: Howard Daniels, Instrumentation and Control Systems Branch, DSS FRON:
Scott Newberry, Reactor Systems Branch DSS
SUBJECT:
IDENTIFICATION OF SAFETY-RELATED SYSTEMS AMD CG1PONENTS "AND INSTRUMENTATION TO FULLOW THE COURSE OF AN ACCIDENT
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.Your memorandum of Septeefier 8,1978. requested that I:
(1) Review Section 7.1 of the Midland FSAR to insure that safety-related systems in the RSB area are identified.
(2) Review Table 3.11-1 to insure that all safety-rolated mechanical and electrical equipment is identified.
(3) Identify those parameters which must be monitored to follow the course of an accident, so that you can complete the review of the instrumentation.
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. My comments on each of these areas are enclosed.i! have also included 4 - M list of those second round RSB questions which interface with ICSB.
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O ENCLOSURE SECTION 7.1 This section identifies all safety systems in the RSB area with the exception of the following:
1.
As we have already discussed, the pressurizer heater controls are listed as a system required for safe shutdown but are not safety grade.
I have asked a question (Q211.112) requesting justification for this design.
2.
RSB question 211.105 lists the requirements of overpressure protection systems while operating at low temperatures.
These requirements include qualification to operate during an operating basis earthquake (0BE),
single failure, and justification for all deviations from IEEE-279.
3.
RSB question 211.35 requests the applicant to discuss the capability to take the plant to cold shutdown using safety-grade systems, assuming loss of offsite power and a single failure. The applicant has not identified these systems / components.
4.
Regulatory Guide 1.45 requires that the airborne particulate radioactivity monitoring system should remain functional when subjected to the SSE and that the leakage detection systems (sump level detectors) should remain operable after an OBE. Applicant response to question 211.31 indicates that the reactor building airborne radiation monitors and leak detection sump level. detectors are seismic Category I, and, therefore, meet the staff requirements; however, the systems (power, etc.) should be reviewed from an electrical viewpoint.
5.
Feedwater Reverse Flow Monitor--This sensor is described briefly in Section 15.2.8.2.1 of the FSAR and plays a role in the mitigation of a feedwater line break.
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6.
F0GG logic--This portion of the AFWAS allows auxiliary feedwater flow to be initiated after the pressure in either (or both) steam generator (s) recovers above 725 psig following an MSLIS (main steam line isolation signal).
TABLE 3.11-1 This table lists all of the safety-related components in the RSB area, however, I have the following comments:
1.
The valves associated with pressurizer spray and relief (IMO-0102-1, 2, 2M0-0202-1, 2, IM0-0111, 2M0-211, IM0-0102, 2M0-0202) are listed; however, no qualification requirements are listed.
The pressurizer electromagnetic relief valves (1M0-0102, 2M0-0202) are part of the Midland I and 2 overpressure protection system (see item 2 above) and should be qualified. The pressurizer spray valves are not safety related and do not require qualification unless the applicant elects to use these components as part of his safety-grade means to go to cold shutdown.
2.
The ECCS high pressure injection system active valves are listed; however, no qualification was performed.
3.
The DHR system components are all listed; however, the following valves are not qualified and should be:
1M0-1012, 2M0-1112 (first valve in the DHR suction line from the RCS hot leg); 1M0-1055A, B, 2M0-1155A, B (DHR pump discharge cross-connect).
MONITORING INSTRUMENTATION In accordance with your request, we have reviewed the FSAR for information readouts available to the operator for monitoring key parameters. With
the exception of post-LOCA " dump-to-sump" flow, it would appear Table 7.5 identifies a representative sample of monitoring instrumentation; however, it is less clear that they are sufficiently qualified for post-accident monitoring.
As you know, the staff presently has no uniform basis to review the acceptabil1ty of such a list. While it would appear that Midland does not have fully qualified instrumentation for post-accident monitoring of some RSB parameters, there is no clear basis for finding their submittal unacceptable.
A Task Force coordinated by the Accident Analysis Branch has been assigned the responsibility of generating further NRC guidance pertaining to post-accident instrumentation.
If the result of this generic effort indicates that additional requirements are warranted, we will identify on Midland which modifications are necessary to assure that an acceptable level of safety is maintained.
It is my judgment that, in addition to those parameters identified in the first group in Table 7.5-1 (ESF Actuation Parameters), the following instruments / indications are also considered to be " key parameters":
1.
High Pressure Injection Flow 2.
Low Pressure Injection Flow 3.
Pressurizer Pressure 4.
Pressurizer t.evel 5.
Reactor Coolant Temperature 6.
Reactor Building Emergency Sump Level 7.
Overpressure Protection System for Low Temperature Operation Indications (enabling alarm, transient pressure alarm) 8.
Post-LOCA " Dump-to-Sump" Flow
'_4, rs SECOND ROUND QUESTIONS WHICH REQUIRE RSB/ICSB INTERFACE 211.18/211.101 Environmental qualification of pressurizer safety valves 211.105 Overpressure protection for App. G (a) alarms, indications (b) relief valve controls IEEE-279 (c) system designed to OBE-(d) single failure (e) lock out power--Tech Specs 211.112 Pressurizer heater controls 211.113 DHR low flow interlock 211.123 LPI flow indication 211.115 Midland RAS function differs from other B&W plants 211.121 ECCS valve closure times 211.125 Submerged valves post-LOCA 211.126
" Dump-to-sump" flow indicators 211.141/143 ICS-initiating events / single failures 211.142 Credit for nonsafety-grade equipment in Chapter 15 events 211.145 Turbine trip signal on loss of AC power 211.152 High makeup flow alarm 211.157/159 MSIV single failure 211.163 Submerged valves after main steam line break
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