ML20216E530
| ML20216E530 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/09/1998 |
| From: | Nunn D SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-361-97-22, 50-362-97-22, NUDOCS 9804160234 | |
| Download: ML20216E530 (5) | |
Text
w%:dl soumn c4 nom 4 e
R J EDISON ttR'in""
An I!DISO V 1%T1 #A4710W'" Comp m3 April 9,1998 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555
Subject:
Docket Nos. 50-361 and 50-362 Reply to a Notice of Violation San Onofre Nuclear Generating Station, Units 2 and 3
Reference:
1)
Letter, Mr. A. T. Howell lli (USNRC) to Mr. Harold B. Ray (SCE),
dated March 2,1998 2)
SCE reply to a Notice of Violation, IR 96-14, D. E. Nunn, (SCE) to USNRC (Document Control Desk), dated April 1,1997 The referenced letter transmitted the results of NRC Inspection Report No.
50-361/97-22 and 50-362/97-22, conducted December 1-5,1997, at the San Onofre Nuclear Generating Station, Units 2 and 3. The enclosure to the referenced letter also included a Notice of Violation (9722-01). This proposed violation involved the failure to include the turbine building nonradioactive sumps system under the 10 CFR 50.65 monitoring program scope. As discussed with Mr. D. Powers on March 31,1998, this letter was delayed in order to provide a complete response.
Reading the Maintenance Rule literally, it is possible to conclude that any SSC mentioned in the EOl's, on the face of the Rule itself, is required to be treated as in scope. However, the industry concluded, during its efforts to develop the means to implement the Rule, that such an interpretation was unnecessary, and proposed instead the guidance contained in NUMARC 93-01. This guidance was accepted by the staff in Regulatory Guide 1.160, and was used by SCE to prepare its program. We have reviewed the basis for the exclusion of the nonradioactive sumps system, and believe it meets the requirements of the NUMARC guideline and Regulatory Guide 1.160.
\\\\
\\
9804160234 980409 O
PDR ADOCK 05000361
, N,'
is O
/
I'. O. IWs 1.'8
$an Clemer te. CA 92o74-0128 714- % 8-14,10 l'as 714 %! 1490
DOCUMENT CONTROL DESK The enclosure to this letter provides SCE's denial of the Notice of Violation.
If you have any further questions, please contact me.
Sincerely, Dwight E.
unn Vice President I
Engineering and Technical Services Enclosure cc:
E. W. Merschoff, Regional Administrator, NRC Region IV K. E. Perkins, Director, Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident inspector, San Onofre Units 2 and 3 i
J. W. Clifford, NRR Project Manager, San Onofre Units 2 and 3 J. Lieberman, Director, Office of Enforcement, NRC
ENCLOSURE The enclosure to Mr. A. T. Howell's letter dated March 2,1998, states in part:
"10 CFR 50.65(b)(2) requires, in part, that the scope of the monitoring program specified in paragraph (a)(1) shall include certain nonsafety-related structures, systems, or components that are relied upon to mitigate accidents or transients, or are used in plant emergency operating procedures.10 CFR 50.65(c) states that the requirements of this section shall be implemented by each licensee no later than July 10,1996.
" Contrary to the above, on July 10,1996, nonsafety-related (normally) nonradioactive sumps system was not included in the licensee's 10 CFR 50.65 monitoring program scope. The system is manipulated in Emergency Operating Instruction SO23-12-4, ' Steam Generator Tube Rupture,' Step 22, to mitigate a radioactive release during a steam generator tube rupture event.
"This is a Severity Level IV violation (Supplement 1) (50-361;-362/9722-01)."
REPLY TO THE NOTICE OF VIOLATION Basis for Disputing the Violation The nonsafety-related nonradioactive sumps system is not manipulated in Emergency
)
Operating instruction (EOl) SO23-12-4, Step 22, to mitigate a radioactive release to the j
public during a steam generator tube rupture event (SGTR). It is manipulated as a i
prudent, post-accident evaluation and clean-up step to minimize the spread of contamination, which may have occurred within the turbine building, and whose effects l
are not significant as defined in the UFSAR.
SCE concluded it properly excluded the turbine building nonradiological sumps from the l
Maintenance Rule monitoring program because the system did not meet NEl guidance i
as provided in NUMARC 93-01 (as endorsed by Regulatory Guide 1.160). When SCE's l
Maintenance Rule Expert Panel reevaluated the system in October 1997 for l
Maintenance Rule program applicability, they specifically considered the guidance provided in NUMARC 93-01 when they evaluated systems for inclusion / exclusion from the monitoring program.
l Specifically, NUMARC 93-01 states, (Section 8.2.1.3), in part.
"For a nonsafety-related SSC to be considered important, it must add significant value to the mitigating function of an EOP by providing the total, or a significant fraction of the total functional ability required to mitigate core damage or radioactive release.. "
SCE implemented this specific guidance in Section 6.6.2 of Procedure
. Enclosure SO123-XIV-5.3.1, " Scoping for the Maintenance Rule," which states that a system, j
structure, or component must add value to the mitigation function of the EOl by j
providing the total, or substantial fraction of the total, functional ability required to mitigate core damage or radioactive release.
The function credited in the SGTR EOl for the nonradioactive sumps, does not add significant value to the mitigation function of the EOl. The sump system does not provide the total, or a significant fraction of the total, functional ability required to mitigate core damage or radioactive release during a SGTR event. As stated in SO23-14-4, " Steam Generator Tube Rupture Procedure Bases and Deviations Justification," Revision 2, the function of the turbine building sumps is to minimize the spread of contamination that has already occurred. It does not indicate a function to mitigate an effluent release to the public.
In October 1997, SCE completed a review of low safety significant systems to ensure the systems were properly monitored by plant level criteria. The review was performed in response to an NOV on smoke damper performance criteria (Reference 2). As a result of that review, SCE switched to a function based scope for low safety significant
)
systems as endorsed by Regulatory Guide 1.160, Rev. 2, paragraph 1.1.3. The Maintenance Rule Expert Panel reexamined the nonradioactive sumps system as a part of this review, and excluded it from the scope of the Rule based on the panel's judgment that it did not meet any of the scoping criteria, including a significant release mitigation function for the EOls.
Specifically, radiation monitor 2(3)RE7821, and discharge valve 2(3)HV5849, provide monitoring, alarm, and isolation of the system from the outfall upon elevated radiological readings at the discharge to the outfall. These components, which support the function of sump isolation in response to a sump radiation monitor signal (2(3)HV5849 and 2(3)RE7821) were included in the scope of the Rule in the Radiation Monitoring System.
The remaining sump system components were excluded from the Rule.
The realignment of the sump discharge is not significant with respect to release mitigation. This judgment is supported by SCE's Hydrological Engineering UFSAR Section 2.4.12 which states that there are no credible accidents (e.g., SGTR) that can occur which will result in an accidental liquid release of radioactive effluents as related to existing or potential future water users. SCE's safety analyses are consistent with the NRC's own evaluation that accidental liquid release pathways are not significant at SONGS (under the guidance of Standard Review Plan 2.4.13), as described in SER Sections 2.4.9 and 15.4.12.
Subsequent to the Maintenance Rule inspection, SCE enhanced its procedural guidance fo-determining when SSC's referenced in EOls can be excluded from the scope of the Maintenance Rule. SCE enhanced the definition of" significance" and "significant value" to be consistent with definitions that have been reviewed by the NRC in Maintenance Rule programs at other plants.
i
, Enclosure To reconfirm that SCE had properly classified the turbine building nonradioactive sumps system, in March 1998, the SONGS Maintenance Rule Expert Panei reevaluated the functions of the turbine building nonradioactive sumps, considering the enhanced procedural guidance and the design and licensing basis, and reverified that the Turbine Building Sump system should be excluded from the scope of the Rule.
Please also note that, contrary to the statement in the NOV, on July 10,1996, SCE had, j
in fact, included the turbine building nonradiological sumps system in the scope of the l
Maintenance Rule monitoring program. The system was removed in October 1997, l
when SCE switched to a function based scope for low safety significant systems, i
l In summary, SCE did not violate 50.65(b)(2) because SCE properly excluded the sump I
system in accordance with NUMARC 93-01, Regulatory Guide 1.160, and SCE procedure SO123-XIV-5.3.1.
l l
l l
t I