ML20035D307
| ML20035D307 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/06/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20035D295 | List: |
| References | |
| NUDOCS 9304130057 | |
| Download: ML20035D307 (5) | |
Text
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UNITED STATES 3
.j NUCLEAR REGULATORY COMMISSION f
WASHINGTON. D.C. 20666 0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.103 TO FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO. 92 TO FACILITY OPERATING LICENSE NO. NPF-15 SOUTHERN CALIFORNIA EDISON COMPANY i
SAN DIEGO GAS AND ELECTRIC COMPANY THE CITY OF RIVERSIDE. CALIFORNIA THE CITY OF ANAHEIM. CALIFORNIA SAN ONOFRE NUCLEAR GENERATING-STATION. UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362
1.0 INTRODUCTION
By letter dated October 2,1992, Southern California Edison Company, et al.
(SCE or the licensee) submitted a request for changes to the Operating Licenses for San Onofre Nuclear Generating Station, Unit Nos. 2 and 3.
The proposed changes would modify License Conditions 2.C.(19)1 for Unit 2 and 2.C.(17)d for Unit 3.
These license amendments will allow tb removal of parts of the license conditions already complied with and v61 replace four Post-Accident Sample System (PASS) requirements with new r quirements to provide needed information by different methods.
NUREG-0737, " Clarification of TMI Action Plan Requirements," requires I
licensees to have the capability to obtain and analyze samples of the reactor coolant and the containment atmosphere. 'The samples must be taken, regardless of the accident scenario, without incurring radiation exposure to any individual in excess of 5 rem to the whole body or 75 rem to the extremities.
The results of the sampling and subsequent analysis are intended to provide information for assessing the status of accidents involving core damage and for determining the amount of hydrogen present in the containment atmosphere.
The PASS does not perform any accident mitigating safety function directly; it j
i provides the necessary information to evaluate the performance of the plant safety systems and to plan the actions necessary during and after an accident.
1 To provide information to assess core integrity, shutdown boron (neutron absorber) concentration, reactor coolant corrosiveness, and containment hydrogen concentration, licensees of nuclear power plants are required (typically as a license condition) to establish a capability for the timely collection and chemical analysis of reactor coolant samples and the containment atmosphere under accident conditions. The chemical analyses for 9304130057 930406 PDR ADOCK 05000361 P
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' j reactor coolant samples for pressurized water reactors (PWRs) designated in NUREG-0737 are for boron, chloride, and either total dissolved gases or dissolved hydrogen. The measurement of dissolved oxygen is recommended, but not required.
Additionally, the hydrogen concentration of the containment l
atmosphere is to be measured.
Regulatory Guide 1.97, Revision 2, (committed to in License Conditions (11) and (9) for San Onofre Units 2 and 3, respectively) recommended the measurement of dissolved oxygen, pH, and boron of the reactor coolant at all plants. NUREG-0737 specified that the analysis could be performed by employing a combination of pressurized /unpressurized, diluted / undiluted grab samples or inline monitoring methods.
If inline sampling was the preferred method of analysis, a capability to collect backup grab samples and to provide procedures for their analysis is required.
In all cases the samples for grab or inline analysis must be able to be acquired without resorting to the operation of any reactor coolant auxiliary system l
(e.g., letdown).
With the exception of the chloride analysis, the time l
allowed by NUREG-0737 for sampling and on-site analysis is three (3) hours or less. The time allowed by NUREG-0737 for the chloride analysis, which may be l
performed offsite, is dependent on the type of water used for the ultimate i
heat sink (fresh, salt, or brackish water) and the number of barriers between the ultimate heat sink and the primary systems in the containment.
Because the San Onofre Units 2 and 3 ultimate heat sink is saltwater from the Pacific Ocean, but is separated from all containment systems by intermediate cooling loops (at least one barrier), the chloride analysis is required within ninety-six (96) hours from the time the decision is made to sample.
2.0 EVALUATION License Conditions 2.C.(19)1 for Unit 2 and 2.C.(17)d for Unit 3, " Post-Accident Sampling System (NUREG-0737, "Clarificaton of TMI Action Plan Requirements," Item II.B.3)," describe SCE's commitments to install and operate a Post-Accident Sampling System in accordance with the guidelines of NUREG-0737 and SCE's commitment letter of April 14, 1983.
License Conditions 2.C.(19)i for Unit 2 and 2.C.(17)d for Unit 3 currently state:
Post-Accident Samplina System (NUREG-0737 Item II.B.3) 1.
By June 1 1983, SCE shall substantially complete all of the PASS procedures identified in Enclosure 3 of the SCE letter of April 14, 1983.
2.
Prior to September 1,1983, SCE shall maintain in effect all compensatory measures other than the PASS that are identified in the SCE letter of April 14, 1983, that are not already covered by Technical Specification surveillance requirements.
3.
By September 1,1983, the PASS shall be operable and the post accident sampling program shall be implemented.
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Until September 1,1983, SCE shall provide monthly progress reports on PASS testing, surveillance, maintenance and modifications, and operator training.
License Conditions 2.C.(19)1 for Unit 2 and 2.C.(17)d for Unit 3 are proposed l
to state.
Post-Accident Samplina System (NUREG-0737 Item II.B.3)
The PASS shall be operable and the post-accident sampling program shall j
be implemented as described in the SCE letter of April 14, 1983, and revised by SCE letter of October 2,1992.
i The proposed change revises the License Conditions to delete those requirements already complied with (items 1, 2, and 4 of the existing PASS License Conditions) and to revise the following four PASS commitments which were made in the April 14, 1992 letter:
i A) Dissolved total gas analysis i
B) Use of the shipping cask C) Collection of an undiluted grab sample i
1 D) PASS containment hydrogen analyzer i
The proposed modifications, detailed in SCE's October 2, 1992 letter, include revising the following four SCE PASS design commitments as follows:
A) Total gas analysis The present PASS design, as documented in SCE's April 14, 1983 I
letter, provides for measuring both total dissolved gases and hydrogen in the reactor coolant.
These analyses are provided by a gas separation apparatus which, because of its complexity, has proven to be less reliable than required.
The PASS now has a new, operating, inline, reliable monitor to measure dissolved hydrogen as a replacement for the gas separation apparatus which will be retired, but not removed, from the PASS skid.
i Total dissolved gasses will no longer be measured in the reactor cool ant. As NUREG-0737 requires only total gas or hydrogen measurement, the requirement will continue to be met.
Additionally,the new dissolved hydrogen monitor complies with the guidance found in Regulatory Guide 1.97 Rev. 2, " Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident," with respect to monitoring range.
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B) Use of the shipping cask.
The present PASS design, as documented in the April 14, 1983 letter, has an undiluted grab sample facility used to provide a reactor coolant sample, which is then transported to an offsite facility for chloride analysis. This process requires handling highly radioactive materials both on and off site and additionally relies on an offsite laboratory whose future license status has become uncertain.
The proposed PASS design provides for a chloride analyzer able to operate at the required accuracy from diluted RCS samples taken within the PASS.
It will no lager be necessary to ship highly radioactive undiluted RCS samples to a facility which can perform a chloride analysis on the undiluted liquid. As chloride analysis will be available as soon as a diluted sample is prepared, the requirements in NUREG-0737 and Regulatory Guide 1.97 Rev. 2 for a backup chloride analysis to be available will continue to be met.
C) Collection of an undiluted grab sample l
The present PASS design, as documented in the April 14, 1983 letter, provides for collecting an undiluted sample of reactor coolant and transporting it, using a licensed shipping cask, to an offsite laboratory where it is analyzed for chlorides.
The proposed PASS design provides for use of an existing chloride analyzer which, by virtue of its accuracy, would eliminate the need for a supplemental analysis from a backup sample. The proposed system can measure the reactor coolant chloride level as low as 0.5 ppm.
The performance of the modified system will meet or exceed i
the existing criteria for chloride analysis found in NUREG-0737. The NUREG-0737 requirement to analyze for stress corrosion potential in the post-accident containment environment will continue to be met without the need to obtain or ship highly radioactive undiluted reactor coolant.
D) PASS containment hydrogen analyzer The present PASS design, as documented in the April 14, 1983 letter, provides for a non-safety-related inline containment hydrogen analyzer to meet the PASS requirement for a containment hydrogen analyzer.
Within each of the Units 2 and 3 containments there are also two additional hydrogen monitors which are safety related, environmentally qualified, and redundant. The PASS hydrogen monitor has proven to be unreliable and maintenance intensive.
The proposed PASS design deletes the non-safety-related PASS monitor and utilizes the inside containment monitors to provide post-accident containment hydrogen concentration. The range of the containment
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o monitors is such that they meet all the requirements of NUREG-0737
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and the guidance of Regulatory Guide 1.97, Rev. 2.
The staff concludes that the modifications proposed for PASS operation, as detailed in SCE's October 2,1992 letter, and described briefly above, meet l
the requirements of NUREG-0737 Item II.B.3.
The staff further concludes that the deletion of items 1, 2, and 4 of the PASS License Condition is appropriate, since these items have already been complied with. Therefore, l
the proposed changes to License Conditions 2.C.(19)i for Unit 2 and 2.C.(17)d for Unit 3 are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the California State official I
was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to the installation or use of a facility component lccated within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.
The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards considera-i tion, and there has been no public cmment on such f'aling (58 FR 8782).
Accordingly, the amendments meet the eligibility ci = %ria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) 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: Mel B. Fields Date: April 6, 1993
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