VR2R-0448_r1

VR2R-0448

① SA Source

• Source: 開啟完整 SA 文章
• Section: Rack Level Infrastructure: Thermal
• Line hint: 376

Context Before

Although NVIDIA initially did not formally publish full specifications for Vera Rubin’s liquid cooling system, we believe the platform will support maximum coolant return temperatures up to 65C. This aligns with Nvidia’s warm-water operating envelope, and while the exact implication for delta-T depends on the chosen supply setpoint and flow control strategy, we can expect a slightly tighter delta-T.

Evidence

The pressure envelope is expected to be unchanged versus GB200, with maximum operating pressure of 72 psig (5 bar) and minimum burst pressure of 217 psig (15 bar), aligning with OCP’s MGX rack-level liquid-cooling specification.

Context After

In practice, cooling follows straightforward physics. To cool a system, you must deliver sufficient water/coolant at the appropriate temperature and pressure through the loop. If you want to increase the cooling capacity of a CDU, you increase flow rate while managing pressure, which in this case implies around a 2.0-2.5x flow increase, depending on how far outlet temperatures are actually pushed by operators.

② Atomic Claim

預期 pressure envelope 相較 GB200 維持不變：maximum operating pressure 為 72 psig（5 bar），minimum burst pressure 為 217 psig（15 bar），並與 OCP MGX rack-level liquid-cooling specification 一致。

• Epistemic Mode: EXPECTED
• Mapping Status: PARTIAL

③ Semantic Frame

{
  "frame_type": "CLAIM_ONLY",
  "qualifiers": {
    "condition_text": "expected; comparison reference is GB200",
    "numeric_mentions": [
      "72 psig",
      "5 bar",
      "217 psig",
      "15 bar"
    ],
    "temporal_mentions": []
  },
  "reason": "PRESSURE_ENVELOPE_SUBJECT_IMPLICIT_IN_SOURCE_CONTEXT",
  "statement": "pressure envelope is expected to be unchanged versus GB200, with 72 psig (5 bar) maximum operating pressure and 217 psig (15 bar) minimum burst pressure, aligned with the OCP MGX rack-level liquid-cooling specification."
}

④ Canonical Entity Mapping

Role	Surface Label	Canonical Target
—	—	—

⑤ Human Review

請在 Properties 逐項確認：

• 原文 → Atomic Claim 是否忠實
• Atomic Claim → Semantic Frame 是否忠實
• Canonical Entity mapping 是否正確
• Epistemic mode 是否保留原文語氣
• 最後選擇 review_action

Review state

Markdown 內文不是正式 approval。只有 Apply bridge 寫入的 Decision Ledger event 才是正式決策。