ML19208A315
| ML19208A315 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/20/1979 |
| From: | Ignatonis A NRC - TMI-2 OPERATIONS/SUPPORT TASK FORCE |
| To: | Dye N, Elam B GENERAL PUBLIC UTILITIES CORP. |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 NUDOCS 7909130362 | |
| Download: ML19208A315 (6) | |
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UNIT 5D STATES 8 y ) *.,, rg( j NUCLEAR REGULATORY COMMISSION
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%s, v j July 20, 1979 MEMORANDUM FOR:
N. Dye, GPU B. Elam, GPU TRRU:
John T. Collins, Deputy Director, TMI-2 Support /
FROM:
A.
Ignatonis, TMI-2 Support S. Newberry, TMI-2 Support
SUBJECT:
TMI-2 MINI DECAY HEAT REMOVAL SYSTEM PRFLIMINARY DESIGN CRITERIA, REVISION A Per your request, enclosed are the NRC's (NRR and ISE) cottaents to the Three Mile Island Unit No. 2 Mini Decay Heat Removal Systen Preliminary Design Criteria.
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k' yW A. Ignhtonis, TMI-2 Support S. Newberry, TMI-2 Support
Enclosure:
As Stated cc:
R. Vollmer J. Collins J. Wermiel M. Greenberg W. Raymond S. Newberry A.
Ignatonis 4
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COMMENTS TO MINI DECAY HEAT REMOVAL SYSTEM PRELIMINARY DESIGN CRITERIA Gene al Comments The design criteria in the subject memo do not address the following:
1.
remote leakage monitoring capability; 2.
redundant train independence and separation criteria (mechanical and electrical);
3.
pump NPSH requirements.
These areas are important and should be considered by the licensee.
Tra in independence and separation criteria (such that leaks or pipe failures are in one train would not effect the other) are especially tmportant, since the system, as proposed, is not Seismic Category I and is a " rapidly" designed and installed type system.
Also, there is an uncertainty on whether or not the proposed design flow rate of 150 gpm through the reactor vessel is sufficient to preclude stratification at boron concentrations greater than 3000 ppm.
The design criteria 11 ted do not address the following in sufficient detail:
1.
Collection of leakage - valve packing and pump seals.
2.
Overpressure protection - drawing does not show sufficient relief devices on isolable portions of the system for thermal expansion or relief de-vices on the pump discharge. The design basis flow rate or capacity of the relie.' devices must be addressed.
3.
Fystem Isolation - criceria do not address (if necessary) overpressure isolation; relief devices may be adequate.
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Instrumentation and controls - no discussion on local operation capa-bility, shielding, location, etc. - only says " provisions shall be made for future installation of controls and remote indicators in the Unit 2 control room."
5.
Recognizing that the mini-DHR system is conceptual at this point during the detailed design review the a uture clean-up system tie-in should include provisions for flush and drain. This would minimize radiation exposure during the tie-in.
Specific Comments 3.3.1 Although the system may not be of Seismic Category I design, the piping, components, and restraints should be designed to accom-modate OBE loads since.the system will be designed for three years' operation.
3.5.2 Provideaschematf}that depicts tie-in of the mini-DER system to the Nuclear Services Closed Cooling System. Also, for the proposed system, why not add another return line interconnected to the existing DER line upstream of DH-V-4A?
3.11 Add:
" Provisions shall also oe made for periodic testing of the redundant components such as the MDHR pump and cooler to demonstrate operation. An automatic alarm annunciation will be provided in the control room."
3.3.17 Consider adding the following:
" Radiation monitoring shall be pro-vided to detect RCS leakage into the Nuclear Services Closed Cooling System (pref erably located on the shell side of the mini-DHR cooler)."
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- 3.11.1 Regarding instrumentation, consider adding flow rate measurement from the NSCC to the shell side of the mini-DHR cooler.
3.2 Code classification for the balance of piping is probably a typo.
It should be in accordance with ANSI B31.1.
3.3Property "ANSI code" (as page type) with input value "ANSI B31.1.</br></br>3.3" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process..16 Although the proposed mini-DHit system will be designed to isolate with double isolation valves, it is not designed for single active failures. Provide justification for omission of this latter design basis.
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